The Golf Estate where a large building programme will be completed is located 140 km north of the economic hub of Gauteng in the Watergberg Region of the Limpopo Province. The Waterberg region has been identified as a major tourism attraction by Limpopo Province and thus a great deal of development will take place in this region during the next 5 to 10 years.
After the development of the golf estate commenced about three years ago, it is now nearing the building phase. There are 770 stands with houses, club houses, and many more facilities which will have to be completed to make the development a success. To supply this part of the development with the concrete requirements appears to be a formidable task and the developers are considering alternatives to deal with the problem.
To supply the quantity of concrete required it is essential that a solution should be found for the location of a concrete plant. Other than locating a concrete manufacturing plant, outsourcing the supply of concrete to a company capable of delivering a finished product should also be considered.
The financial as well as the environmental impact of a project of this nature should be shaded to determine the feasibility. How the community and the developers would benefit from its construction will also have to be considered against the alternative of outsourcing the delivery of concrete.
1

The aim of the project is the following:
To perform a feasibility study for the construction of a concrete plant as opposed to outsourcing it to an external company. The project will focus on the given alternatives to determine the best solution to the problem. The phased implementation of the chosen alternative will also be determined for the project.
The factors that will have to be considered are the following:
Initial Investment Amount.
Running Cost.
Capital Cost.
Benefits to the Community.
Labour Cost.
Road damage due to material handling (Cement Trucks).
Water usage and pollution.
Health Risk and Employment.
After the location of the facility has been determined the facility layout will be designed. During this phase of the project the following problem facets to be borne in mind are: space requirements, interrelationships between activities, system requirements, health and safety of employees, environmental impact, and the materials handling system/equipment.
2

The following objectives will have to be achieved to serve the overall aim of the project:
Research on all the alternatives will have to be done to determine the key requirements.
Discussions with potential clients and stakeholders to establish their perspectives
Reviewing and evaluating the various solutions that may be implemented and executed.
Reviewing and evaluating the different implementation strategies / plans.
The following will be tangible deliverables of the project:
A solution to the construction requirements of the Golf Estate and the surrounding area.
Strategic implementation for the given solution and attendant feasibility studies.
Quantitive and qualitive results on the selected solution and implementation strategy.
A Final Report document detailing all the findings and conclusions made as a result of the study.
The scope of the project can be divided into two main categories:
Geographic
•
This project will only focus on the Golf Estate and surrounding areas.
Functional:
•
Implementation strategies on the selected solution
•
Reports on systems used for concrete production
For the project different problem areas and certain engineering principles will be used and implemented. These include the following:
Facilities Planning
Operational Research
Feasibility Studies
3

Establishment Query
Environmental Impact Studies
Economic Feasibility studies
Figure 1: Example of a Concrete Plant
4

The project will be approached using a suitable engineering problem solving process and a systems approach to successfully complete the project within the given time.
The project planning will be dealt with via the following phases:
The motivation behind the project was found i.e. problem definition
A basic literature study was done on the topic of “Concrete Plants” to achieve a thorough understanding of the concept.
Research on location models to determine the appropriate model to solve the location problem.
Structured interviews with companies and individuals to understand the working systems and structures of concrete plants.
Identifying areas where improvement can be implemented.
A project proposal based on the problem definition and project scope.
Analyze information obtained from interviews to determine the industry norm.
Analyze various location models and determine which is best suited to the specific project.
Make decisions regarding which solutions to implement, as well as the implementation strategy.
Determine the best facilities layout for the concrete plant.
All the information gathered in the previous phases will be used.
Advice given by developers and lectures will be utilized.
Compare all information gathered on the selected solution to determine effectiveness.
Implement the solution. If the most effective and efficient solution chosen should be the “Concrete
Plant” the following approach should be followed.
5

•
- Define the objective of the facility
•
- Develop the facilities plan
•
- Implement the facilities plan.
After completing all the above phases the solution will be found and implemented.
All findings based on the analysis and solution evaluation and implementation will be documented.
Document all results obtained from the findings.
Create a project document with all relevant information.
Make conclusions about the project, with relevant recommendations for improvements.
Summarize all data and information.
A schematic representation of the phases that need to be completed for the project is given in figure 1.
The draft project schedule is given in figure 2.
PHASE 1:
Information
Gathering
PHASE 2:
Information
Analysis
Figure 2: Phased Implementation
6

Figure 3: Gantt chart
7

The following techniques may be applied during the execution of this project:
Performance requirements capture and analysis
Process mapping
Project management
Decision Analysis
Economic Analysis
Flow Charting
Quality Management
Operational Research
Facilities Planning
8

The resources for the project will consist of
Knowledge gained in the field of Industrial Engineering,
Information gathered through the literature study and personal interaction with employees and management of Euphoria Golf Estate.
Access to Internet facilities and relevant books for research purposes
Transport
The primary stakeholders of the project are:
Africon - Civil Engineers and Project Managers
Euphoria Golf Estate
Mookgophong Community’ (
Bokomoso – Environmental Consultants
9

The problem that was addressed in this project originated from the development of a Golf estate situated in the Naboomspruit area. The developers of the property identified the need for a concrete plant to aid them in the execution of the next phase of their project. The following phase that takes place requires a large quantity of concrete for the construction that will take place over the next 3 years of the development. The infrastructure, roads, electricity and water systems have been completed and the building of houses and golf course structures will soon commence.
The specific problem has different segments:
1. Feasibility study of constructing a concrete plant as opposed to outsourcing it to an external company
2. Determining the location of the facility. This will be done by determining current and future clients/customers.
3. Designing the plant layout.
4. Evaluating the solution and improving were necessary.
After considering all of the above the location of the facility is the most important part of this project. Due to the health and safety risks of the community, investment capital, pollution and traffic caused by a facility of this nature it is of utmost importance that the correct solution be found to this part of the project. When determining the location of the facility the following will have to be considered:
Shortest routes to the customer
The Concrete plant has to be centralized
The potential customers of the plant will form part of the problem
Regulations regarding pollution as stipulated by the Mookgophong municipality
Traffic due to the delivery of concrete to clients
Suppliers of raw material to produce the concrete.
The location of the plant will be greatly dependant on its clients/customers. Thus one of the first things that will have to be completed is a market survey to identify potential developments and future clients
10

To complete the project successfully the following steps have been identified:
Step 1: Conduct a study to determine current and future customers.
Step 2: Conduct market research on all options concerned with concrete and concrete plants.
Step 3: Conduct an environmental study so that pollution will not be a problem.
Step 4: Determine the location of the concrete plant using the information gathered in the above steps and by modelling the location problem using the Brown and Gibson Model.
Step 5: Design a facilities layout plan for the concrete plant.
Step 6: Determine the routes to be taken by supply trucks and specify the material handling equipment
that will be used at the facility.
To complete the above mentioned steps this document has been divided into the following sections to reach a decision on the facilities location and all problems mentioned:
Current and future clients
Market research on concrete plants
Major location determinants
Determining the location of the facility using the Brown and Gibson model
Designing the facilities layout
Determining the material handling equipment
Discussions of all the above mentioned sections follow.
11

From studies done by speaking to one of the developers it has been concluded that the customers of the concrete plant will be one of the determining factors in solving the location problem. These customers consist of the following.
The current and main clients will be the developers of the Euphoria Golf Estate. As mentioned before there are 770 stands that have to be equipped with buildings. There are also various other facilities that have to be built including:
•
Golf facilities e.g. Clubhouse
•
Equestrian Centre
•
Cable way
•
Sport facilities
•
Water playground
•
Restaurant
•
Shopping and Business Centre
•
Chapel
The development of all these structures and facilities will require a large quantity of concrete and will be the main customers of the concrete plant. The location of Euphoria Golf Estate will thus be a major contributing factor in solving the location problem.
12

Figure 4: Location of Euphoria Golf Estate
The developers that are currently engaged in the Euphoria project are planning a similar future development. The proposed development will be on a site at the south western entrance to Mookgopong
(Naboomspruit), on the western side of the R101 which leads into the main street (Hans van Rensburg), next to the existing truck stop / filling station. The development will be known as Cedar Falls Properties.
Cedar falls properties will consist of:
•
Shopping Centre
•
Retirement Village
•
Business Centre
•
Entertainment Facilities
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The location of Cedar Falls will therefore also be a major determining factor for solving the location problem.
Figure 5: Location of Cedar Falls Properties
The permanent customers that will also profit from the project will be the community of Mookgophong.
They will consist of all the surrounding farmers and the population of Mookgophong. These people may not sustain concrete production but they will play an important roll in the location problem.
14

To complete the project successfully a concrete plant will have to be constructed that will meet all the specifications of customers. This is the most important aspect of the project and to meet this factor one considers all the different plant types that exist and the output/specifications of such plants.
On completing the research on concrete plant types the conclusion is that there are 3 types of plant, each type consisting of different models. The types are:
1. Wet Batching plants
2. Dry Batching Plants
3. Mobile Batching Plants.
The table below gives all the different models that exist for each type of plant.
WET BATCHING PLANTS DRY BATCHING PLANTS MOBILE BATCHING PLANTS
MB - 30WS MB - 60D MB - 60M
MB - 60W
MB -100W
MB – 120W
MB - 100D
MB - 180D
MB - 100M
MB – 150W
MB – 180W
Table1: Types of concrete plants
The models type numbers denote the following: e.g. MB-30WS
• 30 : 30 m
3
/h capacity concrete batching plant
• W
: Wet
• D
: Dry
• M : Mobile
• S
: Skip Hoist
Each of these models has a specific performance specification. Therefore it is of the utmost importance that the correct model be selected for the project. The technical specifications for wet batching plants can be found in the appendixes. To further understand concrete plants they are discuss in detail and the above mentioned models are evaluated in respect of the most important features..
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The different types of wet batching plants are as follows:
Model 1: MB-30WS
•
Type of plant: With Bunker Feeding and Axial mixer
•
Capacity: 30m³/hour compacted concrete
•
Mixer capacity: 500 lt. (vibrated concrete)
•
Total Motor Power of plant: 50 kW – 380 V / 50 Hz
Model 2: MB-60W
•
Type of plant: With Bunker Feeding and Axial Mixer, Single shaft
•
Capacity: 60 m³/hour compacted fresh concrete
•
Mixer capacity: 1000 lt. (vibrated concrete)
•
Total Motor Power: 150 kW – 380 V / 50 Hz
Model 3: MB-100W
•
Type of plant: With Bunker Feeding and Axial Mixer, Single shaft
•
Capacity: 100 m³/hour compacted fresh concrete
•
Mixer capacity: 2000 lt. (vibrated concrete)
•
Total Motor Power: 180 kW – 380 V / 50 Hz
Model 4: MB-120W
•
Type of plant: With Bunker Feeding and Twin shaft mixer
•
Capacity: 120 m³/hour compacted fresh concrete
•
Mixer capacity: 3000 lt. (vibrated concrete)
•
Total Motor Power: 180 kW – 380 V / 50 Hz
Model 5: MB-150W
•
Type of plant: With Bunker Feeding and Twin shaft mixer
•
Capacity: 150 m³/hour compacted fresh concrete
•
Mixer capacity: 3000 lt. (vibrated concrete)
16

•
Total Motor Power: 200 kW – 380 V / 50 Hz
Model 6: MB-180W
•
Type of plant: With Bunker Feeding and Twin shaft mixer
•
Capacity: 180 m³/hour compacted fresh concrete
•
Mixer capacity: 4500 lt. (vibrated concrete)
•
Total Motor Power: 275 kW – 380 V / 50 Hz
The different types of dry batching plants are as follows:
Model 1: MB-60D
•
Type of plant: With Bunker Feeding dry mixing plant
•
Capacity : 60 m³/hour
•
Total Motor Power : 50 kW – 400 V / 50 Hz
Model 2: MB-100D
•
Type of plant: With Bunker Feeding
•
Capacity: 100 m³/hour
•
Electrical Motors: 380 V / 50 Hz
Model 3: MB-180D
•
Type of plant: With Bunker Feeding
•
Capacity: 180 m³/hour
•
Electrical Motors: 380 V / 50 Hz
The different types of mobile batching plants are as follows:
Model 1: MB-60M
•
Type of plant: With Bunker Feeding and Axial Mixer, Single shaft
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•
Capacity : 60 m³/hour
•
Mixer capacity : 1000 lt. (vibrated concrete)
•
Total Motor Power : 100 kW – 380 V / 50 Hz
Model 2: MB-100M
•
Type of plant: With Bunker Feeding and Italian twin shaft
•
Capacity: 100 m3/hour compacted fresh concrete
•
Mixer capacity: 2000 lt. (vibrated concrete)
•
Total Motor Power: 180 kW – 380 V / 50 Hz
Figure 6: Wet Batching Plant
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The selection of the appropriate concrete plant location depends on various factors that need to be taken into careful consideration. According to Colye et al (2003) some of the major location determinants that might be applicable to the project include:
1.
Availability of Transportation
: This is a major factor as the raw materials to be delivered need adequate modes of transportation to the concrete plant as well as a relevant infrastructure that can be utilized for the transportation of the finished product.
2. Proximity to customers : This factor is possibly the most important since it will be optimal for the location of the concrete plant to be situated in such a way that all the relevant customers can be serviced with the finished product.
3.
Land Costs and utilities renting
: This is of importance in that a minimum size is required for the facility to keep within budget constraints. The availability and expenses of utilities such as electricity, water etc. should be taken into consideration for the decision making process.
4.
Company Preferences
: The Company itself may have certain preferences with regard to various factors concerning the location. In the case of this project such factors may include the following:
•
The facility would have to be located within the Mookgophong district since this is where the owners spend their everyday life and all the customers that need to be serviced are within this area.
•
A factor might be whether the developers prefer to locate the facility in a rural area where land can be less expensive or in areas where quality resources such as electricity are readily available.
5.
Supplier Networks
: For a location problem like this where raw material has to be delivered continuously to the facility a supplier’s network is of utmost importance. The cost and inbound movements from suppliers will be the key factors.
6.
Taxes and Development incentives
: It will be important to have knowledge of taxes that will have a significant impact on operating a concrete plant in the area in question.
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The location of the concrete plant can be determined using more than one method. Some of these methods include the Heuristics model and the Centre of gravity model. The model that will be used in this project is Brown and Gibson Model.
The Brown and Gibson model attempts to deal with multifunctional location problems. This model classifies criteria affecting location according to the model structure, quantifies the criteria, and achieves the balancing or trade-off between criteria.
Classification of Criteria:
The model deals with any list of criteria set by management and classify them as follows:
A. Critical – criteria are critical if their nature may preclude the location of a plant at a particular site, regardless of other conditions that might exist. For example, a water-oriented enterprise, such as a brewery, would not consider a site where a water shortage was a possibility. An energy-oriented enterprise, such as an aluminium smelting plant, would not consider sites where low-cost and plentiful electrical energy was not available. Critical factors have the effect of eliminating sites from consideration.
B. Objective – criteria that can be evaluated in monetary terms, such as labour, raw material, utilities, and taxes, are considered objective. A factor can be both objective and critical; for example, the adequacy of labour would be a critical factor, while labour cost would be an objective factor.
C. Subjective – criteria characterized by a qualitative type of measurement. For example, the nature of union relationships and activity may be evaluated, but its monetary equivalent cannot be established. Again criteria can be classified as both critical and subjective.
Model Structure
For each site i , a location measure LM i
is defined that reflects the relative values for each criterion.
LM i
=
CFM i
×
[ X
×
OFM i
+
( 1
−
X )
×
SFM i
] (1)
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Where CFM i
= the critical factor measure for site i
( CFM
I
= 0 or 1)
OFM i
= the objective factor measure for site i
( 0
≤
OFM i
≥
1 and
∑ i
OFM i
=
1 )
SFM i
= the subjective factor measure for site i
( 0
≤
SFM i
≥
1 and
∑ i
SFM i
=
1 )
X = the objective factor decision weight ( 0 < X > 1 )
The critical factor measure CFM i
is the sums of the products of the individual critical factor indices for site i with respect to critical factor j . The critical factor index for each site is either 0 or 1, depending on whether the site has an adequacy of the factor or not. If any critical factor index is 0, then CFM i
and the overall location measure LM i
will also be 0. Site i would therefore be eliminated from consideration.
The objective criteria are converted to dimensionless indices in order to establish comparability between objective and subjective criteria. The objective factor measure for site i, OFM i
, in terms of the objective factor costs, OFC i
, is defined as follows:
OFM i
=
[ OFC i
× ∑ i
( 1 / OFC i
)]
−
1
(2)
The effect of equation 2 is that the site with the minimum cost will have the largest OFM i
, the relationships of total costs between sites are retained, and the sum of the objective factor measures is 1.
The subjective factor measure for each site is influenced by the relative weights of each subjective factor and the weight of site i relative to all other sites for each of the subjective factors. This results in the following statement:
SFM i
= ∑ k
( SFW k
×
SW ik
) (3)
Where SFW k
=
the weight of subjective factor k relative to all subjective factors, and
SW ik
=
the weight of site i relative to all potential sites for subjective factor k.
Preference theory is used to assign weights to subjective factors in a consistent and systematic manner.
The procedure involves comparing subjective factors two at a time. If the first factor is preferred over the second, then the numerical value of 1 is assigned to the first factor and 0 to the second, and vice versa for
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the opposite result. If one is indifferent regarding the two factors, a rating of 1 is given to both factors.
Procedures are also included for higher-order rankings. As with objective factors, the ratings are normalized, so that the sum of subjective weightings for a given site adds to 1.
Finally, the objective factor decision weight, X, must be determined. This factor establishes the relative importance of the objective and subjective factors in the overall location problem. The decision is commonly based on action by a management committee, reflecting policies, past data, and an integration of a wide variety of subjective factors. The determination of X could logically be subjected to a Delphi process.
With all the data inputs, equation 1 can be used to compute the location measure LM i
, for each site, and the site that receives the largest LM i
is selected. Brown and Gibson extends the model to multi-plant location and present a computed example of the evaluation of six sites, involving capacity constraints.
Sensitivity analyses are shown to indicate how decisions would change when the objective factor decision weight, X, is varied from 0 to 1.0. The entire procedure has been programmed for electronic computing using a 0-1 programming algorithm capable of treating problems as large as 150 variables and 50 constraints.
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The facilities planning process can be divided into two major components:
1) Facilities Location
2) Facilities Design
The facilities location component has been discussed above. To complete the project successfully a facility has to be designed.
According to Tompkins et al (2003:8) the design component of a facility consists of the facility system, the layout, and the handling system. To ensure that an optimal facility is designed, attention must be given to all the above mentioned components. By designing the layout and material handling alternatives simultaneously there will be no compatibility problems, and future needs for both these components will consider the growth and changes in the other component. It is important to be aware of local health and safety regulations while designing the different components. This is especially important when designing and selecting the facility system that must serve the facility.
The design of a facility is determined by the requirements for that specific facility. While designing the facility flow, space and activity relationships must be determined. Space according to Tompkins et el
(2003:79) is a function of lot size, storage systems, production equipment type and size, the layout arrangement, building configuration, housekeeping and organizational policies, materials handling equipment, and office, cafeteria and restroom design. The flow of material or personnel, environmental considerations, the organizational structure and the process requirements, define the activity relationships.
All the factors that have to be taken into consideration when designing the concrete plant are:
•
Activity relationships
•
Material Flow
•
Space requirements
•
The Facility operating system
•
Materials handling equipment
All of the abovementioned criteria are determining factors in designing a facilities layout. In the figure below all of these criteria have been taken into consideration and the basic facilities layout for a concrete
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plant has been designed. This design is however only a concept and alterations may be made as the project reaches completion and system requirements are defined.
Figure 7: Basic Concrete Plant Design
The different components and alternative designs will be described in detail in the following section:
AGGREGATE STOCK
Aggregated Inline Bunker (3 – 6 Compartments)
Aggregate Inline Bunkers of the concrete batching plants have up to 6 bins depending on the capacity of the plant. Aggregate Inline bunkers are designed and manufactured as per related DIN norms to operate under severe working conditions for a long time. There exist 4 electro-pneumatically controlled discharge gates, which provide easiness and choice in the discharge together with suitable elevation. An aggregate weighing belt conveyor of the aggregate bunker, which has ±5 kg sensitivity, manufactured to operate without any problem under severe working conditions with mechanical separator, every kind of safety precautions, air pressure measuring device and etc. as per world conditions. Aggregate is weighed by 4 units of load cells and weighing the belt conveyor has all the necessary safety switches like; a sensor for break off of the belt, a rope controlled safety switch, an emergency stop button and switch that prevent
24

belt slides.
Belt Conveyer
Belt Conveyors, used for feeding aggregate from the aggregate bunker to the mixer, have a width of either
800, 1000 and 1200 mm depending on the capacity of the batching plant. Up to 200 inclination standard smooth surface belts are used if the inclination is more than 200, then chevron type belts are adapted:
· covered with galvanized plates
· one side having a travelling platform from ground level
· all belt conveyors are covered by galvanized metal sheet
· once the belt conveyor is stopped, the lock that prevents returning is always active
Skip Hoist and Bucket Feeding
A Skip hoist and bucket feeding system is used for the aggregate feeding to the mixer. This system is preferred mostly when there is insufficient space at the site for the concrete plant. It is designed in such a way that is takes up less space than a conveyor and thus is preferred over the conveyer for projects where space is at a premium.
Main Chassis
The main components of the chassis are the following:
Table 2: Components of the Main Chassis
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The above can be seen as the main structure of the plant. It is where the inline bunker, conveyor or ship hoist feeding, and the cement silo are combined to deliver the end product. From this point the concrete is pumped into cement trucks and delivered to the customers. The following diagram will show the structure in detail:
Figure 8: Technical Drawing of the Main Chassis of a Concrete Plant
Mixers
Mixers are the most important part of a Concrete Batching Plant, which has an effect on the concrete mixing quality and time. There are two types of mixers, Single Shaft axial mixer and Twin Shaft mixer.
Single Shaft Axial Mixer
Single shaft mixers are easy to operate and long life mixers with very strong spiral shaped mixing arms and pneumatic discharge gate, compact structure and provide fast mixing and practical loading. Linings of mixing arms and easily changeable and inner wearing plates are made from Ni hard cast which is very wear resistant material.
Twin Shaft Mixer
This mixer has synchronously operating two horizontal shafts. The inner part of the mixer is covered with
26

easily changeable wearing plates. Mixing paddles are covered with cast plates that are very wear resistant.
The Automatic lubrication system of the mixer provides the required oil pressure the bearings. The Cover of the discharge gate of the mixer operates hydraulically and has a pump to manually open the gate in case of power a failure.
Figure 9: Graph of Mixing times
Cement Silo
Cement silos of Concrete Batching Plants are made from 4 inch filling pipe. Outside and inside ladders, manhole, platform and parapets are included.
Equipments supplied with standard Cement Silos:
•
Filter
•
Silo Pressure Relief valve
•
Level Indicators (top and bottom)
•
Fluidization Jets
•
Bottom Valve
27

Automation Systems of Concrete Plans
The basic automation system for a concrete plant consists of the following:
•
Visualization and Control based on C7-635 system with integrated CPU S7-314C-2DP PLC,
SIMATIC HMI Panels
•
Siemens Electrical Installation devices and sensors.
•
Remote stations with distributed I/O stations.
•
Real time simulation for operator training. The training is fast and without any loss of material
•
Increasing the production capacity and quality and more quality by using Siemens technology and professional algorithms.
•
All values of parameter setup, receipt and calibration operations can be done on an operator panel screen; process, production and failure information can be taken.
•
Manuel and automatic operation can be done on an illuminated mimic diagram. Voltage and current values are shown by digital indicators on the panel.
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The material handling system of a facility consists of the material-, personnel-, information-, and equipment-handling systems that are required to support the production of the finished product. The material handling system has to do with the moving of material within and between departments of the facility and can be linked with a number of other systems. The material handling system is especially important in the overall design of the facility and Tompkins et al (2003:163) even goes as far as to say:
“the layout design and the material handling system design are inseparable”.
The goal of this part of the project is to reduce the material handling activities since they cannot be eliminated all together. Materials handling is described as a science based discipline and therefore engineering design methods must be applied. The ten most important materials handling principles that must be considered when designing a handling system are:
1) Work principle
2) Unit load principle
3) Automation principle
4) Life cycle cost principle
5) Systems principle
6) Space utilization
7) Standardization principle
8) Planning principle
9) Ergonomic principle
10) Environmental principle.
It is important to build safety into the materials handling system. Even though the equipment used might be safety approved, this does not guarantee that the system will be safe. This is especially important in the project considering the processes involved in delivering the final product. To achieve the required safety factor one should concentrate on the interface between the workforce of the concrete plant and the equipment used.
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It is of utmost importance that the correct strategy be adopted and adapted to find a suitable solution for the successful completion of this project. The purpose of this chapter was to show all the information gathered and to briefly discuss and compare techniques that will be used to complete the project.
In each of the above sections, Customers, Market Research, determining the location of the concrete plant, and designing the facility; different industrial engineering and other techniques of approaching each part of the problem is identified and discussed. From these the best approach has been selected and will be used as a tool for the completion of the project.
Therefore it can be said that by the proper use of these tools the project can be completed in terms of the following factors:
Determining all customers of the concrete plant
Determining the location of the concrete plant
Designing the facility
The tools to be used are:
For research: Research by the use of the Internet and interviews with developers
For determining the optimum solution are: The Brown and Gibson Model
For designing the facility: Discussion of all the principles will be implemented in meeting specifications.
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Part of the research that went into this project was to conduct interviews to extract as much information as possible to help in finding a solution to the location problem. By conducting interviews a greater understanding was attained of the project and the problem. Valuable information was also obtained that was critical to finding a feasible solution to the abovementioned problem.
Interviews were held with the heads of the construction and development project of Euphoria Golf Estate.
All the project requirements and specifications were gathered and critical success factors were determined.
The interviewees were:
1) Dr. G B Erasmus – Project Manager
2) Mr. F Erasmus - Developer
3) Mr. C Pretorious – Project Coordinator
After the interviews with these parties were completed the following information was of utmost importance to the success of the project.
Firstly a total quality management (TQM) program, of which Quality Assurance is an essential part, must be able to:
achieve and maintain a level of quality of the product or service offered that will continually satisfy the needs and expectations of the customer; provide confidence to the customer that the intended quality of the product or service is being achieved;
Provide confidence to management that the intended quality of the product or service is being achieved and maintained.
Provided this program is implemented successfully, the following set of benefits may be achieved: improved client satisfaction improved communications between parties involved in a building project;
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formalized delineation of responsibilities; clearly defined lines of authority and the extent of such authority; systematic checking, resulting in avoiding of costly errors, failures and expensive remedial works; improved and more relevant specification writing; systematized collection of information from clients to ensure that all requirements are defined before detailed design work proceeds; programmed and prompt arrival of all information;
To achieve all the abovementioned factors systems will have to be developed and maintained that will help managers and staff in the following daily operations of running the concrete plant:
• concrete ordering;
• concrete sampling;
• concrete delivery to site;
• batching of concrete;
•
Control of materials for concrete.
Other information that was applicable to the new location of the Concrete Plant and the success of the project are the following:
1) The size of the site should be between 1500 m² - 2000 m²
2) There should be access from and to a good road
3) Sufficient area to load concrete and to unload material
4) Close to the customers as a result of the nature of the product
5) Access to educated workers
These are the most important factors that had to be considered in the development of the concrete plant and played a major role in all the decisions that had to be made.
32

To understand concrete it is important to know how it is made and all the processes involved in delivering a final product of quality. In this part of the document this aspect will be discussed.
Mixing cement, water, and aggregate (Figure 10) produces concrete. By weight, most concrete is made up of about 15% cement, 7% water, and 78% aggregate. The cement and water form a “glue like” paste. The paste must be spread evenly over each piece of aggregate. Through a chemical reaction called
“hydration,” the paste hardens and binds the aggregates. By adding a small amount of air, strong and durable concrete is produced. In many cases, if not most, practices resulting in production and placement of high quality concrete can be performed as economically as those resulting in poor concrete. A basic requirement for all concrete handling is that both quality and uniformity of the concrete, in terms of water- cement ratio, slump, air content and homogeneity, must be preserved. To thoroughly understand the concepts of concrete all of its components need to be discussed.
Figure 10: Concrete Components
Cement
Cement holds the aggregates together. It also determines the strength of the concrete. Different types of cement can be produced for various uses:
•
Type I is a general-purpose cement.
•
Type II cement is cement that is used when moderate sulphate resistance or moderate heat of
33

hydration is desired.
•
Type III is a “high early strength” cement used when strength is needed rapidly. About the same strength is achieved in 7 days as in 28 days with Type I cement.
•
Type IV is a slower setting cement and is used for low heat during hydration.
• Type V is a high sulphate resistant cement .
Water
The water used in making concrete should be free of oil, acid, injurious alkali, sugar, vegetable matter, effluent of sewage disposals, and other substances detrimental to the finished product. The Central Office of Materials and Surfacing should conduct a pH test to determine whether the water can be used for concrete. They also test the water for dissolved and suspended solid material to see if these solids would be harmful to the concrete.
Aggregates
Aggregates occupy most of the space in concrete. Aggregates can come from a wide range of material but are usually confined to:
• Natural Sand
• Crushed Gravel - only used in M6 concrete
• Crushed Rock or Quarry Stone
• Expanded Shale (lightweight aggregate)
These aggregates fall into two size classes - Fine and Coarse. The Fine Aggregate (commonly called sand) is material less than 3/8 inch in size. The Coarse Aggregate (commonly called rock) is the material larger than number 4 sieve.
Admixtures
Admixtures are added to the concrete mix to improve one or more characteristics of the plastic or hardened concrete. They help make the concrete less expensive and/or of better quality. However, with the exception of air entraining admixtures they are not used for all applications. The most common types of admixtures are:
• Air Entraining Admixtures
• Water Reducing Admixtures
• Pozzolanic Admixtures
34

A concrete plant is a factory. The product manufactured is uniform fresh concrete. It is essential that there should be an uninterrupted flow of the concrete from the plant to the construction site. This will provide concrete uniformity and will facilitate a high quality of construction. The following system features are required for concrete to flow in an uninterrupted fashion to the construction site and for materials to be uniform from batch to batch:
1. A site large enough to store materials for continuous operations.
2. A layout that permits all construction and delivery traffic to flow freely in and out of the plant site.
3. Equipment that is kept in a good operating condition.
4. Competent plant and equipment operators who are well supervised.
5. Storage and handling procedures for all materials.
6. Good communications between the concrete plant and the placing operation .
The key to quality and uniformity is using proper proportioning, consistency and a quality control program. All materials must be measured accurately. The term “batch” means either the assembly or mixture of all the ingredients used in one concrete mixing operation. For example, one truck mixer load or one plant mixer cycle in a central mix paving plant is a batch. It is important to proportion each batch of materials to obtain strength and durability. The proportions of aggregate have a considerable effect on the workability of the fresh or “plastic” concrete. Any error made in measuring the quality of materials will also cause a variation in strength. The measurement of materials within narrow accuracy limits
35

should be controlled.
To further ensure the quality of the concrete and the effectiveness of the concrete plant the following checklist has been developed to help managers and supervisors with the everyday tasks of running such a facility.
This is a checklist of duties performed by a concrete plant inspector/manager. The following items contain actions that must be completed prior to producing concrete:
1. The standard specifications, supplemental specifications, special provisions and plan notes that pertain to the project are on hand, are/have been reviewed and are correct for the project.
2. The aggregate stockpiles are being properly built and are/have been checked for separation, segregation, and foreign material.
3. The quality control tests for the aggregates, water, and admixtures are being performed or are on file.
4. The design mix document is on hand.
5. The plant is level on its foundation.
6. The cement and aggregate scales have been checked for accuracy; seals and certificates sufficient for project duration are present.
7. The water and admixture scales have been checked for accuracy; seals and certificates sufficient for project duration are present.
8. The plant automatic controls and timer have been checked and are working properly.
9. The mixer maximum volume and drum mixing speed have been checked and verified.
10. The mixer blades have been checked against the manufacturer’s diagram and are within wear tolerances.
11. The revolution counters on the transit mix trucks have been checked and they work properly.
12. The site layout ensures a logical traffic pattern, safe operations, and proper drainage.
The following items must be checked shortly after the start of production and performed until project completion.
1. The required aggregate gradation tests are conducted.
2. Cement samples are taken and sent to the Central Testing Laboratory.
3. Certificates of Compliance are obtained for the cement and admixtures, if required.
36

4. Aggregate moisture tests are taken and correctly documented.
5. The batch weights are adjusted for changes in volume, aggregate moisture content, workability, and water.
6. Dirt balls and other foreign materials are removed from the aggregate.
7. The mixing time is checked.
8. Haul tickets are issued when needed.
9. Scales are checked for balance and sensitivity.
10. The hauling unit’s cargo boxes are checked for contamination.
11. Cement and fly ash checks are made.
12. All forms are properly filled out.
13. Additional water samples are taken when needed.
14. The strength of the air-entraining agent is checked so the proper amount is being used. Also, each air-entraining agent lot is properly sampled?
15. As necessary, the temperature required to heat water or the aggregates is checked.
16. Safety is a daily critical inspection item.
37

The supply chain can be defined as “the physical, financial, and information network that involves the movement of materials, funds, and related information through the full logistics process, from acquisition of raw material to delivery of the finished product to the end user. The supply chain includes all vendors, service providers, customers and intermediaries’ (Coyle, 2003:689)
Porters value chain depicted in the figure below developed by Michael Porter is a widely accepted method used to understand and explain the businesses basic activities. In the case of the value chain it can be seen that the business has been divided into 2 groups namely the primary and support activities.
Figure 11: Porters Value Chain (Coyle et al, 2003:577)
This project is a mixture between the primary and support activities. All the mentioned activities of the value chain play a major roll in the operations of a concrete plant and have to be managed well to ensure that the plant is effective and productive. This project is unique since the finished product cannot be stored before it is shipped to the customer. This part of the process has to be done directly after production due to the nature of concrete. Other than this the processes involved are standard and all fall within the diagram of Porters’ Value Chain.
The main purpose behind the investigation into the supply chain was to understand all the activities and processes involved in the everyday running of the concrete plant and to manage them in such a way that a quality product can be delivered. It was therefore necessary that a thorough investigation be done to understand the steps and processes involved in the supply chain.
38

To understand the supply chain the following questions where asked.
•
Data concerned with procurement: o Who and where are the main customers? o Who and where are the main suppliers?
•
Data concerned with the location of the facility o Where will the Concrete Plant be constructed?
•
Data concerned with the storage of all the raw material: o How much raw material will be stored? o How frequently will raw material be delivered to the site?
•
Data concerned with transportation: o Which transportation systems will be used? o How often will transportation of the raw material and finished product take place?
Using these questions a supply chain may be constructed to demonstrate the activities of the Concrete plant.
Figure 12: Concrete Plant Supply Chain
39

As already suggested, the factors considered in this location problem may relate to key production inputs, to process technology, or to the environment.
Production Inputs.
The incentive to locate a new location may derive from the need to secure a larger quantity or different quality inputs such as labour, raw materials, energy, or other. These considerations are related to the markets of such inputs.
Raw materials: the dominant factor in plant location is the need to be near the sources of raw materials.
Human resources: for this project which has considerable labour requirements, proximity to the appropriate labour market becomes a dominant factor in the selection of a location.
Process technology: for this project the technology used restricts the number of locations to sites that provide an abundant low-cost supply of some critical input, such as water and electrical energy for the plant.
Environmental factors: Beyond the consideration of factors related to the production process and its critical inputs, the location decision depends on several factors that define the external environment: o The availability and reliability of supporting systems, including public utilities for power and water, fire protection, easy transportation routes to suppliers and consumers, rapid and reliable communication. o Social and cultural conditions may at times discourage the selection of a location that could pass any economic- and technical-feasibility criterion. It is thus necessary to understand the local population not only in terms of demographic variables (size. distribution, age. migration shifts, etc.) but also in terms of their attitudes toward domestic or foreign new industries and the quality, availability and reliability of potential employees. o Legal and political considerations represent a wide variety of restrictions or opportunities and must be studied carefully before making a final choice. In some locations there are very strict laws pertaining to pollution standards, zoning codes, construction specifications, or import regulations.
40

To formulate the location problem more precisely, it is helpful to view the operations system under study in relationship to its market and its sources of supply, i.e. its economic environment. This is shown in the
Figure below, where some of the most important costs that must be estimated for alternative location sites include:
1. The cost of procurement of needed production inputs C
1 that is, the cost of raw materials, labour, energy, etc. (mainly variable costs)
2. The cost of processing the inputs given the technology Cp , that is the overhead cost (mainly fixed costs)
3. The distribution cost involved in shipping product(s) or making services available to customers C d
(mainly variable costs)
Figure 13: Operation Systems
These costs are tangible; i.e. they can be estimated for different locations using standard economic analysis. In addition, must take into account certain intangible costs related to the quality of the labour
41

available in each location, the degree of cooperation and the attitudes of the local government and community, possible relocation adjustments, and others must be taken into account. Finally, there is an opportunity cost for each location resulting from failure to select the best site possible if time and money impose no restrictions in the search for alternatives.
The formulation of the location problem can now be made more complete and precise. Management has the task of selecting among candidate locations one that satisfies existing technological, legal, and other constraints and minimizes the combined cost of the relevant tangible, intangible, and opportunity costs.
The problem of selecting a location is characterized by numerous factors with complex interrelationships.
Several of these factors can only be evaluated qualitatively at best. Furthermore, the information needed is often incomplete due to the inherent difficulty of predicting future conditions. Various sophisticated techniques developed to solve parts of the total problem include linear programming, heuristic and simulation models based on some dominant objective, such as minimizing distribution costs.
Management, however, needs an approach that considers the problem holistically and allows the careful evaluation of both quantitative and qualitative factors. This can be attempted within the framework of a systems analysis, which must cover the components shown in Figure 14.
Figure 14: Interacting Factors in the selection of a Location
42

It is useful to study the location problem in two phases. First, there is a preliminary feasibility study , the purpose of which is to determine whether the environmental changes are important enough to warrant a more detailed analysis. Thus phase one is mainly concerned with the study of trends in the level and geographical distribution of aggregate demand to determine whether they justify the minimum economical addition to capacity obtained by building new facilities.
Along with demand, the preliminary study focuses on other environmental factors such as the availability of critical production inputs, their current and projected costs, and any demographic changes that may affect the distribution of demand and/or the availability of labour or other resources. If the results of the first phase justify the need for a more detailed analysis, management can proceed with the second phase, which is conducted in three successive stages, as set out below:
The data needed to select the most suitable region and the new capacity requirements include the following:
A. Future increase in demand by region translated into productive-capacity requirements
B. Cost relationships for production and distribution
C. Identification of sources of needed production inputs:
1. Raw materials (quality, quantity, cost, reliability)
2. Labour market (available skills, wages, and supply levels)
3. Supporting systems, i.e., economic infrastructure, for supplying a. Energy (sources, adequacy, cost) b. Water (quality, quantity, and cost) c . Transportation and communication networks (adequacy, reliability, cost)
4. Legal, social, and political factors
5. Environmental considerations (pollution, climate, quality of life)
Within the area chosen in stage 2 in figure 15 it is desirable to consider alternative sites for the construction of the new facilities. At this point, it is important to secure detailed economic and demographic data, but most factors that must be analyzed in area and site selection relate to technical, social, and legal considerations.
The factors that must be considered in the selection of a community and a site for a new location can be
43

classified as follows:
A. Projected requirements in production inputs
1) Human resources (skills, amounts, quality)
2) Raw materials, parts, semi finished components
3) Energy, water, and other services
4) Transportation and communication facilities
5) Physical space for planned facilities and future expansion
B. Objective factors that will affect the cost and profits of new installation
1) Projected levels of annual demand
2) Projected annual operating costs a. Costs of purchase and transportation of raw materials b. Costs of wages of required skills c. Costs of requirements in energy (electricity, oil. etc.), water, telephone, etc. d. Taxes on (sales, income, property, inventories, etc.). e. Cost of construction of new facilities
3) Estimates of annual profits for successive years
4) Cost of purchasing construction site
C. Subjective factors that will influence the community and site selection
1) Existing laws that will affect the firm's activities
4) Supporting infrastructure systems (power, telephone, water, waste treatment. Or other) a. Population makeup, attitudes, traditions b. Financial institutions c. Cultural activities, schools, recreation d. Quality of Life (noise, congestion, air pollution, etc) e. Housing d. Services
44

Preliminary Feasibility study
(Study of environmental conditions )
Results
Assessment of need
For further study
Is there a need for a
More detailed
Analysis?
No Stop
Analyze general characteristics of candidate regions :
- Projected capacity requirements
- Economic Factors
- Demographic variables
- Legal and other constraints
Selection of
- Acceptable regions
- Centralized or decentralized
plant capacity
- Production Costs
Determine the best location
- Economic Factors
- Strategic impacts
(Competition , quality)
Selection of
- Best area of community
- Distribution Costs
Evaluate alternative sites
- Objective factors
- Subjective Factors
Selection of the best site
For the new facility.
Figure 15: Procedure for selecting a location for a new facility
45

The first step in solving a location problem is to determine the different alternative location for the project. Secondly constraints or important factors that affect the project on a given site must also be established. After these phases have been completed the weights of the problem variables must be established to find the best possible location for the facility.
Upon completion of the calculations the last variable which has to be determined is the “Objective Factor
Decision Weight”. Company preference plays an important roll in determining this factor. If the company is only driven by a financial gain objective the factor will equal 1 and if it is an organization that is totally dedicated to the community and surroundings the factor will be 0. The developers of the project will eventually determine the weight.
After consulting with the developers of the project three sites where identified for erection of the concrete plant. These sites are:
1. Site A: Euphoria Golf Estate
2. Site B: FLUOR SPAR Mine
3. Site C: Naboomspruit
The figure below illustrates the location of the three sites which are being taken into consideration.
Figure 16: Candidate Locations
46

To further solve the problem there should be consensus on the critical, objective and subjective factors that would play a determining roll in finding the best solution. After all the interviews, meetings and discussions the following factors where identified.
Critical Factors:
•
Water
•
Electrical Energy
Objective Factors
•
Labour Cost
•
Transportation
•
Taxes and development
•
Cost of Site
•
Suppliers
Subjective Factors
•
Labour Supply
•
Community Attitude
•
Proximity to customers
•
Company Preference
•
Support Services (Maintenance)
•
Union Activity
All of these factors where used in the Brown and Gibson model to determine the location of the concrete plant. The values used in the model are order of magnitude values that are unique to the area and in this context are only used for the purpose of demonstration.
47

Criteria are critical if their nature precludes the location of a plant at a particular site, regardless of other conditions that might exist. For this project the plant cannot function without water and electrical energy.
All of these are available at the proposed locations.
1
2
Water
Electrical Energy
Euphoria Golf
Estate
1
1
FLUOR SPAR Mine Naboomspruit
Table 3: Critical Factors
1
1
1
1
Objective criteria that can be evaluated in monetary terms, such as labour, transportation, and taxes, are considered as objective factors. These factors give an objective view of which site will be best for the problem. For example in the table below, Labour costs ranking is as follows:
•
Site A the most expensive,
• site B is less expensive, and
• site C the cheapest.
After completion of the calculations an Objective factor value for each site will be obtained which will be used in the model.
Site i Labour Cost Transportation
Site A
Site B
Site C
0.60
0.65
0.70
0.80
0.50
0.70
Taxes and
Development
Cost
Cost of Site Suppliers
0.70
0.65
0.65
0.80
0.70
0.60
0.80
0.70
0.75
Total OF
3.70
3.20
3.40
Total i
OF a =
OF b =
OF c =
0.308
0.356
0.335
Table 4: Objective Factors
Reciprocal
1/OF i
0.270
0.313
0.294
0.877
48

Subjective criteria are characterized by a qualitative type of measurement for example community attitude. These Factors are described by using different verbal descriptions. For labour supply, community attitude, proximity to customers, company preference and support services the following descriptions were used:
1. Excellent
3. Good
4. Adequate
5. Fair
And for union activity the following were used:
1. Active
2. Significant
3. Moderate
4. Negligible
All the factors can be numerically evaluated as shown in the table below. Comparisons will then have to be made firstly between the subjective factors to determine the most important of them, and then between the sites to calculate which subjective factor is the best satisfied by which site. At the end all the comparisons and calculations the subjective factor for each site will be determined. All the calculations are given in appendix B.
Site I
Site A
Site B
Site C
SF a =
SF b =
SF c =
Labour Supply
Very Good
Very Good
Excellent
Community
Attitude
Very Good
Very Good
Very Good
Proxomity to
Customers
Excellent
Good
Good
0.437
0.279
0.283
Company
Preference
Very Good
Fair
Good
Support Services Union Activity
Very Good
Very Good
Very Good
Active
Moderate
Significant
Table 5: Subjective Factors
49

To determine the best solution to the problem one has to use the critical, objective and subjective factors in calculating the location measure for each site. To do this the company has to determine the objective factor decision weight which is used to combine all the factors. Given below are all the options available to the developers. As can be seen the value of Euphoria decreases as the value of the decision weight factor ( X ) increases and the value of Naboomspruit and FLUOR SPAR increases. Consequently the organization should select a value for X that will meet all their needs.
To further illustrate the effect of the objective factor decision weight a graph has been generated that can be used to make informed decision regarding the location of the concrete plant and the effect it will have on the community and the surrounding areas.
Objective
Factor
Decision
Weight
0.4
0.5
0.6
0.7
0.0
0.1
0.2
0.3
0.8
0.9
1.0
Euphoria
Golf Estate
FLUOR SPAR
Mine
Naboomspruit
0.43745
0.42451
0.41156
0.39862
0.38567
0.37273
0.35978
0.34684
0.33389
0.32095
0.30800
0.27875
0.28648
0.29420
0.30193
0.30965
0.31738
0.32510
0.33283
0.34055
0.34828
0.35600
Table 6: Summary of Location Measures
0.28325
0.28843
0.29360
0.29878
0.30395
0.30913
0.31430
0.31948
0.32465
0.32983
0.33500
50

Figure 17: Locations Graph
51

As noted in the preceding section the optimal solution for the location problem will be determined by the selected objective factor decision weight. The balance between financial orientated and community orientation will be a determining factor.
The balance point in the system is at X = 0.8. At this point the company is leaning towards being more financially than community orientated. Using the figure above one can decide which solution will best fit the need of the developers.
52

To successfully complete this project the last phase is to design the concrete plant facility. To design a facility that would optimize all actions in the plant the following will have to be borne in mind:
I. A site large enough for all operations to flow continuously (Space Requirements),
II. material and activity flow that will take place and
III. Materials Handling Equipment
These will be the determining factors in the design of the concrete plant and will be discussed in detail below.
To operate the facility at 100 % capacity sufficient space is required. In appendix C the blueprint for the design is posted. This is how the facility is designed and the space requirements will be directly linked to this model of the concrete plant.
After all the information was gathered and interviews conducted with all parties involved it was determined that the site area requirements for the concrete plant would amount to 4050 m². This facility would then not only house the concrete plant but all the raw materials required and flow through systems for all operating trucks and suppliers would also be accommodated. All these functions can be seen in figure 18.
After the size of the facility has been determined the flows of all activities and material on site have to be analyzed and a method has to be adopted to keep all the functions of the concrete plant running in an uninterrupted fashion. The adopted method will also ensure that all personnel understand how the facility is operated and maintained.
53

Figure 18: Facility Space Requirements and Activity Flow
The materials handling equipment and systems that will be needed to effectively run this project will include all of the below:
•
All Suppliers (cement, aggregate and admixtures)
•
A front end loader to move raw material and supply inline bunker
•
6 X Cement delivery trucks
•
Operating/Control system
All of these are essential to the success of the plant. A further aspect that will have to be addressed is labour, the number of employees and their skill level that will be required to operate the concrete plant.
54

Euphoria Golf Estate is a unique development with unusual requirement and growth possibilities. The amount of development and construction lead to a cement shortage that had to be addressed. The proposed solution to this problem was to determine the location and to construct a concrete plant that could supply the developers with adequate concrete.
However the location of the facility was not just based on existing customers but also on potential customers. This project included a market study that was conducted in order to determine where these potential customers where situated in the surrounding areas of Naboomspruit. Processing this information the Brown and Gibson model was used to determine the optimal site to erect the concrete plant.
After the location had been determined the facility layout had to be designed to meet all specifications and requirements set by the developers. Standard concrete plant models were used and from them a solution was selected.
The aim of the project was thus completed and it will be up to the developers to select the site that would meet all their demands and preferences.
55

1) Brown, P.A., and D.F. Gibson. “A Quantified Model for Facilities Site Selection – Application to a Multi-plant Location Problem,” AIIE Transactions, 4, March 1972, pp. 1-10
2) Thompkins, J.A., White, J.A., Bozer, Y.A., and Tanchoco, J.M.A. (2003) Facilities Planning. 3 rd edition, New Jersey: John Wiley and Sons, Inc.
3) Chase R., Aquilano N., and Jacobs R., (2004), Operations Management for the Competitive
Advantage, 10 th
edition, New York , NY: Irwin/McGraw-Hill
4) Coyle J.J., Bardi E.J. and Langley C.J., (2003), The Management of Business Logistics: A Supply
Chain Perspective, 7 th
edition, South-Western, Thomson Learning.
5) Fiksel, J., “Measuring Sustainability in Eco-Design,” in M. Charter & U. Tischner,
Sustainable Solutions: Developing Products and Services for the Future , Greenleaf
Publishing, Fall 2000.
6) IE 441 Facilities Planning and Design Course Lecture Notes. Part 1
7) Toward a Sustainable Cement Industry , Sub study #3: Business Case Development, Final
Report, March 2001, Appendix A.
8) The Euphoria Golf Estate Website: http://www.euphoriaestate.co.za
9) Information on Concrete Plants available at: http://www.meka.biz
10) http://www.emeraldinsight.com
56

PLANT TYPE
SPECIFICATIONS UNIT
MB 30 MB 60 MB 100 MB 120
▪ Plant Capacity
Compacted Concrete
Cycle Time
▪ Mixer Specifications
Mixer Capacity
Dry Capacity
Compacted Concrete m³ /hr 30 cyc / hr 60
60
60
100
50
120
45
MB 150
150
40
MB 180
180
40 m³ lt
0,5
750
1,0
1500
2,0
3000
3,0
4500
4,0
6000
4,5
6750 lt 500 1000 2000 3000 4000 4500 kW 2x37 2x55 2x75 2x90
▪ Aggregate Bunker
Total
▪ Aggregate Weighing
Width
Length
Motor Power
▪ Mixer Feeding
Width
Length m³ 45-80 60-120
3x15 4x20 4x30
120-300 120-300 120-400 120-400
4x30 4x40 4x50 6x30 kW 7,5
Bucket
7,5 11
Conveyors
15
Conveyors
15
Conveyors
2x15
Conveyors
2x15
Conveyors mm 800 1000 1000 1200 1200
▪ Batchers
57

Weighing 300 500 1000 1750 2000 2000
Water Weighing lt 120 250 700 1000 1200 1200
▪ Cement Screw Conveyor
Diameter
Length
Motor Power
▪ Cement Silo
Capacity kW 7,5 ton
11 15 15 15 18,5
100 100 100 100
Number
▪ Compressor
Capacity lt /min 1100 1400 1400 2400 2400 2400
Motor Power
▪ Water Pump kW 5,5 7,5 7,5 18,5 18,5 18,5 m³ 2x1 2x1 3x1 3x1
▪ Total Motor Powers
Standard Twin Silos kW
50
(1 Silo)
110 165 215 265 315
Table 7: Wet Batching Plants Technical Specifications
58

Factor j
Labour Supply
Community Attitude
Proximity to Customers
Company Preference
Support Services
Union Activity
Pairwise Comparison
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1 0 0 1 1
0
1
1
1
0
0 0 1 1
1
1
1
1
1 1 1
1
0
0
1
0
1
0
1
1
Sum of
Preferences
Relative Importance
3
2
5
5
3
2
Index w j
0.150
0.100
0.250
0.250
0.150
0.100
20 1 TOTAL
Table 8: Comparison between subjective factors
Labour Supply
Pairwise Comparison Response
Site i
Site A
Site B
Site C
TOTAL
1 2 3
1 0
1 0
1 1
Sum Of
Preferences
Site Ranking
R i1
1
1
2
4
0.250
0.250
0.500
1
Table 9: Labour supply comparison between sites
59

Community Attitude
Pairwise Comparison Response
Site i
Site A
Site B
Site C
TOTAL
1 2 3
1 1
1 1
1 1
Sum Of
Preferences
Site Ranking
R i2
2
2
2
6
0.333
0.333
0.333
1
Table 10: Community Attitude comparison between sites
Proximity to Customers
Pairwise Comparison Response
Site i
Site A
Site B
Site C
TOTAL
1 2 3
1 1
0 1
0 1
Sum Of
Preferences
Site Ranking
R i3
2
1
1
4
0.500
0.250
0.250
1
Table 11: Proximity to customer’s comparison between sites
Company Preference
Pairwise Comparison Response
Site i
Site A
Site B
Site C
TOTAL
1 2 3
1 1
0 0 1
1
Sum Of
Preferences
Site Ranking
R i4
2
1
1
4
0.500
0.250
0.250
1
Table 12: Company Preference comparison between sites
60

Support Services
Pairwise Comparison Response
Site i
Site A
Site B
Site C
TOTAL
1 2 3
1 1
1 1
1 1
Sum Of
Preferences
Site Ranking
R i5
2
2
2
6
0.333
0.333
0.333
1
Table 13: Support Services comparison between sites
Union Activity
Pairwise Comparison Response
Site i
Site A
Site B
Site C
TOTAL
1 2 3
1 1
0 1
0 0
Sum Of
Preferences
Site Ranking
R i6
2
1
0
3
0.667
0.333
0.000
1
Table 14: Union Activity comparison between sites
61

Site Rating R ij
Factor j
5
6
3
4
1
2
A
0.250
0.333
0.500
0.500
0.333
0.667
B
0.250
0.333
0.250
0.250
0.333
0.330
C
0.500
0.333
0.250
0.250
0.333
0.000
Relative
Importance
Index
0.150
0.100
0.250
0.250
0.150
0.100
LM a =
LM b =
LM c
=
X = 0.3
LM a =
LM b
=
LM c =
TOTAL
Table 15: Summary of Subjective Factor Evaluation
The Objective Factor Decision Weight:
X = 0.0
X = 0.1
1.000
X = 0.2
0.43745
0.27875
0.28325
LM a =
LM b =
LM c
=
0.42451
0.28648
0.28843
LM a =
LM b =
LM c
=
0.39862
0.30193
0.29878
X = 0.4
LM a =
LM b
=
LM c =
0.38567
0.30965
0.30395
X = 0.5
LM a =
LM b
=
LM c =
62
0.41156
0.29420
0.29360
0.37273
0.31738
0.30913

X = 0.6
LM a =
LM b =
LM c
=
X = 0.9
LM a =
LM b =
LM c =
0.35978
0.32510
0.31430
0.32095
0.34828
0.32983
X = 0.7
LM a =
LM b =
LM c
=
X = 1.0
LM a =
LM b =
LM c =
0.34684
0.33283
0.31948
X = 0.8
LM a =
LM b =
LM c
=
0.33389
0.34055
0.32465
0.30800
0.35600
0.33500
Table 16: Decision weight Factors
63

Figure 19: Concrete Plant Blueprint
64