EARTHMOVING • The process of moving soil or rock from one location to another and processing it so that it meets construction requirements of location, elevation, density, and moisture content and so on. • It involves excavating, loading, hauling, placing (dumping and spreading), compacting, grading and finishing • Efficient management of the earthmoving process requires accurate estimating of work quantities and job conditions, proper selection of equipment, and competent job management 1. Large Mining Trucks • To move materials around a mine site, workers need heavy-duty trucks. • They include both powerful mechanical models and environmentally friendly electric drive models. • Unlike conventional trucks, they have extra-large tires to support the heavy loads over uneven terrain commonly found around surface mines. • Can carry high payload capacities to accommodate the need for moving weighty mined minerals or ore out of the site • Also need to perform in the most extreme conditions — cold, heat, heavy dust, high altitudes, and steep slopes while hauling heavy loads. • Applications: • Moving materials at surface mines. • Hauling materials up steep slopes. • Carrying up to a 400-ton payload. 2. Hydraulic Mining Shovels (Excavators) • Mining shovels used today often employ hydraulics for moving the shovel to power through tough materials. • Most have a base with either tracks or wheels atop which the pivoting cab sits. • The pivoting action allows the operator to access material in a circle around the shovel without moving significantly. • An articulated arm holds the shovel, both of which the operator controls from inside the cab. • Applications: • Moving earth or mined materials. • Digging. • Scooping material into a loader. • Removing rock or dirt, also known as overburden, mines to open the site. • Transporting some mined materials. from surface 3. Large Dozers • Large mining dozers move materials easily around a mining site. • Dozers can now operate in a broader type of terrain because of vehicles’ choice of different wheels or tracks. • Applications: • Additional attachments can change the dozers’ uses to include the following applications: • Removing the top layer of soil and exposing the underlying rock • Keeping a mining site clean by shoving debris out of the way of workers • Reclaiming the land around mining sites. • Ripping plant matter out of the ground. • Removing rocks and debris from the area surrounding a mine • Raking the land around a mine site. 4. Electric Rope Shovels • Instead of using hydraulics to control the movement of the shovel at the end of the arm, electric rope shovels use a series of pulleys and ropes. Unlike hydraulic shovels, these models use electric operation, allowing for highly efficient performance over time. • Uses of electric rope shovels mimic those of hydraulic excavators. • Applications: • Removing overburden to prepare a mine site. • Digging through hard materials. • Moving earth. • Removing boulders. • Transferring mined material to a loader. • Transporting material. 5. Rotary Drill Rigs and Rock Drills • One of the most important types of mining equipment. • Rotary drill rigs create holes through rock or soil, allowing placement of charges for blasting open mines. • For a rotary drill rig, the drill bit turns under pressure to cut into the rock. As the bit turns, the rock grinds down while compressed air sends it back up the drill to the top to keep the hole and bit clean. • For hammer rock drills, pressure forcefully shoves the bit into the ground to create a hole. • Applications: • Creating holes for blasting charges for surface mining. • Production drilling to make wells. • Presplit rock drilling. • Expanding mines 6. Motor Graders • Mines rarely have ready access to roads. Even those near major roadways still need roads built within the area for moving material and hauling mined goods out. • Motor graders are used for surface operations around mines to create and maintain these roads. • When hauling minerals, ore, or other mined materials along roads, things like debris or ponding water can slow vehicles. • Motor graders ensure the roads have the necessary grading and adequate drainage. • By maintaining the integrity of roads used for transporting the material around and out of the mining area, motor graders play a vital role in ensuring the efficiency of the mine’s operations. • Applications: • Pushing surface material to clear roads. • Creating proper grades to allow water to drain away from roads. • Constructing haul roads. 7. Large Wheel Loaders • For picking up and quickly moving material across a mining site for loading into trucks, nothing matches the versatility of large wheel loaders. Sizes vary from compact to large. • As the wheel loader’s size increases, its bucket capacity and load handling also go up. • Matching the wheel loader’s handling capabilities for both volume and density of materials at the mine is crucial to ensure the machine will hold up to the rigors of daily use without premature wear. • Compact models work best with light materials and have a bucket capacity of about 2 cubic yards. • Large models can handle iron ore or rock and can hold up to 38 cubic yards of rock in the bucket. You will have a varied selection of wheel loaders to fit in the space around your surface mine and handle the loads you need to move. • Applications: • Typically found at surface mines, large wheel loaders can take on many tasks, such as: • Loading materials onto trucks for transport. • Digging. • Supporting jobs of other loading and transport vehicles on-site. 8. Draglines • Draglines are large excavators with a bucket supported by ropes and wires at the end of a boom. • Lowering the bucket and scraping it along the ground collects overburden or mined material. • Swinging the bucket at the end of the dragline around repositions it to dump its contents into a specified location. • Surface mining heavily uses draglines. • Applications: • Moving tons of overburden to prepare a surface mine. • Removing exposed material, such as tar sand, from a strip mine. • Reducing emissions compared to other overburden removal methods. • Cutting into high wall surfaces and removing material. 9. Wheel Tractor Scrapers • `Design similar to motor graders but scrapers typically have an attached bin that collects the material removed from the ground’s surface rather than pushing it to the side as a grader does. • To operate the scraper, the driver uses controls inside the cab to raise or lower the bin to the ground. • When on the ground, the edge of the bin scrapes the ground materials, which feed directly into the bin. • When filled, a vertical flap holds the material inside the bin, so it does not spill during transport. At the deposit location, the bin tilts and opens in the rear to empty the scraped dirt. • Applications: • Building roads. • Making initial cuts into the land for a mine. • Reclaiming land. • Performing mining operations. 10. Underground Mining Loaders and Trucks • Underground mining trucks and loaders require specific operating parameters to function in confined spaces. • These vehicles cannot produce emissions in the enclosed environment of a mine. • Therefore, standard trucks used for surface mining will not suffice for underground work. • Mining trucks and loaders for underground operations have specially built engines that do not produce emissions but still have enough power to move tons of rock. • Applications: • Digging. • Loading rock or mined material into trucks. • Transporting material to the surface. Estimating Production of Earthmoving equipment • The basic relationship for estimating the production of all earthmoving equipment is: • Production = Volume per Cycle x Cycles per hour • The term “volume per cycle” should represent the average volume of material moved per equipment cycle. • Thus the nominal capacity of the excavator or haul unit must be modified by an approximated fill factor based on the type of material and equipment involved. • The term “cycle per hour” must include any appropriate efficiency factors, so that it represents the number of cycles actually achieved or expected to be achieved per hour. • The cost per unit of production may be calculated as follows:
