Environmental Assessment of Phosphate Mining on
Climate Change Greenhouse Gases
Background: Under the National Environmental Policy Act (NEPA), the U.S. Army
Corps of Engineers (USACE) will conduct an Environmental Assessment (EA) on
phosphate mining in the Central Florida Phosphate District (CFPD). The EA is to
determine whether mining has or is likely to result in exceeding thresholds on important
environmental issues. An EA considers both the cumulative impact from mining in the
CFPD, and the incremental impact with new mining. According to the USACE, mining in
the CFPD has occurred on 1.32 million acres (~2,100 square miles). New/proposed mining
applications by the Phosphate Industry are ~100,000 acres.
Request to the USACE: The specific purpose of the following discussion is to request
the need for an EA to include a science-based assessment if specific benchmark levels
for rebuilding soil organic matter (SOM) and soil organic carbon (SOC) should be
achieved in post-mined CFPD soils:
 The amount/percentage of SOM/SOC at various soil depths.
 The composition of SOM/SOC (short-lived active and long-lived stable fractions).
 The Sustainability of sequestering and maintaining soil carbon levels.
Justification of Request: Including SOM/SOC levels, its composition, and sustainability
in the EA is believed to be justified under NEPA using an environmental criterion of
Climate Change (greenhouse gases). Greenhouse gases/Climate Change can cause
environmental degradation on a myriad of issues (e.g., water resources, habitat loss, etc.)
Some potential key questions in an EA could include:
Question 1: Has phosphate mining caused or is it likely to cause an “environmentally
significant” degradation through the release of greenhouse gas emissions from the
combination of: (1) land clearing, (2) soil disturbance, and (3) other potential “life
cycle” factors in the production/manufacturing of phosphate fertilizer?
Question 2: What is the cumulative and projected mass balance of greenhouse gases
from phosphate mining between initial output (release of greenhouse gases) and
subsequent reclamation input/capture (soils and plant flora)? Have mining and
reclamation practices resulted in a mass balance that is relatively carbon cycle
neutral, or have significant carbon deficits resulted from mining in the CFPD?
Question 3: Are historical and future post-mining land practices to capture greenhouse
gases sustainable (specifically, a common practice of creating large land masses of
post-mined grasslands)? Also under NEPA, has the well documented massive weed
invasion of cogongrass on post mined lands been environmentally significant?
Question 4: Are there cost effective, sustainable practices and regulatory incentives
that could be implemented to increase soil SOM/SOC (sequester carbon) on postmined lands?
Intent of Soil SOM/SOC Request to USACE: It is not the intent of this request to
initiate new burdensome rules on the phosphate mining industry. It is believed that if a
credible science-based and peer reviewed greenhouse gas concern is identified in an EA,
that mining companies will be pro-active in doing the right thing. The objectives of this
request are to educate, inform, and encourage the development of voluntary actions to:
 Educate/Inform all Stakeholders of the potential significance of cumulative and
future phosphate mining practices on Climate Change greenhouse gases.
 Develop voluntary cost effective mining practices and market based (e.g., rural
economic development) “Action Plans” to reduce the carbon footprint of mining.
 Implement incentives or remove barriers by Regulatory Bodies (USACE, EPA,
Florida Department of Environmental Protection, Water Management Districts)
to encourage voluntary “Action Plans”.
Discussion of Potential Environmental Significance: In addition to the release of CO2
from land clearing, it is believed that established empirical data associated with
phosphate mining is clear that soil SOM/SOC levels are close to non-existent or
extremely low at the completion of mining. Thus, the starting point of any
“environmentally significant” discussion must address how much carbon (above and
below ground) had been captured/banked on native lands prior to mining.
One possible science based scientific citation that can be used in a initial discussion is the
work performed by Kimble, Heath, Birdsey, and Lal, “The Potential of U.S. Forests Soils
to Sequester Carbon and Mitigate the Greenhouse Gas Effect” (CRC Press, 2003). In
Chapter 3, table 3.2 presents an estimate for total carbon capture (above and below
ground) associated with oak-gum-cypress forests which would be representative of premined CFPD lands.
Table 3.2 Carbon Densities (t/ha) and Forest Area (thousand ha) for Major Forest Types
of the Eastern United States, 1997, on Timberland Only.
Forest Type:
Oak-gum-cypress
(a)
(b)
C in
Biomass
(t/ha)
81.1
C in Dead
Mass (a)
(t/ha)
26.5
Soil Organic C
(1 –m depth)(b)
(t/ha)
152.2
Total
Forest C
(t/ha)
259.7
Dead mass includes standing dead trees, down dead trees, and forest floor.
Soil includes both mineral soil and organic soils (i.e., Histosols).
The following converts the above Total 259.7 C tons per hectare to CO2 emissions per
acre for phosphate mined lands using conversions of 1 hectare equals 2.47 acres; a carbon
to CO2 multiplier of 3.67 times:
Step 1:
Step 2:
Step 3:
Step 4:
Step 5:
259.7 C tons/ha equals 105.14 C tons per acre.
105.14 C tons per acre equals 385.87 tons of CO2 per acre.
385.87 tons CO2 per acre times 1.32 million acres equals 509.35 million tons of CO2.
385.87 tons CO2 per acre times 100,000 acres equals 38.59 million tons of CO2.
385.87 tons CO2 per acre times 1.42 million acres equals 547.94 million tons of CO2.
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Remembering that the intent of this discussion is to initiate science based dialogue, an
initial point estimate of the potential cumulative CO2 emissions released and expected to be
released (through additional mining) would thus be 547.94 million tons of CO2.
CO2 from Phosphate Mining in Context/Perspective: The next question is to put into
perspective/context of how environmentally significant 547.94 million tons of CO2
emissions would be. One illustrative approach is to compare the above estimated CO2
emissions from phosphate mining to that of electricity generation power plants in the
region and within Florida:
Tampa Electric’s Polk Power Station: CO2 emissions from coal use are 1.06 million tons
per year. The environmental impact of cumulative CO2 emissions from phosphate mining
would thus equate to coal operations at the Polk Power Station for ~515 years. CO2
emissions from new phosphate mining permits would equal ~36 years of coal operations at
the Polk Power Station.
Florida’s Coal Fired Electrical Generation: CO2 emissions from all coal fired power plants
in Florida is ~ 70.6 million tons per year. The cumulative CO2 emissions from phosphate
mining would thus equate to ~8 years of operating all coal fired power plants in Florida.
Florida’s Total Electrical Generation: CO2 emission from all electricity generation power
plants in Florida is ~138.9 million tons per year. The cumulative CO2 emissions from
phosphate mining would thus equate to ~4 years of operating all power plants in Florida.
World’s Volcano CO2 Emissions: According to the U.S. Geological Survey (USGS), the
world’s volcanoes (both on land and undersea) generate about 200 million tons of CO2
annually. Thus, the cumulative CO2 emissions from phosphate mining would thus equate
to ~3 years of total volcanic activity in the world.
Other CO2 Considerations in Phosphate Mining: While phosphate mining’s release of CO2
from soils (and also greenhouse gases of nitrous oxide and methane) and land clearing is
believed to be significant, other factors should also possibly be considered in an EA under
NEPA. These additional factors would be identified and quantified in a “life cycle
analysis” of phosphate mining. An obvious factor would be the use of fossil fuels in
mining operations. In addition, phosphate fertilizer production is an energy intensive
industry, where the generation of electricity (using fossil fuels) for phosphate fertilizer
production may also be a significant source of CO2 emissions in a “life cycle analysis”.
Need for Mass Balance Analysis: Of course, the above illustrations reflect only one part of
the total greenhouse gas mass balance -- the initial emissions from land clearing and soil
disturbance. According to landmark research1 on phosphate mined soils performed by the
U.S. Department of Energy's Oak Ridge National Lab (ORNL), mined lands (especially clay
settling areas) have an unique ability for carbon capture/sequestration to quickly restore
SOM/SOC through advanced agriculture practices:
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Soil Organic Carbon Levels Achieved in ~3 Years after Energy Crop Establishment
(ORNL Research on Phosphate Mined Lands)
5.29%
(10-20 cm)
3.06%
(40-50 cm)
SOC Level
SOC Level
According to Dr. Stan Wullschleger of ORNL, phosphate mined lands may
represent one of the greatest new carbon sink opportunities not only in the U.S., but
the entire World.
Putting the above graphic into some perspective, soil science provides general benchmarks
(for clay soils), where (A.) healthy soils have SOC of ~4% and (B.) a red flag exists with
soils that have <1% SOC (which typically exists right after the completion of mining).
In addition, the type of post-mining reclamation is also highly important – especially
regarding whether a carbon management practice is sustainable. For example, on lands
reclaimed to pasture (a common application in post-mining land reclamation), the majority of
the sequestered carbon is soon converted back to CO2 through respiration.2
Requests to the USACE: Four requests are being made, where all science based work
should be performed using highly credible resources and be open to academia and industry
peer review:
(1.) Develop a Greenhouse Gas Mass Balance: A Mass Balance Assessment (MBA)
should reflect the cumulative impact of total mining in the CFPD (1.32 million acres).
The MBA is critical to quantify the significance of phosphate mining on greenhouse
gas emissions and the magnitude/scope of needed voluntary actions.
The USACE should also provide an opinion of reductions in greenhouse gases that
may be necessary for the cumulative impact of phosphate mining not to exceed an
environmental degradation threshold under NEPA. The USACE should clearly state
that because of the newness of the issue of Climate Change under NEPA, efforts to
even address this issue is landmark and involves a great deal of subjectivity.
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(2.) Develop SOM/SOC Benchmarks: Quantitative benchmarks of SOM/SOC should
include target percentages by soil depth levels, composition (active and stable
fractions), and sustainability.
(3.) Develop Voluntary Action Plans: Through USACE sponsored Workshops, “Action
Plans” would be developed to achieve voluntary reductions (based on results from the
MBA) in the carbon footprint of phosphate mining. “Action Plans” should apply to all
phosphate mined lands and operations and not limited to new mining areas.
Participation in Workshops would involve all Stakeholders such as:
(A.) Agriculture Interests: This could include the University of Florida (IFAS),
USDA, the U.S. Department of Energy’s Biomass Energy Program, farming
and energy (i.e., ethanol) interests to recommend cost effective practices and
available incentives that can be used to build soil SOM/SOC for the purpose
of growing crops on mined lands. An additional greenhouse gas benefit in
growing energy crops on mined lands is that the end-use product (e.g.,
ethanol) reduces fossil fuel use (a carbon multiplier benefit).
(B.) Environmental Interests: Participation by environmental interests is critical to
insure that actions to mitigate Climate Change will not degrade other
environmental concerns (e.g., water quantity and quality, etc.). Clearly, the
development of “Action Plans” must include environmental standards.
(C.) Operations of Mining Companies: This could entail internal reviews by
Mining Companies for voluntary actions to reduce greenhouse gas emissions
from their current operational practices. A clear topic to evaluate for potential
improvements would be in land clearing operations (e.g., recycling biomass
from cleared lands to previously mined lands – called mulch matting).
(D.) State and Federal Regulatory Entities: There is a perception (which may be
correct or incorrect) that phosphate mining companies believe their “hands are
tied” through existing environmental regulation in what they can do to allow
new large scale agriculture use on their mined lands. Can current
environmental regulations achieve both environmental and agriculture use?
(E.) Rural Economic Development: This could include regional economic
development councils and municipal governments.
(4.) Annual Reporting: The USACE should require Mining Companies to report annually
as to achievements made in their voluntary actions to reduce greenhouse gas
emissions. This reporting should include all mined lands and operations and not
limited to newly mined areas.
1
Wullschlerger, Segrest, Rockwood, Garten, 2003, Enhancing Soil Carbon Sequestration on Phosphate
Mine Lands in Florida by Planting Short-Rotation Bio-energy Crops, Oak Ridge National Laboratory.
2
Murray, B., 2003. Economics of Forest Carbon Sequestration. In: Sills, E.O., Abt, K.L. (Eds.), Forests in
a market economy. Kluwer Academic Publishers, Dordecht, pp. 221-240.
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