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Mining R&R. Matthew Gloe, Christian Bongard, James Brown Dr. W. Lee Daniels, Dr. Robert Grisso. This is Where Your Power Comes From. Consequences of Coal. Besides the well known air pollution, there are large problems caused by coal that doesn’t even make it to market.
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Mining R&R Matthew Gloe, Christian Bongard, James Brown Dr. W. Lee Daniels, Dr. Robert Grisso
Consequences of Coal • Besides the well known air pollution, there are large problems caused by coal that doesn’t even make it to market. • Impurities that come from coal processing plants are placed in large waste piles (Gob piles), these account for 5% of disturbed mine lands. • Gob piles are scattered throughout Virginia, each having potential to produce strong acid runoff.
How can we fix these problems? • Upon completion of mining, reclamation of these waste piles is much more challenging than the actual mined area. • To remediate and reclaim these sites, a comprehensive plan and design must be devised and implemented.
Our Site • Red River Coal Co. – Norton, VA • Their coal waste pile encompasses more than 100 acres • Current acid mine drainage treatment involves spending $100-$1000 a month on a sodium hydroxide drip, along with man hours for constant monitoring. Red River Coal Mine Site Norton, VA
What are our goals? • Design a passive vertical flow wetland system to treat acid mine runoff and reduce costs; in compliance with SMCRA and the Clean Water Act • Engineer a soil to cover and revegetate the coal waste pile. Schematic of a Vertical Flow Wetland System
Common Design Processes • All passive treatment systems rely on alkalinity production from dissolved carbonate or bicarbonate. 2H+ + CO32- H2O + CO2 H+ + HCO3- H2O + CO2 • Secondary processes vary between designs, to include heavy metal removal.
Wetland Design Org. Layer Limestone Layer
Design Parameters Non-Mn Acidity = Acidity - 1.818 * Mn AlkNet = (99.3*log (tr)) + (0.76*Fe) + (0.23*Non-Mn Acidity) - 58.02 Limestone Volume (m3) = (0.227*Q*tr) / Vv Adtl. Limestone Volume for loss (m3) = (0.0249*Q*AlkNet) / x Where: Q = flow L/min tr = residence time in hours Vv = void volume of limestone layer by % x = CaCO3 content by %
Wetland Calculations Initial Data and Assumptions: • Fe = 3 mg/L • Mn = 12 mg/L • Acidity = 30.35 mg/L as CaCO3 • Influent flow = 190 L/min • Safety margin ≈ 60 mg/L of alkalinity Total Calculated Limestone Volume = 454 m3 At a limestone depth of 0.6 m (2 ft), wetland surface area equates to: 750 m2 or(27 x 27 m)
Important Notes • Wetland treats only the baseflow • Stormwater runoff is not treated, as it has the lowest acid and metal concentrations. • Excess volume of stormwater can damage the wetland system, settling ponds and bypass channels will be used to govern flow.
Preliminary Settling Pond Wetland Location To Secondary Pond
Cost Analysis for VFW • Chemical Treatment ≈ $1000/month • One time VFW construction cost of $60-75 per m2 ($56,250 for a 750 m2 VFW) • 5 years of chemical treatment is equivalent to construction costs of VFW • Our wetland has a design life of 20 years • Maintenance costs may be needed for VFW
Basically… Plants and bacteria work for free; people and machines don't.
How can we get plants to grow on coal waste? Engineered Soil and Revegetation -Direct liming (acid buffer) -Introduction of topsoil (rooting layer, temperature buffer) -Or Add Lime-stablized Bio-solids
What SHOULD be Done! • Environmentally, Scientifically, Logically, and most importantly Economically, biosolidsshould be utilized • Lime stabilized biosolids are FREE! • Reduces fertilizer needed, and growing time • No negative health effects. • Addition of wood waste improves C:N ratio
Why It’s NOT Done • It looks like this! • Local public perception of the idea is so revolting that coal companies don’t even consider it anymore, despite the benefits.
Major Obstacles • Communication with contacts • Industry standard is English units • Wetland sizing… single or multiple? • Maintenance costs • Pricing inconsistencies
In conclusion… • There is an obvious need for mining remediation and reclamation • A VFS and an engineered soil utilizing biosolids will be the most effective solution for Red River Coal. • Our final wetland CAD design is currently underway and will be completed shortly.
We are… Mining R&R Questions?