Waste piles

Mine wastes consist of rock that must be removed in order to access the ore. Generally, this material presents no risk of environmental contamination and it may be piled alongside the mining facility. In some cases, however, waste rock contains minerals that might be leached by water passing through waste piles. When this is considered likely, steps are taken to ensure that the leachate does not enter surface water bodies. 

RCRA s TSDF standards also include provisions to protect groundwater and air resources from hazardous waste contamination. RCRA requires owners and operators of land-based units (i.e., land treatment units, landfills, surface impoundments, and waste piles) to monitor the groundwater below their TSDF for possible contamination, and clean up any discovered contamination. 

FIGURE 12.6 Cross section of a waste pile. (Adapted from U.S. EPA, RCRA Orientation Manual, www.epa. gov/waste/inforesources/pubs/orientat/roml.pdf.)... 

This series of prohibitions restricts how wastes subject to LDR requirements are handled. The most visible aspect of the LDR program is the disposal prohibition, which includes treatment standards, variances, alternative treatment standards (ATSs), and notification requirements. Land disposal means placement in or on the land, except in a corrective action unit, and includes, but is not limited to, placement in a landfill, surface impoundment, waste pile, injection well, land treatment facility, salt dome formation, salt bed formation, underground mine or cave, or placement in a concrete vault, or bunker intended for disposal purposes. The other two components work in tandem with the disposal prohibition to guide the regulated community in proper hazardous waste management. The dilution prohibition ensures that wastes are properly treated, and the storage prohibition ensures that waste will not be stored indefinitely to avoid treatment. 

The sources of contamination are usually those hazardous materials that are contained in drums, tanks, surface impoundments, waste piles, and landfills, as well as heavily contaminated media (such as soil) affected by the original leaking or spilling source. The purpose of defining sources of contamination is to help to identify the source location, potential releases, and engineering characteristics that are important in the evaluation of remedial actions, as well as waste characteristics, such as the type and quantity of contaminants that may be contained in or released to the environment, and the physical or chemical characteristics of the hazardous wastes present in the source. 

The dust suppressant method uses chemicals to (temporarily) strengthen bonds between soil particles and reduce fugitive dust emissions from inactive waste piles. Dust suppressant is expected to be 100% effective for a period of one to four weeks if the use of chemical is appropriate and undisturbed. Dust suppressants can also be used to control dust from work areas however, it is less effective and requires frequent reapplications. 

Owners and operators of landfills, surface impoundments, and waste piles will be required to install double liners and FDSs. 

To reduce the amount of downdrag force on the waste pile, standpipes can be coated with viscous or low friction coating. Standpipes can be encapsulated with multiple layers of HDPE. This material has a very low coefficient of friction that helps reduce the amount of downdrag force on the waste piles. 

The drainage system for removing leachate or other aggressive liquids from landfills, surface impoundments, and waste piles is critically important. Even if a liner has no leaks, the phenomenon of molecular diffusion will allow some of the organics from the liquids ponded on top of the liner system to leach through the FML and the clay. The timely collection and removal of that leachate is at the heart of this section. 

Keller, B., Hoylmass, E., and Chadbourne, J., 1987, Fault Controlled Hydrology at a Waste Pile Ground Water Monitoring Review, Spring, pp. 60-63. 

Subparts 1, J, K, and L Use and Management of Containers, Tank Systems, Surface Impoundments, and Waste Piles Liners and Leak Detection for Hazardous Waste Land Disposal Units... 

Solids - Waste piles, Tailings impoundments and Stream sediments. 

Next the Likelihood of release, of a contaminant, from a waste pile or discharge is considered. It is an assessment of whether there have been releases of contaminants to the environment in the past and addresses whether the waste pile or discharge is in any way contained. The former determines whether there have been releases of the contaminants from the mine site in the past while the latter issues may affect whether there is likely to be releases from the source in the future. In all cases any contaminant must be attributable to the mine site. 

II 1,000- 2,000 Sites requiring general monitoring of most or all waste piles, discharges or stream sediments on an annual basis. 

All facilities operating under Interim Status are subject to a number of general facility standards. In addition, specific standards have been established for management of wastes in containers, tanks, surface impoundments, waste piles, landfarms, landfills, incinerators, and chemical, physical, and biological treatment facilities. 

The air concentrations of thorium and other airborne radioactivity near a former thorium and rare-earth extraction facility in the United States were measured. The maximum radioactivity due to all three isotopes of thorium at a site about 450 feet from the primary waste pile was 0.66 fCi/m. Although the background thorium radioactivity was not reported, the total radioactivity at a site about 4000 feet south of the waste pile was about 3.5 times lower than a site 450 feet from the pile (Jensen et al. 1984). 

Smith, K. S., Campbell, D. L. et at. 2002. Chapter C, Toolkit for the rapid screening and characterization of waste piles on abandoned mine lands. In Seal II, R. R. Foley, N. K. (eds) Progress on Geoenvironmental Models for Selected Mineral Deposit Types. US Geological Survey, Denver CO, USA, US Geological Survey Open-File Report 02-195. 

Exclusion Zone The area surrounding a particular incident site (such as a spill, a fire, or a hazardous waste pile or subarea under remediation), wherein only trained and fully protected hazardous materials workers may enter to perform necessary operation. 

Loredo, J., Ordo nez, A., Baldo, C. and Garcia-Iglesias, J. (2003) Arsenic mobilization from waste piles of the El Terronal mine, Asturias, Spain. Geochemistry Exploration, Environment, Analysis, 3(3), 229-37. 

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