Page 298 - Advances In Productive, Safe, and Responsible Coal Mining

274 Advances in Productive, Safe, and Responsible Coal Mining

mineral origin. Total dissolved solids can be measured by evaporating a water sample
at 180°C and comparing the mass of the evaporative residue to that of the original
water sample [3]. TDS concentration can be estimated by summing concentrations
for all dissolved constituents. The water’s electrical conductivity (EC) is often used
as a proxy for TDS because it corresponds closely to TDS [4], and because it measures
the concentration of solutes in water and is much easier to measure. Because both
water’s dissolved ions and its temperature affect its EC, those EC measurements
are usually converted to specific conductance (SC), a measure of the water’s capabil-
ity to conduct electric current at a temperature of 25°C. Both TDS and SC have
become mining industry concerns because numerous studies have documented
depressed aquatic life in mining-influenced streams with elevated SC [5]. As of this
writing, no federal regulatory standards are in place for TDS or SC, although recent
studies by USA federal agency scientists have suggested that SC levels <300μScm 1
and<500μScm 1 can protect aquatic communities and sensitive aquatic taxa,
respectively [6,7].
Selenium (Se) can also be problematic in mine discharges. Selenium is a naturally
occurring element that can be released at elevated concentrations by environmental
waters’ interactions with some mining-disturbed strata. Selenium is an environmental
concern because of its tendency to bioaccumulate in aquatic systems, causing repro-
ductive abnormalities in higher-trophic level organisms such as piscivorous fish and
birds [8]. US EPA’s recommended water-quality criterion for Se is 3.1μgl 1 or a dem-
onstrated absence of dangerous bioaccumulation in flowing waters [9].
In addition to obtaining water discharge permits, most mining operations must
comply with other CWA requirements. For example, mining impacts to streams
are regulated under the CWA’s Section 404, a program that oversees the discharge
of dredged or fill material into waters of the USA. For example, reductions in stream
distance can occur with mining operations as ephemeral, intermittent, or flowing
streams are covered by excess spoil disposal structures such as valley fills. Such losses
must be approved through permitting. The law requires that mining operations be
designed and operated to avoid stream losses when possible, to minimize such losses
when avoidance is not possible, and to mitigate whatever stream losses do occur. The
“compensatory mitigation” that is required in order to obtain a CWA Section 404 per-
mit is commonly achieved by improving the watershed and habitat conditions of other
streams in the vicinity of the mine and by reconstructing the impacted stream on the
reclaimed mine site, when possible.

14.2.3 Other environmental laws
Depending on the mining situation and reclamation plan, other environmental statutes
can come into play. For example, the Endangered Species Act (ESA) protects threat-
ened and endangered plant and animal species. If the mining operation has potential to
affect habitats for any such species, the ESA’s requirements must be complied with. If
disposal of coal combustion products such as fly ash from coal-fired power plants is
planned for the mining area, Resource Conservation and Recovery Act (RCRA)
requirements must be considered when developing the mining permit.