Natural Resources Extraction: Stressors and Impact Management - Sustainable Practices in Geoenvironmental Engineering - page 162

5.5 Geoenvironment Impacts and Management
There are at least four signiicant kinds of geoenvironment impacts associated with resource
mining and extraction operations: (1) mining excavations, pits, underground caverns, and
debris piles, waste rock, rejects, overburden, etc., (2) acid generation and/or AMD from
exposure of debris piles and exposed mine cavities, etc., (3) slurry tailings containment
facilities, and (4) fate of contaminated luids in underground in situ extraction of hydro-
carbons. The second and third concerns can be seen in Figure 5.7. Mining excavations and
underground mining create situations where the excavated (empty) volumes present chal-
lenges that are beyond the scope of the material discussed in this topic. The impact from
debris discharge and heaping into “tips” has been briely mentioned at the beginning of
this chapter (Section 5.3.1). In addition to the sterilization of the immediate landscape sur-
rounding the tips as a result of the leachates emanating from the tips, possible instability of
the tips is a question and problem that needs attention.
5.5.1 Geoenvironmental Inventory and Land Use
By and large, a major proportion of mining and on-site resource extraction operations are
initially in regions situated some distance from urban centers. Original land use, prior
to the time of mining exploration in such regions, would be characterized by the local
physiographic features such as those discussed in Chapter 1. An environmental inventory
and more speciically a geoenvironmental inventory prior to mining operations is needed
to establish a base upon which decisions regarding impacts on land use, sustainability
indicators, and restorative requirements can be sensibly made. The principal features of
the geoenvironmental inventory, which is a baseline descriptor of the state of the various
constituents of the local geoenvironment ( ab initio condition), include
a. Regional controls such as climate and meteorological factors
b. Local terrain features including linear features, physical attributes, topography,
watershed, local hydrology, surface layer quality, vegetative cover, receiving
waters and water quality
c. Subsurface features such as geological and hydrogeological settings, soil subsur-
face system, and groundwater-aquifer regimes
Decisions on sustainability of potential land uses or site functionality cannot be made
without the inventory and without determination of the qualities of the attributes neces-
sary for various land uses. These are highly dependent on whether (a) the mining and
resource extraction operations remain isolated from urban communities or (b) small urban
communities are located contiguous to the mining site. In the irst instance, where min-
ing operations remain isolated from habitable communities, the return of the exploited
land to original natural conditions, are requirements to satisfy sustainable land use aims.
These conditions entail restoring the original site functionality to protect human health
and other biota. Speciication of ab initio land environment sustainability indicators will
be guided by the geoenvironmental inventory established before mining operations.
Historically, geoenvironmental inventories have not been made prior to and even during
mining operations. Nevertheless, a study of the natural geoenvironment system contigu-
ous to the mining operations will serve to provide the basis for establishment of ab initio
sustainability indicators. Although return of the land to its pristine original function, as a