GEOENVIRONMENTAL MINERAL DEPOSIT MODELS AS AIDS TO THE IDENTIFICATION OF ENVIRONMENTAL CHALLENGES ASSOCIATED WITH THE MINING OF UNMINED AND UNDISCOVERED ORE DEPOSITS

Environmental challenges are an inescapable part of modern mining that affects multiple facets of the viability of all potential mines including their permitting, profitability, and successful closure. Geoenvironmental mineral deposit models provide a means of anticipating potential challenges associated with ore deposits at every stage throughout the life cycle of a mine including exploration, permitting, production, and closure. Geoenvironmental models based on characteristics of modern-style mine wastes present a means of quantitatively comparing, at least in a relative sense, the environmental challenges associated with specific ore deposit types in terms of acid generation, and ecosystem and human-health threats associated with metals and related compounds. Acid-base accounting and various leaching protocols normalized to relevant environmental standards are useful in this regard. However, variations in behavior due to climate must be evaluated on a local or regional basis.

During exploration, geoenvironmental models highlight those deposit types that may pose significant challenges for acid generation or potential threats to surrounding ecosystems or humans related to metals or related constituents, the mitigation of which will affect profitability. During permitting, models can focus attention on the highest priority issues most likely to be associated with a deposit type (acid generation, potentially toxic elements in various media such as ground water, surface, and dusts), and place less-likely concerns in an appropriate perspective. During production, they can identify emerging challenges related to hypogene or supergene zonation in ore bodies, or to differences in mining or ore-processing methods. During closure, geoenvironmental models provide a global perspective on pre-mining background conditions, which are useful in establishing realistic closure goals, as well as highlight specific remediation challenges.