Conducting field investigations and inventorying abandoned underground and surface-mining features associated with the Horse Creek Limestone Mine.

Project Details

Wyoming Department of Environmental Quality, Abandoned Mine Lands Division

2002 - 2011

Near Cheyenne, Wyoming


RESPEC was selected by the state of Wyoming Department of Environmental Quality, Abandoned Mine Lands Division to investigate and evaluate mining features associated with the Horse Creek Limestone Mine. This multiphased project began in 2002 and was completed in 2011.

In Phase 1, RESPEC engineers evaluated over 20,000 linear feet of underground workings and over 10,000 linear feet of surface-cut highwall that were accessible to the public and posed significant safety risks. The investigation and evaluation encompassed historic mining activity over a strike length of over 4 miles, with 178 features identified, prioritized for closure, and presented in a Report of Investigation to the state of Wyoming in January 2003. The work at Horse Creek also included landowner consents and clearances, a determination of eligibility for funding, a threatened-and-endangered species survey, an analysis of historic mining activity, and cultural resource surveys.

Of the 178 features inventoried, 22 were classified as extreme hazards and 12 were classified as severe hazards. RESPEC developed a hazard ranking system that considered feature conditions, accessibility, visibility, and potential consequences. RESPEC recommended the closure of all features that were classified as extreme and severe hazards in addition to 23 features with safety concerns. The state of Wyoming accepted these recommendations and retained RESPEC to produce plans and specifications for closure design.

Features designated for closure were grouped into logical construction packages that resulted in a phased approach to design and construction. Plans and specifications for the first phase were finalized and accepted by the state of Wyoming in October 2003. These plans and specifications formed the bid package that focused on the closure of underground mine workings planned for 2004. RESPEC successfully promoted a very competitive bidding process that attracted several major construction companies that specialize in underground work, and assisted the state of Wyoming in the contractor prequalification process. RESPEC was retained by the state of Wyoming to perform construction management at Horse Creek.

In Phase 2, RESPEC oversaw the work of contractors who were building access roads and filling slot mines. In Phase 3, RESPEC oversaw the closure of mine openings.