Developing a resource evaluation and mine plan for three sand-and-gravel operations.

Project Details

Hilltop Basic Resource


Dayton, Ohio

RESPEC was hired by Hilltop Basic Resources to develop a resource evaluation and mine plan for three Dayton, Ohio, sand-and-gravel operations that the company wanted to divest.

The resource evaluation of the sand-and-gravel operations in Fairborn, Enon, and West Carrollton, Ohio, consisted of several components, including a bathymetric survey of each of the 19 lakes. Using a depth sounder combined with GPS, this survey provided the input data for the three-dimensional modeling of the pit floor.

The historic drilling data at the sites were limited to shallow drilling (approximately 40 feet maximum) to the top of a clay horizon. Additional data review indicated the presence of substantial reserves at depth. RESPEC supervised the sonic drilling of 20 drillholes, which confirmed the extent of the reserves and the presence of two clay horizons. Modeling of the sand-and-gravel reserves was conducted for each pond and for ultimate lakes, and the results were presented for each reserve category.

Using the resource data, various mining approaches were developed to extract the reserves at depth and to reduce operating costs. Based on the review of approaches, the use of a clam-shell dredge was the preferred alternative because it had low operating costs, could extract the reserves at depth, and could mine through the clay horizons. To verify the ability to mine through clay, RESPEC reviewed seven European sand-and-gravel operations that were consistently mining clay.

After the reports were completed, RESPEC assisted Hilltop Basic Resources in presenting the information to interested buyers at a series of briefings. The divestiture process was successfully completed when Colas purchased the three properties.