Minerals Recovery of Copper Mine Tailings on Lake Superior Coastline for use as Raw Material in the Manufacture of Roofing Shingles

Over the past 150 years, copper mining in the Keweenaw Peninsula of Michigan has resulted in the accumulation of approximately 1/2 gigaton of tailing piles. These wastes occur in a number of forms on the uplands and in the lakes and waterways. Today these tailings are drifting along the lakeshore and affecting the beauty of the otherwise pristine coastline of Lake Superior, depreciating the value of the land and hindering development efforts. Lesktech Limited, in alliance with the Institute of Materials Processing (IMP) at Michigan Technological University, will beneficiate the copper mine tailings known as “stamp sands” into a value-added product, G-Sand™, for use as a head lap granule in the manufacturing of roofing shingles. Lesktech Limited is NOT addressing the copper smelting slag stamp sands that were identified as an EPA Superfund Site in the Torch Lake area. At the present time, mining of hard rock for the roofing granule market is occurring; however, production cannot meet the total market demand required to adequately supply roofing shingle manufacturing companies. It is estimated that the energy demands for the grinding and processing to produce granules at the appropriate sizes exceed $6.00/ton. The stamp sand materials are already crushed to this particle size, leading to an overall energy savings of $600,000.00 USD per 100,000 tons of material utilized while benefiting the environment by removing an undesirable product from the shorelines of Lake Superior. In addition, granule manufacturers add copper as an algae deterrent to their roofing granule particles; this can be a costly application. The basalt rock stamp sands have a minute amount of naturally occurring metallic copper within the rock matrix. Initial studies by IMP have qualitatively proved that the basaltic stamp sand exhibits algae deterrence. Further investigation is needed and is within the scope of this proposed project. Lesktech’s mission is to identify a substantial amount of the basalt rock stamp sand suitable to serve the roofing granule market. Along with the research efforts of IMP, Lesktech will approach the research departments of the major granule roofing shingle companies and form strategic alliances to produce a synergetic effect that will offer these companies an avenue by which to fulfill their increasing demand for a quality granule product.