Grantee Research Project Results

Final Report: Minerals Recovery of Copper Mine Tailings on Lake Superior Coastline for Use as Raw Material in the Manufacture of Roofing Shingles

EPA Contract Number: EPD07034
Title: Minerals Recovery of Copper Mine Tailings on Lake Superior Coastline for Use as Raw Material in the Manufacture of Roofing Shingles
Investigators: Popko, Domenic
Small Business: Lesktech Limited
EPA Contact: Richards, April
Phase: I
Project Period: March 1, 2007 through August 31, 2007
Project Amount: $68,959
RFA: Small Business Innovation Research (SBIR) - Phase I (2007) RFA Text |  Recipients Lists
Research Category: SBIR - Water and Wastewater , Small Business Innovation Research (SBIR) , SBIR - Cleanup of Contaminated Sediments

Description:

Over the past 150 years, copper mining in the Keweenaw Peninsula of Michigan has resulted in the accumulation of approximately 500 million tons of tailing piles. This waste occurs both on the uplands and in the lakes and waterways, and occurs in a number of forms. 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), Michigan Technological University (MTU), will benefit 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.

At the present time, there is mining of hard rock for the roofing granule market ; 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 required grinding and processing for producing granules at the appropriate sizes exceeds $6.00/ton. The stamp sand materials are already crushed to this particle size creating an overall energy savings of $600,000.00 (U.S. dollars) per 100,000 tons of material used, while benefiting the environment by reducing CO₂ emissions and 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, which is a costly application. The basalt rock stamp- sands have a minute amount of naturally occurring metallic copper with the rock matrix.

It is Lesktech’s mission, along with the research excellence of IMP, to identify a substantial amount of the basalt rock stamp sand suitable to serve the roofing granule market. Together 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 affect that will present these companies with an avenue to fulfill the increasing demand for a quality granule product.

Summary/Accomplishments (Outputs/Outcomes):

During our course of study, Lesktech and MTU researchers have completed quantitative volume inventory of the G-sand™ material along with a comprehensive chemical and material characterization analysis of the potential roofing granule product. The host rock from which the G-sand™ occurs is a basalt, which is Precambrian in age. Mineralogical and chemical studies have verified that the stamp sands are primarily basaltic, and basalt is the favorite material for roof granule production.

Conclusions:

Properties that are important for roof granule applications have been evaluated. These properties include density, hardness, moisture content, and oil absorption. The results show that stamp sand can meet all of the commercial specifications.

Eighty percent of the G-sand™ material can be used with minimal processing to fit the size requirements necessary for a lap top roofing shingle granule, while 20 percent reports to fines less than 40 mesh. Therefore, the processing of stamp sands to meet the industrial needs can be achieved with a simple screening process. An air classification method also has been investigated. It was found that the screening process can be substituted with air classification for further cost reduction.

Halo tests have been conducted to verify if the stamp sands really have an anti bacterial property. Three bacteria species were tested: Staphylococcus aureus, Kleblsiella pneumonia, and E. coli. All of them were found inhibited by the stamp sands. This shows that the unique elemental copper bearing in the stamp sand can perform the same function as the coated copper from the roof granules.

Shipping costs can be a major part of the overall cost. A logistic study has been carried out, which found that shipping large volume amounts of materials is by far the most efficient when using Great Lake shipping vessels or barge compartmental vessels. The market study shows that the overall cost is very competitive.

The Phase I study concludes that it is feasible to use the stamp sands for roof granule applications from technical, economical, and environmental aspects.

Supplemental Keywords:

small business, SBIR, stamp sand, roofing shingles, basalt rock, algae deterrent, Lake Superior, contaminated sediments,, Sustainable Industry/Business, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Technology for Sustainable Environment, pollution prevention, Sustainable Environment, Environmental Engineering, acid mine waste treatment and reuse, roof shingles, metal recovery, copper mine tailings, cleaner production, clean manufacturing, environmental technology

SBIR Phase II:

Minerals Recovery of Copper Stamp Sand on Lake Superior Coastline for Use as Raw Material in the Manufacture of Roofing Shingles  | Final Report