EMP, BMP, OMG; What does it all mean? Featured

In 2015, LaPointe Iron Company and the United States Geological Survey entered into a cooperative study to investigate the presence and forms of amphibole minerals in the Ironwood Iron formation. About 1.1 billion years ago, the intrusion of the Mellen Complex produced conditions favorable to the creation of amphibole minerals, some of which might be fibrous or also known as elongated mineral particles (EMP). EMPs, if not properly managed, can produce environmental and health impacts

Samples from four drill cores and ten outcrop locations were collected over approximately 35 km of strike length. Samples were taken from each member of the iron formation present in the cores. X-ray diffraction, optical and scanning electron microscopy, and electron microprobe analysis were used to study the origin, distribution, morphology and chemistry of the amphiboles.

Most of the amphiboles were the result of contact metamorphism and decreased with distance from the contact. However, fibrous amphiboles were found in all cores.  The more distal isolated occurrences are believed to be related to localized dikes and sills.

Although only a limited set of samples were analyzed, the presence of these minerals highlights the importance of waste characterization early in the mine planning process and the development of best management and adaptive waste management plans (BMPs) to prevent and minimize particulate emissions to air and water from future mining operations.

Additional Info

  • Presenter(s) Eger, Paul . (Engineer, P.A.)