It is my privilege and great pleasure to introduce Dean Rossell as this year's Goldich Medal recipient. Dean has been an ILSG contributor and stalwart attendee of its meetings and field trips since his student days many years ago. Dean grew up in Minneapolis, and graduated from the University of Minnesota-Duluth in 1979, studying under some of the early recipients of the Goldich Medal (Ralph Marsden, Dick Ojakangas, and John Green). Immediately after graduation he got a temporary job in Nevada, and that summer, by tracing boulders up dry washes, was the co-discoverer of what soon thereafter became the Trout Creek barite mine. But he promptly returned to the Lake Superior region, graduating from Michigan Technical University in 1983, studying under the aegis of another Goldich medalist, Ted Bornhorst. His M.Sc. thesis was entitled "Alteration of the Deer Lake Peridotite in the Vicinity of the Ropes Mine, Marquette County, Michigan." This grew out of his summer student work at that old gold mine, which Callahan Mining Corp. was putting back into production after nearly a century of abandonment. After graduating from MTU, he spent the next seven years as an exploration geologist for Resource Exploration, Inc. out of Marquette, working for Bill Bodwell. His wife Karen also worked in the Resource Exploration office in those days as a draftsperson. Dean himself never spent much time in the office, though. His work for clients during this period included: re-logging all drill core and re-interpreting the Keweenawan Western Syncline sediment-hosted chalcocite deposit, Michigan; mapping, sampling and drilling VMS base metal and shear zone-hosted gold targets in the Archean Ramsay-Lake Gogebic greenstone belt, Michigan; initiating and carrying out field exploration and drilling on numerous grassroots-developed gold targets in the Archean greenstones and felsic intrusives of the Virginia Horn, Minnesota; and drilling for platinum group elements near the Reserve Mining property in the Duluth Complex, Minnesota. In short, he came up the old fashioned way, doing the field work in numerous exploration programs, mapping, sampling and drilling rocks around the Lake Superior region.
Beginning in 1991 Dean worked as a contract geologist for Kennecott Exploration Company out of Crystal Falls, Michigan, initially doing mapping and field sampling in the search for Proterozoic sedex base metal deposits. It was during this time that he alertly found a nickel-copper sulfide-bearing boulder in a logging roadcut that led to a complete change in direction of that program. A few months later, he was the first to discover nickel-copper mineralization in the BIC layered mafic intrusion, and he strongly advocated an investigation of the Yellow Dog peridotite.
In 1995 Dean gained permanent status with Kennecott and carried on with his tireless and imaginative efforts to explore for base metals in Keweenawan Rift-related terranes on both sides of the border. His investigations eventually led to the discovery of the Eagle nickel-copper-PGE deposit at the Yellow Dog peridotite in 2002, the result of a nearly single-handed effort on his part. This very high grade Michigan deposit has now received its permits for underground mining, and promises to be an important contributor to the economy of the Upper Peninsula.
In the early days of 21st Century exploration for nickel-copper in the Black Sturgeon district of Ontario, he acquired and tested one of the known ultramafic intrusions (Kitto), and tested others in elsewhere in Ontario that he is still not authorized to talk about. He carried his ideas into Minnesota, leading Kennecott to search for mineralization in buried ultramafic intrusions in the Animikie Basin. Again with the imagination and persistence that are his hallmarks, this work eventually led to discovery of the Tamarack deposit in Carlton County, Minnesota. Several years of drilling turned up only anomalous Ni-Cu values at Tamarack, but Dean's careful persistence eventually paid off with Kennecott's announcement in June 2008 of a long drill intercept of very high grade nickel-copper. This deposit is currently being intensively evaluated by Kennecott, and Tamarack has the promise of being a larger version of the Eagle deposit in Michigan.
Dean and his family are now based in Salt Lake City, but he still doesn't spend much time in the office. That's not where the rocks are. He has been to nearly every part of the world where one can see the right rocks. In fact, his title in Kennecott's Project Generation Group is "Global Nickel Specialist", and he's now internationally regarded as an expert on exploration for ultramafic-hosted Ni-Cu-PGE deposits. Despite the competitive secrecy that surrounds such efforts, Dean has shared his expertise and knowledge with others in the geologic community when able. As is the case with most company geologists, Dean has had to be restrained in publishing his work, but has made the scientific aspects of it known at ILSG meetings: Duluth, 2004 (Eagle deposit presentation and abstract), Nipigon 2005 (Eagle deposit poster session). He also published on the Eagle deposit at the AIME-SEG meeting in Salt Lake City in 2005 (presentation and abstract), and prepared and led the field trip to the BIC intrusion at the Marquette ILSG in 2008. He has also contributed more indirectly, getting Kennecott to provide access and thesis research funds for graduate students studying the geology of the Eagle and Tamarack deposits, and he has been an important supporter of student involvement in the ILSG. Although his base is now in Utah, he still spends most of his time in the Lake Superior region, something not likely to change anytime soon.
Dean Rossell is a standout in the ranks of exploration geologists: a real minefinder, and one who gives back to the community of his peers (especially the ILSG community), as well. Please join me in congratulating Dean as the 2011 recipient of the Goldich Medal of the Institute on Lake Superior Geology.
Doug Duskin, April, 2011