Serving the Mining Community for Over 30 Years

MDA Staff
MDA Saff
Our Team Member

Neil Prenn, P.Eng.

Neil Prenn has over 45 years experience as a practicing Mining Engineer performing tasks associated with defining and calculating ore reserves, designing mines, optimizing mine designs, mine planning and scheduling, analyzing capital and operating costs, and managing staff. He has conducted feasibility and pre-feasibility studies and scoping studies. He has prepared technical reports for submission to security commissions and NI 43-101 reports as a Qualified Person. Mr. Prenn is Mine Development’s Principal Engineer. He has been with Mine Development since he founded the Company in 1987.

Mr. Prenn has worked with a wide variety of commodities including gold, silver, platinum group metals, copper, cobalt, base metals, limestone, mineral sands, aggregate, bauxite, silica, coal, uranium, and industrial minerals.

Mr. Prenn is a Registered Professional Engineer of Nevada and a Registered Member of Mining and Metallurgical Society of America.


Michael Gustin, PhD.

Michael Gustin has over 35 years experience in exploration and management throughout the Western U.S., Mexico, and the Guiana Shield.  Mr. Gustin has particular expertise in exploration management, project development, and field management and mapping.  Past experience has included target delineation and development, drilling supervision, and all aspects of field geology.  Mr. Gustin is Mine Development’s Senior Geologist and frequently serves as Project Manager, responsible for all aspects of a client’s project.  He has conducted many resource definition studies and has prepared technical reports for submission to security commissions.  He is classified as a “Qualified Person” for Canadian Securities Exchanges. He has been with Mine Development since 2003.

Mr. Gustin is a Certified Professional Geologist, American Institute of Professional Geologists and a Registered Professional Geologist: Washington and Utah.


Steven Ristorcelli, P.Geo.

Steve Ristorcelli has over 35 years experience in exploration and development.  His primary focus has been in deposit modeling, identifying and correcting sampling problems, and directing exploration programs.  He has performed numerous modeling and resource definition studies, including annual updates for projects in development and production and has prepared technical reports for submission to security commissions.  He is classified as a “Qualified Person” for Canadian Securities Exchanges.  Mr. Ristorcelli is Mine Development’s Principal Geologist and frequently serves as Project Manager, directing all work for a client’s scope of work.  He has been with Mine Development since 1992.

Mr. Ristorcelli has worked with a wide variety of commodities including gold, silver, copper, base metals, cobalt, limestone, aggregates, uranium and industrial minerals.

Mr. Ristorcelli is a Certified Professional Geologist, American Institute of Professional Geologists and a Registered Professional Geologist of California and Wyoming.


Thomas Dyer, P.E.

Tom Dyer has over 20 years experience as a practicing Mining Engineer performing essentially all tasks associated with an operating mine, more specifically the Cortez Gold Mine in Beowawe, Nevada and other Placer Dome properties.  His various duties included updating reserve and resource models, pit optimization projects, pit design, short-term and long-term planning, cost tracking, supervising surface and underground mine personnel and participating in the Mine’s Feasibility Study. Tom also has nearly 15 years experience working as a miner in a variety of underground and surface operations, operating a range of equipment in gold, limestone and coal mines.  Mr. Dyer is Mine Development’s Senior Engineer and is a Qualified Person as defined by Canadian NI43-101 regulations.  He has been with Mine Development since July 2007.

Mr. Dyer is a Registered Professional Engineer of Nevada and a Registered Member Society for Mining, Metallurgy and Exploration.


Paul Tietz, CPG

Paul Tietz has over 35 years experience in exploration and management throughout Western, Southeastern and Southern U.S. for precious metals and base metals. Mr. Tietz has particular expertise in exploration management and project development. Past experience has included target delineation and development, drilling supervision, and all aspects of field geology. Mr. Tietz is a Senior Geologist with Mine Development and conducts resource definition studies, including field advisement on exploration drilling QA/QC procedures. He is classified as a “Qualified Person” for Canadian Securities Exchanges. He worked as a consultant with Mine Development for most of 2006 and joined the staff at the end of the year.

Mr. Tietz is a Certified Professional Geologist, American Institute of Professional Geologists.