Cold temperatures and biting winds have not prevented Minerals Processing Corporation (MPC) from working on their Back 40 mineral exploration project west of Stephenson. According to MPC, the Back 40 project is in a data collection and compilation phase. Currently, a team of MPC field technicians is in the process of gathering information on land they either own or have permission to access. The intent is to expand the exploration database that the company uses to locate potential areas of mineralization in the rocks below.

“Most of the work right now involves surveying lines through the woods and measuring out evenly spaced points, or stations, along those lines. Geophysical readings are then taken at each station,” explains Bob Mahin, Senior Geologist for MPC.

The geophysical readings involve the use of sophisticated equipment that measures the gravitational field at each station. According to Mahin, “Different kinds of bedrock can subtly affect the gravity readings. After we collect and compile the data, we try to deduce what the subsurface geology is like based on the changes in the geophysical readings.”

Since there is virtually no outcropping bedrock in the area that MPC is exploring, they have to resort to indirect methods such as this to try and determine what kind of rocks are hidden below. In addition to measuring the gravity, the field crew may use different equipment to measure the magnetism or the conductivity of the bedrock--all of which the geologists are hoping will provide clues to the location of buried mineralization.

For example, a pod of mineralization that is much denser than the surrounding bedrock can result in a measurable increase in the gravitational field directly over it. Other geophysical data might indicate the presence of a concentration of conductive or magnetic mineralization that could be an ore body. “Think of it as high tech water witching,” comments Mahin.

“The only way to know what’s down there for sure is to drill a test hole, but drilling is very expensive,” adds Mahin. “The geophysical data helps us narrow down our drill targets.”

Minerals Processing Corporation intends to continue to a next phase of exploratory drilling after they have completed the geophysical surveys.