During the period of the mid-1980s Molycorp, a subsidiary of Union Oil Company, also known as Unocal, was pursuing base metal exploration in Montana targeting molybdenum targets. The work brought the Molycorp geologists to Neihart, Montana as there exists a substantial molybdenum deposit to the north of Neihart called the Big Ben Deposit, and the geologists were looking for evidence of porphyry style deposits in the historic Neihart District.
The Molycorp explorationists eventually concluded that gold and silver was a better target in the district than molybdenum and came up with the following three possible target scenarios for finding gold-silver mineralization in the Big Seven area:
- Historic high grade and underground vein deposit targets.
- Contact zones between the Precambrian rocks (gneiss & diorite) and the Neihart quartzite where substantial thicknesses of high-grade ore can be expected based on past mining records.
- A disseminated veinlet target in the quartzites is described as when the veins pass beneath the quartzite, and it is inferred that they would shatter and break the overlying quartzite passing upwards to form a large tonnage, low grade disseminated gold-silver deposit. This inferred geological hypothesis is backed by mine records which show drifts passing into the quartzite with 0.1 to 0.25 opt gold and 5 to 25 opt silver.
The USGS publication titled “Geology of the Little Belt Mountains, Montana,” by W.H. Weed, written in 1900, some eighty years earlier, also described these targets, and reinforced the postulations being made by the Molycorp geologists. The combination of scenarios 2 and 3 became a target of high interest to Molycorp as this target postulated an open pit reserve with mine-grade mineralization.
However, despite the strong recommendations of the geologists in charge on the ground to move ahead with the project, the upper management of Molycorp felt the gold-silver target strayed too far from the mission of searching for base metals with a focus on finding molybdenum. Thus, the detailed exploration plans of the geologists were not carried out and the property has remained idle for most of the years since that time.