TMRC Announces Successful Completion of Geophysical Investigation in the Blackhawk Silver/Nickel/Cobalt Mining District, Identifies 16 Potential Drill Targets - Seite 2

All the historic mines in the Black Hawk district started on outcropping ore. The two principal mines -- the Black Hawk and the Alhambra -- are credited with $800,000 and $400,000 (at a silver price of approximately $0.90/oz) although both probably produced more before they closed in late 1893 after the U.S. Government demonetized silver. The Alhambra was briefly reopened in 1957 and again in 1974. Published data and firsthand accounts describe ore in place on all levels of the Alhambra. The Alhambra has been the source on much of the well-known “specimen rock” of this ore type that is traded by mineral collectors.

Historical descriptions of Alhambra mine ore describe the veins as being carbonate filled structures, typically two to three feet wide with a central high grade “core” varying from 1” to 18” thick containing 10% to 50% metallic silver. Individual ore shoots are lens shaped and range from small pods a few feet in diameter to bodies 50’x 70’in the plane of the vein. The potential of this mineral system can be judged by the fact that a single 50’ x 70’ ore lens with a 4” thick core zone of 20% silver could contain 538,688 oz, a value (at a nominal silver price of $25/oz) of over $13.4 million -- from an area a little larger than the size of a tennis court.

Published mine data suggests that in the upper levels of the Alhambra approximately 30% of the vein was mineralized.

Geophysical Investigation

The high metallic silver content within the “core zones” suggests that these lenses are possibly electrical conductors and may respond to electrical geophysical methods. If such an indirect technique could be developed, the high potential areas throughout the district could be identified and drilling costs could be much more targeted and effectively allocated. Based on this premise, TMRC contacted consulting geophysicists and Zonge International, a geophysical service provider, to investigate the possibility of designing a geophysical surveying to spatially locate these lenses.

An initial survey using conventional IP and resistivity was conducted; this survey identified several anomalous features, but it was decided that this technique was too “large scale” to achieve the desired results.

After further consultation it was decided that EM (electromagnetic) methods would provide the best possibility of success, due to the superior conductivity of silver. EM is a well-established and widely used technique to locate buried conductive bodies. Two types of EM are marketed by Zonge, one to explore for very large and deeply buried targets and another, called NANOTEM, used to locate shallow metallic features such as pipe, tanks and unexploded ordinance. The targets sought at Black Hawk fall in between the capability of these two applications. It was decided to modify the small scale TDEM method for our Black Hawk District survey.