Rock Bursts...History.. I believe it is very important to incorporate as much historic mining activity data when it comes to a significant investment of any entity...in this case we must realize that the Seismic Activity that involved historic rock bursts took place at much deeper depths from where they are presently mining at the Macassa Mine.
Please review the following information that is posted on their website...note the region that they continued to work despite the rock bursts that took place. This area is presently where they are mining at this time namely, the South Mine Complex (SMC Zone)...it was determined safe back then and is considered to be safe today.
The first shaft was the 500-foot Elliot shaft that was developed in the Main Break Zone in the late 1920’s. Mining was unsuccessful and operations halted. In 1931, development westward onto Macassa ground from the 2475-foot level of the Kirkland Lake Gold Mine discovered ore on the Main Break for 700 feet along strike and in subsidiary hangingwall veins. These underground workings were connected with the 3100 foot No.1 shaft, and later by two winzes to greater depths. The No. 1 winze connected the 3000-foot to 4625-foot levels and the No. 2 winze the 4625 to 6875 levels. The No. 2 shaft was sunk from surface to a depth of 4625 feet about 1000 feet southwest of the No. 1 shaft. In 1986, the No. 3 shaft was sunk from surface (in what had been Tegren ground) to the 7050-foot level and then to a final level of 7225 feet. Until the mid 1990’s this was the deepest single-lift shaft in the Western Hemisphere. The No. 3 shaft was the most recent access shaft, and gave access to 21 levels from 3800 feet to the 7050-foot level until 1997. As a result of a rock burst on April 12, 1997, only the levels between the 4250 and 5150 levels remained active. Exploration development was underway on the 3800 foot level when production was halted in 1999. Rehabilitation of levels down to the 5700’ level was in progress prior to closure.
As always...the final decision is our own...I believe that the risks are minimal at this time. Historic and present day mining activity support this conclusion.
Digger144