A gravity survey of four (4) boreholes situated on the margin of the massive sulphide ore zone at Lalor is proposed. The boreholes are located close to HudBay Mining and Smelting Co (HBMS) Lalor Mine site and are accessible through a drill road. The boreholes are approximately 300 to 950 m from the main mine road, a wide and well-maintained gravel road (Figure 2).
The exploration boreholes for the downhole gravity survey were drilled in 2011 and intersect hard crystalline rocks. These are open holes (un-cased) except over a thin unconsolidated overburden interval (about 5 m) near the surface. The diameter of the boreholes is NQ size (2.98 inch). The boreholes reach depths between 1500 to 1700 m. The boreholes are steep (85 degrees) near the surface and dip about 75 degrees at their deepest points. The main zone of interest is a discontinuity located at a depth of range of 800 – 1300 m.
The Contractor shall provide all of the necessary facilities, equipment, materials, competent and experienced crew to collect and deliver high quality borehole gravity measurements in a time-efficient manner.
