QUESTION :- 1
Design Problem: An ore body dips at 70° and has a vertical depth of 140m. The top of the ore body is 180m from the surface and surface mining operations have been discarded in favour of underground operations. The strike length of the deposit is 850m. The ore body varies from 8m to 20m and averages 15m. Grades are as follows:
Lead = 10% (90% recovery)
Zinc =15% (85% recovery)
Silver =120 g/t (60% recovery)
Gold =2 g/t (50% recovery)
What is the total ore resource in tonnes, assume an SG of 3.6, and what is it worth at today's metal prices in A$?
Using sub-level open stoping and two main levels with footwall drives and drawpoints show a plan and sections of your mine. A 20m crown pillar will be left below the top main level. Stopes will be 45m long with 15m long pillars (along strike).
All development to production stage must be shown. How much ore will be produced from development?
Note: to calculate the worth of an ore body recovery must be considered. Recovery as quoted in the above figures means mill recovery.
QUESTION :- 2: You are required to report on an operating medium to large underground mining operation.
Included in your report should be all or most of the items listed below:
Production Methods Development Requirements Plans and Sections
Rock Breakage Loading and Hauling Equipment Personnel
Ground Control
Production Costs (if available) Ventilation
Occupational Health and Safety
Power supply and power sources employed Drainage
Environmental Issues
Any other relevant information
Background information may include a brief description of geology, location, history etc., but do not pad this section out. Other sections may include a brief overview of the mineral processing plant, other surface facilities, overland transport etc.
Your report must be typed and finished in a professional manner with all references acknowledged, and bear in mind that a report such as this would not be complete without drawings, sketches, etc.