Jim Dowling - Mining Engineer

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SHAFT PLANNING

 

Self-evidently it cannot be moved, so the location of a new shaft must only be determined after the most exhaustive investigations. These include geology, surface features, topography and environmental constraints, and all possible future changes and contingencies.

 

 

Location of a shaft in relation to a dipping orebody

Location of a shaft in relation to a dipping orebody

 


Defining the shaft pillar in relation to a flat dipping orebody

Defining the shaft pillar in relation to a flat dipping orebody

 

Defining the shaft pillar in relation to a flat dipping orebody, Cross Section and Plan View

Defining the shaft pillar in relation to a flat dipping orebody, Cross Section and Plan View

 

 

Shaft pillar in relation to a dipping orebody

Shaft pillar in relation to a dipping orebody

 

 

Drift pillar protecting a drift when the reserve is flat dipping

Drift pillar protecting a drift when the reserve is flat dipping

 

 

Location of shafts – topographic effects

Location of shafts – topographic effects

 

 

Shaft cross sections

Shaft cross sections

 

 

SHAFT DEPTH

 

Given the high cost of shaft sinking, it is a mine planning question as to whether the shaft should be sunk to the bottom of the ore reserve in one operation, or to an intermediate position in the first instance, and further deepened at a later date. The mine in the next two sketches has 10 years of shallow production and 10 years of deep production. It is quite normal to have lower confidence in deep reserves and higher confidence in shallow reserves. The sketches only show indicative costs. Factors to consider in this situation are sinking cost, interest rates and reserve confidence.

 

 

Sinking to ultimate depth in Yr. 1, total cost, say, £100 million

Sinking to ultimate depth in Yr. 1, total cost, say, £100 million

 

 

Sinking in two stages, total cost, say, £150 million

Sinking in two stages, total cost, say, £150 million

 

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