Stages in the life of a Mine

Precursors to mining

1. Prospecting (Mineral defosit)

Procedure >> search for one

a. Prospecting methods

- Direct : physical, geologic

- Indirect : geophysical, geochemical

b. Locate favorable loci (maps, literature, old mine)

c. Air : aeral photography, airborne geophysics, satellite

d. Surface : ground geophysics, geology

e. Spot anomaly, analyze

2. Exploration (ore body )

Procedure >> Defining extent and value of ore examination/evaluation)

a. Sample (drilling or excavation), assay, test

b. Estimate tonnage and grade

c. Valuate deposit ( Hoskold formula or discount method):

Present value = income – cost

Feasibility study : make decision to abandon or develop

Mining Proper

3. Development (prospect)

Procedure >> Opening up ore deposit for production

a. Acquire mining right (purchase or lease). If not done in stage 2

b. File environmental impact statement, technology assessment, permit

c. Construct access roads, transport system

d. Locate surface plant

e. Excavate defosit (strip or sink shaft)

4. Exploitation (mine)

Procedure >> Large-scale production of ore

a. Factors in choice of method : geologic, geographic, economic, environmental, societal, safety

b. Types of mining methods

Surface : open pit, open cast, etc

Underground : room pillar, block caving, etc

c. Monitor costs and economic payback

Source : Introductory Mining Engineering” (Howart K Hartman, 1987).