MINE PLANNING - BASIC CONSIDERATIONS
S.Narayana Moorthy

Some important steps to remember while carrying out an evaluation program either for a fresh area or an existing working mine are listed below for ready reference.

Choice to be determined as priority:

          a. Mining cost
          b. Lengthening of mine life
          c. Flexibility in mining
          d. OR a combination of all

Deposit 
Classification of the deposit
Transparency of the deposit
complexity of the deposit 
Predictability of the run-off-mine quality

Reserves:
Classification of the reserves
Borehole density and degree of quality fluctuations 
Reliability of classification
Cavities and core losses Structural deformity.
Controls on Borehole locations
Cross sections with borehole dispositions linking chemical analysis and litho logs Individual bore logs with histograms

Analysis:
Sections and slice plans.
Evaluation Trend displays
Run-off-mine quality fluctuations 
Deviation of projected quality from the actual mined
Shape and volume of mineable zone 
Optimal blending and recovery parameters.
Planning Statistical analysis of the entire data
Frequency distribution Variogram models
Correlation between various parameters.

Correlation and fixation:
Quarry scheduling and optimization packages. 
Existing Mines
Preparations Sample from quarry face
Strip samples from trenches Core drilling
Vertical Penetration 
Facilities for continuous chemical analysis
Thin sections and particle size of mineral constituents 
Topographical maps
Borehole logs and chemical analysis.
Evaluation Geological profile
Plausibility check and interpretation 
Set values and standard ratios
Geological model and quarrying data bank 

Planning:
Plotting of deposit boundaries
Design of relevant boundaries Corrected interpolation
Considerations Block size determination
Sections and average quality parameters 
Breaking down production units
Mechanization-type/number-capacity Data
Chemical Mineralogical
Physical Cross correlations 
spatial correlation with variograms
Statistical distribution of variables (to arrive at indications of whether and where additional samples are required and establishing a new drilling grid).

Remember:

Variograms express how grades differ on average according to the distance in a distinct direction. If samples are lying closer, squared differences is small- they are strongly correlated- if they are far apart they are hardly correlated. Variograms express a simple error estimation.
Point of volume between samples - Point kreiging and likewise block kreiging.

Action:

Deposit is to be divided into blocks of the size of a production unit. Desired production levels/control factors for the mineral and means of extraction are to be worked out.
Local factors play a major role and need to be taken seriously. The guidelines only serves the purpose of guiding. Peculiarities and specific conditions are to be considered before deciding any working parameter. As far as possible each deposit is to be taken in isolation and planning restricted to work that particular deposit unless there is a contiguous working.