MINEWD Process

To access this process:

See this process in the Command Table.

Process Overview

Creates LG 'Additional Arcs' for mining width.

The input file is a block model file containing the ore blocks of the main reef. In addition, it should have an OREVAL field which contains a value which is to be compared with the OREMIN parameter. The MINWID parameter defines the required minimum mining width; the WIDDIR parameter defines the bearing in degrees, clockwise from the positive Y-axis (North) along which the minimum mining width extension is to be made. For example, if the main reef lies North-West to South-East and dips towards the North-East, this parameter would be set to 45 degrees. The OREMIN parameter defines the minimum value of the field OREVAL for a cell to be treated as ore.

The input block model must be a regular model with no sub-cells.

This process generates a file of Lerchs-Grossmann structure arcs for input to LGST as 'Additional arcs' for the structure of a block model. These arcs have the effect of ensuring that a required minimum mining width is honoured at the bottom of the pit during the Lerchs-Grossmann optimization. This approach is only appropriate when the main reef meets all of these criteria:

  • Is thin compared with the minimum mining width.

  • Dips at angle which is steeper than the required mining slope.

  • Has a clearly defined strike d

By 'main reef' we mean a reef (ore body) which is mined at the full depth of the mine.

Other reefs may be mined as 'bonuses', and will be considered in the Lerchs-Grossmann optimization. It is necessary to decide on which side of the main reef the extra waste is to be removed to provide the necessary mining width.

Given this decision, MINEWD will set up structure arcs which cause strings of blocks of the length required to reach the minimum mining width to be treated by the optimization module as though they were one block. That is, either all blocks in a string are mined or none of them are mined. This ensures that the bottom of the pit is at least the minimum mining width across.  

Input Files

Name

Description

I/O Status

Required

Type

IN

Input model file containing the ore blocks of the main reef. This must be a regular model with no sub-cells.

Input

Yes

Undefined

Output Files

Name

I/O Status

Required

Type

Description

OUT

Output

Yes

Undefined

Output additional arcs file for input to LGST.

Fields

Name

Description

Source

Required

Type

Default

OREVAL

A field in the model file which contains a value which is to be compared with OREMIN.

Undefined

No

Undefined

Undefined

Parameters

Name

Description

Required

Default

Range

Values

MINWID

Minimum mining width.

Yes

Undefined

Undefined

Undefined

WIDDIR

Bearing in degrees clockwise from the postive Y-direction (North) along which the minimum mining width extension is to be made. e.g. If the main reef lies North-West to South-East and dips down towards the North-East, this might be 45 degrees.

Yes

North

Undefined

Undefined

OREMIN

Minimum value of field OREVAL for a cell to be treated as ore.

No

Undefined

Undefined

Undefined