Method, apparatus and computer program for scheduling the extraction of a resource and for determining the net present value of an extraction schedule

A computer program for scheduling the extraction of a resource within a medium comprising:

• code for receiving drillhole grade data relating to the resource contained within the medium;
• code for creating a plurality of different block models, each formed of a plurality of blocks, each block in each model having a resource grade, each of the block models honouring the drillhole grade data;
• and
• code for scheduling extraction of blocks based on a cut-off grade policy to increase expected net present value having regard to all of the block models.

A method of mining a mine comprising a resource within a medium, the method comprising:

• removing medium and resource from the mine using an extraction schedule created by the following steps;
• obtaining drillhole grade data relating to the resource contained within the medium;
• creating a plurality of different block models, each formed of a plurality of blocks, each block in each model having a resource grade, each of the block models honouring the drillhole grade data;
• and
• scheduling extraction of blocks based on a cut-off grade policy to increase expected net present value having regard to all of the block models.

A method of determining the net present value of a mine comprising a resource within a medium, the method comprising the steps of:

• obtaining drillhole grade data relating to the resource contained within the medium;
• creating a plurality of different block models, each formed of a plurality of blocks, each block in each model having a resource grade, each of the block models honouring the drillhole grade data;
• and
• scheduling extraction of blocks based on a cut-off grade policy to provide the net present value having regard to all of the block models.

A method for scheduling the extraction of a resource contained within a medium, comprising the steps of:

• obtaining drillhole grade data relating to the resource contained within the medium;
• creating a block model with each block in the model having a resource grade;
• scheduling extraction of blocks based on a variable cut-off grade value to increase expected net present value, the variable cut-off grade being represented by a non-linear function;
• and
• converting the non-linear representation to a linear representation and using a mixed integer programming formulation for a simultaneous optimisation of an extraction sequence provided by the scheduled extraction and cut-off grade policy.

An apparatus for scheduling the extraction of a resource contained within a medium, comprising:

• a processor for receiving drillhole grade data relating to the resource contained within the medium;
• a processor for creating a block model with each block in the model having a resource grade;
• a processor for scheduling extraction of blocks based on a variable cut-off grade value to increase expected net present value, the variable cut-off grade being represented by a non-linear function;
• and
• a processor for converting the non-linear representation to a linear representation and using a mixed integer programming formulation for a simultaneous optimisation of an extraction sequence provided by the scheduled extraction and cut-off grade policy.

A computer program for scheduling the extraction of a resource contained within a medium, comprising the steps of:

• code for receiving drillhole grade data relating to the resource contained within the medium;
• code for creating a block model with each block in the model having a resource grade;
• code for scheduling extraction of blocks based on a variable cut-off grade value to increase expected net present value, the variable cut-off grade being represented by a non-linear function;
• and
• code for converting the non-linear representation to a linear representation and using a mixed integer programming formulation for a simultaneous optimisation of an extraction sequence provided by the scheduled extraction and cut-off grade policy.