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− Maximizing NPV of the project,
− Minimizing the risk of achieving production goals,
− Maximizing the life-of-mine.
These goals are somewhat contradictory, for example, a program with a maximum NPV
may not fit with a plan with a minimum risk; in this case, depending on the risk taking and
risk aversion of the designer, a program with a low risk and maximum benefit should be
considered for production. Constraints of long-term production Scheduling are as follows
(Steffen 1997):
− Minimum and maximum tonnage of ore that must be produced at any time interval.
− Minimum and maximum concentrates to be produced at any time interval.
− The minimum waste tonnage that must be extracted at any time interval in order to have
access to sufficient quantities of minable ore in the subsequent periods.
− The maximum number of benches from which extraction is carried out at any time
interval.
− The highest and the lowest benches from which extraction is carried out at any time
interval.
− Minimum and maximum qualitative parameters related to the mine final product.
− The minimum tonnage of the remaining ore at any time interval.
− The minimum remaining waste at any time interval.
− Slope angle constraint.
− Constraints of ore depos.
− Minimum pit floor width.
− Existence of underground mines or large underground spaces around open pit mines that
change the long-term production Scheduling.
− Existence of a waste dump or processing plant waste due to the mining activity that was
previously done in that area.
− Existence of transmission lines and roads around the mine.
3.2 Mid-term production scheduling
The length of the production Scheduling horizon varies from one to ten years. It is divided
into a range of one to six months, and is special in nature. The mid-term production scheduling (MTPS) are, in fact, the basis for short-term production scheduling (STPS) in mines.
The purpose of this plan is to predict production, cost, and revenue. The parameters to be
specified in the preparation of this plan are as follows (Steffen 1997):
− The production and operation of shovels and trucks and drilling equipment in one to six
months’ intervals.
− Grades, retrieval amount, and physical and chemical characteristics of blocks for shortterm Scheduling in later stages.
− Prediction of construction and preparation works required in subsequent years (such as
roads, opening of a new area of the mine, construction of a rinse lake).
− Waste dumps that should be used to accumulate waste in the future.
3.3 Short-term production scheduling
The length of the scheduling horizon in this case is less than one year and short-term plans
are prepared in intervals of one day to one month. Short-term scheduling objectives in mines
are (Steffen 1997):
− Providing blending requirements in terms of the quality of materials conveyed to the plant
at any time.
− Supplying the required blending site and processing plant to provide the required tonnage
for the processing plant.
− Maximizing NPV of the project,
− Minimizing the risk of achieving production goals,
− Maximizing the life-of-mine.
These goals are somewhat contradictory, for example, a program with a maximum NPV
may not fit with a plan with a minimum risk; in this case, depending on the risk taking and
risk aversion of the designer, a program with a low risk and maximum benefit should be
considered for production. Constraints of long-term production Scheduling are as follows
(Steffen 1997):
− Minimum and maximum tonnage of ore that must be produced at any time interval.
− Minimum and maximum concentrates to be produced at any time interval.
− The minimum waste tonnage that must be extracted at any time interval in order to have
access to sufficient quantities of minable ore in the subsequent periods.
− The maximum number of benches from which extraction is carried out at any time
interval.
− The highest and the lowest benches from which extraction is carried out at any time
interval.
− Minimum and maximum qualitative parameters related to the mine final product.
− The minimum tonnage of the remaining ore at any time interval.
− The minimum remaining waste at any time interval.
− Slope angle constraint.
− Constraints of ore depos.
− Minimum pit floor width.
− Existence of underground mines or large underground spaces around open pit mines that
change the long-term production Scheduling.
− Existence of a waste dump or processing plant waste due to the mining activity that was
previously done in that area.
− Existence of transmission lines and roads around the mine.
3.2 Mid-term production scheduling
The length of the production Scheduling horizon varies from one to ten years. It is divided
into a range of one to six months, and is special in nature. The mid-term production scheduling (MTPS) are, in fact, the basis for short-term production scheduling (STPS) in mines.
The purpose of this plan is to predict production, cost, and revenue. The parameters to be
specified in the preparation of this plan are as follows (Steffen 1997):
− The production and operation of shovels and trucks and drilling equipment in one to six
months’ intervals.
− Grades, retrieval amount, and physical and chemical characteristics of blocks for shortterm Scheduling in later stages.
− Prediction of construction and preparation works required in subsequent years (such as
roads, opening of a new area of the mine, construction of a rinse lake).
− Waste dumps that should be used to accumulate waste in the future.
3.3 Short-term production scheduling
The length of the scheduling horizon in this case is less than one year and short-term plans
are prepared in intervals of one day to one month. Short-term scheduling objectives in mines
are (Steffen 1997):
− Providing blending requirements in terms of the quality of materials conveyed to the plant
at any time.
− Supplying the required blending site and processing plant to provide the required tonnage
for the processing plant.