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The effect of various geomechanical uncertainties on the stability of open pit slopes was investigated using a Monte Carlo simulation. The results are illustrated with a case study on the Sungun copper mine in Azerbaijan province, north-west Iran. The slopes generated when the geomechanical variables were randomly distributed were markedly different to those generated without those uncertaintities., The effect of various geomechanical uncertainties on the stability of open pit slopes was investigated using a Monte Carlo simulation. The results are illustrated with a case study on the Sungun copper mine in Azerbaijan province, north-west Iran. The slopes generated when the geomechanical variables were randomly distributed were markedly different to those generated without those uncertaintities.

The economical lifetime of open pit mines is defined based upon block dimensions. The mine life is determined based on reserve geometry and size plus economical and fiscal parameters. The O'Hara cost estimator method was used to calculate capital and operating costs. Correlating drill hole diameter and bucket capacity with bench (block) height made it possible to define capital and operating costs based on block height. Using the database of exploratory drilling for the Chador Malu iron ore mine (Iran), a range of commercial reserves was determined by changing block size. Consequently, a model was developed to predict commercial reserves for each dimension of block. The optimum mine life is calculated in order to equalise mining costs and revenue. The results show that among dimensions of a block, block height is the most effective parameter on mine life. However mine life increases less than one year by doubling the block height., The economical lifetime of open pit mines is defined based upon block dimensions. The mine life is determined based on reserve geometry and size plus economical and fiscal parameters. The O'Hara cost estimator method was used to calculate capital and operating costs. Correlating drill hole diameter and bucket capacity with bench (block) height made it possible to define capital and operating costs based on block height. Using the database of exploratory drilling for the Chador Malu iron ore mine (Iran), a range of commercial reserves was determined by changing block size. Consequently, a model was developed to predict commercial reserves for each dimension of block. The optimum mine life is calculated in order to equalise mining costs and revenue. The results show that among dimensions of a block, block height is the most effective parameter on mine life. However mine life increases less than one year by doubling the block height.

A site-specific vibration propagation law with the highest correlation coefficients was developed based on measurements of 64 blasts carried out at the Sungun open-cast mine in Iran, taking into account peak particle velocity, distance and maximum charge per delay. The upper 95% prediction line was also established for controlled blasting design in relation to both normal and lognormal distributions. The normal distribution gave the more conservative results. Attenuation relationships were developed for two different rock zones to study the role of each zone in the attenuation. Frequency analysis of the events showed that they were quite low at less than 15 Hz, indicating a higher risk of resonance and damage to buildings due to the low particle velocity. Analysis of the data based on US Bureau of Mines and Office of Surface Mining Reclamation and Enforcement norms indicated that there was no risk of damage as a result of the blasts fired., A site-specific vibration propagation law with the highest correlation coefficients was developed based on measurements of 64 blasts carried out at the Sungun open-cast mine in Iran, taking into account peak particle velocity, distance and maximum charge per delay. The upper 95% prediction line was also established for controlled blasting design in relation to both normal and lognormal distributions. The normal distribution gave the more conservative results. Attenuation relationships were developed for two different rock zones to study the role of each zone in the attenuation. Frequency analysis of the events showed that they were quite low at less than 15 Hz, indicating a higher risk of resonance and damage to buildings due to the low particle velocity. Analysis of the data based on US Bureau of Mines and Office of Surface Mining Reclamation and Enforcement norms indicated that there was no risk of damage as a result of the blasts fired.

Flyrock distances were measured for 15 blasts at the Esfordi phosphate mine in Iran and the effects of the specific charge, burden, stemming length and powder factor were analysed. Multiple and polynomial regression analysis of the data was carried out to develop a predictive model for the flyrock distance. A power function regression model showed the best agreement with measured data. An empirical formula is presented for predicting the flyrock distance., Flyrock distances were measured for 15 blasts at the Esfordi phosphate mine in Iran and the effects of the specific charge, burden, stemming length and powder factor were analysed. Multiple and polynomial regression analysis of the data was carried out to develop a predictive model for the flyrock distance. A power function regression model showed the best agreement with measured data. An empirical formula is presented for predicting the flyrock distance.

Two maximum flow methods, Dinic’s algorithm and the Push-Relabel algorithm, were used to determine the optimum pit limit of the Gol-e-Gohar open-cast number 2 iron ore mine in Iran. Factors such as the characteristics of the mine and the orebody, including wall slope and sulphur and phosphorus grade restrictions, were investigated. The result showed that these properties have a significant effect on the determined pit limit. Construction of the network is the essential step in determining the pit limit using maximum flow theory. Each network consists of nodes and arcs. A pit slope of 45 degrees was selected based on geotechnical considerations. Arcs were generated to produce the pit slope and to show the technical constrains. The arc generation pattern was produced using the minimum search pattern method and guaranteed a wall slope of approximately 45 degrees. After constructing the network the algorithms were used to determine the final pit limits. The pit produced by the two methods was the same, but the run time for the Push-Relabel algorithm was faster. The effect of the time-related value of money in the determination of the final pit was investigated. The block extraction sequence was first calculated using NPV-S software taking into account blend optimisation to restrict the amount of sulphur and phosphorus and to generate the highest quality product. The sequence showed the time required for the extraction of each block and was used to calculate the discounted value of each block. The results showed that the new number 2 pit would be smaller and would be inside the number 1 pit. Pit 1 contains 8 222 ore blocks and pit 2 8 200 ore blocks. The total number of blocks in pits 1 and 2 were 61 861 and 60 864, respectively, and the tonnage difference between the two pits was about 3 000 000 t., Two maximum flow methods, Dinic’s algorithm and the Push-Relabel algorithm, were used to determine the optimum pit limit of the Gol-e-Gohar open-cast number 2 iron ore mine in Iran. Factors such as the characteristics of the mine and the orebody, including wall slope and sulphur and phosphorus grade restrictions, were investigated. The result showed that these properties have a significant effect on the determined pit limit. Construction of the network is the essential step in determining the pit limit using maximum flow theory. Each network consists of nodes and arcs. A pit slope of 45 degrees was selected based on geotechnical considerations. Arcs were generated to produce the pit slope and to show the technical constrains. The arc generation pattern was produced using the minimum search pattern method and guaranteed a wall slope of approximately 45 degrees. After constructing the network the algorithms were used to determine the final pit limits. The pit produced by the two methods was the same, but the run time for the Push-Relabel algorithm was faster. The effect of the time-related value of money in the determination of the final pit was investigated. The block extraction sequence was first calculated using NPV-S software taking into account blend optimisation to restrict the amount of sulphur and phosphorus and to generate the highest quality product. The sequence showed the time required for the extraction of each block and was used to calculate the discounted value of each block. The results showed that the new number 2 pit would be smaller and would be inside the number 1 pit. Pit 1 contains 8 222 ore blocks and pit 2 8 200 ore blocks. The total number of blocks in pits 1 and 2 were 61 861 and 60 864, respectively, and the tonnage difference between the two pits was about 3 000 000 t.

A mathematical model based on a non-linear programming problem was developed for loading and haulage equipment selection in open-pit mines. The model provides equipment selection optimisation as part of production scheduling based on minimising cost. The main objective is to provide assistance in the selection of the correct size and number of equipment units. The model integrates capital and operating cost in an objective function, and incorporates constraints related to shovel and truck annual productivity, fleet matching and number of trucks per shovel. The model was verified in studies carried out at the number 2 anomaly at the Gol-e- Gohar iron ore mine in Iran where the optimum mining fleet was determined to be 45 trucks with a capacity of 22 t and 6 shovels with a capacity of 2 m3., A mathematical model based on a non-linear programming problem was developed for loading and haulage equipment selection in open-pit mines. The model provides equipment selection optimisation as part of production scheduling based on minimising cost. The main objective is to provide assistance in the selection of the correct size and number of equipment units. The model integrates capital and operating cost in an objective function, and incorporates constraints related to shovel and truck annual productivity, fleet matching and number of trucks per shovel. The model was verified in studies carried out at the number 2 anomaly at the Gol-e- Gohar iron ore mine in Iran where the optimum mining fleet was determined to be 45 trucks with a capacity of 22 t and 6 shovels with a capacity of 2 m3.

The approach to selecting a dump site uses the integration of multiattribute decision-making (MADM) methods. Different MADM methods often produce different outcomes, so to make the best decision for dump site selection, the results of both subjective and objective MADM methods must be considered. The objective approaches select weights through mathematical calculation, which neglects subjective judgment information of the decision makers. Since either subjective approaches or objective approaches have their advantages and disadvantages, an integrated method seems more desirable in determining the appropriate dump site. The ranking of alternatives by combining the results of these methods was implemented in selecting a waste dump site for Sungun copper mine in Iran. With this approach, it is possible to analyse systematically the specific selection criteria and to select the best place with more accuracy., The approach to selecting a dump site uses the integration of multiattribute decision-making (MADM) methods. Different MADM methods often produce different outcomes, so to make the best decision for dump site selection, the results of both subjective and objective MADM methods must be considered. The objective approaches select weights through mathematical calculation, which neglects subjective judgment information of the decision makers. Since either subjective approaches or objective approaches have their advantages and disadvantages, an integrated method seems more desirable in determining the appropriate dump site. The ranking of alternatives by combining the results of these methods was implemented in selecting a waste dump site for Sungun copper mine in Iran. With this approach, it is possible to analyse systematically the specific selection criteria and to select the best place with more accuracy.

An attempt is made to model long-term production scheduling problems by chance-constrained binary-integer programming in a stochastic environment. The stochastic model is set up to account for ore block grade uncertainty. The probability distribution function of the grade in each block is used as a stochastic input to the optimisation model. This distribution function in each block should be determined using geostatistical simulation approach. The deterministic equivalent of the proposed chance-constrained model is then achieved in the form of a non- linear quadratic equation in binary variables. A confidence level, at which it is required that the uncertainty constraints hold, is specified in each scheduling period. Compared with the previous risk-based model, this formulation will yield schedules with a high chance of achieving planned production targets while simultaneously maximising the expectation of net present value and minimising the variance function. Using this method, grade uncertainty is integrated explicitly into the optimisation process., An attempt is made to model long-term production scheduling problems by chance-constrained binary-integer programming in a stochastic environment. The stochastic model is set up to account for ore block grade uncertainty. The probability distribution function of the grade in each block is used as a stochastic input to the optimisation model. This distribution function in each block should be determined using geostatistical simulation approach. The deterministic equivalent of the proposed chance-constrained model is then achieved in the form of a non- linear quadratic equation in binary variables. A confidence level, at which it is required that the uncertainty constraints hold, is specified in each scheduling period. Compared with the previous risk-based model, this formulation will yield schedules with a high chance of achieving planned production targets while simultaneously maximising the expectation of net present value and minimising the variance function. Using this method, grade uncertainty is integrated explicitly into the optimisation process.

The Gol-e-Gohar iron ore deposits are located in Kerman province, Iran. The No.2 deposit contains an estimated 42 000 000 tonnes of ore reserves, and is to be mined by a truck and shovel operation over a 14-year period. During this time 60 000 000 tonnes of overburden and 43 000 000 tonnes of waste will also have to be removed. A genetic algorithm was used to determine the optimum number of shovels required to remove the overburden, waste and ore. This was found to be two shovels of 8.25 m3 capacity, though a third shovel could be added to the fleet to allow for breakdowns and unpredicted ground conditions., The Gol-e-Gohar iron ore deposits are located in Kerman province, Iran. The No.2 deposit contains an estimated 42 000 000 tonnes of ore reserves, and is to be mined by a truck and shovel operation over a 14-year period. During this time 60 000 000 tonnes of overburden and 43 000 000 tonnes of waste will also have to be removed. A genetic algorithm was used to determine the optimum number of shovels required to remove the overburden, waste and ore. This was found to be two shovels of 8.25 m3 capacity, though a third shovel could be added to the fleet to allow for breakdowns and unpredicted ground conditions.

A parametric method is described which incorporates grade uncertainty in the push back design process. The important characteristics of the method are that high grade zones with low uncertainty are selected for extraction in earlier production periods, high grade zones with medium uncertainty may also be selected for extraction in earlier production periods, high-grade zones with high uncertainty are left to be extracted during the mid-life of the mine, low- to medium-grade zones with low uncertainty may also be extracted during the mid-life of the mine and low- to medium-grade zones with high uncertainty are left to be extracted towards the end of mine life. The number of push backs generated is greater than that using Whittle's method and the achievable, rather than theoretical, net present value is also higher., A parametric method is described which incorporates grade uncertainty in the push back design process. The important characteristics of the method are that high grade zones with low uncertainty are selected for extraction in earlier production periods, high grade zones with medium uncertainty may also be selected for extraction in earlier production periods, high-grade zones with high uncertainty are left to be extracted during the mid-life of the mine, low- to medium-grade zones with low uncertainty may also be extracted during the mid-life of the mine and low- to medium-grade zones with high uncertainty are left to be extracted towards the end of mine life. The number of push backs generated is greater than that using Whittle's method and the achievable, rather than theoretical, net present value is also higher.

The results of 2-D Lerchs-Grossmann optimisation were compared with the final pit limits under the mine's present expansion plan. Total reserves, based on information from all exploration stages and computed using the inverse distance weighting technique and DATAMINE software, are estimated at more than 1 290 000 000 tons grading 0.7134% Cu. More than 915 000 000 t can be mined under the Lerchs-Grossmann optimisation scheme, 7.5% more than under the present plan. The Lerchs-Grossmann cut-off grade was 0.254% Cu, compared with 0.25% Cu in the expansion plan., The results of 2-D Lerchs-Grossmann optimisation were compared with the final pit limits under the mine's present expansion plan. Total reserves, based on information from all exploration stages and computed using the inverse distance weighting technique and DATAMINE software, are estimated at more than 1 290 000 000 tons grading 0.7134% Cu. More than 915 000 000 t can be mined under the Lerchs-Grossmann optimisation scheme, 7.5% more than under the present plan. The Lerchs-Grossmann cut-off grade was 0.254% Cu, compared with 0.25% Cu in the expansion plan.

The physical parameters of blastholes for 27 blasting operations at three Iranian open-pit mines - Sarcheshmeh, Choghart and Chadermalloo - were collected in order to develop a mathematical model for predicting overbreaking. The parameters measured were blasthole diameter, burden, spacing, length of stemming, specific charge, delay time, energy transferred to rock, remaining energy and stiffness ratio. Multiple linear regression and SPSS8 software were used to establish a relationship between overbreak and blasthole parameters. A simple linear equation was developed and the model was tested at Sarcheshmeh copper mine and Choghart iron mine. The difference between measured and predicted overbreak was 9.5% for Sarcheshmeh and 16.5% for Choghart., The physical parameters of blastholes for 27 blasting operations at three Iranian open-pit mines - Sarcheshmeh, Choghart and Chadermalloo - were collected in order to develop a mathematical model for predicting overbreaking. The parameters measured were blasthole diameter, burden, spacing, length of stemming, specific charge, delay time, energy transferred to rock, remaining energy and stiffness ratio. Multiple linear regression and SPSS8 software were used to establish a relationship between overbreak and blasthole parameters. A simple linear equation was developed and the model was tested at Sarcheshmeh copper mine and Choghart iron mine. The difference between measured and predicted overbreak was 9.5% for Sarcheshmeh and 16.5% for Choghart.

To achieve 80 000 t/d production, analytical methods indicate that the mine requires 5 shovels with 9 m3 bucket capacity and 37 trucks of 120 ton box capacity, compared with the 5 shovels and 20 trucks operated at present. The use of linear programming methods to optimise the possible truck paths between shovels and dumps shows that 80 000 t/d production could be achieved using only 30 trucks. The semi-dispatching method would therefore maximise truck productivity and decrease maintenance and repair costs., To achieve 80 000 t/d production, analytical methods indicate that the mine requires 5 shovels with 9 m3 bucket capacity and 37 trucks of 120 ton box capacity, compared with the 5 shovels and 20 trucks operated at present. The use of linear programming methods to optimise the possible truck paths between shovels and dumps shows that 80 000 t/d production could be achieved using only 30 trucks. The semi-dispatching method would therefore maximise truck productivity and decrease maintenance and repair costs.

Since 1991, 5 500 m of exploration drilling has been carried out and 2 500 m of tunnels excavated in the deposit. Datamine software was used to estimate the total reserves. The ore limits were defined as a large block with 1 640 x 1 400 x 770 m dimensions and small blocks were set at 14 x 20 x 50 m. The average grade of each block was calculated using the inverse distance weighting method. Only 21 153 of the 126 280 blocks had an ore grade greater than the cut-off grade of 0.32% Cu, giving total estimated reserves of 740 000 000 t averaging 0.665% Cu., Since 1991, 5 500 m of exploration drilling has been carried out and 2 500 m of tunnels excavated in the deposit. Datamine software was used to estimate the total reserves. The ore limits were defined as a large block with 1 640 x 1 400 x 770 m dimensions and small blocks were set at 14 x 20 x 50 m. The average grade of each block was calculated using the inverse distance weighting method. Only 21 153 of the 126 280 blocks had an ore grade greater than the cut-off grade of 0.32% Cu, giving total estimated reserves of 740 000 000 t averaging 0.665% Cu.