There are many deposits that have the potential to be mined by a combined method of open-pit and ... more There are many deposits that have the potential to be mined by a combined method of open-pit and underground. In this manner, the most sensitive problem is the determination of the optimal transition depth from open-pit to underground or vice versa. To calculate this depth, a model based on block economic values of open-pit and underground methods together with the Net Present Value (NPV) attained through mining is first presented. During the model, NPV of open-pit is compared to the value of underground for the similar levels. A hypothetical example is used in order to analyze the model in detail. Based on the assumptions made such as: a discount rate of 15 %, each pair of contiguous level-cuts have to mine during one year, and one level as the height of crown pillar, the optimal transition depth was determined to be equal to 62.5 m. Then, level 6 was considered as the suitable crown pillar. Finally, maximum total NPV of the combined mining was calculated to be 25.54 units of currency.
In this paper, a relationship between dependant parameters and
the crown pillar thickness is firs... more In this paper, a relationship between dependant parameters and the crown pillar thickness is first introduced. This relationship defines geotechnical problems caused by thin pillars and economic considerations created by pillars that are thicker than the optimum size. For this purpose, a dimensional analysis as an effective physico-mathematical tool was used. This technique restructures the original dimensional variables of a problem into a set of dimensionless products using the constraints imposed upon them by their dimensions. A model is hence introduced that calculates the optimum pillar thickness. The relationship introduced here and the method applied can be used by mining engineers in all situations where a combined open-pit and block caving method is deemed to be the most appropriate mining method.
Selection of the optimum support system for underground openings such as tunnels is a complex pro... more Selection of the optimum support system for underground openings such as tunnels is a complex process. In this paper, a new approach, based on a combination of the Analytical Hierarchy Process (AHP), the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and the Preference Ranking Organization METHod for Enrichment Evaluations (PROMETHEE) is introduced. For this purpose, the selection process is assumed to be a multi criteria decision-making problem. First, different support systems by using FLAC 3D numerical code, based on technical, safety and stability parameters of the tunnel are specified. Then, taking economic and performance parameters as the decision criteria, by using the combination of AHP, TOPSIS, and PROMETHEE, the optimum support system is selected. As a real mine case study, this approach is used in the main access entry to C 1 coal seam of Tabas collieries. Results clearly demonstrate that the proposed support system selection method is advantageo...
The underground spaces and particular tunnels have special place in mining and civil projects. . ... more The underground spaces and particular tunnels have special place in mining and civil projects. . Of 5000 years ago to now use of various methods and tools, for tunneling. At last age Tunnel Boring Machines utilize currently in massive scale in underground construction, tunneling both in civil construction and the mining industry. The reason for TBM price is expensive, its suitable choice has to be important. In any project correct appoint of TBM parameters is to be determine include power, cutter head velocity… . In this paper first presentation two methods for design of TBM technical parameters (Norway Rock Mechanic Institute and Colorado School of Mine) and to make us this methods for analyze of Karaj- Tehran tunnel TBMs .This tunnel is to length of 16000 meter and diameter of 4.566 meter and excavation by double shield TBM. Aim of apply this tunnel is transport of 350 million m3 per years water of Amirkabir dam to Tehran number 6 purificatory. Analyze of two methods results and c...
Productivity and profitability have been previously noticeable subjects for classic economists. N... more Productivity and profitability have been previously noticeable subjects for classic economists. Nowadays, optimization and productivity are main challenges of industry and development. It is estimated that drinkable water consumption in Tehran city will increase during the next 25 years. In order to decrease probable crisis and to prevent lack of water in the future, many projects have been designed and executed. Karaj-Tehran water supply tunnel is a sample of these projects. In this paper, optimum advance rate will calculate through economical view and productivity. Optimum advance rate is calculated for Hara Co (Contractor) according to fix and variable costs. In the conclusion, it was observed that slope of the cost graph is nearly horizontal and the advance rate is between 1200 to 1500 meters per month. Therefore, decrease in graph and also productivity increases by means of advance rate are not noticeable. According to current advancement of the tunnel, (average 400 meters per ...
The most initial investment in longwall face equipping is the cost of powered support. Selection ... more The most initial investment in longwall face equipping is the cost of powered support. Selection of proper shields for powered supports is based on load, geometric characterization of coal seams and economical considerations.
There are many deposits that have the potential to be mined by a combined method of open-pit and ... more There are many deposits that have the potential to be mined by a combined method of open-pit and underground. In this manner, the most sensitive problem is the determination of the optimal transition depth from open-pit to underground or vice versa. To calculate this depth, a model based on block economic values of open-pit and underground methods together with the Net Present Value (NPV) attained through mining is first presented. During the model, NPV of open-pit is compared to the value of underground for the similar levels. A hypothetical example is used in order to analyze the model in detail. Based on the assumptions made such as: a discount rate of 15 %, each pair of contiguous level-cuts have to mine during one year, and one level as the height of crown pillar, the optimal transition depth was determined to be equal to 62.5 m. Then, level 6 was considered as the suitable crown pillar. Finally, maximum total NPV of the combined mining was calculated to be 25.54 units of currency.
In this paper, a relationship between dependant parameters and
the crown pillar thickness is firs... more In this paper, a relationship between dependant parameters and the crown pillar thickness is first introduced. This relationship defines geotechnical problems caused by thin pillars and economic considerations created by pillars that are thicker than the optimum size. For this purpose, a dimensional analysis as an effective physico-mathematical tool was used. This technique restructures the original dimensional variables of a problem into a set of dimensionless products using the constraints imposed upon them by their dimensions. A model is hence introduced that calculates the optimum pillar thickness. The relationship introduced here and the method applied can be used by mining engineers in all situations where a combined open-pit and block caving method is deemed to be the most appropriate mining method.
Selection of the optimum support system for underground openings such as tunnels is a complex pro... more Selection of the optimum support system for underground openings such as tunnels is a complex process. In this paper, a new approach, based on a combination of the Analytical Hierarchy Process (AHP), the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and the Preference Ranking Organization METHod for Enrichment Evaluations (PROMETHEE) is introduced. For this purpose, the selection process is assumed to be a multi criteria decision-making problem. First, different support systems by using FLAC 3D numerical code, based on technical, safety and stability parameters of the tunnel are specified. Then, taking economic and performance parameters as the decision criteria, by using the combination of AHP, TOPSIS, and PROMETHEE, the optimum support system is selected. As a real mine case study, this approach is used in the main access entry to C 1 coal seam of Tabas collieries. Results clearly demonstrate that the proposed support system selection method is advantageo...
The underground spaces and particular tunnels have special place in mining and civil projects. . ... more The underground spaces and particular tunnels have special place in mining and civil projects. . Of 5000 years ago to now use of various methods and tools, for tunneling. At last age Tunnel Boring Machines utilize currently in massive scale in underground construction, tunneling both in civil construction and the mining industry. The reason for TBM price is expensive, its suitable choice has to be important. In any project correct appoint of TBM parameters is to be determine include power, cutter head velocity… . In this paper first presentation two methods for design of TBM technical parameters (Norway Rock Mechanic Institute and Colorado School of Mine) and to make us this methods for analyze of Karaj- Tehran tunnel TBMs .This tunnel is to length of 16000 meter and diameter of 4.566 meter and excavation by double shield TBM. Aim of apply this tunnel is transport of 350 million m3 per years water of Amirkabir dam to Tehran number 6 purificatory. Analyze of two methods results and c...
Productivity and profitability have been previously noticeable subjects for classic economists. N... more Productivity and profitability have been previously noticeable subjects for classic economists. Nowadays, optimization and productivity are main challenges of industry and development. It is estimated that drinkable water consumption in Tehran city will increase during the next 25 years. In order to decrease probable crisis and to prevent lack of water in the future, many projects have been designed and executed. Karaj-Tehran water supply tunnel is a sample of these projects. In this paper, optimum advance rate will calculate through economical view and productivity. Optimum advance rate is calculated for Hara Co (Contractor) according to fix and variable costs. In the conclusion, it was observed that slope of the cost graph is nearly horizontal and the advance rate is between 1200 to 1500 meters per month. Therefore, decrease in graph and also productivity increases by means of advance rate are not noticeable. According to current advancement of the tunnel, (average 400 meters per ...
The most initial investment in longwall face equipping is the cost of powered support. Selection ... more The most initial investment in longwall face equipping is the cost of powered support. Selection of proper shields for powered supports is based on load, geometric characterization of coal seams and economical considerations.
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Papers by Kazem Oraee
the crown pillar thickness is first introduced. This relationship
defines geotechnical problems caused by thin pillars and economic considerations created by pillars that are thicker than the optimum size. For this purpose, a dimensional analysis as an effective physico-mathematical tool was used. This technique restructures the original dimensional variables of a problem into a set of dimensionless products using the constraints imposed upon them by their dimensions. A model is hence introduced that calculates the optimum pillar thickness. The relationship introduced here and the method applied can be used by mining engineers in all situations where a combined open-pit and block caving method is deemed to be the most appropriate mining method.
the crown pillar thickness is first introduced. This relationship
defines geotechnical problems caused by thin pillars and economic considerations created by pillars that are thicker than the optimum size. For this purpose, a dimensional analysis as an effective physico-mathematical tool was used. This technique restructures the original dimensional variables of a problem into a set of dimensionless products using the constraints imposed upon them by their dimensions. A model is hence introduced that calculates the optimum pillar thickness. The relationship introduced here and the method applied can be used by mining engineers in all situations where a combined open-pit and block caving method is deemed to be the most appropriate mining method.