reza khaloo kakaie

One of the most critical designs in open-pit mining is the ultimate pit limit (UPL). The UPL is frequently computed initially through profit-maximizing algorithms like the Lerchs-Grossman (LG). Then, in order to optimize net present value (NPV), production planning is executed for the blocks that fall within the designated pit limit. This paper presents a mathematical model of the UPL with NPV maximization, enabling simultaneous determination of the UPL and long-term production planning. Model behavior is nonlinear. Thus, in order to achieve model linearization, the model has been partitioned into two linear sub-problems. The procedure facilitates the model solution and the strategy by decreasing the number of decision variables. Naturally, the model is NP-Hard. As a result, in order to address the issue, the Dynamic Pit Tracker (DPT) heuristic algorithm was devised, accepting economic block models as input. A comparison is made between the economic values and positional weights of blocks throughout the steps in order to identify the most appropriate block. The outcomes of the mathematical model, LG, and Latorre-Golosinski (LAGO) algorithms were assessed in relation to the DPT on a two-dimensional block model. Comparative analysis revealed that the UPLs generated by these algorithms are consistent in this instance. Utilizing the new algorithm to determine UPL for a 3D block model revealed that the final pit profit matched LG UPL by 97.95%.

The ventilation design of mines is based on fluid dynamics. Air is the main fluid in mining ventilation. This fluid is analyzed by two models: incompressibility and compressibility. The air-fluid in the compressibility model is examined in two models of dry and wet air along with thermal analysis. This paper argues that a number of presented parameters in the common thermodynamic analysis of mine ventilation should be modified. Accordingly, issues of the Earth's true gravity acceleration, potential energy difference, the specific heat capacity of air at constant pressure and volume, enthalpy difference of air, the average volumetric mass of dry air, and the amount of output moisture are rechecked. Therefore, a new method is presented in this paper for correcting thermodynamic equations in mine ventilation design. The name of this method is the Complete Model of Wet Air Analysis (CMWAA method). The results of this paper show that the CMWAA method can accurately perform thermodynamic analysis of air-fluid in mine ventilation without requiring a specified evaporation rate in mine networks, with minimal iteration of calculations.

Ventilation network design is done in manual and computerized methods. Computerized method is based on mathematical approximate methods. Several algorithms were presented in mathematical approximate methods for analyzing of water distribution and ventilation networks. Hardy Cross method is the most commonly model of mathematical approximate method for analyzing of ventilation networks in mine. For faster convergence to at the final result of Hardy Cross method were presented other models such as Wang model, conflation model and Newtonian models (First, third and sixteenth). In this paper is performed an initial review of Hardy Cross method and its modified models. Then first, third, and sixteenth modified models of Newtonian are presented for more accurate analysis of ventilation networks in mines. Finally, second conflation model will be presented as the fastest modified model of Hardy Cross method to achieve at the final result.

Production scheduling is the most important and influential issue in open pit and underground mining design and planning. The main purpose of mine production planning is time scheduling and determination of mine activities sequencing under some technical and extraction constraints in order to achieve one of the following goals: maximizing Net Present Value (NPV), the amount of ore extraction or mine life. Underground mine planning optimization which is used to determine the sequence of stopes extraction, is difficult due to the complexity of decision making and the interaction between existing constraints. Since, mathematical programming techniques are capable for solving complex and multi-limiting problems, they can be used for optimization purposes. In this study, after reviewing previous studies on the design and planning of underground mine production, the step by step explanation of a proposed model based on Integer Programming (IP) has been addressed. In order to validate proposed model, an example of 9 stopes was considered. First, the sequence of extraction was carried out using manual design and then using extended mathematical model in GAMS/CPLEX software. The current NPV obtained by manual production scheduling was 8.211 million dollars. While, this value for mathematical model was 8.331 million dollars. In other words, NPV value in mathematical model was 1.46% higher than manual method which indicate the power of mathematical programming for solving complex problems.

Determining the limit of underground mining and stope layout is one of the most important points in underground mining and production planning. Numerous algorithms have been offered to address the stope layout optimization problem both in two-dimensional and three-dimensional space based on economic value. In this paper, a new heuristic algorithm with different strategies was developed to generate optimal and sub-optimal underground stope layouts. In this algorithm, all possible stopes were created based on an entirely economic block model considering stope dimensions in the three-dimensional space. Afterward, the algorithm generated a family of non-overlapping stopes over all possible stopes and selected the highest economic value as the final solution.  Also, a user-friendly computer program named Stope Layout Optimizer (SLO3D) was designed in C# object-oriented program, and two separate examples were set for a better understanding of the algorithm. The application of the proposed computer program was implemented on a real copper deposit, considering three different strategies. The final output consisted of 29 stopes with a value of US$ 37 million. The results proved that the new heuristic algorithm was able to increase the final economic value by 49.04% compared to the floating stope method. Furthermore, the three proposed strategies were investigated for the same deposit. The results of this procedure illustrated that the probabilistic approach could generate higher economic values and sub-optimal values compared with the other two strategies discussed in previous studies regarding this issue.

One of the factors affecting overbreak or slough of the roof and walls of underground stopes, causing unplanned dilution is blast vibration. The amount of damage caused by earth vibration can be measured in terms of peak particle velocity (PPV). In this study, in order to investigate the effects of blast vibration on the occurrence of unplanned dilution, 72 three-component records acquired upon 24 blasts were obtained at underground Venarch Manganese Mines. Once finished with data analysis, scale distance was used to propose an exponential equation for predicting PPV based on the cubic root of the charge weight per delay. Then, the effect of blast vibration on walls and roof of the stope was examined on 24 different explosions, dilution values were recorded at various scaled distances to the face, and the relationship between them was determined. Equivalent linear overbreak/slough (ELOS) was used to determine dilution, with cavity monitoring system (CMS) being used to calculate it. Then a practical diagram was presented to predict the boundary of the dilution area from the explosion. Finally, The relationship between the amount of ELOS against the PPV was presented and it was determined if the PPV was fewer than or equal to 6.73 mm / s, the dilution will not occur.

In underground stopes, unplanned dilution occurs due to the overbreak and slough of walls and roof and consequently contamination of ore with wastes. This phenomenon not only leads to a reduction in the grade and, consequently costing to deficit grade, but also leads to the cost for mining the waste. Hence, the measurement of the amount of overbreak and slough of roof and walls of stopes in order to determine the unplanned dilution and, consequently, the study of the economic effects of it, is very important in underground mining. In this paper, using the cavity monitoring system (CMS), the effects of unplanned dilution on reduction of grade and increase in the cost of mining and reduction in the profit investigated. For this purpose, by defining the linear equivalent of overbreak and slough (ELOS) for the dilution, the system was implemented on 24 stopes of Venarch Manganese Mines and led to the discovery of the relations between the overbreak and dilution parameters and the economic parameters, including prediction relationship of the loss of profit. Results of data analysis indicate that the break-even of over break is in the 2.18 (m) that results 67.38% dilution.