A short-term production planning model for dimension stone quarries

In this paper, problem of short-term production planning for dimension stone quarries was mathematically modeled using a binary integer programming. The model includes an objective function, which was founded as the minimization of the costs due to the total cutting planes of the blocks. This objective may cause to maximization of the net present value (NPV) in dimension stone quarries. During the mathematical modeling the essential constraints are dimension stone quarry capacities and the market demand, block accessibility for the equipment and the reserve constraints. As a base, an optimal size and shape of extractable blocks should be first assigned according to the available extraction technique and the market demand, in order to create a geological block model. Then an economical block model is provided by assignment of a value of "one" for ore blocks and "zero2 for waste. Maximum profitability and minimum amount of the ore wastage can be gained using this plan and modeling

Roof falls: An inherent risk in underground coal mining

The occurrence of rock falls in underground coal mines entails detrimental effects as fatal or non-fatal injuries on workers, stoppages in mining operations and breakdown of equipment. In this paper, a risk assessment approach on the basis of a decision analysis trend is employed in order to assess the possibility of and manage roof falls. Risk is then assessed by determination of likelihood of occurrence and the cost of consequences (outcomes). In this regard, collected real roof fall data from Tabas and Kerman coal regions comprising of several underground coal mines are used. It is concluded that the annual accidents due to the roof falls occurrence in the all investigated mines are so high that it is economically feasible to improve the support systems and to implement a suitable educational program as well as an accurate supervision and other elements of safety management

An approach towards ascertaining open-pit to underground transition depth

In this study, in order to determine OP to Ug mining TD of tabulate deposits, through various states some formulas were concluded. These formulas resulted based on the allowable and overall stripping ratios. For this objective, an analytical procedure was served. The contemplated states are variously combined from the deposits with outcrops or overburden and including maximum or minimum possible pit floor width

Determination of the Optimum Crown Pillar Thickness Between Open Pit and Block Caving

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

Assessment of risks of tunneling project in Iran using artificial bee colony algorithm

The soft computing techniques have been widely applied to model and analyze the complex and uncertain problems. This paper aims to develop a novel model for the risk assessment of tunneling projects using artificial bee colony algorithm. To this end, the risk of the second part of the Emamzade Hashem tunnel was assessed and analyzed in seven sections after testing geotechnical characteristics. Five geotechnical and hydrological properties of study zone are considered for the clustering of geological units in front of tunneling project including length of tunnel, uniaxial compressive strength, rock mass rating, tunneling index Q, density and underground water condition. These sections were classified in two low-risk and high-risk groups based on their geotechnical characteristics and using clustering technique. It was resulted that three sections with lithologies Durood Formation, Mobarak Formation, and Ruteh Formation are placed in the high risk group and the other sections with lithologies Baroot Formation, Elika Formation, Dacite tuff of Eocene, and Shear Tuff, and Lava Eocene are placed in the low risk group. In addition, the underground water condition and density with 0.722 and 1 Euclidean distances have the highest and lowest impacts in the high risk group, respectively. Therefore, comparing the obtained results of modelling and actual excavation data demonstrated that this technique can be applied as a powerful tool for modeling risks of tunnel and underground constructions

Mining method selection and transition depth determination problems - which one is in priority of consideration?

During this paper, in order to identify the priority of consideration between the problems of “mining method selection” and “determining transition depth from open-pit to underground mining” an accurate procedure is introduced step by step. First, it is essential to specify if an ore deposit that potentially will have mined by a combined method of open-pit and underground mining. In this case, optimal final open-pit limit and depth must be initially determined. After that, if the rest of deposit below open-pit limit is economically considerable, it is necessary to select the most adequate underground method with emphasis on the high production rate and low cost methods. Then, it is necessary to determine optimal transition depth from open-pit to underground mining considering a crown pillar immediately below open-pit mining. Finally, the procedure with its algorithm was used for an iron ore deposit with the combined mining potential

Applying an integrated fuzzy gray MCDM approach: A case study on mineral processing plant site selection

The accurate selection of a processing plant site can result in decreasing total mining cost. This problem can be solved by multi-criteria decision-making (MCDM) methods. This research introduces a new approach by integrating fuzzy AHP and gray MCDM methods to solve all decision-making problems. The approach is applied in the case of a copper mine area. The critical criteria are considered adjacency to the crusher, adjacency to tailing dam, adjacency to a power source, distance from blasting sources, the availability of sufficient land, and safety against floods. After studying the mine map, six feasible alternatives are prioritized using the integrated approach. Results indicated that sites A, B, and E take the first three ranks. The separate results of fuzzy AHP and gray MCDM confirm that alternatives A and B have the first two ranks. Moreover, the field investigations approved the results obtained by the approach

Effective Factors Investigation in Choice Between Surface and Underground Mining

Under similar conditions, surface mining is generally regarded to be more advantageous than underground mining. In the selection between surface and underground exploitation methods, there are a number of most significant factors must be briefly studied and determined. In this study, these factors were extensively studied and then considering effect of these factors on surface and underground mining, a comparison was done

A Model for Determining Optimal Transition Depth over from Open-Pit to Underground Mining

In this paper, the authors consider to the deposits which have potential for exploiting initially by Open Pit (OP) method, and as it is proved to greater depths, the pit is planned to transfer to Underground (Ug) mining methods. The most significant problem connecting to the deposits is determination of optimal Transition Depth (TD) from OP to Ug mining. Here, a heuristic algorithm as a basic model based on Block Economic Value (BEV)s of OP and Ug was represented. Initial part in the model is, recognizing mineable main blocks of 50*50 m due to the both mining methods and comparison between sum of OP and Ug main block values in each main level from upper to lower, respectively. To increase accuracy and capacity of the model, the final main level of OP is imperative to separate to sub-levels and related sub-blocks of 12.5*12.5 m. The performed stages of the algorithm for main levels and blocks must be supplied for the sub-levels and sub-blocks, too. To state the model in detail, it was employed as a tool for determining the optimal transition depth and total profit in the combined method of OP and Ug for a hypothetical deposit

Wybór metody wybierania oraz optymalizacja przejścia od kopalni odkrywkowych do podziemnych w podejściu mieszanym

There are occasionally deposits with a potential of exploiting by a combined mining of open pit and underground. Hence, the most significant query emerges: where is the optimal transition depth from open pit to underground? In this study, in order to profitably select a single or combined mining of open pit and underground, as well as to determine optimal transition depth a methodology is presented. The model is established upon the economical block models of open pit and underground methods together with the Net Present Value (NPV)s gained by their mining. Main process in the model is economical comparison among several options of single and combined mining. To evaluate the model in detail, a hypothetical case is used. In this regard, among the all options a combined was selected that implying a height of 62.5 m as the optimal transition depth and the amount of 25.54 units of currency as the maximum total NPV achieved by the option