Yashar Pourrahimian

University of Alberta | UAlberta · Department of Civil and Environmental Engineering and the School of Mining and Petroleum Engineering

Production scheduling is one of the most important steps in the block-caving design process. Optimum production scheduling could add significant value to a mining project. The goal of long-term mine production scheduling is to determine the mining sequence, which optimizes the company’s strategic objectives while honouring the operational limitatio...

As a factory-like method, sublevel caving consists of development activities, stockpiling and production activities that are carried out on different levels independently. Therefore, considering the operation from the development phase to the plant will lead to more reliable production scheduling. This paper presents a mixed-integer linear programm...

Extraction and development sequences must be scheduled strategically in order to maximize the life of mine. The complexities and computational difficulties associated with underground mine planning makes it challenging and open to further research. This paper presents a mathematical programming framework based on mixed-integer linear programming (M...

Explosive energy usage when fragmenting a rock mass is a complicated phenomenon. It is highly influenced by the rock mass response to higher stresses, higher loading rates, and the presence of discontinuities. An approach is presented to analyze the effects of rock mass properties on explosive energy. It is divided into steps to estimate blast ener...

This year, we have prepared a report including 16 papers. We continue to update all the research results on the MOL webpage www.ualberta.ca/mol on the members section. Sponsors have access to current and past research results, publications, prototype software, and source code. Let’s review the contributions in the MOL Report Ten (2021/2022) by cons...

This paper presents the machine learning (ML) method, a novel approach that could be a profitable idea to optimize fleet management and achieve a sufficient output to reduce operational costs, by diminishing trucks’ queuing time and excavators’ idle time, based on the best selection of the fleet. The performance of this method was studied at the Ze...

The significant increase in data availability and high-computing power and innovations in real-time monitoring systems enable the technological transformation of the mining industry. Artificial Intelligence (AI) and data-driven methods are becoming appealing solutions to tackle different challenges in mining operations where an increasingly larger...

Despite the upward trend in using semi-mobile in-pit crushing and conveying system (SMIPCC), some mining companies still hesitate to use SMIPCC in their operations. Therefore, a framework is needed to facilitate decision-making between SMIPCC and truck and shovel system (TS) and satisfy the location and relocation time of the semi-mobile crusher (S...

This paper presents a methodology to integrate mineral resource uncertainty from scarce orebody sampling and material mixing uncertainty due to ore flow into the life-of-mine production scheduling of block caving mines. Geological uncertainty is integrated using a Sequential Gaussian Simulation workflow and material mixing uncertainty by simulating...

Production scheduling determines the most beneficial mining sequence over the life of a mine. Developing a schedule that meets all mining aspects can substantially reduce mining costs and increase profitability. Among all underground mining methods, the sublevel caving method is a common method with moderate development requirements, a high product...

Cemented rock fill (CRF) is commonly used in cut-and-fill stoping operations in underground mining. This allows for the maximum recovery of ore. Backfilling can improve stope stability in underground workings and then improve ground stability of the whole mine site. However, backfilling step scenarios vary from site to site. This paper presents the...

Cemented rock fill (CRF) is commonly used in cut-and-fill stoping operation in underground mining. This allows for the maximum recovery of ore. Backfilling can improve stope stability in underground workings, and then improve ground stability of the whole mine site. Backfilling step scenarios vary from site to site. This paper presents the investig...

In-pit crushing and conveying (IPCC) systems have drawn attention to the modern mining industry due to the numerous benefits than conventional truck-and-shovel systems. However, the implementation of the IPCC system can reduce mining flexibility and introduce additional mining sequence requirements. This paper investigates the long-term production...

This paper reviews the state-of-the-art in short-term underground mine planning, which is critical for future mining activities. According to the literature, the research is conducted in the categories of mathematical programming optimization and discrete event simulation. Mathematical programming aims at minimizing an objective with the functional...

The main objective of this study is to provide a practical and near-optimal mine production schedule for block caving operations considering operational uncertainty. The problem is defined in the context of goal programming optimization to meet the operational objectives, including tonnage and grade as daily production targets. The considered opera...

Block cave mining operations face challenges to meet daily operational production targets. The optimistic long-term and medium-term plans along with uncertainty and the synergistic effect of the mechanical and structural failures in operational levels of the mine cause a significant deviation from production plan targets. The on-site tuning of the...

In oil sands mining, bitumen and fines contents are used to predict ore processability. However, experimental results show that certain solid fractions known as Organic Rich Solids (ORS) negatively affect the overall bitumen recovery. A conceptual mine planning framework based on a goal programming model for oil sands production scheduling and wast...

The definition of caving economic limits is one of the initial steps in the planning and design of caving projects. This paper proposes a binary optimization framework to integrate the caving envelope and production schedule that maximizes the net present value of the project under technical constraints that model the caving operation mechanics. Th...

Rock mass fragmentation process plays a major role in the design of the block cave mining. To assess rock mass fragmentation, identification and determination of influencing parameters are crucial. In most case studies, the cross-impact or indirect interaction of influencing parameters has not been considered in the assessment of rock mass fragment...

The investigation of the dynamic response of the tunnels and structures under the acting of train vibrating load is significant for subway tunnels. In this paper, the intersection of Line 4 of Tehran subway with Tohid Tunnel is investigated using numerical modelling. Because these tunnels are excavated in the soil, the model is considered as a cont...

In mining projects, all uncertainties associated with a project must be considered to determine the feasibility study. Grade uncertainty is one of the major components of technical uncertainty that affects the variability of the project. Geostatistical simulation, as a reliable approach, is the most widely used method to quantify risk analysis to o...

Rockburst is a common engineering geological hazard. In order to evaluate rockburst liability in kimberlite at an underground diamond mine, a method combining generalized regression neural networks (GRNN) and fruit fly optimization algorithm (FOA) is employed. Based on two fundamental premises of rockburst occurrence, depth, σ θ , σ c , σ t , B 1 ,...

Rock mass fragmentation process plays a major role in the design of the block cave mining. To assess rock mass fragmentation, identification and determination of influencing parameters are crucial. In most case studies, the cross-impact or indirect interaction of influencing parameters has not been considered in the assessment of rock mass fragment...

In achieving maximum benefit in oil sands mining, the time and sequence of removing ore, dyke material and waste from the final pit limit is essential to the long-term production schedule. In-pit waste management strategy requires the simultaneous construction of dykes with the advancement of mining operations. This paper seeks to determine: 1) the...

High production rates and low operating costs highlight block caving as one of the favorable underground mining methods. However, the uncertainties involved in the material flow make it complicated to optimize the production schedule for such operations. In this paper, a stochastic mixed integer linear optimization model is proposed in order to cap...

Some production scheduling optimization models for block caving exist in the literature; however, few of them include the material flow and resulting dilution within the optimization model. In this paper, a 3D mixing methodology is proposed to be incorporated into the production schedule model. To capture horizontal and vertical mixing, different s...

Solving the stope boundary optimization problem is the primary step that should be taken after selecting an underground mining method. Obviously, this solution should be optimal because suboptimal boundaries may lead to wasting both mining capital and mineral resources. Four decades have passed since the first algorithm was developed to solve this...

Large-scale mining methods are commonplace in the mining industry, and caving has become the preferred underground mining technique. The use of block caving has increased worldwide and is expected to grow because of high production rates, low mining costs, and low waste production. One key engineering consideration in block caving is the drawpoint...

Production scheduling is one of the key steps in the decision-making process of any mining operation. In block caving, it is the choice of the amount of caved rock to extract from drawpoints in different periods. One of the main differences between block caving and other mining methods is the influence of the material flow on production, and draw c...

The selection of an elevation for the placement of the undercut level is a decisive initial step in the planning and design of block caving mines. It is key for the success of a caving project to define the undercut elevation that will most likely yield the highest possible net present value (NPV) of the operation, considering the discounting perio...

This year, we have prepared a report including 20 papers. We continue to update all the research results on the MOL webpage www.ualberta.ca/mol on the members section. Sponsors have access to current and past research results, publications, prototype software, and source code. Let’s review the contributions in the MOL Report Nine (2017/2018) by con...

This paper reviews the state-of-the-art in short-term underground mine planning, which is critical for future mining activities. According to the literature, the research is conducted in the categories of mathematical programming optimization and discrete event simulation. Mathematical programming aims at minimizing an objective with the functional...

Discrete event simulation is a simulation method has been used in forecasting and analysis the mining process and scheduling during last years. Discrete event simulation requires the pre-and post-processing of data and the results. In this paper, our focus is on pre-processing of data for simulation goal. Capturing the system behaviour and more pre...

Determining stope boundaries is one of the critical steps to be taken when an underground mining method is selected; because of their significant impact on the profitability of the mining project, the stope boundaries have to be optimum to achieve maximum profits. This paper introduces a new hybrid algorithm that is a combination of dynamic program...

The mining industry often uses shotcrete for ground stabilization. However, cracking within shotcrete is commonly observed, which delays production schedules and increases maintenance costs. A possible crack reduction method is using expansive shotcrete mixture consisting of calcium sulfoaluminate cement (CSA), ordinary Portland cement (OPC), and c...

The mining industry often uses shotcrete for ground stabilization. However, cracking within shotcrete is commonly observed, which delays production schedules and increases maintenance costs. A possible crack reduction method is using expansive shotcrete mixture consisting of calcium sulfoaluminate cement (CSA), ordinary Portland cement (OPC), and c...

Human factors (HFs) play an important role in the mining and mineral industry, affecting operational and maintenance efficiency and safety. Despite the introduction of new technologies and automation in this sector, it is well known that a significantly large proportion of total human errors occur during the operation and maintenance phase. A compr...

Planning of caving operations poses complexities in different areas such as safety, ground control and production scheduling. Draw control is fundamental to the success of block-cave operation. Although some complex theories and mathematical draw control systems have been applied in block-cave mines, most of them did not have an exact production ra...

Block-cave mining has become more popular in the last few years and the trend is expected to continue. The operating costs in this mining method could be as low as for open-pit mining; however, production scheduling for such an operation is complicated, mainly because of the production uncertainties resulted from the material flow. The material flo...

Planning of caving operations poses complexities in different areas such as safety, ground control, and production scheduling. Draw control is fundamental to the success of block-cave operation. Although some complex theories and mathematical draw control systems have been applied in block-cave mines, most of them did not have an exact production r...

The objective of this study is to investigate the role of different atmospheric temperature on the effectiveness of chemical suppressants to control mine haul road dust. In this study, water and selected chemical surfactants-salt, chloride free agents, polymers, and molasses-were tested experimentally for their dust retention efficiency under three...

Long-term planning is one of the most important stages that determines the distribution of cash flows over the mine life and the feasibility of the project. However, it is not feasible in block caving to generate a production schedule that will provide optimal operating strategies without considering geotechnical constraints. This paper develops a...

Block caving is a complex and large-scale mining method. The application of block caving is for low-grade, caveable and massive ore-bodies. Among the underground mining methods available, caving methods are favoured because of their low cost and high level of production. Generating a production schedule that will provide optimal operating strategie...

Among the underground mining methods available, caving methods are favoured because of their low cost and high production rates. Block caving operations offer a much smaller environmental footprint compared to equivalent open pit operations due to the much smaller volume of waste to be moved and handled. In general, draw control is fundamental to s...

The current trend of deeper and lower-grade deposits makes open pit mining less profitable. Mass mining alternatives have to be developed if mining at a similar rate is to be continued. Block cave mining is becoming an increasingly popular mass mining method, especially for large copper deposits currently being mined with open pit methods. After fi...

The economics of today's mining industry are such that the major mining companies are increasing the use of massive mining methods. Caving methods have become the underground bulk mining method of choice and are expected to continue as such in the foreseeable future. Caving methods are favoured because of their low cost and high production rates. T...

Human factors (HF) play an important role in the mining and mineral industry; affecting operational and maintenance efficiency, and safety. Fatalities and major accidents are not acceptable to the mining and mineral industry, and the role of HF and human errors (HE) can help with the goal of eliminating them. The human factor analysis and classific...

This year, we have prepared a report including 19 papers. We continue to update all the research results on the MOL webpage www.ualberta.ca/mol on the members section. Sponsors have access to current and past research results, publications, prototype software, and source code. Let’s review the contributions in the MOL Report Eight (2016/2017) by co...

Assessment of rock mass fragmentation is one of the most significant engineering design issues in geomechanics and mining industry. There are several influencing factors on the fragmentation which can be grouped into geometrical, geomechanical, environmental and operational. These factors need to be identified and quantified for fragmentation asses...

A large-scale wildfire had broken out at Fort McMurray in Alberta, Canada during May 2016. Many oil sands mining activities were affected due to the wildfire and the associated ash emissions. In particular, ash emission generated from the fire outbreak is a huge problem during the post-fire cleanup. These emissions pose a severe health hazard to wo...

The mineral resources close to the surface are being used so fast and deep mining is getting more popular. Block-cave mining with high rate of production and low operation costs seems to be one of the best options among mining methods. Using continuous ore handling systems can increase the safety and capability of the block-cave operation so that i...

Near-surface deposits that extend to considerable depths are often amenable to both open pit mining and/or underground mining. This paper investigates the strategy of mining options for an orebody using a Mixed Integer Linear Programming (MILP) optimization framework. The MILP formulation maximizes the Net Present Value (NPV) of the reserve when ex...

This year, we have prepared a report including 13 papers. We continue to update all the research results on the MOL webpage www.ualberta.ca/mol on the members section. Sponsors have access to current and past research results, publications, prototype software, and source code. Let’s review the contributions in the MOL Report Seven (2015/2016) by co...

This year, we have prepared a report including 14 papers. We continue to update all the research results on the MOL webpage www.ualberta.ca/mol on the members section. Sponsors have access to current and past research results, publications, prototype software, and source code. Mohammad Mahdi Badiozamani defended his PhD thesis in June 2014. Eugene...

Planning block-caving operations poses complexities in different areas such as safety, environment, ground control, and production scheduling. Production schedules that provide optimal operating strategies while meeting technical constraints are an inseparable part of mining operations. Applications of mathematical programming in mine planning have...

High rate of production, low operational cost, and automated systems have made block caving attractive to mine owners and mining engineers. Two of the key steps in block-caving operation scheduling are the development direction and the drawpoints’ precedence determination. An optimum direction for cave development and precedence for drawpoint extra...

Production scheduling is one of the most important problems in a mining operation, as it has a significant impact on a projects profitability. As open-pit mines go deeper, because of the massive amount of waste removal which is required to extract the ore as well as high operational costs per tonne, underground mining has become more attractive. Am...

Production scheduling is one of the most important problems in mining operation which has a significant impact on the profitability of the mining project. Most of the common production-scheduling methods in the industry rely only on manual planning methods or computer software based on heuristic algorithms. These methods cannot guarantee the optima...

Planning block-caving operations poses complexities in different areas such as safety, environment, ground control, and production scheduling. The objective of this paper is to develop a practical optimisation framework for production scheduling of block-caving operations. A mixed-integer linear programming (MILP) formulation is developed, implemen...

Production schedules that provide optimal operating strategies while meeting practical, technical, and environmental constraints are an inseparable part of mining operations. Relying only on manual planning methods or computer software based on heuristic algorithms will lead to mine schedules that are not the optimal global solution. Mathematical m...

Planning caving operations poses complexities in different areas such as safety, environment, ground control, and production scheduling. Production schedules that provide optimal operating strategies while meeting technical constraints are an inseparable part of mining operations. Applications of mathematical programming in mine planning have prove...

Production schedules that provide optimal operating strategies while meeting practical, technical, and environmental constraints are an inseparable part of mining operations. Relying only on manual planning methods or computer software based on heuristic algorithms will lead to mine schedules that are not the optimal global solution. Mathematical m...

Planning of caving operations poses complexities in different areas such as safety, environment, ground control, and production scheduling. As the mining industry is faced with more marginal resources, it is becoming essential to generate production schedules that will provide optimal operating strategies while meeting practical, technical, and env...

Production scheduling of any mining operation has an enormous effect on the economics of the venture. The scheduling problems are complex due to the nature and variety of the constraints acting upon the system. Relying only on manual planning methods or computer software based on heuristic algorithms will lead to mine schedules that are not the glo...

Planning of caving operations poses complexities in different areas such as safety, environment, ground control, and production scheduling. As the mining industry is faced with more marginal resources, it is becoming essential to generate production schedules which will provide optimal operating strategies while meeting practical, technical, and en...

Relying only on manual planning methods or computer software based on heuristic algorithms will lead to mine schedules that are not the optimal global solution. The objective of this paper is to develop a practical optimisation framework to schedule production for caving operations. We present two Mixed-Integer Linear Programming (MILP) formulation...

One of the main obstacles in using mixed integer linear programming (MILP) formulations for large-scale open pit production scheduling is the size of the problem. The objective of this work is to develop, implement, and verify deterministic MILP formulations for long-term large-scale open pit production scheduling problems. The objective of the mod...

Long-term mine scheduling is among one of the optimization problems. Block caving technique is a mass mining method in which gravity is used in combination with internal rock stresses to fracture and break the rock mass into pieces that can be handled by miners. This method is normally applied to large, low-grade ore-bodies because of its low produ...