Underground Mine Production Research Articles

Justification of Longwall Mining Technology for the Development of Kieselguhr Deposit in Sig Mine, Algeria

The improvement of mineral extraction technology in underground mines to increase productivity has become an important objective of the mining industry in Algeria in the race for price competitiveness, especially after the sharp decline oil prices as the main income of Algeria. But the increase production in underground mines where the deposits do not have good mechanical characteristics is a major challenge for the decision-makers, as the case of the kieselguhr mine of sig (Western Algeria) which uses the Room and pillar mining method that do not fit the condition of soft deposits and do not have sufficient strength, which causes a lot of collapses from time to time. The only way to ensure the increase of production, by improving the method of extraction and efficiency of the equipment used. In this article, we will combine the Room and pillars mining method and use the technology of the longwall mining method to increase the production of the mine and ensures the safety of workers during operation.

Resource and Grade Control Model Updating for Underground Mining Production Settings

A key requirement for the mining industry is the characterization of the spatial distribution of geometallurgical properties of the ore and waste in a mineral deposit. Due to geological uncertainty, resource models are crude representations of reality, and their value for forecasting is limited. Information collected during the production process is therefore of high value in the mining production chain. Models for mine planning are usually based on exploration information from an initial phase of the mineral extraction process. The integration of data with different supports into the resource or grade control model allows for continuous updating and is able to provide estimates that are more accurate locally. In this paper, an updating algorithm is presented that integrates two types of sensor information: sensors characterizing the exposed mine face, and sensors installed in the conveyor belt. The impact of the updating algorithm is analysed through a case study based on information collected from Reiche-Zeche, a silver–lead–zinc underground mine in Freiberg, Germany. The algorithm is implemented for several scenarios of a grade control model. Each scenario represents a different level of conditioning information prior to extraction: no conditioning information, conditioning information at the periphery of the mining panel, and conditioning information at the periphery and from boreholes intersecting the mining panel. Analysis is performed to compare the improvement obtained by updating for the different scenarios. It becomes obvious that the level of conditioning information before mining does not influence the updating performance after two or three updating steps. The learning effect of the updating algorithm kicks in very quickly and overwrites the conditioning information.

Optimizing Production Plan for Underground Coal Mining: A Genetic Algorithm Application

Developing an optimal production plan of an underground coal mine is complex due to several factors such as: economic, physical, environmental and social, etc. In this paper, an attempt has been made to apply genetic algorithm (GA) to maximise net present value (NPV) of a real life underground coal mine. It is first highlighted that the inefficacy of using direct optimisation methods and then a numerical illustration shows the efficacy of application of bio-inspired computation approach; because of its multiple advantages such as simplicity, user friendliness and parallel processing. This paper establishes the proposition that 'simulation-based stochastic optimisation for underground mine production plan would lead to better results than optimisation based on customary gradient optimisation approach'.

A simulation–optimization framework for short-term underground mine production scheduling

Mine operations are supported by a short-term production schedule, which defines where and when mining activities are performed. However, deviations can be observed in this short-term production schedule because of several sources of uncertainty and their inherent complexity. Therefore, schedules that are more likely to be reproduced in reality should be generated so that they will have a high adherence when executed. Unfortunately, prior estimation of the schedule adherence is difficult. To overcome this problem, we propose a generic simulation–optimization framework to generate short-term production schedules for improving the schedule adherence using an iterative approach. In each iteration of this framework, a short-term schedule is generated using a mixed-integer linear programming model that is simulated later using a discrete-event simulation model. As a case study, we apply this approach to a real Bench and Fill mine, wherein we measure the discrepancies among the level of movement of material with respect to the schedule obtained from the optimization model and the average of the simulated schedule using the mine schedule material’s adherence index. The values of this index decreased with the iterations, from 13.1% in the first iteration to 4.8% in the last iteration. This improvement is explained because the effects of the operational uncertainty within the optimization model can be considered by integrating the simulation. As a conclusion, the proposed framework increases the adherence of the short-term schedules generated over iterations. Moreover, these increases in the adherence of schedules are not obtained at the expense of the Net Present Value.

A Stochastic Mixed Integer Programming Framework for Underground Mining Production Scheduling Optimization Considering Grade Uncertainty

Conventional mine planning approaches use an estimated orebody model as input to generate optimal production schedules. The smoothing effect of some geostatistical estimation methods cause most of the mine plans and production forecasts to be unrealistic and incomplete. With the development of simulation methods, the risks from grade uncertainty in ore reserves can be measured and managed through a set of equally probable orebody realizations. In order to incorporate grade uncertainty into the strategic mine plan, a stochastic mixed integer programming (SMIP) formulation is presented to optimize an underground cut-and-fill mining production schedule. The objective function of the SMIP model is to maximize the net present value (NPV) of the mining project and minimize the risk of deviation from the production targets. To demonstrate the applicability of the SMIP model, a case study on a cut-and-fill underground gold mining operation is implemented.

Stability Analysis and Support Control for a Jointed Soft Rock Roadway Considering Different Lateral Stresses

The stability of coal mine roadways in jointed soft rock masses is an important issue for safe and efficient mining production in underground mines. Taking a main haulageway of a coal mine in Guizhou Province in China as the research background, the instability failure caused by large deformation of a roadway in a cracked rock mass was analysed, and its support control measures were put forward. First, the stability of the surrounding rock was evaluated by field investigation on the failure characteristics and statistics for the development of joints and fissures in the surrounding rock. Second, the corresponding numerical model was established by using FLAC3D software, and the influence of the lateral pressure coefficient λ on the plastic zone and principal stress were analysed quantitatively. In addition, the evolution process of the plastic zone over time was summarized. Furthermore, the key points of the reinforcement plan and support parameter design were provided on the basis of the technical approach for deformation control of the surrounding rock of the roadway. The original supporting scheme was optimized step by step, and the combined supporting scheme with “short bolt, long anchor cable and two-step grouting shell” serving as the main concept was put forward. Finally, the results of numerical calculation and field practice showed that the optimized scheme could effectively restrain the local deformation in the plastic zone of the surrounding rock of the roadway. The overall deformation was in a controllable range. In addition, the reinforced anchor cable was anchored to the deep part of the surrounding rock, ensuring the safety and stability of the roadway.

Low Cost Low Power Smart Helmet for Real-Time Remote Underground Mine Environment Monitoring

Underground mining production process is vulnerable and highly dynamic in nature. Among the various causes of accidents in underground mine, major one is presence of flammable and noxious gases. Though many existing safety gadgets are there but they could not work reliably because of the typical nature of mines structure and production variability. Wireless data and communication network is also not successful because wireless communication in underground mine is significantly more challenging than through air. This work introduces the application of mobile wireless sensor network in order to monitor a variety of parameters in underground mines which have life threatening effects towards them. Each node of the network placed over the safety gear (helmet wore statutorily by every miner) comprises of various sensors depending on the requirement with microcontroller unit and other low power accessories. The proposed work has a unique feature that it will make the personnel aware about the situation of the gases present and surrounding by automatically generating different alarms and different light indicators. Other function of this device will be to transmit the data sensed by the sensors in the device to the control room wirelessly so that the responsible person would be aware of the situation. This work is focused on the design of such a prototype model for the underground mines with the aforementioned specification.

An experimental framework for simulating stress corrosion cracking in cable bolts

Stress corrosion cracking (SCC) of cable bolts in underground mines is a universal issue with limited cost effective solutions at present. Understanding the SCC mechanism of cable bolt failure is crucial in maintaining effective ground support and hence increasing the safety and productivity of underground mines. However, to date, no practical laboratory system has been developed to replicate the SCC mechanism which occurs in underground mines. In this study, based on the chemical properties of mine water, an acidified solution containing sulphide is synthesized. The solution is exposed to the wire strands from cable bolt in the laboratory to model service failure. It is shown that the applied stress intensity and time to failure have an inverse power law relationship in wires of cable bolts. Similar features are observed in both laboratory-failed specimens and the service-failed cable bolts under macroscopic and microscopic examinations, demonstrating the ability of the proposed framework to simulate failure of cable bolt subjected to SCC in the laboratory. Furthermore, the impact of stress intensity and hydrogen concentration on SCC are examined and a cohesive failure mechanism on the cable bolt SCC crack initiation, growth and catastrophic failure are presented. The proposed framework can be applied to the reinforcement materials for improved understanding of the SCC mechanism in underground mines and tunnels.

Conceptual overview and preliminary risk assessment of cryogen use in deep underground mine production

This research conducts a formal risk assessment for cryogenic fueled equipment in underground environments. These include fans, load haul dump units, and trucks. The motivating advantage is zero-emissions production in the subsurface and simultaneous provision of cooling for ultra deep mine workings. The driving force of the engine is the expansion of the reboiled cryogen following flash evaporation using ambient temperature heat. The cold exhaust mixes with warm mine air and cools the latter further. The use of cryogens as ‘fuel’ leads to much increased fuel transport volumes and motivates special considerations for distribution infrastructure and process including: cryogenic storage, distribution, handling, and transfer systems. Detailed specification of parts and equipment, numerical modelling and preparation of design drawings are used to articulate the concept. The conceptual design process reveals new hazards and risks that the mining industry has not yet encountered, which may yet stymie execution. The major unwanted events include the potential for asphyxiation due to oxygen deficient atmospheres, or physical damage to workers due to exposure to sub-cooled liquids and cryogenic gases. The Global Minerals Industry Risk Management (GMIRM) framework incorporates WRAC and Bow-Tie techniques and is used to identify, assess and mitigate risks. These processes operate upon the competing conceptual designs to identify and eliminate high risk options and improve the safety of the lower risk designs.

Studies on Propagation Characteristics of Radio Waves for Wireless Networks in Underground Coal Mines

Communication systems relying on wireless technology can significantly improve the safety and production in underground mines; however, their unreliable operation in such high-stress environments is a significant obstacle to achieving this. Underground mine tunnels offers several distinctive features that are quite different from regular rail/road tunnels. While several studies have been performed on electromagnetic (EM) wave propagation in tunnel environments, there is limited understanding of the inter-working of tunnel dimension with long range tilt variations (a typically feature of coal mines) on the propagation characteristics of wireless radio waves. In this paper, we study and describe a new hybrid multimode model for wireless communication applications in underground coal mines; and analyze it with respect to significant parameters such as operating frequency, mine tunnel size, transmitter–receiver position, electrical parameters and antenna gain. The characterization results suggest that the mine tunnel size and transmitter–receiver position affects the signal behavior significantly. However, the electrical parameters have almost negligible effects on the propagation.

Intelligent Mining Engineering Systems in the Structure of Industry 4.0

The solution of the problem of improving the human environment and working conditions at mines is based on the provision of the rationale of parameters and conditions for the implementation of an environmentally balanced cycle of comprehensive development of mineral deposits on the basis of the design of mining engineering systems characterized by the minimization of the human factor effect in danger zones of mining operations. In this area, robotized technologies are being developed, machinery and mechanisms with the elements of artificial intelligence, and mining and transport system automatic controls are being put into service throughout the world. In the upcoming decades, mining machines and mechanisms will be virtually industrial robots. The article presents the results of zoning of open-pit and underground mine production areas, as well as mining engineering system of combined development depending on the fact and periodicity of human presence in zones of mining processes. As a surface geotechnology case study, the software structure based on a modular concept is described. The performance philosophy of mining and transport equipment with the elements of artificial intelligence is shown when it is put into service in an open pit.

On the design and selection of vehicle coordination policies for underground mine production ramps

Traffic management in underground mines, especially on production ramps, is a difficult problem to optimize and control. Most operations use one of a few common policies; e.g., the so-called “lock-out” and “loaded-vehicle-priority” policies. The work presented in this paper uses discrete-event simulation to study the efficiency of multiple policies. Based on simulation results, an improvement to the common lock-out policy is proposed. This new policy utilizes the rules of the lock-out policy but integrates an option that allows a group of vehicles to be given temporary priority in a certain direction of travel. Quantitative results are provided and, based on these, a systematic technique for ramp design that aims to optimize the efficiency of underground mine ramp traffic flow is described.

An Approach to Realizing Process Control for Underground Mining Operations of Mobile Machines.

The excavation and production in underground mines are complicated processes which consist of many different operations. The process of underground mining is considerably constrained by the geometry and geology of the mine. The various mining operations are normally performed in series at each working face. The delay of a single operation will lead to a domino effect, thus delay the starting time for the next process and the completion time of the entire process. This paper presents a new approach to the process control for underground mining operations, e.g. drilling, bolting, mucking. This approach can estimate the working time and its probability for each operation more efficiently and objectively by improving the existing PERT (Program Evaluation and Review Technique) and CPM (Critical Path Method). If the delay of the critical operation (which is on a critical path) inevitably affects the productivity of mined ore, the approach can rapidly assign mucking machines new jobs to increase this amount at a maximum level by using a new mucking algorithm under external constraints.

Cave-to-Mill: a Mine-to-Mill approach for block cave mines

A refinement of the traditional Mine-to-Mill integration opportunity for copper block cave mines is introduced here as a Cave-to-Mill production management concept. This is essentially the integration of underground mine production scheduling and monitoring with surface mineral processing management based upon fragment size and geometallurgical ore characteristics.Cave-to-Mill defines ore block models with respect to both mine and mill performance. Linkages between key cave and mill parameters have been established so that coordinated efforts towards maximizing net present value (NPV) can be made. Discrete fracture network (DFN) based methods were found to hold significant value within the Cave-to-Mill approach. The variable and relatively uncontrollable nature of cave fragmentation is considered to be a key distinguishing feature of Cave-to-Mill when compared with typical Mine-to-Mill strategies established for open-pit mines. It is envisioned that Cave-to-Mill will be an important design and operational strategy for block cave mines.

Future Challenges of Positioning in Underground Mines

The mining industry is facing a difficult challenge in the coming decades. High grade ore is becoming increasingly difficult to obtain and production in underground mines is constantly being carried out at deeper levels. This increases the production cost for the companies and a technology shift is needed to secure the production.One solution often discussed is to introduce more autonomous machines and robots in the mine. This would improve personnel safety and also increase the productivity. Autonomous machines are already being used in mines, but often in restricted areas and they are typically not deployed on a large scale. Introducing unmanned machines on a large scale requires a completely new positioning solution compared to those being used today. Current solutions are primarily intended for personnel safety and emergency rescue, but these are not intended nor suited to be used for tracking and controlling unmanned vehicles.The state of the art in positioning technologies has generally had a strong focus on consumer industry; this paper will describe a more challenging research topic, the underground mine. It will describe the state of the art in underground mining positioning applications as well as the foreseen future positioning applications. Taking the special mining requirements into account, the challenges of positioning in underground mines are thereafter identified and discussed.The paper concludes that there are many challenges to solve in several areas, and that the research community has an important role to play.

Optimization-based heuristics for underground mine scheduling

Underground mine production scheduling possesses mathematical structure similar to and yields many of the same challenges as general scheduling problems. That is, binary variables represent the time at which various activities are scheduled. Typical objectives seek to minimize costs or some measure of production time, or to maximize net present value; two principal types of constraints exist: (i) resource constraints and (ii) precedence constraints. In our setting, we maximize “discounted metal production” for the remaining life of an underground lead and zinc mine that uses three different underground methods to extract the ore. Resource constraints limit the grade, tonnage, and backfill paste (used for structural stability) in each time period, while precedence constraints enforce the sequence in which extraction (and backfill) is performed in accordance with the underground mining methods used. We tailor exact and heuristic approaches to reduce model size, and develop an optimization-based decomposition heuristic; both of these methods transform a computationally intractable problem to one for which we obtain solutions in seconds, or, at most, hours for problem instances based on data sets from the Lisheen mine near Thurles, Ireland.

Clustering of mining-induced seismic events in equivalent dimension spaces

High energy release during seismic events induced by mining operation is one of the major dangers perturbing production in underground mines. In this work, temporal changes of seismic event parameters for one of the Rudna Mine (Poland) panels are investigated. The study aim was to find whether the temporal clustering of smaller events in different parameters can be observed before and after the high energy events (Ml ≥ 3) in the mining panel. The method chosen for analysis was the study of temporal variation of fractal dimension of the seismic events parameter sets composed from: the interevent epicentral distance (dr), logarithm of seismic energy (lE), and interevent energy coefficient (dlE), which is the absolute difference between logarithms of energy of two consecutive events. Temporal variations study was performed in equivalent dimension (ED) space. The transformation of the seismic source parameters into ED space allowed to estimate and compare the temporal changes of the fractal dimension of different parameter spaces using the same method—correlation fractal dimension, and then easily compare the obtained temporal changes of fractal dimension of different parameter sets. The effect of grouping is expressed by decrease of fractal dimension, which is connected with the similarity of events parameter values. The temporal changes of the fractal dimension of seismicity before the strong induced events would indicate some initiation phase of the process leading to the high energy release. In the case of the studied Rudna Mine panel, the temporal behavior of the fractal dimension values in different parameter spaces before seismic events showed significant changes before three out of four events with CLVD dominant source mechanisms.

Introduction to the Interfaces Special Issue on Operations Research in Mining

This special issue in mining presents surveys and applications. Specifically, in the former category, the issue contains a tutorial on open-pit mine-scheduling models, a literature review on equipment selection, and a combination of a tutorial and literature review on ventilation systems in underground mining. In the latter category, the issue contains applications on open-pit mine scheduling, underground mine design, underground mine production scheduling, and logistics and mining.

Passing bays in an underground mine

Some mining companies are investigating the use of road trains to increase productivity in underground mines. Road trains require dedicated passing bays in declines. The spacing of these passing bays can have a significant impact on haulage productivity. This technical note describes the use of simulation to find the optimal spacing. If the distance between passing bays is sufficiently small then descending trains can be interleaved with ascending trains, which increases productivity. If the spacing is too small, however, productivity can decrease as descending trains wait in passing bays for ascending trains. For a real mine the spacing should be less than the theoretical critical distance to cope with variations in loading and unloading durations.

Implementing a Production Schedule at LKAB?s Kiruna Mine

LKAB's Kiruna Mine, located in northern Sweden, produces about 24 million tons of iron ore yearly using an underground mining method known as sublevel caving. To efficiently run the mills that proc...