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By S. R. Dindarloo

"Truck-shovel systems are the dominant material loading and haulage machinery in open pit mining operations. Optimal selection, sizing, and allocation of this capital intensive equipment is highly desirable for both achieving production targets and improving the mine’s economics. In this study, discrete event simulation technique was applied for modeling material transportation in Golegohar open pit iron ore mine in Iran. Direct observation of the material loading and haulage for duration of three months resulted in statistical modeling of the operation in the form of probability distribution functions. These probability models were used as the inputs of a stochastic simulation model constructed in GPSS/H simulation language. The model was validated through comparison with the actual operation and was used to test different what-if scenarios and sensitivity analysis of the current system. Some modifications in the number of trucks, shovels, and dispatching strategies were proposed. Simulation resulted in considerable improvements in the mine’s production and economics.INTRODUCTION There are three different mechanisms of discrete, continues, and hybrid material transportation in open mines, including but not limited to: i) in-pit crusher and conveyor belts (hybrid), ii) slurry piping (continues) and iii) truck-shovel system (discrete). Although, each mechanism has its advantages, the truck-shovel system is the dominant method of material loading and handling in open pit mines owing to its high production rate, excellent flexibility, relatively low operating and capital costs, and good maintainability. General objectives of optimal equipment selection include: i) meeting the long and short term requirements of production rates, ii) human & equipment safety, iii) environmental protection, and iv) economic operations (Figure 1).The two most important decision factors on a truck-shovel system selection and sizing are the equipment geometry and size. Geometry (equipment width, weight, turning radius, swing angle, etc.) is mostly controlled by mine’s designs and layouts, as well, as operational constraints. After selection of a favorable geometry based on the constraints; the next step is to select the equipment manufacturer. Once the geometry and manufacturers are selected; the next step is to decide on models (e.g. Bucket size) and required number of each unit"

Jan 1, 2015

By Sahin Furkan Sahiner, Onur Golbasi

Effective maintenance planning is vital for coal mining operations, where haul truck fleets directly determine production continuity. This study presents a discrete event simulation (DES) model for evaluating maintenance strategies under multiple failure modes and their interdependencies. The model integrates corrective, periodic preventive, and opportunistic maintenance, dynamically updating equipment lifetimes through probabilistic time-betweenfailure and time-to-repair distributions. Applied to a fivetruck coal haulage fleet over a one-year horizon, results show that periodic preventive maintenance delivers the highest availability (76%) under unconstrained conditions, slightly outperforming corrective-only maintenance (75%). Opportunistic and integrated approaches performed worse (68% and 69%), reflecting redundancy from overlapping interventions. These findings suggest that structured preventive programs provide the most reliable outcomes when costs and resources are not limiting. The DES framework serves as a baseline for future models incorporating cost, spare parts logistics, and workforce availability, supporting robust maintenance planning in coal mining operations.

Feb 22, 2026

By C. L. Lin

The characterization of rare-earth resources in 3D is now possible using high-resolution X-ray microtomography (HRXMT) to describe ore texture and mineral phase composition. In addition, detailed texture analysis, including grain exposure and mineral association, can be described. Preliminary examination of a sample of Mountain Pass ore is reported to describe the spatial distribution of the mineral phases (calcite, barite and bastnaesite), particularly the grain size distribution of bastnaesite. The examination includes analysis of selected particle size classes to determine the appropriate size for liberation of the rare-earth mineral bastnaesite. Good liberation is expected to be achieved if the material is ground to a top size of -150 µm.

By J. F. T. Agapito, L. J. Gilbride

High horizontal stresses were recognized to impact roof stability more than 60 years ago. Since then, numerous measurements associated high horizontal stresses with difficult ground conditions. This paper presents case histories illustrating the practical usage of roof stress determinations for helping assess stability, not only in the case of high horizontal stresses but also of low stresses. Examples are given of high stresses associated with faults, mine design changes, quantification of stress shadow effect, and anistrophy. The paper concludes with a comparative evaluation on the effect of various stress fields on ground support requirements.

Jan 1, 2002

By Thomas A. Simpson

Heretofore, underground coal mines in Alabama have operated under only 60 to 360 meters of cover: however, new mines (at least 5 in the early opening or development stages) will be operating under cover ranging from 600 to 660 meters. With increased rock confining pressures, roof stability problems will become more critical. Initial studies in two 7 ½ -minute quadrangle areas in the Warrior coal basin of Alabama indicate that the orientation of certain lineament and fracture-trace modes mapped from ERTS-1 (Earth Resources Technology Satellite) imagery correlate closely with the strike of joint and fault modes. High altitude (118,000 m) U-2 aircraft data were used to support these findings. In addition, over 50 percent of the normal faults mapped in the study area could be directly correlated with ERTS and U-2 lineaments and fracture traces. These correlations provide clues to the structural development of the Warrior coal basin and may, in turn, be used as a guide to the prediction of roof-stability conditions in advance of mining.

Jan 1, 1975

By Karoly (Charles) Kocsis, August Greth, Jon Fox

"It is the duty of the mine operator to ensure the mine environment is healthy and safe for the mine workers. For deep and hot underground mines, this requires maintaining adequate working temperatures by means of mitigating the heat load generated by strata, auto-compression, mining equipment, explosives, ground water and human metabolism. The heat load is best reduced by minimizing the amount of heat transferred to the mine air from these sources and through the use of efficient ventilation with effective cooling systems. The heat emitted by mining equipment and vehicles contributes a significant proportion to the combined heat load of an underground mine. This is especially a problem for diesel equipment due to the fact that besides heat, a large amount of water vapor is produced, which increases the humidity in the production workings. Diesel engines have proven advantageous in recent history due to their high power output and reliability. However, as mines continue to become more mechanized and deeper the climatic problems introduced by elevated heat generation will continue to rise. With that, the issue of heat generated by diesel equipment must be addressed.The economic alternative for diesel engine equipment fleets in underground mines is the electric engine. Technological advances in battery technology, increased mechanical output and improved reliability have made the electric engine significantly more competitive in comparison to diesel engines. Because electric engines do not utilize internal combustion, the heat produced by them is significantly less than the diesel engines. Battery-powered mining equipment likewise eliminate diesel particulate matter (DPM) produced by diesel engines. Utilizing battery electric equipment in underground mines provides many advantages, such as: (a) reduced heat load, (b) healthier and safer environment for the mine workers and (c) reduced mine operating costs due to lower ventilation requirements"

Jan 8, 2018

By Vivek Priyadarshi, VIVEK KUMAR HIMANSHU, A. K. Vishwakarma, M. P. Roy, A. K. Mishra, RAVI SHANKAR

The nature and orientation of joints in rock strata affect the damage pattern under explosive loading. Most of the limestone deposits in India are found with severity of joints. Categorically, these joints may have variable orientations such as dipping out of the blast face, inside the face, horizontally or having strike parallel to the face. The damage pattern under the varying category of orientation will be different. Accordingly, a numerical model in Ansys-Explicit Dynamics was prepared to compare the damages of rock mass under different joint orientations. The physical nature of a joint reflects frictional and stiffness behaviour. Accordingly, the damages have been compared under bonded and frictional nature of joints. The output damage pattern from the model has been validated on the basis of blastability index proposed by Lilly. Different limestone mines in India show different nature of jointing in their rock strata. Accordingly, the blasting outputs from three different limestone mines, viz. Rawan limestone mine, Sagmania and Birhauli limestone mine and Injepalli limestone mine, have been compared along with their blast design parameters and the nature of joint. The comparative results show that the closely spaced horizontal joints support maximum in burden movement and rock fragmentation due to blast.

Nov 23, 2023

By R. L. Wiegel

Some of the mineral deposits that are being processed today, and especially those expected to be processed in the future, have relatively low compositions of the valuable mineral. With these low-grade ores, it is necessary to be able to design processes that are sufficiently low-cost to permit exploitation. One approach to minimizing the capital and operating costs for these processes is to use the capabilities of computer process simulation in the design phase of development, to make important technical and economic decisions regarding the evaluation of alternative process flow schemes, the selection of equipment and the choice of operating conditions. There are mathematical simulation models for most mineral processing operations, including several each for size reduction, size classification and mineral separations. To be able to tie these individual operating models together in an integrated mineral process simulation, however, it is important, in fact in some cases essential, that there be a model which describes how the mineral system responds to size reduction in making the liberated valuable and waste mineral particles available for concentration or rejection operations and the locked particles available for possible recirculation. This, then, is the role played by the mineral liberation model, showing the relationship between particle size, quantity and composition throughout the process.

Jan 1, 2011

By Oscar Cabello, Luis Mendieta, Maribel Guzman

Mineral flotation processes generate large volumes of tailings, which must be disposed of efficiently and safely. In addition to dry stack disposal, the possibility of reusing these tailings as aggregates in shotcrete is an interesting alternative. Tailings samples from a mining operation in southern Peru were characterized by granulometric analysis, X-ray diffraction and Scanning Electron Microscopy. Concrete samples were obtained with different tailings formulations. The samples were subsequently subjected to geomechanical testing. The results showed that replacing 20% to 30% of the tailings with aggregates in shotcrete production achieved compressive strengths exceeding 30 MPa after 28 days of curing, with an energy absorption capacity of 500 joules. Results show that this shotcrete can be used in the support stage of the mining cycle in underground mining.

Feb 22, 2026

By T. J. Lien

AMAX Coal Company's Belle Ayr coal dryer is the first industry attempt to commercialize sub-bituminous coal drying which has been the subject of laboratory and pilot plant tests for almost two decades. This paper presents the historical background, construction, start-up and operation of this adaption of fluidized bed coal drying technology to Powder River Basin coal. The flowsheet and operational problems encountered during plant start-up are discussed together with general material balance and product quality.

Jan 1, 1990

By S. Torno

The elimination of ultrafine (<10 µm) clay particles is essential to the treatment of abandoned coal-washing plant tailings for the recovery of the remaining coal fraction by enhanced gravity processing. Effective hydrocyclone classification is required to remove this fraction. The highly variable composition and particle size distribution of such wastes creates significant difficulties in the operation of hydrocyclones for such classifications. Hydrocyclone laboratory investigations and their plant setup require lengthy or time-consuming tests. The use of empirical models of such classifications frequently requires modification to correspond to actual operating conditions. Results of the evaluation of computational fluid dynamics (CFD) modeling to predict hydrocyclone classification of coal-washing plant tailings are presented. Results of the standard k-epsilon turbulence, SSG turbulence and large eddy simulation CFD models are compared with the results obtained from analyzed hydrocyclone classifications. The CFD models tested are shown to be very effective in the simulation of hydrocyclone classifications for the determination of the classification particle size and adequate for determining the efficiency index values for many applications. The large eddy simulation model was identified as the most precise, but it is recommended that all three models be improved simulations of classifications above and below the classification particle size.

Jan 1, 2011

By G. J. C. Young

The paper describes the replacement of a conventional filtration, clarification and zinc precipitation plant by a carbon in pulp (CIP) electrowinning plant, with the objective of improving the recovery of gold from cyanide leached, acid plant calcines. The discussion covers the early laboratory studies to the design and erection of the full scale plant. Particular emphasis is placed on the problems encountered with commissioning and the strategies which were employed to solve them.

Jan 1, 1982

By R. K. Mehta

Stirred ball mill feed used for ultra-fine grinding application requires fine size separation step in order to avoid over-grinding. This paper presents the selectivity curves obtained for oil shale and complex sulfide are using 460 mesh (30 micron) Derrick vibrating screen. Interestingly, the selectivity curves generated from the experimental data were monotonic increasing selectivity for oil shale but not monotonic increasing for sulfide ore. These non-monotonic increasing selectivity curves were similar to the mechanical air separator fishhook selectivity curves described by Luckie and Austin. A 2 stage classification in series model describing the fishhook selectivity curve has been used in proposing the classification mechanism for fine vibrating screens when heterogeneous multicomponent sulfide are undergoes size separation.

Jan 1, 1992

By Michael Gauna

A high seam geologic condition exists at Jim Walter Resources No.4 mine which requires immediate rib support after a continuous miner cuts a place, High seam mining heights are typically 2.4 to 2.6 m (8 to 9 it) and a thick rock layer is present in the upper portion of the coal rib side. The 610 m (2000 ft) mining depth at No. 4 mine induces horizontal rib line movement after excavating an entry. Horizontal rib movement greater than 30.5 cm (12 in) have been noted. When lateral movement occurs in the high seam areas, the thick rock layer, and the coal above the rock layer, become fractured and tend to roll into the entry. If not adequately supported, large rib rolls develop in the place being bolted as well as in previously mined areas which endanger men and equipment. To control this situation rib support must be installed in the roof bolting operation as the bolting crew works towards the face. A rib control system has been developed for this high seam mining condition utilizing a mechanical anchor bolt placed at an angle in the rib and installed with a modified Fletcher DDFI- 15 bolting machine. Over 120 km (75 mi) of entry have been supported with angle rib bolts. These angle bolts constitute 43 to 60% of the total roof and rib bolt footage in the high seam port- ions of No.4 mine. The angle rib bolting system has proven safer, more effective, and more efficient than the earlier support method employing bolts installed horizontally into the rib. No rib roll accidents have occurred since the angle drill bolting machines were placed in service in 1981. By securing the broken rib material with an angle bolt anchored above the coal pillar, a more effective means of rib control is achieved. Angle rib bolting does not interfere with continuous miner productivity. In addition, bolting crews are now reduced from three to two people and the total drilling supply costs are approximately 60% the previous cost, when compared to the previous support method using horizontal rib bolts.

Jan 1, 1983

By M. Moats, I. E. Paschalidou, K. Awuah-Offei

Tellurium (Te) is a rare metalloid that is predominantly produced from the treatment of anode slimes formed during copper (Cu) electrolytic refining. The US Government lists Te as one of the 50 critical minerals, partly, because of its use in thin-film photovoltaic (PV) technology. Given policy initiatives to increase Te production, it is important to evaluate the life-cycle environmental impacts of Te recovery as a by-product of Cu processing. The literature contains a few specific life cycle assessment (LCA) studies of groups of metals that include Te without proper regard to impacts per life-cycle stage of Te production or the effect of allocation on the results. This study builds an LCA model of the production system of Te from anode slimes treatment to evaluate the effect of allocation on life-cycle impacts. We build life cycle inventories using data from the Ecoinvent v3.7.1 database, literature, and engineering calculations and allocate impacts in proportion to products’ mass and economic value. The results show that economic value-based allocation yields greater impacts than mass-based allocation indicating the significant effect of the allocation approach on life-cycle impact estimates.

Feb 1, 2023

By Rod L. Norfleet

Cemented tungsten carbides are a sintered powder - metallurgical product essential to modern industry. Because of their moderate unit price and our dependence upon foreign sources for the component raw materials, a growing recycling industry has developed in the United States. There are two basic approaches taken to recycling cemented carbides; those which leave constituting materials unaltered or direct-reuse and those which separate the constitutes back to the raw components. To separate the carbides back to their raw components usually requires expensive chemical processing and is thus confined to the lower value materials such as grinding sludges. The direct-reuse methods recycle cemented carbides back to an intermediate level, a powder capable of being recompacted and resintered into a functional end-product. The three most commonly used methods of direct-reuse recycling, the coldstream process, bloaching and the Bernard or zinc process, are reviewed,

Jan 1, 1984

By Mads Aniksdal

New Nedre Fiskumfoss is a construction project in North Trøndelag, Namsen River. The purpose of the contract is construction of a new hydropower plant, that will phase out the existing power plant in the same waterfall. The contract consists of a tunnel system with cross sections from 16 m2 to 150 m2, powerhouse and transformer in rock caverns, 6 shafts and major works with inlet and outlet below river level. Technical challenges consist of demanding design on rock extraction, cofferdams, solid constructions with challenging design and demanding rebar work, as well as restrictions and unpredictable water flow in a national salmon river.

Jun 13, 2023

By B. C. Darst

Developments in the agricultural use of potassium (K) have been based solely on the essential role K plays in crop production. Crop plants cannot complete their normal life cycle if K is deficient or absent. In fact, no essential plant nutrient other than nitrogen is required in greater quantities. Table 1 shows the amounts of K some crops take up from the soil. Although the exact functions of K in the plant are not well known, its primary role seems to be tied to plant metabolism. Potassium is vital to the process of photosynthesis. When K is deficient, photosynthesis declines, but respiration increases. These two K-deficient conditions. . . reduced photosynthesis and increased respiration ... lower the plant&apos;s carbohydrate supply, the end result being poor agronomic crop production. Potassium is also essential to several other plant functions, including the following: 1) Protein synthesis. 2) Water use efficiency, through the influence of K on stomata opening and closing, to maintain the turgidity in plant leaf cells. 3) Translocation of heavy metals such as iron and zinc. 4) Ionic balance. 5) Control of enzyme reactions within plants.

Jan 1, 1985

By James L. McGregor

St. Joseph Lead Company has been paying incentive bonuses for well over 40 years. In 1958 almost half of St. Joe&apos;s 1,860 employees in Southeast Missouri received some form of incentive bonus in addition to their guaranteed wages. There are very few payroll jobs in St. Joe s Southeast Missouri organization that lend themselves to a reasonably good measurement of production or quality, or both, where an incentive bonus is not paid. The term "Incentive Bonus" is used to differentiate betwen bonuses that are based on quantity or quality of work, and those that are merely additional pay of a standard amount per hour or day because of an employee being temporarily assigned to some unusual task, An employee temporarily assigned to a job where the working conditions make the job performance unusually difficult or where a special skill is used is often given a bonus of some standard amount per hour or shift in addition to his usual rate. This is merely a convenient way of paying something extra without disturbing the normal rate structure. Actually, it is differential pay similar to that almost universally paid for evening and night shift work. Bonuses of that type are not being considered in this paper. The basic reason or theory for paying incentive bonuses 9s to get improved production at lower cost, Unfortunately, it is often difficult, if not impossible, to find a yardstick by which it can be definitely proved that a particular bonus plan is accomplishing its purpose, It becomes, then, a matter of judgment on the part of management personnel as to the value of the bonus plan. The fact that St. Joe Lead Company has continued to pay bonuses for over 40 yews and has increased the number of bonus schedules used attests to a definite belief that they are beneficial to the company&apos;s successful operations.

Jan 1, 1960

By M. A. Giralico

A new generation of hydraulic efficient pumper and auxiliary impeller designs is the result of an extensive research program focused on improving the overall performance of optimized SX/EW plants. Combined with the proper scale-up, these optimized designs will greatly reduce aqueous and organic entrainment losses, reduce or eliminate air entrainment and crud formation, enhance mass-transfer and maximize the overall copper yield. Currently, these new pumper and auxiliary impellers are installed full-scale in numerous plants ranging in flow rates from 90 to 15000 G.P.M. and developed heads up to 51 inches. Operational results reported by the independent metallurgist at each processing plant are reporting the lowest entrainment results in the industry. Further R&D has just been completed on a new mixing configuration that separates the systems mixing and pumping requirements. Results from the system pilot test document further improvements in reduction of both chemical entrainment and crud formation, while keeping mass transfer stage efficiencies.

Jan 1, 1998