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By J. Lorengo, C. H. Bucknam

"Standardization of the Inductively Coupled Plasma Mass Spectrometry (ICPMS) method for gold in cyanide solutions was undertaken to provide a more sensitive method to quantify the gold content than the atomic absorption method standardized in 1994 (E1600). The gold concentration range covered is from 0.001 mg/L Au - 0.3 mg/L Au (0.00005 toz/t Au – 0.009 toz/t Au). Interlaboratory testing was carried out with the assistance of the American Society of Testing and Materials (ASTM) International on two committees to determine the within laboratory and between laboratory reproducibility. Three barren solutions from metallurgical operations were measured in triplicate to satisfy statistical requirements for Committee E1 on Analytical Chemistry of Metals, Ores and Related Materials. A synthetically prepared matrix representing the metallurgical processing solutions was used to prepare Youden pairs to satisfy the requirements of Committee D19 on Water. Results of the standardization program are presented. INTRODUCTION Analysis of process solutions for gold concentration requires accurate and sensitive analytical methods in order to manage process control and metallurgical accounting. Flame atomic absorption spectrophotometry (FAAS) has been the work horse of the assay lab for this duty for decades. In 1994 the FAAS standard method was approved by the American Society for Testing and Materials (ASTM) (1). Six process solutions were collected and preserved by measuring the pH and adjusting to greater than pH 10, if necessary. Duplicate solutions were provided to eight laboratories in random order for analysis by FAAS covering the gold concentration range of 0.19 µg/mL (0.006 toz/t.) to 10.7 µg/mL (0.312 toz/t). A high precision method was used, which involved bracketing the sample with the higher and lower standards nearest to its concentration repeating readings three times and averaging the results. The optimum precision for the FAAS gold method was found to be at the 1.00 µg/mL (0.029 toz/t) and lower scope limit 0.3 µg/mL (0.009 toz/t) gold concentration. Since tailings solutions typically have concentrations below the lower scope limit, use of ICPMS was developed at Newmont USA Limited (Newmont) to assay the lower range solutions."

Jan 1, 2016

By Justin Reed, Sara Bewley, Dwight M. Kinnes, Maryam Sadeghi, Ed Hart

This study compares wet gravity and dry magnetic separation for preconcentrating an allanite-rich rare earth ore from the Halleck Creek deposit. Material in the –300/+86 μm size range was treated to define a flowsheet that maximizes total rare earth oxide (TREO) recovery. The ore is dominated by feldspar and quartz, with hastingsite, an iron-bearing aluminosilicate. Because hastingsite’s density and magnetic response closely match allanite, it is difficult to reject using conventional methods. Two separation approaches were evaluated: MG12 spirals for gravity concentration and an Induced Roll Magnetic Separator (IRMS) for dry magnetic upgrading. MG12 spirals performed well in the rougher stage but provided limited gains when used as cleaners. When IRMS was applied as the cleaner stage, TREO grade and recovery improved substantially, showing that a dry magnetic cleaner circuit can effectively replace the wet gravity cleaner step. MG12 spirals remain suitable for highcapacity rougher duty, but dry magnetic separation delivers higher selectivity, simpler operation, and eliminates water use—offering a more efficient and sustainable preconcentration route in water-constrained environments.

Feb 22, 2026

By O. M. Arafat, J. A. Finch

Since its development, the functional performance equation for ball milling (McIvor, 1988) has facilitated a new understanding of industrial circuit cause and effect relationships, leading to significant strides in operational performance. Success stories of this approach to plant circuit performance improvement are now too numerous to list. Finch and McIvor (circa 1986) also discovered that the functional performance mill grinding rate at the size of interest was the same cumulative grinding rate that is calculated from mill feed and discharge size distributions using a first-order rate equation. By calculating these cumulative grinding rates for all screen sizes, a complete ball mill model is generated (as used by Finch and Ramirez, 1981). Others in industry, Hinde and Kalala (2009), for example, have noted the same. Lacking the complexity needed to maintain their interest, most researchers have ignored this model, broadly opting instead for Epstein’s (1948) characterization of grinding as a chemical reaction, combining selection rate and breakage size distribution functions. The much simpler ball mill model has previously been incorporated into a proprietary circuit modeling program (McIvor, 2005) and used for plant improvement work (for example, see McIvor and Finch, 2007, and McIvor, 2014). Now, by combining this business-friendly ball mill model with optimization criteria from functional performance analysis, a circuit modeling system (including the needed supplementary steps to assure successful plant implementation of circuit design changes) is at the disposal of every plant metallurgist, grinding equipment/ material provider and circuit designer.

Jan 11, 2017

By Gabriel Böde Jimenez Leon, Michael Karmis, Christopher Newman, Zach Agioutantis

"When utilizing high recovery underground mining methods, such as longwall or high-extraction room-and-pillar mining, the movement and deformation of the overburden propagate toward the surface and may affect the integrity of overlying surface streams (Peng et al, 1996). Published studies cite three major mechanisms of subsidence as most likely to impact streams: displacement, slope and strain. While subsidence-induced vertical displacement cause little structural damage to the stream bed, it may create adverse drainage and stream flow issues as the subsidence trough allows for ponding (Dawkins, 2003). Subsidenceinduced changes to the slope, or tilt, of a stream may have adverse effects on water flow. As the stream enters the subsidence trough, the gradient increases providing potential erosion control problems. When exiting the subsidence trough, a reduction of the gradient may inhibit stream flow, causing localized ponding (Peng, 2008). While vertical displacement and tilt both may have detrimental effects to surface streams, the resulting strains have been documented as being the most damaging to surface streams and structures causing distortion, fractures, or failure (Singh, 1992). When stream beds are subjected to high tensile strain, tensile cracks may form at the surface level allowing for the direct loss of stream flow through fissures. When stream beds are located in areas of high compressive strain, rock layers forming the stream bed can fail as the stream bed ruptures, upward, blocking stream flow or having the stream diverted into the fracture zone at the base (Iannacchione, et. al., 2010).Recent investigations on the effects of underground mining on surface bodies of water suggest that to determine the degree of stream impact one must also consider the geologic structure and thicknesses, surface topography, watershed drainage areas, width of river bed and rate of mining. Due to the complex nature and number of parameters affecting surface streams, subsidence modeling tools and software packages should be implemented throughout all stages of subsidence planning, prediction and control. The Surface Deformation Prediction System (SDPS) utilizes the influence function for the calculation of final subsidence deformations with respect to the angle of influence, supercritical subsidence factor as a function of the percent hard rock, edge effect offset distance, and surface topography. Developed more than 25 years ago, SDPS has been continually updated with new analysis and prediction features, providing a reliable and versatile program for subsidence management methodologies. Most recently, the program has been updated to evaluate the effect of varying surface topography in the prediction of horizontal displacements, referred to as ground strain, allowing for the accurate three-dimensional representation of surface deformations in mountainous terrain (Agioutantis and Karmis, 2014). Ground strain has become one of the predominant deformation indices used in the evaluation of potential damage to surface structures (Karmis et al., 1995). Ongoing work with SDPS software seeks to investigate the calculation of ground strain in SDPS and its ability to accurately and realistically predict damage to surface streams due to underground mining operations."

Jan 1, 2015

By F. G. Crack, R. V. Ramani, R. L. Frantz

Management for mine construction and development differs from that needed for routine mine production and maintenance. An integrated approach to managing mine development projects must consider contract documents; management organization of a project; the project manager's role and the field supervisor's responsibility; and the use of scientific techniques for planning, scheduling, executing, and controlling projects. Professional project management encompasses the following: • Preparing contract documents that establish technical and financial schedules, and detail the responsibility for the physical work commitment. • Developing a project's organizational structure, to clearly define the roles of the project manager and the field supervisors. • Establishing project management and field supervisor relationships, to avoid ambiguity in assigning responsibility and to ensure desired project progress. • Using management science techniques, particularly networking techniques such as the critical path method for planning scheduling, executing, and controlling projects. Project Versus Production Management Project management differs from routine production management in the following ways: • Uniqueness: A project is unique. Production operations tend to be repetitive. The magnitude of one-time capital expenditures for many facets of mine development warrant special skills and attention. These professional project development skills must already be available by prior experience in the management team. • Personnel: In projects, personnel are usually assigned on a specialty basis and frequently change with the project activity. On the other hand, production personnel work together, more or less permanently. • Management Structure: In a project there may be several staff-line relationships that are not clearly defined and change with changing project activities. In a production situation, the lines of communication and authority are usually well defined. • Time Frame: A difference between project and routine production management is that project activities have comparatively less well defined durations and often tend to be relatively short-term. Production usually has both long-term and short-term plans and well defined long-term and shor-term goals. In project management, formal, critical, short-term reviews are frequently required. In production management, five year plans can be formally adjusted quarterly and annually. Short-term weekly or daily reviews can be informal. • Response to Delays: Delays in a development project may occur without anyone being immediately aware of their existence or suspecting the magnitude of consequence. In contrast, any delays in the production process can be easily identified from prior results comparison. Additionally, the response is quick, usually in a set routine. This can be traced back to the management structure and personnel. • Control Techniques: Measurements of project progress for control are not easily made due to the variety of activities that are carried on at the same time by different work groups. The yard-sticks of performance measurement for individual activities, let alone for the total project, are not easily established. However, due to the difficulty in detecting project delays, a workable control system is vitally important to a project manager. To apply a scientific project control technique such as "management by exception" requires specific planning and monitoring from the project manager for each activity in the project. Production and productivity are quick and effective yard-sticks of measuring performance in a routine operation. Control techniques required in production management usually revolve around these measures. Construction Contracts The construction contract is an important document that establishes contract scope, technical and financial details of the work, and achievement deadlines. It may also serve as the contract document to pay for work done and to verify field progress with planned progress. In practice, it is a good idea to develop a job-specific contract. This whole area is replete with legal precedence and procedures, and it is not the intent here to deal with the intricacies of establishing a contract document. But it is necessary to have an understanding of major contract types. Construction contracts are extremely important legal documents. They may vary in work specifications and enforcement of the provisions. Due to their nature, they must be composed with legal help and will take some time to compile. Even with all the precautions and provisions, it is not uncommon to find owner and contractor disagreeing. Therefore, it is important to include a way to resolve any difference quickly and to incorporate aspects of the contract as part of an overall management control tool for efficient project management.

Jan 7, 1982

By D. Blackwell, W. R. Reed, G. Ross, S. Peters, M. Shahan

Dust collectors for roof bolting machines generally use a dry box to collect the roof bolting material. Recently, an underground mining operation converted a dry box dust collector to a wet box dust collector with a unique exception from MSHA for testing purposes. Water is routed to the roof bolter from the main water line of the continuous miner. The wet box utilizes a water spray to wet the incoming material. Testing was conducted comparing the two different collector types. Respirable dust concentrations surrounding the roof bolter with the different collection boxes were similar. The main difference in respirable dust concentrations occurred when cleaning the dust boxes. The average respirable dust concentration during cleaning of the wet box was 0.475 mg/m3, and during the cleaning of the dry box the average respirable dust concentration was 1.188 mg/m3. The silica content of the roof material was high, ranging from 28.9% to 52.7% during this study. The results from this study indicate that using the wet box as a collector reduced exposure to respirable dust up to 60%when cleaning the collector boxes. INTRODUCTION Currently, the dry vacuum dust collection system is the standard dust collector on roof bolters in underground coal mining. It has been proven to be an effective dust control to prevent roof bolter operators’ overexposure to coal mine respirable silica dust during roof bolting operations [Potts eta l, 2011 and Colinet, 2013]. The dry collection system works as follows: drill cuttings are vacuumed into the precleaner. The precleaner dumps oversized material onto the mine floor while undersized material enters the dust box via vacuum airflow produced by a blower. The cuttings entering the dust box are either deposited on the floor of the dust box or into a dust collector bag. The vacuum airflow leaves the dust box through a final filter which removes any small particles from the airflow. Figure 1 shows the internal view of two dry collection system boxes; one that does not use the dust collector bags and another that uses the dust collector bags. Dust collectors that use dust collector bags to contain material inside the dust collector box have been shown to provide better protection to roof bolter operators than dust collectors that do not use the bags [Listak and Beck 2008]. The dry collectors are very efficient at reducing respirable coal mine dust exposure from roof bolting activities. Recently, Blue Mountain Energy’s Deserado underground coal mining operation, outside Rangely, CO, made a modification to the dry collector system to convert it to a wet collector system with a unique exception from the Mine Safety and Health Administration (MSHA) for testing purposes. The wet collector system still uses a vacuum system to pull material from the vertical roof bolt hole, but incorporates a water spray nozzle located inside the dust box to wet the incoming material. The flow through the nozzle ranges from 1.9–7.6 lpm (0.5–2.0 gpm) at 0.69 MPa (100 psi). The conversion to the wet collector system removes the precleaner and the cyclones inside the dust box. The wet material (sludge) then empties through a specialized valve in the bottom of the box. The final filter is still used to prevent respirable dust from leaving the dust box through the exhaust. During operation, the wet collector dust box is opened and hosed clean after roof bolting every place. After every two entries the final filter is changed out. Figure 2 shows the inside of the wet collector box.

Jan 1, 2019

By J. R. Patts, A. B. Cecala, E. J. Haas

Exposure to respirable crystalline silica (RCS) remains a serious health hazard to the US mining workforce who are potentially exposed as various ore bodies are drilled, blasted, hauled by truck, crushed, screened, and transported to their destinations. The current Mine Safety and Health Administration (MSHA) permissible exposure limit (PEL) for RCS remains at approximately 100 μg/m3 , but it is noteworthy that the Occupational Safety and Health Administration (OSHA) has lowered its PEL to 50 μg/ m3 (with enforcement dates staggered through 2022 for various sectors), and the National Institute for Occupational Safety and Health (NIOSH) has held a 50 μg/m3 recommended standard since 1976. To examine a method for reducing RCS exposure using a NIOSH-developed video exposure monitoring (VEM) technology (referred to as Helmet-CAM), video and respirable dust concentration data were collected on eighty miners across seven unique mining sites. The data was then collated and partitioned using a thresholding scheme to determine exposures that were in excess of ten times the mean exposure for that worker. Focusing on these short duration, high magnitude exposures can provide insight to implement controls and interventions that can dramatically lower the employee’s overall average exposure. In 19 of the 80 cases analyzed, it was found that exposure could be significantly lowered by 20% or more by reducing exposures that occur during just 10 min of work per 8-hour shift. This approach provides a method to quickly analyze and determine which activities are creating the greatest health concerns. In most cases, once identified, focused control technologies or behavioral modifications can be applied to those tasks.

By Ingemar Marklund

INTRODUCTION Today at LKAB, the primary mining method used is sublevel caving, independent of ore-body size, shape, dip, and geographical location. The mining of small ore bodies with relatively flat dip involves a lot of develop¬ment work, a large initial investment, big dilution, and large ore losses. In 1975 serious investigations into other possible methods, especially for those small ore bodies which do not lie in direct contact with other ore bodies, began. Different methods were studied and a number of in¬teresting ideas came from Russian mines. An analysis was made of one of the proposed methods, sublevel benching, in which mining is carried out from raises, and which uses the throw from the blast to place the broken ore. However, there were reservations about working in big open rooms at great depth, and doubts about the possibility of getting acceptable drilling results in an acceptable environment from raised platforms. Testing was therefore delayed for a time. However the investigations continued and in the fall of 1976, it was decided to try vein mining in a small ore body (Indian) (see Figs. 1 and 2). MINING RESULTS The results are now available from the mining of Indian and are as follows: Ore plan area 1200 m2 Level height 50 m Ore volume 60 000 m3 Ore tonnage 270 000 t Iron content 62% Dip 0.69 rad (40°) Ore thickness 14 m Ore compressive strength 26 MPa Ore C-factor (fracture density) 0.21 Hanging wall compressive strength 28 MPa Hanging wall C-factor 0.27 About 40 000 m of the holes were drilled by ring drills with an average productivity of 85 m/shift; loading of a round (2 rows, 750 m of hole) was usually accomplished in one shift. The total ore recovery was about 270 000 t with an average iron content of 59%, and three to four shifts were required per round (4700 t) to load. The principal of "throwing" the rock during blast¬ing worked well, and no ore remains on the footwall. ROCK CONTROL Before mining commenced at Indian, it was dis¬covered that the rock strength in its vicinity was rela¬tively poor. Since the ore is flatly dipping, and mining was to take place with open rooms, the strength of the hanging wall was of great importance. A supplementary program of exploration drilling was done during the fall of 1976 in order to assess fracture spacing and rock strength from the drill cores. Results showed that the strength of the hanging wall was low because of the many fractures. A decision was made to try cable bolting of the hanging wall by extending some of the ordinary blast¬holes. Cables (20 mm diam) were grouted in these larger holes and the rest of the hole was then utilized for ordinary loading (see Fig. 2). About 100 bolts altogether were installed and, to date, only small falls have occurred and the hanging wall is holding. Its exposed area is 2100 m2 DEVELOPMENT WORK On the 350-m level, four crosscuts (two per mining room), one longitudinal drift, and two elongated drifts (one per raise) for the raise climber were developed as shown in Fig. 1. Of the 230 m of drift, 60 m were in ore and the rest in waste. For mining room A alone, a total of 115 m of drift were needed with 30 m in ore. The drift dimensions were about 4.5 X 5.5 m. In the drifting on the 300-m level, two connecting drifts were driven from one existing transport drift forward to the respective raises. The total development was 93 m, all in waste (Fig. 1). The two raises having a length of 80 m each were driven at an angle of 0.68 rad (39°) from the hori¬zontal. They were driven along the footwall contact with a separation of 30 m and had an area of 10 m2. LONG-HOLE DRILLING The drilling of long holes with the ring drilling unit began in the fall of 1977 in raise A. The equipment consisted of an Alimak raise climber, equipped with a lower platform from which the charging was done.

Jan 1, 1982

By L. M. English

When plotted as head vs. volume, fan curves start high and decrease in head with increasing volume while mine head curves start low and rise with increasing volume. Their intersection is the system operating point But wait a minute: Isn't head loss a negative number, a debit? And isn't fan head an energy addition, a credit? This, as every ventilation instructor knows, is often a stumbling block to student or audience comprehension. It is possible to use the intuitively correct curves -pressure losses as negative values and energy additions as positive values -and still obtain the correct operating point: adding the two curves produces a third curve that intersects the x-axis at the operating point, the point at \\tIich the fan energy input exactly matches air circulation energy loss. Using this technique also makes it easier to account for outside influences on the system, such as natural ventilating pressure; with the standard approach it is quite easy to add or subtract such influences to the wrong curve. This approach can be extended to the graphical solution of any series/parallel circuit or ventilation net\wrk. The results are the same, and the approach is logically consistent and less confusing.

Jan 1, 1997

By R. E. McIvor, Brian Cornish, J. A. Finch, Yue Tan, Claude Gagnon

Fred C. Bond is recognized throughout the mineral processing world as the father of comminution equipment applied science and engineering. The Bond Work Index became a universal standard, and is the most widely used measurement tool for comminution energy consumption. This biography is the story of his lifetime of study, work experiences, experimentation, analyses and findings. His numerous published writings are reviewed. His legacy is one of comminution process engineering that will be used in perpetuity.

Feb 1, 2024

By D. K. Steele

The U.S. Bureau of Mines has investigated the recovery of metals from copper industry wastes by sulfuric acid leaching in a semi-continuous, bench-scale system to solubilize arsenic, copper, and molybdenum. Leach residues contained approximately 40 wt pct PbSO4, suitable for processing at a lead smelter. Arsenic and molybdenum removal from leach solution was examined using solvent extraction with tri-n-butyl-phosphate (TBP), and copper was subsequently recovered by cementation. Bleed electrolyte from a copper refinery was determined to be a viable source of acid for the initial leach stage.

Jan 1, 1991

By N. Edmonson

The demand for sulfur divides into two major categories: agricultural and industrial. Most of the agricultural demand is related to the production of phosphate fertilizer products. Industrial demand is derived from the demands for a large number of products and is related to a variety of industrial processes, no one of which characterizes it in a simple way.

Jan 1, 1994

By Ashish Kumar, Khadija Said, Ulupi Mishra, Sekhar Bhattacharyya

Using battery-powered equipment in underground mining can improve safety, advance automation, and reduce greenhouse emissions. In this context, rechargeable lithium- ion batteries (LIBs) have a competitive edge due to their high Coulombic efficiency, superior energy density, and extended cycling stability. However, several conditions must be met for their safe operation. Their failure can cause thermal runaway (TR), which poses a significant safety risk in underground mines. Despite studies having investigated this phenomenon using physics-based models, limited research has used deep learning to predict its implications. This study aims to bridge this gap by characterizing LIB TR under dynamic airflow through simulations and predicting temperatures using two of the most common recurrent neural networks: long short-term memory (LSTM) and gated recurrent units (GRU).

Feb 22, 2026

By Mehmet Ali Recai Önal, MAHMUT CAMALAN

Mineral liberation is one of the primary objectives in comminution circuits for the downstream separation of valuable minerals. Breaking minerals through their grain boundaries (grain-boundary breakage) enables mineral liberation in their natural grain size, removing the need for intensive grinding. This study aimed to evaluate if gaseous carbon dioxide, oxygen, or hydrogen can be used as grinding additives to promote the liberation of chromite grains by grain-boundary breakage. For this purpose, chromite ore particles in the −9.53 + 6.35 mm size fraction were pretreated by exposing them to carbon dioxide, oxygen, or hydrogen flow. Then, the untreated and pretreated samples were broken in a drop-weight tester under the same conditions. Finally, the graderecovery plots of chromite grains in the selected progeny size fractions and the overall progeny distributions were measured and compared. Pretreatment with carbon dioxide flow was found beneficial for grain-boundary breakage. It significantly enhanced the liberation of coarse chromite grains along with the overall progeny fineness. EPMAanalysis showed that the adsorption of carbon dioxide seems to reduce aluminum concentration at grain boundaries, which could be the reason for grain-boundary weakening. These results suggest that carbon dioxide can be used as a grinding additive, reducing the carbon footprint of the mining industry.

Oct 29, 2020

By Nathaniel Arbiter

The increasing size of flotation cells as the use of flotation has increased is traced from the first United States application of the process in Montana in 1911 through the following eight decades, using data from the Taggart handbooks (1927) and (1945), from the SME Handbook (1984), and from recent manufacturers' catalogues and other sources for the 1980s and 1990s. With the earliest mechanical cells less than 1 m3 (359) in volume and the largest now available at 200 m3 (7,000ft3), three requirements are necessary: 1) demonstration of advantages in replacing smaller volume by larger volume cells; 2) estimating power requirements, impeller dimensions, and operating rpm by correlation equations; 3) considering effects of using larger cells, in necessarily much shorter rows, on process kinetics. The resulting seven tables that address these problems are presented, and their implications discussed.

Jan 1, 1999

By S. G. Britton

"Strategies to improve performance in mining production, maintenance and mineral processing operations have evolved over time from straightforward time studies of individual machine performance in the 1960s-1970s to more sophisticated and better focused statistical and financial tools that have emerged in the 1980s-1990s. These newer strategies fall under the broad descriptive category of operational excellence.Operational excellence is the term that embodies a number of performance evaluating strategies, the most popular and relevant to mining include the following:• Six sigma for addressing errors within mining or milling process and work standards.• Lean manufacturing to optimize organizational and operational performance through continuous improvement.There are other strategies that can be applied as well and this paper is not focused on a review of the pros and cons of any one strategy. However, the common threads in these strategies embody the expectation that expected results from these efforts can be quantified and that value will positively benefit the targeted work process, organizational unit, equipment deployment or time schedule when applied to it as part of continuous improvement efforts.The priority for proceeding with any one or more of these efforts is based on the calculated net value of the required resources to make the change versus the estimated value gained. The practice is identified as the value mapping process.This discussion summarizes the value mapping process methodology used at a mature uranium mine and mill in northern Canada to work through the myriad of potential improvement efforts available through the operational excellence process for continuous improvement."

Nov 1, 2016

This paper presents the results of a unique study conducted by the National Institute for Occupational Safety and Health (NIOSH) from 2016 to 2019 to evaluate the effects of longwall-induced subsurface deformations on shale gas well casing integrity and underground miner safety and health. At both deep and shallow cover instrumentation sites, surface subsidence measurements, subsurface in-place inclinometer measurements, and underground pillar pressure measurements were conducted as longwall panels were mined. Comparisons of the deep and shallow cover test site results with those from a similar study under medium cover reveal an interesting longwall-induced response scenario. Under shallow and medium covers, measured horizontal displacements within the abutment pillar are one order of magnitude higher than those measured under deep cover. Conversely, measured vertical compressions under deep cover are one order of magnitude higher than those under shallow and medium covers. However, FLAC3D simulations of the casings indicate that, in all three cases, the P-110 production casings remain intact under longwall-induced deformations and compressions, which has serious implications for future mine design in areas where shale gas wells have been drilled ahead of mining.

Jan 7, 2020

By J. A. Marts

Reservoir properties including porosity and permeability distributions in longwall coal mine gobs have direct application to modeling the flow patterns and gas distributions in the gobs. Proper assessment of these distributions is required to assess gob gas hazards such as spontaneous combustion and explosive methane mixtures and to optimize gob gas venthole operation and nitrogen inertization. Determining the reservoir properties is difficult given that the gob is inaccessible and direct measurements cannot be easily taken. Several techniques had been used by previous researchers and will be discussed. This paper will present the methodology used to model the gob compaction by simulating the sequential extraction of coal. Two Western US coal mines were used for case studies. By determining volumetric strain, the porosity and permeability distributions in the gob can be calculated. The geo-mechanical model predicts an axisymmetric volumetric strain distribution with a steeper slope near the start-up room and a shallower slope near the active face.

By Scott Ellenbecker

Mining has evolved in recent years, taking steps forward in the way that the industry is considerate of the environment and the communities in which it operates. Technology plays a major role in that evolution. Osisko Mining?s Osisko Mine near Malartic, Quebec is developing a new way of doing business. One manager said, ?We are building the Osisko culture,? but the company is doing many things that could become industry changers. Much of the change is driven by mine ownership and management to offer a better workplace and better community relations. Mining equipment manufacturers are changing, too, by engineering products with more operator comfort, fuel economy, ease of maintenance and more cleanly designed machines. And for those drills working close to communities, smaller bore sizes and sound retention are just two changes for the better.

Jan 1, 2012

By Cem Şensöğüt, Özer Ören, Yaşar Kasap

The mining sector, which has an important place in terms of raw material and energy supply, is referred as a sector with one of the highest fatal accidents in comparison with other sectors. In this century, where occupational health and safety awareness has increased, it is important to review the past accident statistics and to determine the current deficiencies by using the information in the inventory. In this study, the Malmquist total factor productivity index (MPI) has been utilized to investigate the changes in the work accidents occurring in the Western Lignite Corporation (Turkey), where underground and surface production methods are applied, and to determine the measures to be taken. According to the results obtained, both the decrease in production amount and the increase in the number of accidents caused inefficiencies during the period in concern due to the expected 10-year economic life of the mechanized system operating in the underground production panel that came to an end in 2007 and the flooding took place in early 2017. Compared with the underground operations, it has been determined that production can be carried out at the appropriate scale despite the heavy working conditions encountered due to the changing climatic conditions and the progress of production in the surface operations.