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By C. J. Pritchard, R. D. Jacksha, K. V. Raj, C. Sunderman

"In underground metal/nonmetal mines, repeated short-term exposure to high levels of airborne contaminants can become a serious health issue. Currently there are no common mechanisms to control or mitigate these localized short-term high exposures to contaminants. To improve miners’ health and safety, the National Institute for Occupational Safety and Health (NIOSH) Spokane Mining Research Division (SMRD) is developing a Smart Monitoring and Control (SMAC) system for real-time monitoring of mine air quality, with integrated countermeasures to reduce these high concentrations of airborne contaminants in localized sections of mines. To develop and test a SMAC system that could be implemented in an underground mine, researchers at SMRD built a test apparatus incorporating a fan, louver, ducting, and sensors combined with atmospheric monitoring and control software. This system will institute effective countermeasures to reduce contaminant levels, improving miner safety and health. INTRODUCTION Underground metal/nonmetal mines continue to expand production by employing large equipment in greater numbers and by mining into hotter and more challenging environments which are typically further away from fresh air sources. This challenges the ventilation system to provide adequate quantities of fresh air to the workplace and increases the potential for air contamination that could result in immediate and long-term health and safety issues to miners. Currently, airflow and contaminant concentration in mines are typically based on full-shift sampling which may not identify repeated short-term exposures to high levels of airborne contaminants such as NO2, CO, diesel particulate matter (DPM), and dust with high silica contents. Repeated short-term exposure to these high levels of airborne contaminants over long periods can lead to serious health issues which are documented in several studies [1-3]. Based on data from ventilation surveys and contaminant measurements, mines often attempt to minimize exposures by sending more fresh air to the working areas where contaminant concentrations are found to be high. Real-time monitoring and control allows mines the option to monitor contaminants and implement controls in real-time. Real-time monitoring and control of the underground mine atmosphere has been a subject of research since its beginning in Finland at Outokumpu’s Pyhäsalmi Mine in 1969 [4]. More recently, the real-time monitoring and control problem has been addressed using ventilation on demand (VOD) systems [5, 6]. A VOD system attempts to deal with this issue on a global level by controlling fans, louvers, and doors to increase airflow to active work areas and reduce contamination. However, a VOD system only controls the distribution of airflow and may not be helpful in mines where the airflow is at maximum capacity. Researchers at SMRD are developing a SMAC system for real-time monitoring of mine air quality with an integrated ability to trigger countermeasures to reduce high concentrations of airborne contaminants in localized sections of mines. The SMAC system will be designed, tested, and refined in the laboratory environment before being demonstrated in an underground mine. This system will not only try to minimize the gaseous contaminants by regulating the airflow locally, but will also potentially employ a filtration system to reduce the airborne contaminants in case the maximum airflow capacity is reached. This paper presents development of the test apparatus for the SMAC system."

Jan 1, 2017

By Enrique Jelvez, Pierre Nancel-Penard

The traditional way of generating open-pit mine production schedules has several limitations. This work addresses the design and production-scheduling problem by considering minimum operational space requirements under a Direct Block Scheduling approach to generate extraction sequences that satisfy the operational space required. For this, traditional formulations were extended by including a new set of constraints that generate operating spaces for mining equipment to move and extract material. Then, a heuristic algorithm produces close to optimal practical pushbacks. This proposal was applied in a case study, and the results show its ability to generate practical production schedules without sacrificing expected return, obtaining differences in terms of Net Present Value (NPV) lower than 1% when compared to the traditional approach.

Jun 25, 2023

By Ihsan Berk Tulu, Mustafa Can Suner

The synthetic rock mass (SRM) approach and discrete fracture network (DFN) model, generated from the field surveys, are novel methodologies to study fracture rock mass behavior. In this paper, SRM and DFN methodologies were used to understand the influence of natural fractures on the mechanical response and failure mechanisms of stone mine pillars. First, a multi-stage up-scaling procedure with the homogenization process is established. Later, a stochastic sampling process on the SRM model to have further insight on the stone mine pillar mechanics is performed. Two-dimensional Universal Distinct Element Code (UDEC) is utilized to represent intact rock with the Voronoi-Trigon discretized blocks and to capture fractured rock mass behavior. The laboratory-size limestone mine rock specimens are systematically up-scaled to the average width of the field-size stone mine pillars. Then, the DFN model, generated from field data, is sampled to construct the SRM of the field-size pillars. By doing so, the effect of discrete discontinuities on pillar stability is studied by assessing the pillar strengths and failure mechanisms in various width-to-height ratios.

Jul 8, 2022

By Ihsan Berk Tulu, Ted Klemetti, Deniz Tuncay

"The Analysis of Retreat Mining Pillar Stability (ARMPS) program was developed by the National Institute for Occupational Safety and Health (NIOSH) to help the U.S. coal mining industry to design safe retreat room and pillar panels. ARMPS calculates the magnitude of the in-situ and mining-induced loads by using geometrical computations and empirical rules. In particular, the program uses the “abutment angle” concept in calculating the magnitude of the abutment load on pillars adjacent to a gob.In this paper, stress measurements from U.S. and Australian mines with different overburden geologies with varying hard rock percentages were back analyzed. The results of the analyses indicated that for depths less than 650 ft, the ARMPS empirical derivation of a 21° abutment angle was supported by the case histories; however, at depths greater than 650 ft, the abutment angle was found to be significantly less than 21°. In this paper, a new equation employing the panel width to overburden depth ratio is constructed for the calculation of accurate abutment angles for deeper mining cases.The new abutment angle equation was tested using both ARMPS2010 and LaModel for the entire case history database of ARMPS2010. The new abutment angle equation to estimate the magnitude of the mining-induced loads used together with the LaModel program was found to give good classification accuracies compared to ARMPS2010 for deep cover cases.INTRODUCTIONIn the early 1990s, the Analysis of Longwall Pillar Stability (ALPS) was introduced by Mark (1990) as a chain pillar design software and was generally accepted and used by the U.S. coal mining industry. Following the success of ALPS, the National Institute for Occupational Safety and Health (NIOSH) developed the Analysis of Retreat Mining Pillar Stability (ARMPS) program for designing retreat mining pillars using a similar approach as ALPS (Mark and Chase, 1997). The Australian mining industry also recognized the success of ALPS, and Colwell, Frith, and Mark (1999) calibrated the program to Australian conditions. The ALPS and ARMPS programs draw their strengths from the large databases that are used to calibrate them (Mark, 2009). However, following the Crandall Canyon Mine collapse in 2007, NIOSH had to reconsider the pillar design criteria used in deep-cover retreat mining (Mark, 2010). The ARMPS overburden load prediction algorithm was improved to more accurately predict the loading of narrow panels with high overburden depths by implementing the pressure arch concept, and this new version is called ARMPS2010."

Jan 1, 2019

By C. Arthur Lefler

The Smoky Valley Mine is jointly owned by Louisiana Land and Exploration Company, Felmont Oil Corporation and Case Pomeroy Company. Copper Range Company, a subsidiary of L.L. & E. is the operator of the mine. The mine is located about 60 miles (100 km) north of Tonopah, Nevada on Highway 376 (formerly 8A) in the Big Smoky Valley on the western flank of the Toquima Mountain Range In the shadow of Mount Jefferson. The mine is at an elevation of about 6100 ft. (1860m) and is situated on the southwestern flank of Round Mountain, the hill for which the town of Round Mountain is named. The ore is a rhyolitic iglmbrite with coarse gold occurring along fractures and with fine microscopic gold disseminated in the rock mass. Minor silver is associated nth gold. Annual mining is planned at 5.8 million tons (5.3 million tonnes) per year with 2.2 million tons (2 million tonnes) as ore (7,000 tons or 6,400 tonnes per day).

Jan 1, 1981

By K. V. K. Prasad

Forecasting mined grade variability from exploration information is a challenging task in mine planning. For effective planning of activities such as workplace scheduling, ore grade quality control etc. development of realistic numerical/simulation models of in-situ variability from exploration information is an essential first step. Geostatistical conditional simulation (GCS) is one of the well known methods to develop these simulations. Recently, stochastic fractal models based on the assumptions of scale-in variance and self-similarity have been used for developing simulations of several natural phenomena. It has been suggested that these models might permit generation of short-scale variability information from exploration data with greater fidelity when the data satisfies the attendant assumptions. In this paper the stochastic fractal models are reviewed and their relationship to geostatistical variogram models is examined. A comparison of the two simulation techniques has been per-formed using coal sulfur data from a mined out coal property. The results of this comparative analysis are also presented in the paper.

Jan 1, 1992

By J. Kemeny, B. Norton, T. W. BoBo

Digital image analysis systems to quantify particle size of crushed materials have successfully been applied in large-scale mining operations throughout the world. Particle size measurement at various crushing and sieving stages, especially in aggregate production, will facilitate the industry’s desire and need to achieve higher levels of process control and automation. This paper will 1) summarize applications of digital image analysis in the industrial minerals industries and introduce the Split-Online technology; 2) detail an actual recent test application of digital image analysis that ultimately lead to the installation of an automatic, non-invasive particle size distribution monitoring system; 3) document how this information is being applied: and 4) summarize the new Split-Online Aggregates Module now available.

Jan 1, 2004

By George A. Komadina

The Pima Mining Company lies 20 miles southwest of Tucson, Arizona, and some 45 miles north of the Mexican border. The mill is situated on a hillside overlooking Tucson and the Santa Cruz Valley, the ground generally sloping northeast at a 2.5 percent grade. The hillside location allows for gravity flow generally through the plant as well as for: tailing disposal.

Jan 1, 1965

By C. G. Bock

Geologic profiles constructed from exploratory drill holes gave basic geologic information for bidding on 4913 ft. of twin rock tunnels under the Potomac River. To provide additional geologic information for construction, tunnel faces and shafts were mapped throughout excavation. This information was plotted in plan and section so that geologic structure could be projected ahead and prediction of conditions could be made. In structurally complex areas, 3-D models were made and used to show the geologic structure. Core from exploratory drill holes was relogged and structure oriented with that found in the tunnels to make the ultimate use of the core and refine the geologic picture. As excavation proceeded, geologic mapping showed that the projection-prediction approach was useful and essentially correct.

Jan 1, 1974

By W. J. Fotheringham

This paper deals with the mining techniques employed at Canada Tungsten's northern Canadian operations, particularly with respect to their effect on productivity, safety, and stability of relatively large underground openings. The ore body was originally mined commencing in 1974 using conventional pneumatic jumbos in a topslice and horizontal benching room and pillar layout. Pillar stability became an increasing problem as mining progressed, leading to a re-examination and ultimately a conversion of mining method. Rock mechanics considerations and the effect of extraction rate on ground control costs and conditions are analyzed. Other areas discussed concern the results acheived through the use of large diameter I.T.H. drills, radio remote controlled L.H.D. units, and a unique system of hydraulic backfill placement.

Jan 1, 1985

By Fred J. Fleischauer

Industry requires higher speed sheet stacking. High speed sheet stacking requires equipment and techniques to solve several inherent difficult problems, such as the tendency for sheets to sail, and the need for a means to absorb the kinetic energy of the sheet without damaging the sheet. Accurate alignment of the sheets on the stack is another problem difficult to solve. The paper first analyzes the process of sheet handling into its basic elemental steps. It then describes equipment and techniques presently used for moderate sheet handling speeds, with emphasis on how each step in the stacking process is accomplished by the present equipment. The limitations to speed-up of present equipment is discussed. New high speed equipment, either recently introduced to the market, or in the process of development, is described. Magnetic, air float and vacuum conveyor stackers are compared.

Jan 1, 1973

By L. Yuan, J. Soles, W. Tang, R. Thomas

Lithium-ion battery pack fires pose great hazards to the safety and health of miners. A detailed experimental study has been conducted at the National Institute for Occupational Safety and Health (NIOSH) Pittsburgh Mining Research Division (PMRD) to investigate the effectiveness of different fire suppression systems on Li-ion battery pack fire extinguishment. Tests were conducted in a well-ventilated container. Two sizes of battery packs (12V, 24V) were heated by heater strips to trigger thermal runaway and fire. Water mist with different flow rates, ABC powder, type D dry chemical, and water mist with F500 additives were used as the fire suppression agents. Multiple thermocouples were installed on the battery packs to measure the temperature evolution during the tests. The results indicated that the water mist with F500 additives is the most effective suppressant among the agents tested. Dry chemicals, however, do quench the fire for a moment, but cannot prevent re-ignition of the battery since they do not provide enough cooling. The findings of this paper can be used to develop safer battery fire suppression techniques in mining environments.

Feb 1, 2023

By Javad Sattarvand, Milad Ghahramanieisalou

As new technologies are introduced to the mining industry, the challenges related to their safe assimilation and the potential changes they bring to mining techniques necessitate adjustments to the current operations. Predictive simulations are critical to understanding unforeseen scenarios and shifting costly changes from the operational stage to the design. The Digital Twin methodology has gained a lot of attention in recent years. Many industries, from manufacturing to engineering and even social sciences, are adopting this approach to understand better the complex systems they are working with. By considering the enormous expenses and risks related to a pilot project, DT could replace that by acting as a prototype in which realistic tests and simulations are carried out with close to zero cost. DT includes a data hub, simulation and analysis tools, and visualization platforms to enable appropriate designs and monitoring plans focusing on unknown areas. A few examples of DT's application in mining include fleet management, Mine-to-Mill optimization (especially D&B), geotechnical digital twin (gDT), etc. When developing regulations, testing the efficiency of the mine layout, design, and magnitude of the restricted area and its access points, human-machine interactions, risk identification, and management processes, examining the efficacy of control systems, and monitoring, DT could help speed up (or completely replace) the process in the physical world.

Jun 25, 2023

By A. Delgado-Jimenez, O. J. Restrepo-Baena

"Sustainability is a concept that involves several aspects like social, economy and environment. For the concept of sustainable mining is an action that involves to do more in social acceptance, distribution of welfare, an stable economy and the environment. Understanding the mining operation that creates a new state that is necessary to prepare and conduct searching for the best results in sustainability. The results of sustainable mining could be directed to achieve less net environmental impacts, more economic development through the transformation of the natural capital and the social acceptance as the result of good negotiations with the communities in the surroundings. To do that, one option is to create frameworks to planning the regional mining developments that allows the stakeholders to decide and develop different strategies to addresses the sustainability in a mining environment. Strategies based on the understanding of the whole mining business, the environment in which it operates, composed for a natural resources network that interact in a complex system, social system composed by different groups, communities and economies that could be subject to big transformations. INTRODUCTION The mining sector represents one of the most significant challenges for sustainable development, given the magnitude of the impacts that it has on the social and natural systems and the potential to generate welfare associated with its exploitation. Some of the main challenges of mining to contribute to sustainable development are the reduction of the environmental and social impacts of mining operations, to advance in the distribution of benefits in the community and the investing in the development of substitutes. To help in this direction it is necessary to integrate more actors than those who have been considered traditionally in the development of the mining business, and consider the natural environment, communities and the several dynamics generated by the interaction of these elements that contribute to sustainable development. This work provides some useful considerations for sustainable development of mining operations in regions with mining vocation, through the convergence of objectives and the finding of synergies between the existing conditions in the territories and the potential conditions that are generated by new mining developments. A DEFINITION FOR SUSTAINABILITY IN MINING The definition of the Brundtland Commission in 1987 established that sustainable development is ""the ability to ensure that it meets the needs of the present generations without compromising the ability of future generations to meet their own needs""."

Jan 1, 2015

By Robert F. Conley

Attrition milling, once employed exclusively for the dispersion of pigments, has in recent years found a host of new applications in the area of mineral processing and mineral-pigment production. Broadly categorized, attrition milling is divided into two classes, as defined by the machinery's function, vibratory milling and rotational milling. Each mill type has been defined as a variation on ball milling and the terms, "vibratory ball mill" and stirred ball mill" appear in the literature. The primary design differences between attrition and ball mills are: (1) a stationary canister (or shell) (2) smaller grinding media (3) grinder energy is motor limited rather than gravity limited (4) strong media/feed size dependance.

Jan 1, 1983

By Sara Swiokla Korsikas, Toren Olson, Amado Guzman, Yuri O. Zepeda

Ore agglomeration has been used as part of the heap leaching process for the last 40 years. However, industrial experience shows that the lack of a universal agglomeration standard has limited the benefits of this otherwise valuable unit process. The more complex the ore in terms of the nature and relative abundance of fines (particle size smaller than 74 μm), the more important that the agglomeration product satisfies some minimal requirements. This paper presents an agglomeration scale that identifies the quality standards for agglomerates and documents the resulting mechanical, physical and hydraulic (hydrodynamic) behavior associated with each level on the agglomeration scale. The hydrodynamic properties of an agglomeration product are critical for the proper design of a leaching operation and, as shown in this paper, can be used to select the optimal pretreatment method for a given ore sample. Agglomeration as a unit process not only allows better conditioning of the hydrodynamic behavior of the ore but also creates an opportunity for optimized delivery of reagents to kickstart the leaching process, which may ultimately improve the economic performance of leaching. Industrial case data are used to demonstrate the shortfalls associated with low-quality agglomeration and the benefits of improved agglomeration, which range from enhanced porous structure (better percolation and drainage characteristics) to better metallurgical response (faster kinetics and higher metal recovery). Proper agglomeration has been used to render otherwise untreatable ores into valuable leaching resources.

Sep 1, 2024

By D. W. Park

Geologic condition is one of the most important factors for longwall mining operations, especially, the existence of faults limits the mineable area, or cause stress variations at the longwall face. Recently, a longwall panel passed through a fault at the Shoal Creek Mine of Drummond Company, Inc. The fault was situated diagonally along the longwall face and the coal seam was displaced up to 2.4 m (8.0 ft) in a mode of a normal fault. LoSCoMS (Longwall Strata Control and Maintenance System) was used for monitoring shield pressure every minute and interpreting data in terms of setting, developing and final pressures. The results of the analysis regarding the influence of the fault on the shield pressure are presented.

Jan 1, 1999

By Levent Ozdemir, Charles Merguerian

Between 1996 and 1999, a high-performance Robbins TBM [235-282] excavated a 5 mile long, 23´2? wide, and ~700´ deep tunnel through the subsurface of southwestern Queens. Low penetration rates (~6´/hr [actual] vs. ~9´/hr [anticipated])resulted from changed rock mass conditions mostly attributable to high-grade metamorphism of the rocks. Over a three-year period, as-built circumferential geologic mapping (scale 1?=10´) and digital imagery of the tunnel, fracture and fault analysis, structural, lithologic, and petrographic studies have shown that the rocks of the Queens Tunnel consist of orthogneiss of mesocratic, leucocratic, and mafic composition. These metaigneous rocks developed coarse-grained fabrics during Grenvillian (~1.0 Ga) granulite facies metamorphism, and retained their nearly anhydrous, poorly foliated character during subsequent high-grade Ordoviciande formation. Lacking a penetrative foliation, the coarse granoblastic rock texture and extraordinary garnet content (up to 50% in some zones) together proved animpediment to efficient chip production and resulted in bimodal production of blocks and excessive fines. TBM excavation of the Queens Tunnel was also hindered by geological conditions that included unexpected lithology and rock fabric orientation, a zone of crosscutting hypabyssal rhyodacite dikes, and unanticipated extent of brittle faults. The dikes and brittle faults produced blocky ground conditions and a collapsing face condition that produced cutter damage and decreased utilization. Such fundamental textural, mineralogic, and lithologic control over hard-rock TBM penetration can be predicted by careful pre-bid geological analysis. To determine the causes of lower than anticipated TBM performance, a detailed investigation was carried out that included analysis of operational data from the TBM data logger and an extensive laboratory test program on cores retrieved from tunnel walls. Integrated laboratory testing included punch, point load, tensile strength, Cerchar abrasivity, and linear cutting tests, independent petrographic analysis and machine performance analysis. These allied investigations have provided quantification that the rock mass exhibited an unusually high degree of toughness and rock directional properties and established geological causes for decreased TBM penetration rates.

Jan 1, 2003

By Donald I. Bleiwas

The U.S. Bureau of nines evaluated the potential availability of tungsten from 57 tungsten mines and deposits in 19 market economy countries (1). The 38 properties that were producing at the time this study was performed contain approximately 375,000 tons1 of W03 (tungsten trioxide). The total estimated recoverable resource from all properties studied, both producers and nonproducers, was 1.2 million tons W03 (demonstrated level). Approximately 143,000 tons of W03 is recoverable from producing properties with costs at or below the January 1983 market prices. The study indicates that by 1990 production from currently operating mines in market economy countries will decrease as their demonstrated resources become exhausted. Some of this potential decline may be offset by lower than anticipated levels of market demand, discoveries of additional resources at producing mines, development of other known deposits, and/or discoveries of new deposits. Development of new tungsten resources in market economy countries will likely result in costs higher than exist at currently producing properties. The People's Republic of China has been steadily increasing production and export of tungsten in various form and currently supplies about 25 pct of U.S. imports. China's tungsten mines are large, high-grade operations capable of producing at relatively low cost. These factors, coupled with China's apparent need for foreign exchange, could lead to further expansions of production and exports from China, with a consequent increased dependence by market economy countries on China for tungsten requirements and a threat to the survival of the market economy countries' tungsten industries.

Jan 1, 1984

By G. C. Kachel

Significant effort has been expended and considerable success has been realized m the application of instrumentation and automatic control equipment in the mining and ore processing industries. This effort has been applied principally to process equipment with the objective of increasing throughput, minimizing labor requirements and/or improving grade or product quality. Less spectacular, but quite rewarding has been the successful application of instrumentation and automatic control equipment to a wide variety of material handling equipments. This paper describes some of this work including: (1) automatic weighment of load-haul-dump units and trams underground; (2) automation of skip loading; (3) instrumentation applied in feeders and conveyors; (4) level measurement in bins, silos, vessels and sumps; (5) automatic blending of sized materials; (6) automatic loading of ships, trains and trucks; (7) automatic control of tailings disposal facilities

Jan 1, 1973