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By P. Lopez, E. Wellman, N. Risso, A. Anani

Current machine learning models used for roof fall hazard prediction are mounted on expensive sensors, computationally expensive, or lack the robustness for accurate prediction in the underground mining environment. This research aims to provide a design methodology for a robust, low-cost, deep learning-based algorithm for underground mine roof fall hazard prediction. A data sampling plan is developed to ensure the replicability and robustness of the developed model. In addition, feature engineering and transformation methods are described to identify relevant features for hazard identification. The methodology described here will be used in model development, tested, and implemented as a real-time mobile device application. The new tool will be expected to detect roof fall hazards in real-time and contribute to a crowdsourcing approach for underground hazard detection.

Feb 1, 2023

By J. A. Luppens

Five years ago, Phillips Coal Company decided replacing mainframe/workstation programs with a new package of PC software was clearly the best solution for computer reserve modelling. The system chosen was actually three programs distinguished by their power, cost, flexibility and integration, and ease of learning and use. Phase I involves the use of the "StratiFact" program for borehole data management and seam correlation. This phase is probably the most neglected, yet critical aspect of reserve evaluation. Phase II employs the "PC/Cores" package for modelling and volumetrics. Phase m is "PC-Cut" which provides mine planning tools including an automated cut generator.

Jan 1, 1996

By G. E. Jones, G. K. Hoffman

Through the USGS National Coal Availability pro-gram, two San Juan Basin studies have been completed. The study areas are in the northwest Bisti field, Fruitland Formation and in the eastern Standing Rock field, Menefee Formation. Original resources are 4.66 Gt and 3.46 Gt (5.14 billion stand 3.82 billion st), respectively, in the Bisti and Standing Rock areas. Bisti coal resources are greatly reduced by the Bisti-De-Na-Zin wilderness area (1.13 Gt (1.25 billion st)). Technological restrictions remove 31% from Standing Rock original resource. Available resources are 60% (2.79 Gt(3.07 billion st)) of the Bisti original resource and66% (2.26 Gt (2.49 billion st)) of the original Standing Rock resource.

Jan 1, 2000

By B. Yarar

The critical surface tension of wetting (?c) of Cu2S, FeS2, PbS, and MoS2 were determined by plotting flotation recovery versus YLV which was arranged by methanol, and Extra-polating to % R = 0. ?c values ranged from 26 dyne cm-1 for MoS2 to 49 dyne cm-1 for PbS and elemental sulfur gave a value of 31.5 dyne cm-1. Minerals exhibiting natural flotability of different extents, could be separated from their mixtures in the absence of conventional flotation reagents, but controlled ?LV. Correlations between non-stoichiometry and degree of natural hydrophobicity for MOS2 are also reported in this paper.

Jan 1, 1983

By M. R. Shahan, W. R. Reed, S. Klima, T. W. Beck

"Testing was conducted to determine the ability of foam to maintain roof coverage in a simulated longwall mining environment. Approximately 27% of the respirable coal mine dust can be attributed to longwall shield movement. Developing controls for this dust source has been difficult. The application of foam is a possible dust control method for this source. Laboratory testing of two foam agents was conducted to determine their ability of foam to adhere to a simulated longwall face roof surface. Two different foam generation methods were used; compressed air (CA) and blower air (BA). Using a new imaging technology, image processing and analysis utilizing ImageJ software produced quantifiable results of foam roof coverage. For CA foam in 3.3 m/s (3.3 m/s (650 fpm)) ventilation at 3 minutes after application, 98% of agent A was intact, while 95% of agent B was intact on the roof. At 30 minutes after application 94% of agent A was intact while only 20% of agent B remained. For BA in 3.3 m/s (3.3 m/s (650 fpm)) ventilation, the results were dependent upon nozzle type. Three different nozzles were tested. At 30 minutes after application 74-92% of foam agent A remained, while 3-50% of foam agent B remained. CA foam seems to remain intact for longer durations and is easier to apply than BA foam. However, more water drained from the foam when using CA foam which demonstrates that BA foam retains more water at the roof surface. Agent A seemed to be the better performer as far as roof application is concerned. This testing demonstrates that roof application of foam is feasible and is able withstand a typical face ventilation velocity, establishing this technique’s potential for longwall shield dust control. INTRODUCTION NIOSH personnel have visited many longwall operations at various geographical locations in the U.S., conducting benchmark surveys to characterize current operating practices and dust control measures in use. Sources of respirable dust generated from the longwall face have been identified as: intake (10%), stage loader (20%), shields (27%), and shearer (43%) [1]. Dust generated from the shearer, armored face conveyor, and the stage loader can mainly be controlled by water sprays and increases in ventilation air quantities, however, research has demonstrated limited effective controls for dusts generated by shield movements [2]. One possible approach to mitigating shield dust generation is to apply a layer of water or foam to the shield-roof interface. Once this interface is blanketed with foam or water, dust will be less likely to become airborne and contaminate the airways over the personnel walkways. Though water is an abundant and common dust control measure, roof applications have limited success because water is unable to remain in-place in adequate quantities for the necessary duration between application and shield advance. Past and current testing of foam for material properties has shown that it has longer applicability times, ranging from 10 to 60 minutes [3] and has shown better performance for dust control, ranging from 19-96% improved efficiency over water [4, 5, 6, 7, 8]. The majority of this foam dust control research has focused on dust control efficiency at the longwall shearer or continuous miner cutting drum."

Jan 1, 2017

By T. J. Close

On September 10, 1991, Secretary of the Department of Interior Manuel Lujan deleted the Silver Peak Range North Wilderness Study Area from the list of U.S. Bureau of Land Management lands in Nevada to be considered for wilderness designation. This decision was based in part on the U.S. Bureau of Mines mineral investigation of the wilderness study area which found that it has indications of precious metals resources. The following is a summary of the results of that mineral investigation. The study area lies between the Silver Peak and Dyer mining districts of west-central Nevada. The Silver Peak mining district, to the east, has a long mining history dating back to 1907 when precious-metals-bearing veins were discovered. The major producer in the Silver Peak district was Sunshine Mining Company's Sixteen-to-One silver mine. During the Bureau's study the Sixteen-to-One mine was operating; it has since been idled due to low silver prices. Precious metals-bearing veins were discovered in the Dyer district, to the west of the study area, in the 1860's. Mineral activity in Dyer district consisted mainly of prospecting. The Silver Peak study area itself has no mining history and contains only a few mining claims, but the Bureau examined 13 mineralized sites, most previously unknown and unclaimed. These sites are along two zones that cross the study area from the Silver Peak to the Dyer mining district. The two zones transect a volcanic center of fractured and altered rocks that contain epithermal veins of quartz, calcite, and jasperoid with gold, silver, and base metals. At the surface these veins are poorly defined and poorly mineralized. The more than forty veins examined in the study area are as thick as 17 feet and as long as 1,000 feet. Samples from surface exposures of these veins contained as much as 0.02 ounce per ton gold, 2.1 ounces per ton silver, 1.0 percent copper, 2.6 percent lead, and 0.4 percent zinc. Analyses of the Bureau data disclosed no vein large enough or of high enough grade to be classified a mineral resource. However, most do have indications of silver-and gold-bearing resources at depth. Subsurface exploration had to be done on the vein at the Sixteen-to-One mine to outline reserves (a vein averaging about 22 feet thick and containing 6-to 7-ounces per ton silver); the same is true of veins in the Silver Peak Range North Wilderness Study Area.

Jan 1, 1993

By Thomas C. Shrake

The Lomas Bayas copper property is located93 km (58 miles) east of Antofagasta, Region II, Chile (Fig. 1). The deposit was discovered in 1880. The deposit produced intermittently until 1992. Production at Lomas Bayas took place in high-grade veins and breccias mined underground. During 1991, Empresa Minera Mantos Blancos SA (EMMB) optioned the property from Compania Doña Ada SA. Doña Ada maintained the right to continue mining the ores by open-pit and block-caving methods and hauling the ore to its plant located60 km (37 miles) to the north. EMMB conducted exploration and column test programs. On May 9, 1994, Compania Minera Gibraltar Ltda.(CMGL) signed a purchase option agreement to acquire the Lomas Bayas property. CMGL conducted 8,612 m(9,490 ft) of reverse-circulation drilling, 2,028 m (6,650ft) of diamond drilling, a series of metallurgical tests and geologic mapping. The company then decided to exercise its purchase option.

Jan 1, 1996

By J. S. Young

During 1975, the Reclasource Corporation constructed and commissioned a plant for the recovery of mill scale, coke breeze, blast furnace dust, blast furnace sludge and basic oxygen furnace dust at the site of Crucible Alloy Division, Midland, Pennsylvania. The Reclaform Process was employed as the criteria for plant design. This Process takes the solid in-plant fines as listed above, commonly found in integrated steel mills, sizes and forms them through the use of a carbonaceous binder briquetting system and cures the binder through a final heat-treating step. 15,000 tons of Reclaform briquets have been tested in the Crucible blast furnace in several campaigns structured to assess material handling properties, burden feasibility and finally culminating in an iron and carbon assessment campaign. Data are presented from the records of the blast furnace operation and conclusions are drawn that both iron and carbon utilization have been demonstrated.

Jan 1, 1977

By E. A. Zawadzki

The problem of pollution of water by mine drainage is at least as old as the mining industry itself. However, research on the formation, composition, treatment, and abatement of mine water is a relatively recent historical event. At Bituminous Coal Research, Inc., acid mine drainage control has been an important area of work since 1944, at which time BCR began sponsorship of research at West Virginia University. The work at West Virginia University involved a detailed study of the acid mine drainage problem and led to the identification of iron oxidizing bacteria as important factors in the formation of acid mine water. The results of this research were summarized in 1954 by Temple and Koehler (1) who concluded that "no practical solution for the problem" of controlling acid mine drainage is yet known.?

Jan 1, 1967

By S. Dawson

The Republic of South Africa has become a major producer of opencast coal in recent years. Opencast production commenced in 1970 and by 1977 some 10 million run of mine tonnes were being produced annually, Since then surface mine activity has increased to more than 60 million tonnes which represents approximately one third of the total annual South African? coal production. Whilst a substantial portion of this production is exported, the majority is used in the domestic market, The largest consumer, being the South?\ African Electricity Commission (Eskom), produces most of South Africa's electricity using coal fired power stations,

Jan 1, 1990

By John W. Sweeney

Florida is usually thought of as a vacation State, not a mining State, yet Florida has been the leading producer of phosphate rock in the United States for 85 consecutive years and in 1978 supplied over 80 percent of the national output and over 30 percent of the world's output. It is estimated that the Central and South Florida phosphates contain 412,800 short tons (374,000 metric tons) of U308, that 115,000 short tons (104,000 metric tons) of U308 will be contained in the wet-process phosphoric" acid procsssed in the United States through the year 2000, and that 54,000 short tons (49,000 metric tons) of U308 will be available from Florida. In 1978, two companies in Florida and one in Louisiana went on-stream recovering uranium oxide from wet-process phosphoric acid and three others started construction of U308 extraction facilities. These six companies will have the capacity to recover 2,137 short tons (1,900 metric tons) of U308 annually in 1980, which will account for about 15 percent of our domestic requirements.

Jan 1, 1979

By Frank E. Chase

Retreat mining is one of the most hazardous operations conducted underground. One of the keys to miner safety and an efficient recovery of the reserves is to design adequately sized production pillars to prevent pillar squeezes, excessive pillar spalling, severe floor heave, roof falls, and pillar bumps. Currently, few pillar design approaches are available which consider the abutment pressures generated by the gob. The Bureau of Mines is developing a method called Analysis of Retreat Mining Pillar Stability (ARMPS) to aid in the design of retreating sections. Back analysis of 42 case studies indicates that ARMPS can be helpful in predicting stability during retreat mining operations.

Jan 1, 1993

By D. R. Wilburn

This summary of international mineral exploration activities for the year 2009 draws upon information from industry sources, published literature and U.S. Geological Survey (USGS) specialists. The summary provides data on industry exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry and presents analyses of exploration activities by the mineral industry based upon these data. Two types of information are reported and analyzed in this annual review of international exploration for the year 2009: 1) budgetary statistics expressed in U.S. nominal dollars provided by Metals Economics Group (MEG) of Halifax, Nova Scotia, and 2) information on regional and site-specific exploration activities that took place in 2009 and were compiled by the USGS. The MEG information summarizes planned company budgets for worldwide exploration activities in 2009, primarily for base metals (copper, lead, nickel and zinc), diamond and precious metals (gold, platinum-group metals and silver). Information on uranium exploration was included in the MEG overview for the first time in 2007, although this information was not included in the USGS analysis prior to 2008. The MEG survey methodology was changed in 1999 to include companies with exploration budgets greater than $100,000, as well as those companies included in prior studies whose anticipated budgets were above $2.9 million. MEG estimates that its post-1999 surveys cover at least 90 percent of world nonferrous nonfuel mineral exploration budgets. The 2009 survey is reported by MEG to cover an estimated 95 percent. Companies who chose not to participate in the MEG study, private companies that do not publish data and government-funded exploration activities make up the majority of the remaining 5 percent. MEG included 86 more companies in its 2009 survey than it did in 2008.

May 1, 2010

By K. Fountain

In Novemeber of last year I visited a mica mine in Hunan Province, China. For nine months , we had been trying to sell Chinese mica to a customer in Belgium. Talking to the customer was like negotitating with a stone wall. The buyer refused to communicate any -thing other than his steadfast refusal to consider Chinese mica. He would not advise us what he wanted, what specifications or grades. He would give no indication if our price at market, or reasonable, or totally out to lunch. He would not even accept samples. It took no genius to guess that the mica buyer had at some time in the past bought a shipment of Chinese mica and had received a disaster. I invited the mica mine in Hunan in order to see for myself what could be done - without massive investment in equipment and instruments - to upgrade the quality of the mica for export. We had seen this type of customer reaction before. One disgruntled customer who had pur¬chased pigment grade barites direct from China ranted and raved about unreliable and inconsistent quality. It did no good to explain to him that China is a big country, with hundreds of mines scattered throughout many areas, each producing a different product. Our further explanation that Chinese export organizations also varied in degree and efficiency of customer service fell on deaf ears. Samples had no effect on his perception. Eventually we showed him photoraphs of two mountains of pigment grade barites. One lot was our sales of pigment barites to a major European minerals processor. Our Chinese barites stood proudly white and beautiful next to a hill of other material which now appeared at best mediocre and dull by comparison, and which the buyer had decided to reject after he received our Chinese barites. Finally the customer was sufficiently impressed to look seriously at our guaranteed specification and the outturn analysis performed by our other customer.

Jan 1, 1987

By M. Ralchenko, C. Samson, M. Svilans, C. Walsh

"Through-the-Earth (TTE) radio has been proposed as a means of emergency communications in mines. The propagation of a TTE radio signal depends chiefly on the subsurface conductivity distribution. Robust forward models of signal propagation can be computed based on a realistic conductivity estimate. These models can be used, for example, to optimize frequency, estimate signal range, identify zones of anomalously strong or weak signals, or to optimize the position of the above-ground TTE radio unit. A method was developed to determine the conductivity distribution of a mine overburden using TTE radio transmission data. At multiple locations in an underground test mine, we recorded a wideband electromagnetic signal, spanning a frequency range of approximately 500 to 8,500 Hz, transmitted from a vertical magnetic dipole at the surface. Using a finite-difference time-domain forward modeling code, a layered Earth conductivity model that accounts for topography was fitted to the observed data, which minimizes the difference between the calculated and observed attenuations for each transmitter-receiver pair, for each frequency of interest. Introduction and objectiveThrough-the-Earth (TTE) radio has been proposed for emergency underground communications. The most common type of TTE radio is based on the transmission and reception of signals by electromagnetic induction. These signals are in the extremely low to very low frequency range — in practice, between 400 and 9,000 Hz. This technology was historically developed for mine safety, although recently other applications have been suggested, such as communications in civilian infrastructure like high-rise buildings or tunnels, in the military, and even for wireless detonation and activation. In a coal mine, which is a setting of particular importance for TTE radio due to the higher risk of accidents, day-to-day communications can be done through a wired link. High-frequency line-ofsight systems, whose signals cannot penetrate rock, are also used for communications from nonfixed points. Another option is a leaky feeder system, which is a permutation of a line-ofsight system and a wired link, where a partially shielded coaxial cable allows the signal to “leak” (Delogne, 1982). In an incident such as a mine collapse or explosion, a TTE radio system can still provide a communication link, as wired systems can be severed, and line-ofsight systems cannot penetrate through collapsed portions of the mine, or to the surface (Forooshani et al., 2013; Yarkan et al., 2009)."

Jan 7, 2018

By Verya Nasri, Mehdi Bakhshi

"Fiber reinforcement has emerged as an alternative to steel bars in precast concrete segments due to advantages such as saving cost and reducing production time while developing a more robust product with improved handling and long-term durability. ACI recently drafted a new report as the first design guideline on FRC tunnel segments to provide specific guidance for this emerging technology. ACI document offers general information on the history of FRC precast segments from tunneling projects throughout the world; a procedure for structural analysis and design based on governing load cases, and a description of the material parameters, tests and analyses required to complete the design. This paper summarizes the design considerations in this ACI guideline prepared by the authors of this paper as the main contributors. Application of this guideline to design of a tunnel with an internal diameter of 5.5 m (18 ft) results in elimination of steel bars.INTRODUCTIONPrecast concrete segments are installed to support the tunnel excavation behind the Tunnel Boring Machine (TBM) in soft ground and weak rock applications. The TBM advances by thrusting off the completed rings of precast concrete segments that provide both the initial and final ground support as part of a one-pass lining system. These segments are typically designed to resist the permanent loads from the ground and groundwater as well as the temporary loads from production, transportation and construction. Tunnel segments are generally reinforced to resist the tensile stresses at both the Serviceability (SLS) and the Ultimate Limit States (ULS). With traditional rebar, a significant amount of labor is needed to assemble the cages and place the rebar, which results in higher production costs.Fiber Reinforced Concrete (FRC) can be used to enhance the production, handling, and placement of precast concrete segments. This is because of the uniform dispersion of fibers throughout the segment to include the concrete cover, which is very advantageous for resisting the bursting and spalling stresses. These stresses develop as a result of the high loads induced on the segments during the TBM jacking process. The presence of fiber in the concrete matrix helps mitigate against unintentional impact loads during segment handling and tunnel construction operations."

Jan 1, 2016

By R. L. Unger

Restricted fields of vision are a common problem with underground mining equipment. Also, when lighting systems are provided, they may be positioned where they cause glare. This restricts the visibility around the machines even further. To help address these problems, the US Bureau of Mines has developed a PC-based software package to aid in the analysis of certain human engineering aspects of mining equipment design. The software is available for use by equipment manufacturers and mining companies for design work on new machines, as well as for evaluating proposed modifications to existing machines.

Jan 1, 1995

By Scott Rosenthal, David Gilkey, Michael McGivern, Lorri Birkenbuel, Daniel Autenrieth, Ty Murphy, Hadi Aldossari

A safety climate case study was carried out at a surface metal mine where investigators administered the Liberty Mutual Short Scale Safety Climate Survey to 365–368 miners to measure safety climate in consecutive years. Following the baseline safety climate survey in 2019, Foundations for Safety Leadership (FSL) training was conducted with 81 middle to upper management employees at the mine site. Investigators found statistically significant differences in the pre vs. posttraining FSL assessment scores of the middle to upper management employees who attended the training. The follow-up safety climate evaluation was compared to baseline scores and revealed no significant improvement. The overall baseline company safety climate score of 76.38 increased minimally to 76.50 (p-value = 0.616). Investigators also evaluated differences in safety climate between the company’s three major divisions (operations, maintenance, and administration). Both years administration had the highest mean score and operations had the lowest mean score. The authors attributed the statistically significant differences found among the three major divisions to various dissimilarities in their work environments.

Aug 13, 2021

By M. J. Hannan

Considerable interest has arisen in developing analytical methods suitable for measuring resource commodity substitution patterns. some of this work has applied the Translog method to estimate actual elasticities of substitution. Recent examples incl.uae Privolos and Dunietz (1987), Kopp and Smith (1983), and Moroney and Trapani (1983). Another method, one which has received attention earlier in the work of Fisher and Pry (1970), is that of the logistic or diffusion function. We believe that the latter method has properties suitable for analyzing current problems of material substitution. The present study thus evaluates this method in its original logistic form as well as an extended version incorporating additional explanatory influences. The analysis is applied to copper/aluminum substitution and iron ore beneficiation. Substitution for copper by aluminum is examined in the building wire and cable, and magnet wire end-use markets. For iron ore, the substitution of pellets for sinter is considered for the U. S. market.

Jan 1, 1990

By PETER ROBINSON, KEVIN BARBER, OLIVER WHATNALL

Investigation and uptake of filtered tailings continues to grow throughout the globe. This is driven by a wide range of site-specific considerations, which include such factors as tailings characteristics (e.g., amenability to filtration), production rates, climate, water availability, cost drivers, environmental requirements, and social factors. Despite the aforementioned technological growth, the currently available filtration technology is not able to meet the needs of many operations and projects that would otherwise adopt the technology. Experience with large-scale industrial filtration shows that vacuum belt filter systems meet the needs of many modern users, exceptions being the inability to effectively dewater tailings at altitude and/or with a fine particle size distribution: a potential fatal flaw. This paper presents a case study on the utilization of the patented Viper Filtration technology on gold tailings to overcome this challenge and shares the resultant full-scale plant design, highlighting the features designed to overcome cost and scalability deterrents. This technology is a novel mechanical process which complements the vacuum pressure in dewatering the filter cake as it travels along the belt filter. This project commenced with a pilot testing program, which successfully met the objective to rigorously test, measure and record any performance improvements achieved when engaging the Viper technology. Of the two tailings products tested, gross improvements of 4.2%w/w and 5.7%w/w were achieved when compared to the conventional vacuum belt filter operation. This pilot testing facilitated measurement of operating and design data, which forms the basis of the full-scale system design and resultant equipment supply of three vibration roller assemblies for retro-fitting on the existing vacuum belt filter.

Jan 25, 2021