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By Raúl Castro, René Gómez

In underground mining, rock fragment size is a key variable for productivity because it impacts equipment selection and mining structure design. This study characterizes granular material fragmentation during its flow to understand its characteristics and mechanisms. Tests were conducted using a laboratory setup to emulate various heights where material is drawn. The fragment-size distribution was measured before and after tests for clay, concrete fragments, and gravel. Results showed that fragmentation mainly occurs in minor sizes, with significant increases in fine material as travel distance increases.

Jan 10, 2022

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 M. Fan

Coal has in general a wide range of density from minus 1.3 to plus 2.0 g/cm3 because of its variations in purity, rank, and porosity, etc. The coal density has great impact on froth flotation performance, but much less attention has been paid to particle density than particle size. Our previous research results demonstrated that cavitation-generated nanobubbles around 700 nm in diameter can significantly improve coal and phosphate flotation performance over a wide particle size range. In this study, the effect of nanobubble on the flotation performances of different density fractions (minus 1.3, 1.3-1.4, 1.4-1.5, 1.5-1.6, 1.6-1.8, 1.8-2.0, 2.2-2.2, and plus 2.2 g/cm3) of coal was investigated using a bank of 10-liter flotation cells, a specially designed 50-mm-inside-diameter column, and a 152-mm-inside-diameter column. It was found that nanobubble has the biggest impact on the flotation performance of 1.4-1.8 g/cm3 medium-density coal particles.

Feb 23, 2014

By Ashish Ranjan Kumar, Barbara Arnold, Luis Sanchez Gonzalez

The health and safety of miners is critical in the industry. Prolonged exposure to dust-laden air results in irreversible ailments like pneumoconiosis that have a severe impact on their lives. Operations use various personal protective devices (PPEs) to alleviate their exposure to respirable dust. Powered Air Purifying Respirator (PAPR) is one such device that uses high- efficiency filters and positive pressure masks to shield miners from airborne contaminants. Used in the medical and other industries, these respirators efficiently protected healthcare workers during the COVID-19 pandemic. Recently, the mining industry has shown a growing interest in adopting this PPE to ensure safe working conditions for the miners. We present an introduction to the PAPRs and discuss their dust capture efficacy in this manuscript.

Feb 1, 2025

By Ava Segal, Doga Cagdas Demirkan, Abhidipta Mallik, Sebnem Duzgun, Andrew J. Petruska

Search and rescue operations in mining heavily rely on humans. In the context of emergency situations within underground tunnels, the potential to utilize sensory technology for navigation assistance holds the promise of saving human lives. Our research introduces a device configuration designed to enhance the performance of search and rescue teams. This setup integrates LIDAR and thermal cameras with the Microsoft Hololens, facilitated by the NUC computer and ROS Bridge. Performance assessment involves quantifying the extent to which a user is willing to venture into a light-deprived section of the mine prior to necessitating supplementary illumination. The preliminary outcomes highlight the significant potential of augmented reality assistance in offering indispensable aid to first responders, thereby greatly augmenting the efficiency of search and rescue missions conducted during critical circumstances.

Feb 1, 2024

By K. Nielsen

The Norwegian tunnelling industry has made remarkable improvements both with regard to productivity and cost efficiency over the last 30-40 years. This development has been made possible by continuous improvement driven by innovation. Based on a generic description of the innovation process and the innovation system, the paper has used the development of modern tunnel drilling in the Norwegian tunnelling industry to discuss the characteristics of its innovation system with a focus on human capital issues and knowledge management.

Jan 1, 2006

By A. Rai

"This paper provides an overview of the current use of auxiliary ventilation product and the challenges with limited air quantity in dead-end entry or working face. The PVC low frictional factor, low physical constraint and minimum leakage ventilation duct was development with ""made in US and used in US"". The PVC duct development covering operational and total cost of ownership with on-going success will be presented. This paper will discuss mine sites using new PVC vent duct underground and the results from operational and technical side making a difference. INTRODUCTION The Turquoise Ridge Joint Venture (TRJV) is located in northern central Nevada, and is situated within the Basin and Range province, near the northeast end of the Osgood Mountains (see Figure 1). The TRJV mine consists of typical Carlin type- gold mineralization characterized by low strength rock of altered limestone’s, siltstones, and mudstones. The weak nature of the ground facilitates the underhand cut and fill mining methods [3].Mining Method; Underhand cut and fill : The mine uses underhand cut and fill method which has 12’x12’ top cuts and several different size undercuts. The ore body is accessed off of a secondary development heading, utilizing a heading with a cross section of 14W x 14H or 15W x 16H configuration. In the wider and more massive zones, two headings in a production panel may be worked at any one time. Drift round lengths are determined by the type of drilling machine being used. An example of a typical topcut and associated undercut layout is shown in Figure 2. SECONDARY / AUXILIARY VENTILATION IN UNUNDERGROUND METAL MINES The auxiliary ventilation system provides the required air volumes at the face of dead-end developments and production workings, which in many cases may be considered as the primary method of assuring that the air quantity and quality standards in these working areas are satisfied. The Auxiliary fans and ducting systems are usually the primary means of delivering the required air volumes to the face of dead-end developments and production workings. Both centrifugal and axial-flow fans are used in underground auxiliary ventilation systems, usually electric powered. The internally direct driven axial-flow fans tend to be more popular because of their compactness and adaptability to staging. The most commonly used materials for ridged tubing are coated steel, alloyed steel, fiberglass and resin. Flexible (collapsible) ventilation tubing is also used and is usually made from neoprene-coated or nylon material. To add stiffness and reduce collapsibility these fabric ducts can be formed over a steel spring frame. A very important factor in the design of an auxiliary ventilation system is to minimize leakage and reduce the frictional pressure losses along the auxiliary ducting systems by minimizing their friction factors (K)."

Jan 1, 2015

By George K. McCord

It is a pleasure to participate in this Fall meeting of the Society of Mining Engineers to discuss energy conservation trends in the cement industry. Energy is the "life blood" of American industry, and the ability to use available energy resources efficiently may well determine the future of our nation and of its industries. The Federal Energy Administration has classified cement manufacture as one of several energy-intensive industries in the U.S. and has selected the Portland Cement Association to make a detailed study of possible energy conservation measures. Member companies of the Portland Cement Association represent about 85% of the cement producing capacity of the United States and 100% of Canadian capacity. Stated briefly, the purpose of the Association is to extend the uses of portland cement and concrete through research and development, market promotion, education, and public affairs work. PCA's general offices and research laboratories are located in Skokie, Illinois. Our staff of engineers, scientists, and research personnel make the PCA uniquely qualified to perform an energy conservation study of the kind requested by FEA.

Jan 1, 1975

By Terry S. Maio

In 1978, Ozark Lead Company made the decision to expand the capacity of its mine/mill complex by 33%. The objectives of the expansion were to (a) increase mine' production capacity by 1816 tonne/d(2000 TPD), (b) increase lead metal pro¬duction by 21,790 tonne/y (24,000 TPY) and to (c) construct new facilities and/or modify exis¬ting equipment to accomodate the increased pro¬duction. The intent of this paper is to give a brief explanation of the equipment installed and the overall production and metallurgical benefits-realized from this expansion. The expansion was completed in the second half of 1980 with all equipment debugging and fine tuning completed by the first' quarter of 1981. The concentrator modifications and improvements were basically restricted to four areas: (1) materials handling, (2) automation: of the mill grinding circuit, (3) the increase of flotation capacity, and (4) concentrate dewatering.

Jan 1, 1983

By T. J. Lutz, D. S. Yantek, L. Yan, J. R. Srednicki, J. A. Yonkey, G. T. Homce

Federal regulations require the installation of refuge alternatives in underground coal mines. Of the inuse refuge alternatives, more than 95 percent are mobile refuge alternatives, with the remainder being built-in-place (BIP) refuge alternatives. Heat/humidity buildup has been one of the major concerns with mobile refuge alternatives. For BIP refuge alternatives, however, there is a lack of in-mine heat/humidity test data to determine the extent of heat and humidity buildup. To quantify heat/humidity buildup in BIP refuge alternatives, the U.S. National Institute for Occupational Safety and Health (NIOSH) performed a series of heat/humidity tests on a 60-person BIP refuge alternative with and without a borehole air supply. At various times during the year, tests were performed with cooled, heated or unconditioned borehole air to examine how various outdoor temperatures may affect the thermal conditions inside a BIP refuge alternative. The results show that the air supplied to a BIP refuge alternative may require heating or cooling, depending on the outside air temperatures and the temperature of the mine. For example, during tests with an external ambient temperature above 21 °C (70 °F) and a relative humidity of 90 percent, providing 13 °C (55 °F) dew point air at 775 scfm, which is slightly higher than the mandated flow rate of 12.5 scfm per person, kept the internal apparent temperature below the mandated 35 °C (95 °F). Results for each test case are presented.

Jan 1, 2018

By S. Natansohn

A prevalent technique for the recovery of silver from wastes generated in silver-tungsten electrical contact fabrication is electrowinning. Such scrap is placed in a permeable plastic basket which constitutes the anode compartment and this basket is suspended in a larger cell in which the cathode is mounted. A silver nitrate solution is used as the electrolyte and, upon application of an electric field, the silver migrates to the cathode where it deposits out. At times, there is tungsten migration to the cathode compartment and consequent co-deposition with the silver. This W contamination, which may amount to several thousand ppm, necessitates additional purification of the deposited Ag and its removal would therefore be advantageous. The elimination of the W impurity would also extend the operating period of the cell with corresponding increase in the Ag output and savings in labor costs.

Jan 1, 1982

By MATT RENAUD, Mustafa Kumral

Mining corporations have spread their operations worldwide in the last few decades. The reason behind widening operations geographically can be seen as it being part of a risk diversification strategy. Given that the technical, financial and social risks are high, favorable deposits, taxation regimes and legislative frameworks create incentives for international mining operations. On the other hand, international mining activities add the risks of permitting, investing, operating and decommissioning to the corporations. These risks could emerge from defaulting, corruption, resource nationalism, social license to operate, and political and legislative uncertainties and instabilities.

By Kenneth Deaton

"A packaged cooling system is being developed for refuge alternatives (RAs) that will meet U.S. Mine Safety and Health Administration (MSHA) qualification guidelines for deployment in coal mines. This system will allow full occupancy ratings of deployed refuge alternatives to be maintained by keeping the apparent temperature inside the RA from exceeding 35° C (95° F).Research investigations sponsored by the National Institute for Occupational Safety and Health (NIOSH) have shown that heat buildup caused by occupants in mobile RAs will result in apparent temperatures that exceed the 35° C (95°F) limit established in 30 CFR 7.504.Figure 1 shows the temperature rise in an inflatable RA having an occupancy rating of 23 people at an 27° C (81°F) mine air temperature. This plot shows the need for either heat mitigation or occupancy derating in warmer mines.The Refuge Alternative Environmental Control System (RAECS) will be designed to provide enough heat mitigation to eliminate occupancy derating due to heat buildup over the 96-hour refuge period.This article describes testing of a prototype cooling system that uses proven vapor compression technology powered by batteries to keep the RA interior below the 35° C (95° F) limit for a minimum of 96 hours. Testing of this prototype cooling system was conducted in December of 2015 and January of 2016 at the NIOSH test mine in Bruceton, PA. December testing was conducted at the prevailing mine ambient temperature — approximately 15.5° C (60° F). The January testing was done with the mine ambient temperature in the immediate vicinity of the RA artificially elevated to 29° C (85° F). Realistic heat gain from RA occupants was provided by human simulators developed by NIOSH. These simulators add sensible heat corresponding to human metabolic processes and latent heat generated by respiration and perspiration. Heat generated by CO2 scrubbers was also added. Results of cooling system performance using these simulated loads at the two ambient conditions are described. A comparison of the apparent temperature in the RA using two different control techniques is also presented. This work documents the ability of the cooling system to meet the established apparent temperature limit at the full occupancy rating of a six person RA. A new cooling system intended for use with existing RA deployments and having greater cooling capacity is currently in development and will be described.Expendable desiccant modules were also used to provide supplemental water vapor removal and their role in mitigating cooling load is addressed."

Dec 1, 2016

By William L. Young

I think I should let you in on one of Canada's best-kept secrets, if you will promise not to tell it all over the place. Believe it or not, good, honest, enterprising capitalism is still alive and flourishing north of our common border, and I am living proof that capitalism is still working for the little guy. My personal story of mining development in Canada isn't all that rare -- you've probably heard something like it from other areas and other days several times -- but my case brings it up-to-date. I would like to Tell you briefly the history of Northumberland Mines Limited, a contemporary case of individual enterprise getting a mining operation underway. And if I can do it you probably can too.

Jan 1, 1981

By Nik Sokol, Mike Jaeger, Leo C. Weiman-Benitez

Silicon Valley Clean Water signed a progressive-design-build (PDB) contract with Barnard Bessac Joint Venture (BBJV) to design and construct the Gravity Pipeline tunnel in Redwood City, CA. Owner and Design-Builder teamed with designer Arup to provide a final product: 3.3 miles of 182 in. O.D. precast concrete segmentally lined tunnel with 10 ft. and 11 ft. I.D. Fiberglass Reinforced Polymer Mortar (FRPM) carrier pipe, complete with two FRPM Drop Structures. BBJV and Arup collaborated with SVCW to evaluate alternative design concepts, negotiate an agreeable price and reduce contingencies through a transparent estimating process, and deliver the project ahead of schedule.

Jun 13, 2023

By Gordon Clark, Basar Arioglu, Nasri Munfah, Sanja Zlatanic, Tolga Togan

"The 13.2 m (43 ft) external diameter, double deck Istanbul Strait Road Tube Crossing is one of the most challenging underwater tunnel projects in the world. Subjected to 11 bars of hydrostatic pressure, variable geology, and being in a very active seismic area, the execution of the project required innovative solutions, sophisticated construction techniques and prudent risk management approach. The 5 km (3.1 mile) tunnel consists of a 3.4-km (2.2-mile) tunnel boring machine- (TBM) bored tunnel, 1 km (0.62 mile) twin NATM tunnels and cut-and-cover sections. The project is being delivered in a build-operate-transfer (BOT) contract in a public-private partnership. The technical challenges, coupled with financial and commercial risks required the implementation of sophisticated risk management tactics including the provision of independent design verification. The project was opened to traffic on December 20, 2016, four months ahead of schedule.. This article presents the technical challenges of the project from the design, construction, and risk management aspects..Project backgroundThe $1.245 billion Istanbul Strait Road Tunnel Crossing project, dubbed the Eurasia Tunnel, is one of several major infrastructure projects being implemented in the Republic of Turkey in a public-private partnership approach. The project provides a direct and easy connection between the Anatolian (Asian) side of Istanbul and the heart of its historical district on the European side across the Bosphorus Strait which connects the Black Sea with the Sea of Marmara. The project improves connections to a wide network of motorways on both sides, increase capacity across the Bosphorus by 100,000 vehicles a day, reduces congestion and saves motorists an average of 45 minutes of commuting time in each direction bringing significant economic benefits to the city and the region. It eases traffic across the strait, reduces congestion, decreases pollutants and emission while maintaining Bosphorus. It is the most complex part of the project with the greatest challenges and risks. Part 2 is 5.4 km (3.6 miles) long consisting of 3.4 km (2.2 miles) of 13.2 m ( 43.3 ft) external diameter TBM bored tunnel under the Bosphorus Strait, 1-km (0.62-miles) of twin NATM tunnels on the Asian side, cut-and-cover transition boxes in the Asian and the European sides and depressed approaches on both sides. In addition, this segment includes the toll plazas, ventilation buildings, and the tunnel control and maintenance facilities."

Mar 1, 2017

By J. W. Wilson

In the ultrafine coal cleaning process, small coal particles (-400 mesh) are produced during the pulverizing operation. After the coal cleaning process, these ultrafine particles are very difficult to dewater, and create problems in coal transportation, storage and handling at utility plants. Research work on ultrafine coal dewatering and briquetting has resulted in the development of a single stage operation that is potentially more effective and economic than conventional thermal drying and briquetting processes. The final coal product have a moisture content of less than 15% and possess high strength and water resistance that satisfies coal transportation, storage and handling requirements.

Jan 1, 1995

By P. Rosario

During the last few years high-tonnage plants have been designed with comminution circuits using semiautogenous grinding (SAG) mills, high pressure grinding rolls (HPGR), or both, followed by ball mills in different configurations. A strong interest in improved energy efficiency and reduction of carbon footprint, along with the recent launch of new high-capacity crushers and stirred grinding mills, has driven the industry to investigate the development of novel flowsheets. This paper presents work based on recent projects that include modeling and simulation of two innovative circuits recently considered for current projects. One circuit uses autogenous (AG) mills and parallel trains of crusher-HPGR and the other is a modified three-stage crushing circuit with the use of HPGRs and pebble mills. The paper indicates the potential savings in operating costs provided by the HPGR-pebble mill circuit when compared to a more conventional SAG-mill-based circuit.

Jan 1, 2010

By Paul T. Allsman

The guiding principle in developing this plan resulted from evaluating potential future markets for oil, the quantity of mineable oil shale and the optimum rate of production comensurate with market demand on the available oil from shale. In addition, the rate of production may depend upon a solution to the problems of scarcity of resources other than oil shale. The rate of production finally will tend to establish the choice of technologies with these limits. The principle components discussed will be: 1) The place of oil shale among the various energy sources and its relative adaptability for use in the area of major consumptive demand. 2) A recalculation of the reserves and their classification on the basis of quantity, grade - gallons per ton, - and physical characteristics principally thickness, overburden and depth.

Jan 1, 1982

By Andre Vien, SANDRO DAVID DI, Frank Laroche

In 1994, Claude Bazin presented a novel method for linking size data from milling models to the feed input of flotation models. It was achieved with the simple addition of a metal/mineral distribution–size distribution relationship. This allows grade and recovery predictions from a varying mine plan through product size distribution predictions.