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By Georgene Renner, William R. Yernberg, Steve Kral

Advanced Terra Testing (ATT)is a full-service geotechnical testing laboratory. It specializes in rock and soil mechanics and geosynthetic materials testing. ATT provides services to the global mining industry. The company has performed more than 1,000 projects for more than 300 commercial and government clients. Services include coal pillar design testing, leach pad material and performance testing, tailings pile consolidation testing and closure and remediation services. Rock and soil mechanics tests include unconfined and triaxial strength, shear and tensile strength, permeability, index testing, consolidation, liquifaction potential, elastic moduli determinations, heap height versus percolation rate, long-term batch testing and dynamic loading tests.

Jan 1, 2003

By Brianna Eiter, Max Barham, Tim Bauerle

While not well established, there is evidence that the mining industry is encumbered by several work-related fatigue risk factors. Compared to other industries, mine workers are more likely to report inadequate sleep and work longer hours per day. Given these observations, there is a critical need to identify effective ways to intervene, manage, and mitigate mine worker fatigue and sleepiness when present. One barrier to this is confusion around the similarities and differences between fatigue and sleepiness, which can result in these terms being treated as interchangeable regardless of context and make it difficult to assess and mitigate safety risk.

May 1, 2024

By BARBOSA AMILTON, Denise C. R. Espinosa, David B. Dreisinger

Chelating resins can be used to recover important metals from different sources, and it is important to understand which resin is most suitable for each metal [1]. This review  benefits the mining industry because chelating resins can be used to recover metals from low-grade ores and mining tailings, increasing the industrial process efficiency [2–4]. Furthermore, the use of chelating resins in mining processes and mining tailings has the common problem of metals contamination, with iron being the main contaminant in low-grade ores and tailings. Understanding how contaminants decrease ion exchange efficiency is significant for industries [5

By Jerry C. Tien

The rare earth elements (REEs) are a group of 17 chemical (metallic) elements which appear in the periodic table. The group consists of 15 lanthanide elements along with yttrium and scandium (Table 1). They share many similar properties, which is why they occur together in geological deposits. Although commonly referred to as rare, they are really quite common; the reason they are perceived as rare is because it is not common to find them in commercially viable concentrations. These metals are critical to advanced technology, ranging from smart phones to global positions system (GPS) receivers, medical devices and jet engines. They are critical in green, high-tech and defense industries (Fig.1 and 2). Although there have been increasing efforts to find alternative supplies, these efforts have been complicated by the pollution that rare earth mining and processing creates. To extract rare earths minerals from mined ore is a complicated and costly process. The ore is first mined through normal mining process, the bastnaesite, which generally contains a number of minerals of little value, is first removed through a floatation process. The bastnaesite containing the REEs is further separated into their respective pure forms in a separation plant using acid and various solvent extraction separation steps. Each element has its own unique extraction steps and chemical processes. At times, these elements, in the form of oxides, will require reprocessing to achieve ideal purity. The last steps would be to further process into metals first, then alloys for various applications. The entire process takes approximately 10 days. The mining and processing of REEs, if not carefully controlled, can create environmental hazards. This is one of the reasons the Mountain Pass Mine in California was closed down in the 1980s.

Dec 1, 2013

By J. M. Barker

New Mexico is the leading domestic producer of perlite, a hydrated volcanic glass that can be expanded thermally to form a white, very porous, lightweight material. The United States is the leading consumer and producer of perlite in the world (Pettifer 1981). New Mexico produced, at five mines (Fig. 1), about 86% of all domestic crude ore mined in 1984 (Meisinger, 1985). Perlite is mined in 6 other western states, ore is expanded in 33 states, and the expanded ore is consumed in all states (Meisinger, 1985). Gross value of domestic ore mined in 1984 was about $16,500,000 (FOB mine; Meisinger, 1985) with much value added by expansion and processing prior to sale to end users. In contrast to the ubiquitous nature of perlite products in the U.S. economy, facilities for testing perlite ore, expanded perlite, and perlite products are notably lacking on a commercial, cost-effective, or readily accessible basis. The New Mexico Bureau of Mines and Min¬eral Resources (NMBM&MR) established a perlite¬testing facility in 1984 to mitigate this lack and to further the mining of perlite in the state.

Jan 1, 1985

By David A. Hedderly-Smith

Sealaska Corporation, the Alaska Native Regional Corporation of Southeastern Alaska, was organized under the laws of the state of Alaska pursuant to the federal Alaska Native Claims Settlement Act of 1971. Large areas of Sealaska's 630,000-acre (250,000 hectare [ha]) fee subsurface holdings are underlain by carbonate, and while much of this material is assumed to be common variety limestone and lesser dolomite, at least two areas in the Silurian Heceta Limestone contain high-quality limestone at tidewater. This limestone has many potential commercial uses. On northern Prince of Wales Island, about 90 miles (144 km) north-northwest of Ketchikan, resource development at Sealaska's Calder deposit has established a reserve of 13 mil- lion short tons (st) (12 million metric tonnes [mt]) of carbon- ate rock containing an average of greater than 98 percent CaC03, approximately 0.5 percent MgO, less than 0.5 per- cent Si02, and approximately 0.15 percent Fe203, with insolubles averaging less than 0.5 percent and an average Hunter Brightness of 92.07 for the -150 mesh grind (with a bright- ness cutoff of 90). The deposit is open at depth and to the south. Ultimate reserves will likely be several times those currently established. In 1998, Sealaska began mining the Calder deposit, with about 100,000 st (90,000 mt) produced, and also completed a marine terminal one half-mile (800 m) from the deposit. The terminal can load ships up to 680 feet (200 m) in length at a rate of 2,000 st (1,800 mt) per hour. 0 m) in length at a rate of 2,000 st (1,800 mt) per hour. On Dall Island at Breezy Bay, about 60 miles (100 km) southwest of Ketchikan, Sealaska has identified a limestone reserve in excess of 150 million st (135 million mt) that (based on 18 surface samples distributed evenly over about a section of land) contains about 98 percent CaC03, and less than 0.5 percent MgO, 0.5 percent Si02, and 0.15 percent Fe203. Brightness of the Breezy Bay carbonate is considerably less than at Calder. Five samples of brighter material from Breezy Bay returned brightness analyses in the high 80s and low 90s; average brightness is probably below the mid- 80s. Sealaska has also identified a deposit containing more than 19 million st (17 million mt) of similar rock near View Cove, a few miles south of Breezy Bay.

Jan 1, 2001

By VIVEK KUMAR HIMANSHU, PK SINGH, AK MISHRA, MP ROY, RAVI SHANKAR

Underground blasting has many challenges. The primary aim of blast designers is to optimize drilling and blasting parameters to deal with the associated challenges. Optimizing these parameters is currently based on various rules of thumb, which have many site-specific limitations. Accordingly, computation of these parameters using empirical rock fragmentation predictors can be useful for blast designers. This paper presents the results of work on burden-spacing determination by back-calculation from the empirical Kuz-Ram model for underground stope ring blasting.

By VASU GANGRADE

Large-opening underground stone mines pose significant ground control challenges, including the risk of massive pillar collapses. These collapses can result in dangerous air blasts characterized by tremendous force and high velocity. Estimating the velocity of these air blasts proves challenging due to the absence of accurate air velocity instruments near the mine portals. To address this issue, this paper proposes a novel approach that leverages closed-circuit television camera footage from the mine. Specifically, it employs the optical flow algorithm implemented in Python to estimate the velocity of the air blasts, providing a valuable tool for assessing and mitigating risks in such mining environments.

Feb 1, 2024

Newmont Mining Corp. has been producing gold from the Carlin Trend for more than 45 years. Naturally, the focus, scale and complexity of the operations have changed considerably during this time. Newmont discovered and developed the Carlin Main orebody that is located about 32 km (20 miles) north of Carlin, NV. The property was developed as a one-mine, one-gold mill treatment plant operation, which produced about 6.2 t/a (200,000 oz/year) of doré gold bars. The initial mine, mill and gold refining facilities were relatively small in comparison to today?s standards. The milling circuit used the Merrill-Crowe zinc precipitation process to recover dissolved gold and prepare a concentrated precious metal ?precipitate? to be melted into a doré bar for sale.

Jan 1, 2012

By Dan Swidrak, Bill Zietlow

Halfway through a 17,770-ft long stormwater tunnel, an 11-ft diameter TBM encountered a karst void below the Mississippi River in Missouri, resulting in significant inflow. It was decided that the TBM could not safely advance without external intervention. Low-mobility grout was pumped from the surface. A rescue shaft was constructed and a conventional tunnel with spiling support was mined back to the machine. The TBM was removed and a 14-ft diameter TBM equipped with probing drills was relaunched. Probing from the new TBM encountered one additional karst feature but the machine advanced after grouting and successfully completed the tunnel.

Jun 23, 2024

By L. Yuan, R. A. Thomas

"Atmospheric monitoring systems (AMS) have been widely used in underground coal mines in the United States for the detection of fire in the belt entry and the monitoring of other ventilation-related parameters such as airflow velocity and methane concentration in specific mine locations. In addition to an AMS being able to detect a mine fire, the AMS data have the potential to provide fire characteristic information such as fire growth — in terms of heat release rate — and exact fire location. Such information is critical in making decisions regarding firefighting strategies, underground personnel evacuation and optimal escape routes. In this study, a methodology was developed to calculate the fire heat release rate using AMS sensor data for carbon monoxide concentration, carbon dioxide concentration and airflow velocity based on the theory of heat and species transfer in ventilation airflow. Full-scale mine fire experiments were then conducted in the Pittsburgh Mining Research Division’s Safety Research Coal Mine using an AMS with different fire sources. Sensor data collected from the experiments were used to calculate the heat release rates of the fires using this methodology. The calculated heat release rate was compared with the value determined from the mass loss rate of the combustible material using a digital load cell. The experimental results show that the heat release rate of a mine fire can be calculated using AMS sensor data with reasonable accuracy.IntroductionFires at different stages generate different gases and smoke toxicity hazards. When fires occur in underground mines, a significant amount of toxic gases and smoke enter the mine ventilation system and are carried throughout the mine ventilation network, increasing the hazard potential for personnel even if far away from the actual fire. Although fires that develop to the point of rapid flame spread pose imminent hazards, fires in their smoldering, pre-flaming stages can also contaminate the mine atmosphere with debilitating levels of smoke and toxic gases.The most important parameter for evaluating the fire hazard in mines is the heat release rate (HRR), which is directly related to the rate at which heat, smoke and toxic gases are produced and transported by the ventilation system and which provides an indication of the time available for escape or firefighting (Babrauskas and Peacock, 1992). The HRR is also an important input parameter to mine fire simulation models."

Jan 6, 2017

By A. W. Khair, S. S. Peng

Background The mine is located in Ebensburg, Cambria County, PA. Cambria County is located within the Allegheny Mountain section of the Appalachian Plateau Province. The geologic structures in the mine area included folds, faults, joints and cleats in the coal. These geologic structures seem to have genetic relationships with the Allegheny Front (lannacchione and Puglio, 1979). The mine's geologic structures have been influenced mainly by Ebensburg Anticline and Wilmore Syncline (Watson, 1979). Current longwall panels lay along the western limb of the Wilmore Syncline oriented south 30° west. Surface topographic relief in the area is less than 152 m (500 ft) and overburden thickness varies from 183 to 244 m (600 ft to 800 ft). The coal seam in the mine is part of the Lower Kittanning Formation. The thickness of the B-seam is the subject of discussion. It varies from 1.2 to 1.5 m (48 to 60 in.) and consists of two parts. The lower part is 1.1 to 1.2 m (44 to 48 in.) of soft coal and the remainder is bony coal. The coal seam dips slightly from 0° to 6° to the east-south direction. Panel entries are driven 61 m (200 ft) wide, consisting of three 5.5 m (18 ft) wide entries and two pillars 24.4 x 30.5 m (80 x 100 ft) centers. The mine has a history of cutter roof problems in the entries (Fig. 1) that has delayed the advance rate of entry development considerably and the cost of maintaining those entries is very high due to the requirement of very heavy artificial supports (Fig. 2). Due to excessive convergence in the headgate, installation of additional support and often resetting of steel beam, to provide enough clearance, in these entries imposed additional delay during the retreat of the longwall face, as the shearer cuts coal adjacent to the headgate and shield support at the headgate needs to advance under the steel beams (Fig. 3). Methodology Extensive underground observation indicated that roof cutter [ ]

Jan 1, 1992

By P. B. Moran, J. W. Rozelle, J. Forbort

"The Mount Todd gold mine is located approximately 50 km (31 miles) north of the town of Katherine in the Northern Territory (NT) of Australia just off the Stewart Highway, and was operated in the 1990s until 2000 (Fig. 1). After cessation of mining operations, meteoric precipitation and acid rock drainage (ARD) associated with surface water runoff continued to report to the retention ponds across the mine site. In 2000, the mine site entered receivership and the NT government became responsible for the care and maintenance program. In 2006, Vista Gold Corp. (as Vista Gold Australia) acquired the rights to resume exploration on the mine site without the financial responsibility of the environmental liability. In January 2007, Vista Gold assumed the care and maintenance activities on behalf of the NT government, with the environmental liability remaining with the NT government, with the goal of reinitiating mining operations. A critical path component of the planned upgrades to the existing mine/milling facilities and infrastructure was the development of a cost effective treatment and dewatering program for the approximately 11 GL (2,900 million gal) of ARD stored in the Batman Pit (RP3), which has a maximum capacity of approximately 12 GL (3,200 million gal). The Batman Pit must be dewatered in order for Vista Gold to restart mining activities. The Batman Pit Lake had reached a maximum water depth of 104 m (341 ft) when Vista Gold initiated water level monitoring. It is important to note that the ARD water in the Batman Pit has been pumped into it from 2000 to 2012 under an NT government-approved environmental control program.The Batman Pit has virtually no connection to the local ground water regime due to the intensive silicification that accompanied the mineralizing event. In October 2012, just prior to treatment, the pit lake profile was characterized by uniform acidic pH (approximately pH 3.2) and oxic conditions (dissolved oxygen greater than 7 mg/L with depth (Fig. 2). The temperature decreased by approximately 4 °C (39 °F) between the lake surface and approximately 20 m (66 ft) deep, and remained near constant with increasing depth. This temperature difference is believed to be associated with an existing shallow mine bench at approximately 20 m (66 ft) deep around the perimeter of the pit. Similarly, electrical conductivity, an estimate of total dissolved solids, decreased by about 85 microSiemens per centimeter (µS/cm) from 2,800 to 2,715 µS/cm between 10 and 20 m (33 and 66 ft)."

Apr 1, 2016

"Above ground, elevated belt conveyors with span >200m between support points can cross valleys, rivers, forests and buildings with minimal footprint. The Cable Bridge Conveyor is a new type of suspension bridge based belt conveyor system that has long span between support points. It combines typical belt conveyor and the improved simple suspension bridge to form a conveyor bridge. The improved simple suspension bridge places a widened bridge deck directly on suspended cables, without the need for high truss towers. The benefits include reduced cost and increase aerodynamic stability compared to conventional suspension bridges. The Cable Bridge Conveyor’s compatibility with current belt conveyors allows the versatility in application. INTRODUCTION Belt conveyor is a ubiquitous material handling system. Conveyors can be placed directly on ground or elevated above ground by support structures. Considerations of cost, design, environment, civil work, safety and process requirements are all factors in choosing the ground based or elevated conveyors (1). The ground based conveyor has the lowest structural cost, where the conveyor is laying on an existing road. Maintenance access is easy and straight forward. Compared to the ground based conveyor, the elevated conveyor can cross existing buildings and structures, give passage to traffic beneath the conveyor, has smaller footprint, and requires less civil work to pass mountainous areas. The drawback of the elevated conveyor is higher structural cost, which can be compared with savings in civil work and other benefits. Conventional elevated conveyors are supported by rigid truss type structures, with typical span of 15m to 25m between concrete support bents or steel trestles. Triangular truss, using steel pipes instead of hot rolled steel sections, is more efficient. The typical span of triangular truss supported conveyor is around 30m to 40m, while the weight is about 10% less than conventional box truss with shorter span (2). Long span elevated structure based on suspension bridge is another step forward in increasing the distance between support bents, reaching 100m~400m and beyond. The very wide distance between support points of an elevated conveyor offers unique benefits. The conveyor can cross rivers, valleys, highways, forests and other obstacles with minimal footprint and reduced civil work. The versatility from long span conveyors makes bulk material transportation over previously impossible terrains now a feasible option."

Jan 1, 2015

By Eero Pokki

The Päijänne Tunnel is being constructed to conduct raw water from Lake Päijänne to the Helsinki Metropolitan Area. The length of the tunnel will be 120 km and the cross-sectional area is 15.5 sq m. Excavation started in 1973 and will be completed in 1982. 94 km of the tunnel have been constructed from Lake Päijänne towards Helsinki. The construction has advanced according to plan, and due to Finland's hard bedrock there have not been any great surprises. When completed, the tunnel will meet the water requirements of the Helsinki Metropolitan Area for a long time in the future because, with a free fall of 36 m, 9.6 cu m/s of water can be conducted through the tunnel from Lake Päijänne to the Helsinki Area. With pumping it will be possible to obtain a flow of 15 cu m/s, although at first the discharge will only be 5 cu m/s. The tunnel was partly taken into service as early as March 1979 when it was possible to conduct water to the municipalities north of the Helsinki Area. It is already possible now to conduct water to Helsinki, too, but from the Korpimäki pumping station onwards it must be done through the River Vantaa, which is polluted. When the tunnel is completed in 1982, good quality water can be conducted from Lake Päijänne to the Helsinki Metropolitan Area through a continuous rock tunnel. The cost estimate in 1973 was $ 88 million while it is now $ 90 million notwithstanding high inflation. AREAS NEEDED FOR CONSTRUCTION The areas needed for construction were bought through voluntary deals. Areas of 4 - 5 hectares were bought along the tunnel line at about 5 km intervals. The excavation of access tunnels was started from these places, and the crushed rock from the main tunnel was also transported there. However, it was not necessary to buy the area

Jan 1, 1979

By Phil Dakin, Rajiv Chandramohan, John Lo Grande, Greg Lane

Crushing and grinding circuit availability is a critical design factor defining the installed equipment selection and the process buffers required to maintain throughput during maintenance. The comminution circuit typically accounts for a process plant’s largest capital expenditure and energy use. Effective process and equipment selection and layout optimization are crucial steps when combining the objectives of cost-effective design and high circuit availability in operation. This paper outlines fit-for-purpose design principles for optimizing process flow, eliminating standby equipment and reducing buffer residence time whilst improving maintainability and operability.

Feb 1, 2025

By Ataç Başçetin, Hasan Çelt, Hüseyin Onur Dönmez, Kürşat Hasözdemir

Phenolic foams, known for fire resistance, show broader industrial potential, particularly in mining, through property enhancements. Adjustments to the formaldehyde-to-phenol (F/P) ratio, bio-based additives like lignin, and nano-silica improve foam strength and thermal stability. Density modifications allow foams to range from flexible, low-density forms to rigid, high-density supports. In mining, enhanced phenolic foams could reduce coal ignition risks by acting as oxygen-blocking barriers. Current findings suggest these foams offer viable, sustainable solutions for safety in hazardous environments. Continued development could make them essential for thermal and mechanical applications under extreme conditions. This paper aims to provide a comprehensive overview of the mechanical characteristics of phenolic foams, current enhancement strategies, and standardized testing methods used to evaluate foam properties.

Feb 1, 2025

By Patrick McElhinney, Jacob Carr, Bruce Whisner, Cory DeGennaro, Jingcheng Li

Since 2016, electromagnetic interference (EMI) of personal dust monitors (PDMs) with magnetic proximity detection systems (PDSs) has been observed in underground coal mines. The EMI causes the magnetic field measurements of a PDS to change, which, in turn, alters the calculated location of the miner relative to the machine. Any altered location calculation can potentially cause the PDS to fail to warn a worker who is at an unsafe distance from the machine, arousing a serious concern on safety hazard caused by EMI in underground mines. The search for EMI mitigation strategies led to the development and use of large shielding pouches and boxes to hold the entire PDM to reduce its magnetic emission. Research on these pouches and boxes found that although they were able to reduce the emitted radiation from the PDM, they also disturbed the magnetic field of the PDS, affecting its performance. Researchers from the National Institute for Occupational Safety and Health (NIOSH) have focused on shielding internal PDM components rather than shielding the entire PDM. The PDM air pump motor is one of the PDM components that has been identified as a major source of electromagnetic radiation and has been selected for further study and tests. The measurements show that a small copper or aluminum foil enclosure can effectively reduce the magnetic emission of the motor by between 50 and 85% at 73 kHz. This study compares the test results of the air pump motor with various cost-effective shielding materials. The data provided in this paper can serve as a reference for shielding enclosure design of the PDM air pump motor to reduce its electromagnetic emission as one form of EMI mitigation strategy.

By John O. Marsden

"This article is an attempt to capture a presentation given at the 2016 SME Mineral & Metallurgical Processing Division (MPD) Luncheon held on Feb. 24, 2016, in Phoenix, AZ. It was presented as a tongue-in-cheek, lighthearted view of several of the issues facing our industry, while identifying some of the challenges and opportunities available to new engineers entering the industry today.Disclaimer• What you are about to read includes personal preferences, biases and occasionally arbitrary opinions.• Some readers may have dissimilar opinions on the contents and/or the rank order of the lists.There are eight top ten lists offered in this article: (1) Industry realities (2) Things a metallurgical or mineral process engineering graduate should do (3) Books every metallurgist should have on their shelf (4) Things I wish I had known (5) Legends of metallurgy (posthumous, with highlights) (6) Things we’ve forgotten (7) Mineral processing innovations of the past 20 years and, finally, (8) The future? For some items, additional context or clarification is provided after the item, while for other items no further explanation is warranted and none is offered. Top 10 industry realities1. Metal price cycles.2. Bigger is better (except when it isn’t).3. Ore grades declining across the board of metals/commodities.4. Ores becoming more complex.5. Three-fold increase in capital costs between 2004 and 2015.6. Three-fold increase in operating costs between 2004 and 2015.7. Less capital availability/challenging financial markets.8. Environmental constraints increasing.9. Socio-political constraints increasing.10. The mine manager is always impossible to work with.As Table 1 shows, there was more than a three-fold increase in gold operating costs between 2004 and 2014. The increases for copper, iron ore and other commodities were similar."

Aug 1, 2016

By Leo Gentile, David Selhorst

The $528 million Toledo Waterways Initiative (TWI) was implemented by the City of Toledo in 2002 and completed in August 2020. Toledo is one of many US cities required to implement a Long-Term Control Plan (LTCP) but one of few to have completed its plan. TWI consists of three storage and conveyance tunnels, four below grade storage basins ranging from 4 to 36 million gallons (MG), miles of sewer separation and interceptor improvements, green infrastructure and other appurtenant structures to dramatically reduce combined sewer overflows to the Maumee River, Ottawa River and Swan Creek. All three rivers flow into Lake Erie. The City’s 180-year history as a Midwest shipping, manufacturing and transportation hub provided design engineers and contractors no shortage of unknown underground challenges to complete the projects. The City will begin its 5-year Post-Construction Compliance Monitoring in 2021 to satisfy the final LTCP requirement. A program overview and experience from tunnel and underground basin construction in urban areas with buried active and legacy infrastructure will be discussed.

Jun 13, 2021