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By David A. Summers

In May 1975 the U. S. Bureau of Mines contracted with the University of Missouri-Rolla, Rock Mechanics and Explosives Research Center to develop a Hydrominer modification to a long-wall shearer unit, wherein the rotating pick-laced drums and connecting gear drives are replaced by a water jet cutting head.1 The concept of the water jet cutting head is based on using the high localized energy of the water jets to isolate a slice of coal by cutting a slot under, at the back of, and at the top of the web. The plow blade of the head then advances into the cut and wedges the pillar over onto the conveyor (Figure 1). There were several potential advantages foreseen for the system of which perhaps the most significant were the elimination of coal dust from the working area2 and the ability, with a variation in nozzle geometry, to cut webs of greater depth with a small increase in equipment horsepower. The University initially designed the head, based on experiments carried out in the laboratory, under an earlier Bureau of mines contract. The experiments showed that it was more advantageous to work at a pressure of 10,000 psi with an estimated flow rate of 50 gpm than go to the higher pressures and lower flow rates which have been advocated elsewhere.

Jan 1, 1977

By William Gleason

The mining industry is under immense pressure to not only meet increasing demand for minerals, but to do so in an environmentally safe and sustainable manner. Growth in electric vehicles, battery storage, renewable energy infrastructure and data centers to power artificial intelligence (AI) has led to an unprecedented demand for minerals such as copper, lithium, rare earth elements and others. The need for these minerals for national defense has only increased the pressure on the mining industry. Increased geopolitical tensions between the United States, China and Russia has added a sense of urgency as supply chains have become a focal point for the U.S. Department of Energy (DOE) and Defense (DOD) and other government agencies. The International Energy Agency (IEA) predicts that copper demand is expected to grow by 50 percent by 2040 while demand for lithium could increase eight-fold by 2040 and demand for nickel and cobalt could double. The challenges to meet the increased demand include technological, workforce, exploration and environmental issues. From Feb. 22-26, the global mining industry will converge on Salt Lake City, UT for the MINEXCHANGE 2026 SME Annual Conference & Expo where these challenges and others will be addressed by some of the leading minds in the industry. Included in this year’s conference is the Resilient Energy in Mining Symposium, a symposium with input from across SME that looks to address some of the most significant challenges the industry is facing. “Adopting environmental, social and governance (ESG) best practices has become a necessity for the mining industry, not an option. The Resilient Energy in Mining Symposium is crucial for MINEXCHANGE 2026 because it addresses the complex challenges of transforming traditional mining operations to support a sustainable and secure energy future,” Lisa Gonzales, principal engineering at Arcadias and MINEXCHANGE 2026 SME Annual Conference Chair and chair of the Resilient Energy in Mining Symposium said. “Mining is inherently energy-intensive, yet it is also foundational to the global energy transition, supplying the critical minerals needed for renewable technologies. By bringing together industry leaders, the symposium fosters collaboration and actionable change, showcasing advancements and real-world solutions that demonstrate the tangible benefits of resilient energy strategies. This unique forum enables knowledge sharing, inspires innovative thinking, and helps set the standard for sustainable practices across the sector.” The symposium was created in direct response to a SME member survey in 2023 conducted by the Responsible Mining and Underground Construction (RMUC) Strategic Committee. “The survey highlighted a strong demand for technical resources on energy transition, carbon reduction, renewable power, climate change, and ESG reporting,” Gonzales said. “To address this, I collaborated with RMUC to engage committee members from all SME Divisions, ensuring a diverse and comprehensive platform that reflects every aspect of mining. We intentionally structured the symposium to centralize key content and minimize duplication across divisions.”

Jan 1, 2026

By M. Laliberte

"Gold-mine effluents are often characterized by high concentrations of copper, ammonia and cyanide derivatives (mostly cyanates and thiocyanates). While not acutely toxic to birds, this water can be acutely toxic to fishes and invertebrates. In many jurisdictions, the effluent requires further treatment in order to pass a mandatory requirement to be nonlethal to species like the rainbow trout (Oncorhynchus mykiss) or Daphnia magna. Using actual mine water, it has been demonstrated that aerated moving bed biofilm reactors will biodegrade the ammonia, cyanides, cyanates and thiocyanates, thereby removing the toxicity associated with these components. By removing copper by precipitation the water can be made to pass acute toxicity tests. Tests have demonstrated that the process is stable between 4 and 25°C, with no significant changes in the treated water composition. Once the biomass is acclimatized, the process is resistant to upsets and requires very little inputs except for phosphorus and air. Furthermore, it has been demonstrated that an anoxic reactor can be added downstream of the aerated reactors to remove nitrates if required.IntroductionThis paper will demonstrate that gold-mine effluents, which are toxic to fishes and invertebrates, can be made nontoxic by using a combination of chemical precipitation and biological oxidation.The typical composition of gold-mine effluents will first be described. The applicable legislation will then be introduced, with its requirement that the treated effluent be nontoxic. The toxicity of a typical untreated effluent will then be confirmed, and the sources of the toxicity identified. After that, a number of toxicity reduction treatment methods will be presented, and the selected method will be described.The lab tests that confirmed the efficiency of the treatment method will be presented, with three phases of testing as the understanding of the process gradually improved. Toxicity test results showing that the water is nontoxic after treatment through the temperature range will be presented."

Jan 1, 2015

By T. Hayes

Track-type tractors remain one of the most cost-efficient stripping tools available to coal miners. Whether they are "sweetening up" a dragline operation with pre-benching or serving as the primary stripping tool, dozers can play an important role in driving down mining costs. This paper reviews the application zone of track-type tractors. In addition, it provides tips on site set-up, equipping of tractors, and machine operation which the audience can take home and apply.

Jan 1, 1996

By R. David Williams

Old mine workings are found throughout the Western United Sates on lands administered by the U.S. Bureau of Land Management (BLM), U.S. Forest Service (USFS) and private lands. Some of these mine workings date back to the late 1800s. There may be as many as 100,000 sites on lands administered by the U.S. Forest Service and Bureau of Land Management. The Bureau of Land Management has worked with the State of Montana and other agencies to identify and prioritize these sites on BLM administered lands. Following completion of the AML inventory work, the Bureau began an aggressive program to clean up priority sites. This presentation will highlight completed work as well as work in progress on several sites.

Jan 1, 2000

By Zhenqi Cai

The ongoing Overpeck Valley Parallel Sewer Project of Bergen County Utilities Authority (BCUA), New Jersey, is a US $65 million CSO improvement program to meet a State DEP consent order by 2010. One major program component includes a total of 1.8 km (1.2 mile) long, 1,800 mm (72 in) diameter reinforced concrete pipe (RCP) installed by a Herrenknecht AVND1800AB MTBM. The alignment includes drives through 850 m (2,788 ft) of extremely soft glaciolacustrine varved clay, 980 m (3,214 ft) of loose to medium dense mixed soils containing silty sands, gravels, and boulders, and crosses under the New Jersey Turnpike, US Highway Route 46, and a CSX Railroad Intermodal Yard and a branch mainline. Two types of MTBM cutterheads are being used, one configured for the weak varved clay, and one for the mixed soil conditions. The MTBM is also equipped with a double-steering system consisting of a standard front steering joint and a second trailing steering joint to assist grade control should adequate steering not be achieved by the front primary steering in extremely weak soil conditions. This paper discusses the significant engineering aspects and challenges related to site settings, ground characterization, key MTBM features and performance, and required ground treatment.

By Y. J. Wang

Along with the inexpensive availability of computing hardware, a proliferation of powerful personal computers is being realized throughout the mining industry. People from every arena within the industry are designing, developing, and/or applying mining specific software, which is increasing at a rapid rate. In this section applications (or potential applications) that are being made in the analysis and design of mine systems are discussed, including the design of compressed air networks, the simulation of hoisting operations, analysis of longwall face maintenance, and a summary of computer and software applications for analysis and design of coal operations. In "Computer Aided Design of Mine Compressed Air Networks" the authors describe software, called CompAir, and the underlying theoretical and mathematical foundations of it that can be used to make accurate, cost-effective designs of compressed air systems for mines. It includes algorithms for network analysis and the optimization of pipe diameters. The techniques embodied in the software replace traditional rule-of-thumb approximations which have been used in the past and avoid the operating problems that often result from using average, steady-state parameter values, estimated for ideal operating conditions. CompAir, coded in Turbo Pascal for personal computer use, bases calculations on compressible fluid theory, which gives more accurate results than incompressible fluid theory whenever high flow rates or long line distances are involved. The net- work and pipe diameter analysis is formulated as a nonlinear programming problem. The solution technique requires a trial and error approach that iteratively applies the unconstrained optimal pipe diameter algorithm to successive solutions of the constrained network problem until the diameters become "fixed." The authors conclude by recommending the use of a mine-wide monitoring system to improve cost control and provide a better understanding of flow regimes in compressed air networks.

Jan 1, 1989

By I. Sanchez

The development of the recent generation of large mining projects in South America has been challenging in many ways, but especially in the management of water in all its aspects. As a result, a number of projects have experienced difficulties and in some cases significant delays due to a lack of a clear and approved definition of the supply, use and discharge of water from mining and processing sites. The development of the recent generation of large mining projects in South America has been challenging in many ways, but especially in the management of water in all its aspects. As a result, a number of projects have experienced difficulties and in some cases significant delays due to a lack of a clear and approved definition of the supply, use and discharge of water from mining and processing sites.

Feb 23, 2014

By L. Bloom

In 1996, lack of confidence in assaying methods and sample handling affected companies as diverse as Bre-X and Timbuktu. Both share prices and the ability to raise financing are impacted when the quality of assay data is suspect. Overseas projects are subject to enhanced scrutiny when local facilities are used that are unfamiliar to brokers, financing agencies and banks. Quality control systems can be -implemented but there are associated costs. These costs should reflect the risk to the mining company, investors and financiers and the size of the proposed investment. In this regard, assay control call is considered a form of insurance to enhance the value of an exploration or mining project.

Jan 1, 1997

By Werner Burger

After its first introduction in 2013, Variable Density TBMs have increased their application significantly in mechanized closed mode tunneling. Throughout a variety of successfully completed and ongoing projects since then, Variable Density TBM technology has demonstrated its advantages in a wide range of applications. This paper will present the developments and lessons learned from these projects as well as the future potential of Variable Density TBMs.

Jun 13, 2021

By D. Zim

Mining activity in South America is a growing enterprise. One of difficulties found in many areas of the South American continent, especially in north Chile and south Peru, is the shortage of water supply. In order to overcome this difficulty some mining companies proposed to transport the water from Pacific Ocean up to the mountains. This can be accomplished by the use of stainless steel pipelines, but this is a cost prohibitive solution and is also subject to severe pitting corrosion in a saline environment. The use of mild steel may be a lower cost solution than stainless steel as the material of construction for pipelines but it is subject to corrosion anyway. The corrosion in this case can be internal or external corrosion although cathodic protection as well preventive maintenance usually is enough to mitigate external corrosion without the need to shut down the pipeline. The same is not true about the prevention of internal corrosion. It is not practical, sometimes not even possible, shutdown a pipeline to carry out an inspection and fix sections where potential failures are detected. It is possible avoid corrosion caused by sea water within the mild steel pipelines by applying a proper chemical program designed to virtually eliminate dissolved oxygen in the water commonly called deaeration.1 This type of treatment obviously involves additional capital investment since it requires the construction of one deaerator with the first pumping station and additional equipment at each point where the water can come into contact with oxygen. Deaerators will increase operational costs and subsequent injection of chemicals will be required in the case of multiple degasification facilities thus increasing the consumption of chemicals. grams based on oxygen scavengers, the objective of the present study is to develop a new water treatment capable of preventing mild steel corrosion in aerated sea water. The new treatment must be able to prevent both generalized and localized (pitting) corrosion and overcome the necessity to construct and operate deaerators.

Feb 23, 2014

By E. D. Attanasi, J. H. DeYoung

Several factors contributed to continued declines in mineral-exploration activity in the US in 1985. Low metal prices and, what appears to be worldwide chronic excess capacity in copper, molybdenum, lead, and uranium, have resulted in mineral-exploration expenditures remaining anemic. Economic recovery could result in a healthier mining industry and more cash flow to fund exploration. This is because general economic activity and US mining industry activity have historically been closely linked. However, as the worldwide economic recovery has expanded, the mining sector has continued its downward slide. New cuts in industry exploration budgets in 1985 shocked those who thought the exploration situation could not become worse. Some personnel and equipment had been redirected from base metals exploration to precious metals in the past few years. Last year, continued reductions in exploration sent many professionals out of the mining industry. Recent staff reductions or consolidations of operations were made by Noranda, Chevron, Molycorp, and other exploration companies. The latest data from the Society of Economic Geologists (SEG) summary of exploration statistics show that professional staff at year end in major US exploration companies (domestic and foreign operations) fell from 2355 in 1981 to 1868 in 1983 and 1277 in 1984. By the end of 1985, two economic trends were established that could improve the future profitability of mining and hence exploration. First, the price of crude oil began a decline. If sharply reduced energy prices increase worldwide economic expansion, the substantial excess capacity in some of the base metals industries could disappear, and prices could improve. Furthermore, if energy price declines reduce mining and processing costs significantly, metals may recapture some lost markets. The decline in oil revenues has already encouraged some oil-producing countries, such as Venezuela, to look toward development of mineral resources to earn foreign exchange for debt repayment. Second, the decline of the dollar by 21% during 1985 could also help US producers meet foreign competition. During 1985, industry restructuring continued as many oil companies sold off mining subsidiaries and minerals properties. Gold, silver in new discoveries Precious metals continued to dominate the announcement of new discoveries and exploration projects in 1985. A review of domestic exploration and development activities reported in several industry journals shows that 60% to 80% of these projects were directed primarily at precious metals, particularly gold. Base metals exploration activities frequently involved polymetallic deposits with gold or silver values. Because much of this exploration was done on identified targets (on-property exploration), the decrease in wildcat or grassroots (off-property) exploration may be more substantial than indicated by reductions in total exploration activity. Significant gold discoveries in 1985 included several in Nevada, among them the Genesis property of Newmont (near the Carlin mine), Goldfields' discovery of the Chimney deposit in Humboldt Co., and Freeport's discovery of two mineralized sites near Jerritt Canyon. Gold exploration continued to be focused in the western US and Alaska, but gold production starts at the Haile mine in South Carolina, and the Ropes mine in Michigan as well as Amselco's feasibility studies on deposits near Ridgeway, SC, are evidence that gold exploration is not limited to the West. The dominance of gold projects in exploration is not limited to the US, as demonstrated by gold dis¬coveries and exploration projects in Australia, Brazil, Canada, the Caribbean region, China, Guinea, Ivory Coast, South Africa, the South Pacific islands, and Thailand. From the standpoint of US metal miners, it is perplexing that worldwide exploration and development is also taking place in copper, zinc, tungsten, and other metals with depressed prices. During 1985, the US Geological Survey's efforts to map the sea floor of the Exclusive Economic Zone shifted from the Pacific Coast to the deep water areas of the Gulf of Mexico and to areas off the coast of Puerto Rico and the Virgin Islands. An atlas containing sea-floor maps of the west coast area was published as US Geological Survey Miscellaneous Investigations Series Map 1-1792. Results of the 1985 surveys are expected to be published by January 1987. Exploration trends - Statistical evidence Data from the SEG showed continued decline in the US mining industry's exploration expenditures through 1984. The share of US companies' domestic exploration expenditures directed toward base and precious metals has increased from 51% to 84% from 1980 to 1983 and to 86% in 1984. US mining companies spent about $0.67 of each exploration dollar in 1984 in the US. However, this represents an increase from earlier years. The 1983 data also show that firms spending more than $5 million on exploration accounted for 77% of exploration expenditures. Since 1981, the Bureau of Land Management (BLM) has been assembling data on claims and an-

Jan 5, 1986

By Paloma Lazaro, Moe Momayez

Heat-related illnesses (HRI) are relatively common in both hot surface and underground mining operations. When workers are exposed to extreme heat or strenuous work in a hot environment, they become prone to heat stress. Heat strain is the result of the body’s response to external and internal heat stress. It is therefore vital for the conditions leading to heat strain be detected and treated in a timely manner. Heat-related illnesses are manifested by exhaustion and heat stroke. The predicted heat strain (PHS) [ISO 7933 (2004)] model has been developed to predict the health condition of the worker in terms of core body temperature and water loss. The PHS model tested in this study is based on eight physical parameters that are measured at different intervals during a work shift. They include air temperature, humidity, radiation, air velocity, metabolic rate, clothing insulation, posture, and acclimatization. The model predictions are then compared with a direct physiological measurement, such as core body temperature. We present the results of an extensive study that monitored and predicted body’s response to heat stress under different environmental and working conditions. The PHS model provided reliable results in most instances in comparison with other prediction methods currently in use in the field.

By J. S. Gardner

Fortunately, few mining professionals have dealt with what all mining professionals fear---a mine disaster. Unfortunately, many have dealt with ?accidents? which may or may not claim lives but nevertheless rise to the level of a ?disaster? given the fallout of liability and litigation in today?s society.1 The undersigned authors published an article some ten years ago regarding crisis management2 based upon their collective first-hand experiences in actual disasters to that point in history. Unfortunately, disasters have occurred since that time, prompting legislation, and a fresh analysis and expansion of those basic principles is certainly in order. Without question, no two disasters are ever alike, yet general guidelines for forming an effective plan of action can be formulated?and if a mining operation is to have any chance of survival after a disaster, such a plan is vital. The primary concern as any disaster evolves remains as stated a 2003 SME article3--the protection of human life. From that point, the focus moves to any assistance that may be needed given the magnitude of the situation. Permeating throughout this process is "damage control." The first step in dealing with a disaster, however, begins long before any threat of danger arises?formulation and implementation of an Emergency Response Plan.

Feb 23, 2014

By Robert A. Jankowski, Jonathan Kelly, Edward F. Divers

Results for the first underground test of the ventilated drum in a U.S. coal mine are presented. Tests were conducted by the Bureau of Mines through a contract research program with Foster-Miller, Inc., to evaluate dust control effectiveness in a western mine and for gas control in a full scale laboratory facility. The ventilated drum is designed to reduce the amount of dust from cutting by drawing dust-laden air from the cutting zone through twelve water- powered "dust capture" tubes built into the shell of the shearer drum. High pressure water up to 1 12.48 kg per cm2 (1,600 psig), released from sprays, induces maximum airflow of 1.89 m3/sec (4,000 cfm) from the face side of the drum and provides cleaning for respirable dust and improved methane dispersion. At the gob side of the drum a deflector plate, attached to the cowl arm, turns the water spray and a proportion of the cleaned air back into the cutting zone. More than 50 ventilated drums have been installed to date in England, and their tests carried out on fixed height and single-ended ranging drum shearers have shown reductions in respirable dust of 60-80 pct, as compared with conventional wet cutting. The U.S. test on a double drum shearer showed slightly lower reduction.

Jan 1, 1987

By L. Tondo, W. Lim

The high pressure grinding rolls (HPGR) is a relatively new technology which offers the potential benefits in energy savings, circuit simplicity and improved product characteristics in minerals processing applications. Over 300 machines are now operating world-wide, but most of these are used for grinding cement clinker, and relatively few are used in conventional mineral processing. One of the rea- sons for its current limited use in the minerals processing industry is that design, scale-up and flowsheet assessment procedures are seen to be relatively immature and untested. This has reduced confidence in the potential application of the technology. To help rectify this situation an industry funded research project was undertaken, one of whose aims was to develop and prove a mathematical model of the HPGR and a scale-up procedure. Data were collected from tests using laboratory, pilot and in one case a full scale unit (2.2m diameter). A range of feed types were tested including quartz, limestone, kimberlite, bauxite, iron ore and gold ore. These data were then used to develop models of the size reduction performance, power draw, throughput and operating gap for a wide range of pressures, feed sizes, and roll speeds. This paper describes the models that have been initially developed and illustrates their accuracy using some of these data.

Jan 1, 1998

By Jakub Nalaskowski, Robert Aranowski, Jan D. Miller, Jan Hupka

The polyolefins, mainly polyethylene and polypropylene particles, are used as an active filler material in polymer-polymer blends and are being used for the modification of asphalts to pro- vide for high-load, low-maintenance road construction. The stability of prepared blends depends on the interaction forces between polyolefinfiller and the matrix and/or between two polyolefin filler surfaces in the polymeric matrix. Various additives, especially surfactants, can be used to modify these interactions and improve the stability of polymer blends. In current research, direct force measurements between polyethylene (PE) surfaces in n-tetradecane, a nonaqueous solvent imitating the polymer matrix, were performed in the presence of lauric acid and dodecylamine using the AFM colloidal probe technique. Additionally, the zeta potential of polyethylene particles in the presence of surfactants in n-tetradecane was measured. The interac- tion forces between the polyethylene surfaces can be described as a combination of electrical double layer repulsion and steric repulsion between polymer chains extending into the n-tetradecane sol- vent. The addition of surfactant to the n-tetradecane was found to increase the repulsive force between the PE surfaces. The strongest repulsion was observed for dodecylamine. Additionally, the temperature efect on the interactions in n-tetradecane was studied. It was found that steric repulsion between the PE surfaces increases with an increase in temperature.

Jan 1, 2003

By Jon Bowler

Daw Mill Colliery, UK Coal, near Coventry in England, mines the Warwickshire Thick Seam at 800 m/2500 ft depth using longwall retreat with gateroads supported by rockbolts. Over the last eight years the mine has worked longer and wider panels with extraction heights of over 5 m. Recently the mine has experienced high deformation conditions principally from the rib sides resulting in operational issues and production delays. Investigation of rib deformation was undertaken using new inspection and measurement techniques, including systematic laser surveying, and improved rib support consumables were developed and introduced. A new rib trussing system using textile webbing has proved very successful.. A rib support management system was also developed and introduced for face retreat. This allowed rib support to be more effectively managed both for production and safety. For the current developments, new 28-mm-diameter roof and rib bolt systems have been introduced and rib bolt length has been increased to 3 m, with the aim of achieving gateroad stability over the life of the panel. Significant reductions in roof and rib deformation have been confirmed by the latest monitoring results. These ground control innovations are allowing Daw Mill?s potential to be realised. Production from 302?s face in 2008 set new UK and European records. However the support enhancement process continues and further innovations are planned.

Jan 1, 2009

By F. Scott Carpenter

During the past several years, more frequent reference to Wollastonite has appeared in print, both in this country and abroad. The reason for this is the apparent growing interest in this mineral as it approaches commercial maturity. Twelve years ago, wollastonite was available in only limited commercial quantity. In 1933, a deposit in California was worked for a short time to provide a calcium silicate raw .material for the manufacture of mineral wool* It was not until the spring of 1953 that Cabot Corporation put into operation a modem commercial plant to produce this material in a variety of grades. These grades covered both a range of particle size and of particle shape. At that time, applications for wollastonite were largely speculative, although a few commercial applications in glass frits and welding fluxes did exist, For all practical purposes, it was a new material for which few commercial uses had been fully proven.

Jan 1, 1964

By Darrell E. Young

This presentation will define what talc is, how it is mined and processed, and how talc is used in the paper industry. It will also give you some idea about who Luzenac America is and from where it came. Luzenac America was formed in July, 1992 as a result of the acquisition of the talc assets of Cyprus Minerals by RTZ of the United Kingdom. Cyprus Industrial Minerals was then merged with the other RTZ talc interests under the Luzenac name. Luzenac is a town in the Pyrenees of Southern France -and the home of Talc de Luzenac, RTZ's first talc acquisition. The Luzenac Group is the largest talc producer in the world.

Jan 1, 1993