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By NICHOLAS BELLUSCI, D. Erik Spiller, Patrick R. Taylor, VICTOR BRAMAN

Approximately 30% of the world’s production of soda ash comes from mining and processing of naturally occurring deposits of sodium carbonate containing species. Of these deposits, the largest and most profitable have been the trona beds found near Green River, Wyoming. Processing of trona ores is water-energy intensive, particularly due to unit operations of calcination, dissolution, and evaporative crystallization to wield a high-quality dense soda ash product and reject the insoluble gangue species, primarily in the form of oil shale. However, it is speculated that the glass-manufacturing industry, the largest consumer of soda ash, may be able to use a product of a lower grade and consistent level of the insoluble constituents. Thus, pre-concentration of trona ore was investigated using sensor-based sorting, to produce a beneficiated trona stream that would be fed to calcination. The study encompassed preparation of a run-of-mine (ROM) Green River ore sample, selection of 25–75-mm-sized specimens, imaging of the specimens by x-ray transmission (XRT), color, and laser-induced fluorescence (LIF)-based sensors, insoluble analysis of the specimens, and a bench-scale sorting test. Results of the study established that a correlation between the color of the individual ore particles and their insoluble content existed and that a surface detection-based sensor, particularly LIF, was apparently more suitable than XRT to produce a beneficiated trona stream. The bench-scale sorting test demonstrated that a 65% separation efficiency and a 70% recovery of trona could be achieved.

Aug 9, 2022

By J. P. H. Steele, M. U. Ozbay

As mining operations progress toward tele-mining and autonomous procedures, the need for machine performance monitoring increases. Presently, through a combination of vision, sound, and other subjective observations, an operator attempts to optimize the mechanical excavator’s operation. As the operator is moved away from the face in the case of tele-mining or completely removed for autonomous operation, the qualitative sensory input is lost. This lost information must be replaced with quantifiable sensory input. Chip formation detection may be a suitable replacement sensory input. Chip formation can be predicted with high confidence (>80%) through the analysis of the load waveform associated with the bit/rock interface.

Jan 1, 2002

By R. L. Derick

On a regular basis, mine personnel should obtain air samples directly from active underground areas as well as remotely from sealed locations. These samples provide mine officials with data relative to the makeup of the various atmospheres. Should conditions underground change, these results can provide a baseline that can assist officials in determining the extent of change. Relating the concentrations of individual gases to time, applying gases to equations, and examining their change over time are tools that have been successfully used to determine if a heating event exists and, if so, the extent of the emergency. These atmospheric status equations have either been developed for the mining industry or adapted from other industries. They serve as tools to assist personnel in determining the condition of underground mine atmospheres. As long as the problem area continues to be ventilated, certain gases, gas ratios, and equations can be used to determine if a fire exists, what type of material could be burning, and what quantity of coal is burning. Once the mine or the involved section has been temporarily sealed, gases, ratios, and gas-derived equations can assist personnel in determining how conditions within the sealed volume are changing over time. To alleviate potential explosions when fresh air is once again introduced into the sealed volume, equations and a diagram have been developed to predict the likelihood of an explosive atmosphere. Similarly, prior to commencing recovery of a mine or section, equations exist that can assist in determining if the fire will rekindle when air is reintroduced. This paper serves as an overview to remind and/or instruct readers about gas-sampling methodologies and gas analyses to assist in determining the status of underground atmospheres.

Jan 1, 2006

By K. G. Correia

The replacement of the dry mining method at Guajú Mine by the dredging method was a means of ensuring its feasibility by maintaining the production levels. Dry mining increased the cost of the deposit with the distance and presented a limited mined volume, while the decreasing grade of the deposit led to a production drop. With the new methodology, there was a considerable reduction in unit cost of the mine and an increase in the production level of a deposit with low heavy minerals content.

Jan 1, 2005

By H. Gurgenli

Mining companies require accurate short-term mining forecasts to meet budget targets and customer needs. Challenging mining conditions along with employee turnover and lack of standard geologic modeling and mine planning processes can result in time-consuming and inconsistent mine plans. Documentation and automation of the processes involved in mine planning, as well as proper software utilization, are critical in overcoming these challenges. This paper discusses the steps involved in achieving an optimized mine planning system to accomplish productive and cost effective operations. In addition, a case study is included to describe the process of implementing a semi-automated system whereby the geologic model and mine scheduling database are updated monthly to incorporate changes in geology in a relatively complex open-pit coal mine. This case study proves that the ability to update geologic models based on the latest information gathered from production drilling and mining activities can greatly enhance the ability to accurately predict short-term mining production.

Jan 1, 2011

By B. P. Spigarelli

To meet the growing need for CO2 capture and storage technology, Michigan Technological University is researching CO2 capture and storage using carbonate solutions. The objective of the present study was to increase the absorption rate of CO2 into the carbonate solution without reducing the absorption capacity of the solution. This approach used a polypropylene glycol methyl ether (PPGME) as a surfactant to chemically alter the gas bubble size. Experiments were conducted to study the absorption rate of CO2 at varying surfactant concentrations of 0, 0.12, 0.24, 0.36, and 0.48 g/L. Results showed that as the concentration of surfactant increased in solution, the absorption rate also increased. The CO2 absorption rate increased from 3.45 mmol/min CO2 at 0g/L PPGME to 3.92 mmol/min CO2 at 0.48 g/L PPGME. This amounted to a 14% increase in the CO2 absorption rate with no decrease in absorption capacity of the solution.

Feb 27, 2013

By D. R. Dolinar

The fall of small pieces of rock between roof bolts causes over 80 pct of the ground fall injuries in underground coal mines. Roof screen, if installed on the bolting cycle, can significantly reduce the number of these injuries. As the surface of the roof fails, the screen will have to retain the broken rock without failing or excessive deformation. Welded wire screen is the most common type of screen material used for roof surface control in underground coal mines. The load-deformation characteristics and the load capacity of welded wire screen were evaluated in the laboratory in a specially built test frame. In the frame, the square screen sections were held in place by bolts and bearing plates at the four corners while a center load was applied to the screen. The parameters evaluated included the wire gauge and configuration, the bearing plate loads and bolt spacing. The wire gauge of the tested screen was 4, 6, 8, 9 and 10. Maximum screen capacities for both load and displacement were developed for each of the wire gauge sizes along with the screen stiffness. This information can be used for screen selection and for the evaluation and determination of screen performance. DISCLAIMER: The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.

Jan 1, 2009

By Mark A. Krall, Robert L. Geddes, James C. Frost

Introduction The Conda Partnership's Dry Valley phosphate mine is a thinly bedded, multiple seam open-pit mining operation where selective mining techniques are used to recover phosphatic shales. The mining methods used are truck/shovel and scraper/dozer operations. Ore is shipped 32 km (20 miles) by rail to a beneficiation facility. The ore is upgraded by washing and calcining. The mine and beneficiation complexes are owned by the Conda partnership. It is a joint venture between Beker Industries Corp., of Greenwich, CT, and Western Co-Operative Fertilizers (US) Inc., of Alberta, Canada. The Partnership operates as a separate entity of the two partners. The Dry Valley mine is located 48 km (30 miles) northeast of Soda Springs in Caribou County in southeastern Idaho. The mine is situated on the Caribou National Forest. Mining operations take place between 2 and 2.4 km (6400 and 7900 ft) in elevation. It is accessible partly by 32 km (20 miles) of paved roads and 16 km (10 miles) of dirt roads. The winters are long and severe, and the summers are short and mild. This article describes the history, geology, exploration, mining, and reclamation that makes this mine Idaho's largest producing mine and the western US' leading phosphate producer. History and production In the mid-1950s, Western Fertilizers of Salt Lake City, UT, drove an exploratory drift in Maybe Canyon. A large bulk sample of phosphatic shales was analyzed for phosphate content and processing characteristics. No large scale mining or processing operations were undertaken. In the late 1950s, the Dry Valley property was sold to Central Farmers of Chicago, IL. No major operations took place. In 1964, Central Farmers sold the property to El Paso Products Co. of Odessa, TX. El Paso Products supervised the mining operations of Wells Cargo Mining Co. from 1965 through 1967. During this time, El Paso Products built a beneficiation facility and a fertilizer complex in Conda. A 32-km (20-mile) railroad was also constructed from the mine to this facility. From 1968 through 1972, the mine was shut down due to a depressed fertilizer market. In 1972, El Paso products sold its ore reserves, beneficiation plant, and fertilizer complex to Beker Industries Corp. In 1979, Beker Industries sold 50% of its ore reserves and 50% of its beneficiation plant to Western Co-Operative Fertilizers (US) Inc., of Alberta Canada, forming the Conda Partnership. It has operated the mine and beneficiation plant since January 1979. From the mid-1950s to the mid-1960s, no substantial production took place. From 1965 to 1967, El Paso Products stripped 3 Mm3 (4 million cu yd) and mined 2.3 Mt (2.5 million st). From 1972 through 1983, 50 Mm3 (66 million cu yd) were stripped and 18 Mt (20 mil¬lion st) were mined. Geology The Wells Formation forms high ridges and hillsides in the Dry Valley area. It is best exposed along the west face of Dry Ridge. It forms the imposing wall on the east side of Dry Valley. The formation is divided into two members. The lower member, about 213 m (700 ft) thick, is dominantly thin to medium-bedded limestone and silty limestone. It contains nodules and stringers of chert and minor sandstone. The upper member is composed principally of thick-bedded to massive cross-bedded, light-gray to orange-yellow, fine grained sandstone. There is some interbedded brown to light-gray limestone. This member varies from 369 to 457 m (1300 to 1500 ft). Recent investigations indicate that the upper Wells is of Permian age. Under some conditions, the Wells may be water-bearing. Otherwise, it has no apparent economic significance. Grandeur Member (Park City Formation) Overlying the Wells Formation is a distinctive light-gray to white dolomitic fossiliferous limestone. This unit has been identified by the US Geological Survey (USGS) as the Grandeur Tongue Member of the Park City Formation. This member is sometimes absent due to its contact with the Meade Peak Member of the Phosphoria Formation. It is easily detectable by its color, hardness, and fetid odor. Phosphoria Formation The Phosphoria Formation of Permian age was named from Phosphoria Gulch, Bear Lake County. The formation has been studied extensively and developed for its economically valuable phosphate reserves.

Jan 11, 1985

Several common ratios used for determining spontaneous combustion activity rely on comparing the amount of various products of oxidation with the amount of oxygen consumed to produce these products. As coal gets hotter, oxidation reactions become more efficient meaning more products produced for less oxygen consumed. There are many problems associated with accurately determining the true amount of oxygen used. These problems relate to the monitoring technique (and its associated uncertainties) used to generate the results, deficiencies in the established equations utilized in calculations, dilution with other gases and other sources of oxygen depletion. Typically the oxygen deficiency is over estimated, resulting in the under estimation of the indicating ratio. For this reason the use of ?one off? calculations to determine the status of the underground environment is not recommended. Instead trends of these ratios should be used to identify increases which indicate an increase in oxidation intensity. This paper outlines problems associated with the monitoring techniques and equations used to determine the oxygen deficiency.

Jan 1, 2009

By S. Janisko

Studies have linked long-term inhalation of diesel exhaust with adverse health effects such as cardiovascular disease, cardiopulmonary disease, and lung cancer. Diesel exhaust levels in underground mines can approach 100 times the environmental level and are therefore monitored closely in the mining industry. Elemental carbon (EC) (a product of diesel combustion commonly referred to as ?soot?) has proven to be a good indicator of diesel exhaust levels. The current procedure for measuring EC levels involves taking personal samples from a mine worker?s breathing zone and/or stationary samples in various parts of the mine and subsequently sending these samples to a lab for analysis by NIOSH 5040 method. Unfortunately, the whole process can take up to several weeks to complete. To address the problem of waiting weeks for results, NIOSH?s Pittsburgh Research Laboratory is developing a portable device for measuring levels of elemental carbon. This optical device takes a continuous sample of air in the surrounding environment and measures the absorbance of light passing through a filter that collects diesel exhaust particulates within the instrument. This technology can provide a near real time measurement of EC with accuracy within 10% error. The ability to take near real time measurements, combined with the instrument?s portability (currently small enough to be worn on a miner?s belt), makes this device extremely useful in the mining industry.

Jan 1, 2009

By M. J. Gregory

The Pebble Cu-Au-Mo deposit in southwest Alaska is one of the world's largest porphyry deposits. The western part of the deposit was discovered by Cominco America in 1987, who sold the project to Northern Dynasty Minerals Ltd., in 2001. Northern Dynasty discovered the high-grade eastern part of the deposit in 2004 and went into a 50:50 partnership with Anglo American PLC in 2007, forming the Pebble Limited Partnership (Lang et al., 2008). The Pebble Limited Partnership has continued to delineate the deposit through diamond drilling with the most recent resource estimate released in February 2010 (Pebble Limited Partnership, 2010). The Pebble deposit mineral resources comprise 5.94 billion tonnes of measured and indicated resources grading 0.78% Cu EQ, containing 55 billion pounds of copper, 67 million ounces of gold and 3.3 billion pounds of molybdenum. Also delineated are 4.84 billion tonnes of inferred mineral resources grading 0.53% Cu EQ, containing 25.6 billion pounds of copper, 40.4 million ounces of gold and 2.3 billion pounds of molybdenum (Pebble Limited Partnership, 2010). Resources are calculated using a 0.3% Cu EQ cutoff. GEOLOGY AND MINERALIZATION Deposit Geology The Pebble deposit is located in the Kahiltna terrane, between terminal strands of the north-east-striking Lake Clarke strike-slip fault. This fault represents an accretionary boundary and separates the Kahiltna terrane to the north-west from the Peninsular terrane to the south-east (Lang et al., 2008). The Pebble deposit represents a large magmatic-hydrothermal system centered on a group of 90 million year old porphyritic hornblende granodiorite intrusions. An east-west cross section through the southern part of the deposit (Figure 1A) shows the typical relationships between the various rock units which host sulfide mineralization. Sub-parallel ~96 million year old granodiorite and diorite sills were intruded into siltstones of the Jura-Cretaceous Kahiltna flysch. In the west, these sills were cut by a ~96 million year old alkalic intrusive complex composed of porphyritic monzonites and monzodiorites and related intrusion breccias (Bouley et al, 1995). The mineralized 90 million year old hornblende granodiorite intrusions cut all rock types and comprise four small stocks in the western part of the deposit and a larger pluton in the eastern part of the deposit. Recent deep drilling indicates that these intrusions coalesce at depth. The strongest porphyry-style mineralization is centered on the eastern granodiorite pluton and extends into the surrounding rock units (Figure 1A). The western half of the deposit crops out at surface, whereas the eastern side is un-conformably overlain by a cover sequence of Late Cretaceous to Eocene sedimentary and volcanic strata. The deposit was tilted 20º to the east during the Eocene.

Jan 1, 2012

By William R. Yernberg

The early part of the decade was marked by world-wide problems and economic difficulties. In 1980, President Jimmy Carter ordered the failed military mission to rescue hostages in the U.S. Embassy in Iran, Mt. Saint Helens, WA erupted killing 60 people and the Soviets and Mujaheddin guerrillas clashed in Afghanistan after the Soviet invasion. Later in the year, Ronald Reagan was elected president, defeating Carter. The first launch of a space shuttle (Columbia) occurred in 1981. Also in 1981, the first IBM-PC’s begin to roll off the lines. In 1982, Argentina invaded the Falkland Islands and Mexico’s economy was in collapse. In 1980, the U.S. unemployment rate stood at 7.1 percent, and by 1982 the rate increased to 9.7 percent. 1980 marked SME’s first full year in its new office building in Littleton, CO. The new facility was dedicated in November 1979. Claude L. Crowley was executive director of SME in 1980 and remained in that position throughout the decade. SME’s membership stood at about 26,000 throughout this period (1980-1982).

Jan 1, 2007

By H. Do, R. Yoon

Mineral flotation is effective over a relatively narrow particle size range of approximately 10 to 100 µm. If the upper particle size limit can be increased, however, a run-of-mine ore may be coarse ground, and only the middlings are ground further to achieve required grades. This will result in significant energy savings and increased throughput. In this communication, methods of increasing the upper particle size limit will be discussed on the basis of a flotation model that can predict flotation from both hydrodynamic and surface chemical parameters. An example of increasing flotation recovery by control of a chemistry parameter is given.

Jan 1, 2007

By William R. Yernberg

The Fifth International Conference on acid rock drainage (ICARD 2000) was held May 21-24, 2000, in Denver, CO. The three-day conference consisted of about 150 oral presentations and poster sessions that described the state-of-the-art of acid-rock-drainage (ARD) science and technology. The conference also featured a trade show. It included representatives from consulting companies and government agencies with interests in ARD, as well as other environmental issues related to mining. The conference also included field trips to ARD treatment sites and short courses on acid rock drainage issues. ICARD 2000 was planned and promoted by the ICARD 2000 Organizing Committee and the Society for Mining, Metallurgy, and Exploration, Inc. (SME). Financial support was provided by Barrick Gold, BHP Copper, Homestake Mining, Noranda, Phelps Dodge, PlacerDome, the US Bureau of Land Management, the USEnvironmental Protection Agency and the US Geological Survey. Since the original ICARD was held in Roros, Norway, in 1988, knowledge has improved of the behavior of mine wastes as have methods of environmental mitigation. The ICARD 2000 presented the latest advancements in the field of acid drainage.

Jan 1, 2000

By Martin Herrenknecht

Tunnel boring machines continue to develop to take on not only larger and larger diameters but also more difficult ground conditions. Ground conditions consisting of unstable faces with water pressures up to 15 bar has required innovative design approaches. A systems approach has been required to produce tunnelling machines that can not only safely excavate the tunnel but do so in an efficient, cost effective manner that stresses production and labor saving approaches. This paper will review the current design developments and present recent projects where these most recent principles have been applied.

Jan 1, 2008

By Wieda Azani, Alexander Tarigan, Willem de Beer

In block caving, the rates and sequencing of undercut production blasting, drawbell blasting, and mucking are the key levers for attempting to manage cave performance. Cave performance encompasses a range of factors, which include growth, shape and the effect of the cave on the abutments, excavations, geological structures and lithology. We compare production data in several panels in the Grasberg DMLZ and GBC block caves with the seismic response in work areas, around geological structures, and in geotechnical domains. These comparisons enable evidence-based conceptualising of the effect of production rates and mining layouts. By also considering the correlation of seismic release rates in different parts of the rock mass, the wider influence of a cave can be gauged through considering possible stress and / or deformation transfer. This concept is not novel, but it is rarely implemented in a routine fashion, principally because production data rarely are easily available. Previously, it has also been used to retrospectively compare seismic hazard between different mines. This paper discusses practical, day-to-day tools to manage seismic response to mining. Therefore, the paper presents a methodology for presenting seismic release and production rates on integrated plots at any time to facilitate quick identification of correlated spatial regions. This methodology explores the production data collection and geolocation at Grasberg, which will be described in some detail.

Apr 26, 2022

By C. S. Harman, C. A. Enright, J. F. Brune

"The mining environment presents challenging and complex situations for the application of medical care. The combination of remote locations, difficult access and longer response times may create an increase in morbidity and mortality in the event of serious accidents. The U.S Mine Safety and Health Administration (MSHA) has only minimal requirements of first aid training for mine workers. For mine rescue team members, MSHA requires medical training at the Emergency Medical Responder (EMR) level, as only prescribed by mine rescue contest rules. This paper examines, based on mine accident statistical information, whether a higher level of medical training, for example at the Emergency Medical Technician (EMT) or at the Advanced Life Support (ALS) level can better address injuries most commonly disabling or leading to the death of miners in the United States. BACKGROUND Prehospital emergency medical care for the sick and injured has evolved considerably from first inception. Ambulances used to be staffed by persons with little training and equipment and prehospital care was focused largely on the rapid transport of the injured person to a hospital and. The modern prehospital care model was initially developed in military applications, where medics were responsible for some treatment on the battlefield and rapid transport to the care of a physician. In 1965, the National Academy of Sciences and National Research Council Committees on Trauma and Shock published Accidental Death and Disability: The Neglected Disease of Modern Society (National Research Council Committees on Trauma and Shock, 1966). This white paper laid out the consequences of the insufficiency of the Emergency Medical System (EMS) in the United States at that time. According to this paper, in 1965, 107,000 people were killed from accidental injury, with another 400,000 injured with permanent disability. The authors estimated that approximately 50% of ambulance services were provided by local morticians that were not capable of rendering advanced life support. The paper states that, based on experiences in the Vietnam war, seriously wounded soldiers had a better chance of survival in the battle field compared to traffic accident victims with similar traumatic injuries because the military was capable of providing first aid and efficient transportation to emergency care facilities. The white paper states that death rates from battle injuries declined significantly from 8% in World War I to 2% in Vietnam. The publication of this white paper is credited for the broad evolution and rapid advance of the civilian EMS system after 1965. It eventually lead to the creation of the National Highway Transportation Safety Administration (NHTSA) National Standard Curricula (NSC) for emergency medical care in 1985. Training, and therefore required skill and knowledge for prehospital emergency care has continued to grow to reach the current standard."

Jan 1, 2016

By Faruk Oksuz

The owners of large infrastructure projects are challenged on how to implement sound engineering and construction contracting strategies that address their prime expectations: a quality job, on time and within budget. With the increasing number of large engineering and construction projects worldwide, owners continue to search for alternative contracting strategies to address their risk, quality, sustainability (operability and performance), schedule, and budget concerns. Coupled with the shortage of resources, delays, political pressures, and other obstacles in procurement and negotiation processes, engineers and contractors are also looking for creative ways to optimize contract packaging strategies for efficient and successful project delivery. This paper compiles an array of decision making criteria and suggests a balanced evaluation, ranking and selection strategy in procurement of both engineering and construction services for large tunneling and other infrastructure projects. A number of owners? general preferences and viewpoints are discussed on large tunnel programs encompassing water and wastewater conveyance systems, pump stations and treatment facility upgrades. Contract packaging strategies and project phasing and segmenting alternatives for preliminary engineering, final design, construction management, and actual construction of facilities are featured for several large water and wastewater infrastructure projects. While the selection (and the relevant selection process and criteria) and performance of service providers, whether for engineering or construction, have profound effects on the outcome of any given project, this paper only examines strategies for con-tract packaging. More specifically, the authors evaluated case studies and developed a range of recommendations for packaging of large water and wastewater infrastructure projects with multiple components.

Jan 1, 2008

By M. J. Price

The usage of Geographic Information Systems (GIS) is increasing rapidly throughout the Mining Industry, especially in the Industrial Minerals sector. GIS provides an efficient and robust link between spatial (often CADD) and tabular (database/spreadsheet) components. Mineral economists and corporate planners employ GIS to perform market analyses, to source raw materials, and to schedule and monitor deliveries to customers. Exploration and acquisition groups apply spatial analysis to identify high quality resources that meet economic guidelines. Mining regulators and environmental affairs departments expedite and monitor permitting, environmental compliance, and best management practices reclamation through GIS data management and Electronic Permitting. Operations staffs monitor overburden removal, material extraction, quality control, and stockpile volumes with GIS. This paper summarizes the many aspects of GIS in Industrial Minerals. It also introduces and addresses issues and concerns commonly encountered during a mining GIS implementation.

Jan 1, 2001

By D. J. Rose

The San Miguel Mine is owned by San Miguel Electrical Cooperative, Inc. and operated by Atascosa Mining Company, a wholly-owned subsidiary of Morrison-Knudsen Company, Inc. This multiseam, single-zone lignite surface mine is located near Jourdanton, Texas, 110 kilometers (68 miles) south of San Antonio. Lignite extracted from four closely-spaced seams is used to fuel the 400-MW San Miguel Power Plant. Recovery depths range from 7 to 37 meters (25 to 120 feet). The mine began stripping operations in the spring of 1980 and now produces approximately 2.5 million tonnes (2.8 million tons) of lignite annually. Atascosa Mining Company is responsible for production, maintenance, engineering, and management services. Production responsibilities include topsoil removal, overburden removal, lignite mining, spoil pile regrading and topsoil replacement, as well as ash disposal and construction and maintenance of water retention and diversion facilities.

Jan 1, 1984