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By G. Goellner

The thick alluvial sand and gravel deposits along the base of the San Gabriel mountain range in Southern California area have been mined for construction aggregates for over 100 years. Encroachment of high-density urban populations in this area has led to concentrated mining in a handful of open pit mines with single production faces reaching up to 55 m (175 ft) in height, and long transportation distances from the pit to the processing plant. Aggregate producers have responded to these challenges by developing innovative mining systems which enable low-cost, full-face mining of the alluvial material, and low cost delivery of this material to the plant.

Jan 1, 2004

By F. L. Pierson

Since the discovery of 'potash in the Carlsbad area in 1926 and the start of mining operations in 1931, "first mining," operations have been carried on. This is a room and pillar system in which approximately 62% of the total ore is removed. Or the basis of ore reserves and rates of extraction, the life of the mine in the early; days was estimated to be well over 50 years, however, even with an increase by additional ore reserves, it became increasingly apparent that the life of the mine was being shortened considerably by increased production. Further cause for the shortening of mine life was due to the exceptionally weak back over the northeast quadrant of the main orebody which had .caved in on first mining up to a height of 8 feet. Thus, in 1953 the decision was' made to begin pillar pulling, also called, second mining or final mining, and in December of 1953 this program was started after much discussion.

Jan 1, 1965

By Devin Burns, Saima Ghazal, Michael Owusu-Tweneboah, Kwame Awuah-Offei

Trust in AI systems and the nature and amount of information about the system can influence decision-making. It is, therefore, crucial to understand how AI-powered monitoring systems (e.g., gas monitoring systems) influence miners’ trust and decision-making in emergency evacuation. This work focused on measuring the differences between how participants respond to a simulated underground mine emergency evacuation situation when warnings are represented as coming from a human or AI-based monitoring system. We also manipulated the amount of information participants received about the system, yielding a 2×2 between-participants survey design. The participants received an alert message about rising gas levels in a mine and provided a response on how they would react and reported their perceived safety. We also asked questions to assess their trust in, preference for AI over human-based gas monitoring systems, and whether they are willing to delegate the duties of underground gas monitoring to AI systems. The experiment results show the amount of information had a significant influence on miners’ trust and decision-making. The safety perception of participants based on age, number of children and ethnicity was significantly different from one category to another. This work provides valuable insights as the mining industry deploys AI systems to aid mine safety.

Feb 1, 2025

By E. L. Montgomery

Salar basins in the Andean Highlands of Northern Chile contain ground-water resources which could be used to satisfy requirements for the mineral industry in the region. Salars occur in arid zones; average precipitation is about 200 millimeters per year at altitudes of about 4,000 meters, and average annual evaporation is two meters or more. The salar basins are hydrogeologic sinks where water flows from recharge areas at the margins of the basins to discharge areas at the salt encrusted salar at the lowest point of the basin floor. Groundwater circulation occurs principally in the alluvial and fractured bedrock aquifers. Results of pumping tests for exploration and production water wells indicate a range in maximum sustained pumping yield of 62 to 126 liters per second, and where abundantly fractured, ignimbrite comprises the most prolific aquifer. Chemical quality of groundwater is good. Long-term pumping from properly located production wells in the salar basins would result in lowering of groundwater levels and salvage of water in areas where groundwater is lost via evaporation.

Jan 1, 1986

"Quang Ninh province is located in the north east of Vietnam and the coal mining in the province generates two thirds of the province’s GDP. The coal is extracted from both open pit and underground mines for the country’s complete coal export and by a share of more than 90% for domestic coal usage. Overburden generated through open pit mines is piled up nearby in the form of large waste rock dumps. The side-hill fill dumping near open pit mines is the source of environmental degradation in the region. Among the current problems at solid waste rock dump sites are dust emissions during and after dumping as well as Acid Rock Drainage (ARD). One of the major existing problems at waste rock dumps is dump stability (comprising erosion, sliding and subsidence issues). The RAME R&D project (Research Association Mining and Environment in Vietnam) is - among other activities - actively involved in the research for stabilisation and rehabilitation of mine waste rock dumps in Vietnam in the form of several sub-projects. The Institute of Mining Engineering I of RWTH Aachen University is leading the sub-project of mine waste dump stabilisation in co-operation with Chair of Geotechnical Engineering and Brenk Systemplanung GmbH. Mine waste dumping in the form of layers as an alternative to the side-hill fill dumping is expected to bring up environmental and economical benefits by minimising the problems of dump sites with the contribution to a sustainable development. Reduction of the post construction settlements, long term stable dump profile with minimum erosion, improvement of material parameters for geotechnical slope stability through compaction from hauling trucks as well as economical evaluation of new dumping concepts are the areas of the current research. The project has been financed by German Federal Ministry for Research and Education (BMBF). The ultimate aim of the sub-project is the compilation of the project results in the form of a "Best Practice Guide" and software based "Decision Support System" for planning and management of solid mine waste dumps."

Jan 1, 2011

By U. S. Geological Survey

In 2025, the estimated total value of nonfuel mineral production in the United States was $112 billion compared with $106 billion in 2024. The estimated value of metal production in 2025 increased by 13 percent to $38.1 billion from a revised total of $33.6 billion in 2024. The total estimated value of industrial minerals production was $73.7 billion, 2 percent more than the revised total of $72.2 billion in 2024 (Table 1). Increases in production of certain nonfuel mineral commodities, along with increases in prices of some industrial minerals contributed to the overall increase in the total value of domestic nonfuel mineral production in 2025. For the industrial minerals sector, the production value of natural aggregates, which comprised approximately 60 percent of the total production value of all industrial minerals, increased by 4 percent even though production volumes decreased by 1 percent in 2025 compared with production in 2024. The largest percentage increases in production value in 2025, in descending order, were for dimension stone, wollastonite, potash, mica and portland cement. The largest percentage decreases, in ascending order, were for high-purity quartz, industrial sand and gravel, lithium carbonate, bromine and boron. For the metal sector, production decreased for several mineral commodities and prices decreased for several metals due to oversupply. Lithium, manganese and nickel had some of the largest percentage decreases in production value.

May 1, 2026

By Jon C. Jenkins

In order to plan the most efficient mine installation, a company should take advantage of all available information and tools. One of the first factors of a coal reserve that needs to be determined as accurately as possible is the quality of coal the mine will have access to during the life of the installation. With the aid of many types of well logs and computor analysis, we are investigating several methods of log correlation to determine such data as moisture, ash, sulphur, and BTU on an in place basis. It may be possible to determine this data more accurately in this manner than by using diamond drill cores for analysis and thus allow for a more profitable mine installation. The production of an underground mine is based on many factors, two of these being roof control and line water, where present either in the roof or coal seam. Using many of the same logs obtained from reserve and active mine areas, we have attempted to determine roof and floor characteristics such as strength, lithology, and moisture properties. Using data obtained from this program, we will make comments on possible length of bolt to be used, possible mining width, and pillar size as they would pertain to these reserves and active mine areas.

Jan 1, 1969

By T. Gouri Charan

Indian coals, which are of Gondwana origin, contain high amounts of mineral matter, wherein the extraneous material was intimately mixed in the coal matrix during the formation stage, causing a high level of impurity in the run-of-mine (ROM) material. These coals possess difficult to very difficult washability characteristics. Beneficiation of high-ash non-coking coals of India has become the prerequisite for improving the overall economics and efficiency of power generation. The use of dry cleaning systems in India for beneficiation of non-coking coals has gaining renewed interest recently. The benefit of the dry beneficiation process is to exploit the given resources while providing a more reliable and consistent quality fuel with a low operating cost. M/S Allmineral has introduced a technique for the dry beneficiation of coal, which is being tried in India for the treatment of high-ash non-coking coals. The first commercial air jig of 50 t/hr capacity was installed and commissioned to beneficiate high-ash coals of 40 x 5 mm feed with an ash content of 40%; a clean coal product of 33% ash was produced and is being used for a sponge iron plant.

Jan 1, 2011

By T. Umadevi, A. Pratap Singh, R. Sah, K. Abhishek

"It was possible to beneficiate a low-grade iron ore fines sample from Bellary-Hospet, Karnataka, India assaying 56% Fe, 9.1% SiO2 and 5.2% Al2O3 and produce two concentrates, namely, a sinter-grade fines concentrate (43.7% by weight), assaying 63.6% Fe, 2.6% SiO2 and 1.7% Al2O3, and a pellet-grade concentrate (30.7% by weight) assaying 64.7% Fe, 2.9% SiO2 and 1.7%Al2O3. Rejects (25.6% by weight) assayed 32.5% Fe, 27.9% SiO2 and 15.4% Al2O3. The mineralogical characterization indicated that the sample consisted of 69.5% ironbearing minerals (56% hematite, 7.5% martite and 6% goethite-limonite), 12.5% quartz and 15.2% clay, and the rest were minor minerals. Liberation size was found to be in the size range of 25 to 100 µm. The process flow sheet consists of jigs, spirals, grinding and low- and high-intensity magnetic separation of the deslimed feed. IntroductionJSW Steel Ltd is a 10-Mt/a integrated steel plant. To produce 10 Mt/a hot metal requires nearly 16 to 20 Mt/a iron ore fines. The fast depletion of highgrade iron ore fines, increased industrial demand and an increase in iron ore prices have necessitated the exploitation and use of low-grade iron ore fines in the steel-making process after beneficiation. Thus, the beneficiation of low-grade iron ores by removing the associated gangue minerals and enhancing their grade is essential. The use of these iron ore fines in sinter and pellet making has prompted the undertaking of systematic studies on low-grade iron ores.Finely disseminated low-grade iron ores with siliceous impurities have been upgraded by gravity, magnetic and flotation-based processes (Burt, 1994; Svoboda, 1987; Houot, 1983). The processing of low-grade Indian hematite ore containing high levels of alumina-bearing minerals as impurities present separation challenges and pose special problems in martite and magnetite, in association with quartz and clay as the gangue-forming minerals. Alumina is mainly contributed by clay (kaolinite, montmorillonite, illite, alunite), lateritic material and gibbsite; some alumina occurs as solids in iron oxide minerals, namely, goethite and limonite. Silica is mainly contributed by quartz and the associated clay. achieving a high-grade concentrate (Pradip, 1994; Singh and Mehrotra, 2007). Hematite ore basically consists of varying amounts of hematite, goethite,"

Jan 1, 2015

By T. Bednarski, T. McCallum, L. Moya, B. Gay

"Molybdenum recovery by solvent extraction has gained interest partly due to advances in concentrate leach technology. Historically, both molybdenum and rhenium have been produced using amine-based extractants with the ability to co-extract both metals. Alternatively, a phosphinic acid-based extractant (CYANEX® 600) can be used depending on the flow sheet. CYANEX® 600 selectively extracts Mo leaving Re in the raffinate, which is a valuable feature in plants which require rejection of the rhenium from the molybdenum circuit. CYANEX® 600 piloting results are reviewed and compared to commercial experiences with an amine-based extractant. INTRODUCTION Molybdenum is most commonly found as molybdenite (MoS2) in primary porphyry deposits (about 59% of global reserves) and copper porphyries (about 39% of molybdenum reserves)[1]. Recovery from molybdenite traditionally involves flotation (concentrates typically containing 85 – 95% MoS2) followed by roasting to produce MoO3. Solvent extraction is also used to recover molybdenum from acidic aqueous solutions resulting from scrubbing of roaster and smelter off gasses and leaching of molybdenite (uranium ores). Molybdenum is also frequently found in low concentrations in copper leach inventories[2]. More recently, pressure oxidation has gained interest to treat molybdenite concentrates. Molybdenum Chemistry The chemistry of molybdenum is complex with a series of extractable species existing dependent on the pH and oxidation state as shown in Figure 1.Under strongly basic conditions, molybdenum primarily exists as MoO42- while under strongly acidic conditions MoO22+ becomes the predominant species. In between, a number of isopolymolybdates such as Mo7O246- and Mo8O264- are dominant. Equations (1) – (3) demonstrate some of the proposed molybdenum equilibrium reactions[1]."

Jan 1, 2017

By Langtry E. Lynd

Ilmenite concentrates prepared from beach and dune sands of Florida, India, Australia, and other localities deviate to varying degrees from the theoretical composition of pure ilmenite, and generally contain more Ti02 than the formula FeTiO3 would indicate, and some Fe203. This variation in composition is due to different amounts of altered ilmenite in the concentrates.(l) The alteration has been shown to take place by oxidation and leaching of the iron in ilmenite, to yield residual products consisting of amorphous or very finely crystalline titanium dioxide and ferric oxide, Other studies (2) have stressed that ilmenite may alter first to an amorphous titanium-iron oxide, or to an amorphous mixture of titanium and iron oxides, with later alteration to crystalline titanium dioxide. There has been some speculation as to whether alteration of ilmenite is usually caused by weathering or by hydrothermal processes,(3, 4, 5) Three main methods of approach were used to study the mechanism and rate of ilmenite weathering, (1) Etch tests were used to learn the relationship between crystallographic orientation and the rate of chemical attack on ilmenite. (2) Altered ilmenites in New Jersey sands were compared with ilmenite in rocks of the area from which the sands were probably derived, (3) Experiments were carried out to determine at what rate, and by what agents, originally fresh ilmenite could be altered in the laboratory under simulated weathering conditions.

Jan 1, 1959

This study was conducted to evaluate the effects of a diesel particulate filter (DPF) regeneration process on the concentrations and size distributions of aerosols in an underground mine. Two active regeneration strategies were examined for an electrically regenerated sintered metal fiber filtration system, and the effects were compared with those observed for a muffler and the same system operated in a passive configuration. The effects were assessed for three steady-state engine operating conditions. The number and mass concentrations and size distributions of aerosols in mine air were found to be strongly affected by the exhaust configuration, engine operating conditions and the regeneration process. When the system was operated in active configurations, the concentrations exhibited a transient and cyclic nature. At light load conditions, the distributions of aerosols in mine air were dominated by accumulation mode aerosols for all exhaust configurations and regeneration strategies. High concentrations of nucleation aerosols were observed when the DPF system was used and the engine was operated at high load conditions. A positive correlation between accumulation of particulate matter in the filter and the efficiency of the filter in removing accumulation mode aerosols was observed for all conditions. In the case of high engine load, reductions in accumulation mode aerosol concentrations were linked to a substantial increase in number concentrations of nucleation mode aerosol. Overall, the filtration system was found to be very effective in reducing total aerosol mass and elemental carbon concentrations for all engine operating conditions. However, the system was substantially more effective in passive than in active regeneration configurations.

Jan 1, 2012

By Sadatoshi Ohmori, Karen Shinoda, Nobuharu Isago

Method of tunnel excavation is generally classified such as full-face excavation, bench-cut excavation, diaphragm with center pillar excavation, center drift advancing excavation and so on. These excavation methods should be selected properly in terms of ground condition, the area of tunnel section, the arrangement of construction. Center drift advancing excavation method in mountain tunnel construction, is often applied under quite weak ground condition, prior to the main tunnel widening excavation. Recently, the advancing drift is for the excavation of extreme larger section in main tunnel to confirm the stability of face. In addition, we make advancing deformation occur in drift when the construction was done in poor ground like squeezing and swelling ground, and the force occurred in main tunnel was expected to reduce by the effect of ‘dodging’ for support structure. Mechanical relation between drift and main tunnel has been mainly grasped on past experiences in Japan. However, the characteristic of tunnel enlargement was partially discussed by using the three dimensional analysis and the result was grasped by past experiences on the basis of each tunnel construction. It is considered that the natural ground stress is normally released as the advance displacement, but it was released after the main tunnel widening, causing a displacement and deformation increase. Up to now, the construction practice has shown the reduced displacement during the main tunnel widening excavation by the drift, and the numerical analysis agreed with above observation. However, there is no report found that the displacement and deformation at the time of widening excavation of the main tunnel become larger in case of a drift application. In Kyusyu area, western part of Japan, the northern part of Yoshinomoto tunnel was applied an advancing bench-cutting method for a center drift for the purpose of obtaining the geological information for support selection of the main tunnel in widening excavation. The shape of center drift was a perfect circle with a diameter of 4.0 m or 6.0 m and the same temporary support regardless of the geological situation. As a result, the displacement and deformation of the main tunnel after widening excavation were larger than the section where the center drift was not applied. Furthermore, the displacement and deformation of the main tunnel after its widening excavation was considered larger in the section where the cross-section of the center drift with 4.0 m diameter was applied than one with 6.0 m. Therefore, the center drift with a high rigidity support structure had the effect of suppressing the advancing deformation prior to the main tunnel widening excavation.

Jun 13, 2021

By Nancy J. Wheatley

I. INTRODUCTION The Massachusetts Water Resources Authority (MWRA) is a regional water and sewerage authority which provides wholesale water and sewer services to the Metropolitan Boston area. The MWRA was created by the Massachusetts Legislature as an independent authority in 1985 following the filing of a lawsuit in federal court to correct the pollution of Boston Harbor resulting from inadequate and inadequately maintained sewerage facilities. Immediately upon its creation, the MWRA began to tackle treatment plant issues, including addressing the need for a secondary treatment plant, planning for ceasing ocean discharging of sludge, and making interim repairs to the existing, antiquated treatment plants. The MWRA's initial activities led to a court-ordered schedule for construction of a single new primary and secondary treatment facility, for development of sludge management plan focussed principally on reuse, and for completion of a short term program of repairs to existing facilities. Once a schedule for completing these activities had been negotiated, the U.S. Environmental Protection Agency (EPA), a plaintiff in the federal court case, asked that the MWRA take "responsibility" for controlling discharges from combined sewer overflows (CSOs) within its service area. Combined sewers (sewers in which both sanitary sewage and storm water runoff are carried in a single pipe) presently discharge over 10 billion gallons of untreated wastewater into Boston Harbor and its [ ]

Jan 1, 1991

By H. B. Charmbury

In Pennsylvania there are two distinct coal regions, bituminous and anthracite, in which the mining conditions and production trends are different. Bituminous mining is more mechanized, and production is increasing. This report is concerned specifically with the bituminous area. The bituminous coal industry apparently is facing a shortage of miners and mine officials which may become acute by 1970. Since 1949, when Pennsylvania had more than 100,000 bituminous coal miners, the number has steadily decreased. There are two principal reasons for the decrease of certified miners and mine officials. These reasons are the fact that apprentices are almost a thing of the past and the fact that the image of the coal miner is a poor one to people in general and to parents in particular. This has contributed greatly to the high average age of our miners today. The average age of all those employed in the mines is 50. Yet it is known that the progress in mine mechanization requires younger and more alert men to operate the newer type equipment.

Jan 1, 1966

By R. Bhaskar

The control of respirable dust in mines has been given paramount importance due to the health and safety implications associated with fine dust. The understanding of the temporal and spatial behavior of dust has been recognized as essential for increasing the efficiencies of the existing control techniques and for developing new control strategies. Mining-related studies in this area are, in general, limited. They are also mostly experimental. Some mathematical and computer analyses have been attempted. In this paper, first a review of the mathematical studies performed in the last three decades in this area is presented. Second, a mathematical model for analyzing dust flow in mines is proposed. The model takes into account a number of factors affecting dust transport. It incorporates varying dust generation source strengths and dispersion, deposition, and coagulation of dust in mine airways. Finally, application areas for the model are discussed. A computer program based on the mathematical model has been developed. The program will output the dust concentration in the mine atmosphere as a function of time and distance from the source. The amount of dust deposited on the sides, roof, and floor of the airway is also determined.

Jan 1, 1985

By K. Baba

Liberation of valuable minerals from a gangue matrix during size reduction of multiphase mineral particles is an important objective in mineral separation processes. A methodology for the prediction of volumetric grade distribution from one dimensional, linear intercept image analysis is being developed using a transformation function to describe the relations hi p between the linear and volumetric grade distributions. As part of this research effort it has been found that a transformation function, derived from Monte Carlo simulations of irregularly shaped particles, mainly depends on the volumetric grade and the dispersion density, i.e., the number of nuclei (or grains) per particle. A possible mathematical form for the transformation function is described in detail.

Jan 1, 1985

By James L. Hendrix

This paper is intended to give the reader an update on the work being done at the Mackay School of Mines about the fate of cyanide on precious metals mill tailings waste. During the last two years several tailings impoundments have been sampled and analyzed for total and free cyanides. From our sampling program we are beginning to learn valuable information concerning the fate of cyanides in precious metals mill wastes. Included in this paper is a detailed description of our sampling and analytical techniques. Also, some of the data obtained from five sites are given.

Jan 1, 1986

By Xuehui Zhang, Yun Bai, Qiaosong Li, Huiming Wu

"Construction activities account for a large share of the global Greenhouse Gas emission. In the past 10 years, project decision-makers and researchers have been paying more attention to the carbon emission of tunnel projects. In this paper we study the carbon emission calculation in shield tunneling. The objective of this paper is to: (1) analyze the complex variables which affect the total emission of shield tunneling; (2) develop and illustrate a new data-mining-based method to estimate the carbon emission in the construction phase; (3) assess the emission prediction reliability of a data-mining-based method—the Randomforst model, with R programming language. This study is based on a large-diameter shield tunnel built in Shanghai, China, and shows that a reliable predictive performance can be achieved with this new data-mining-based method. INTRODUCTION Climate change caused by the Greenhouse Gas (GHG) emission has been a hot topic in recent 20 years. Both governments and non-government-organizations are trying its best to control the climate change. Since the 1990s, the general consensus is that carbon emission reduction and carbon sinking (the work of capturing the emitted carbon) are two ways of mitigating the global warming effect, with the former being more exercisable. The challenge posed by global warming also motivates the project decision-makers to take measures to reduce the GHG emission. The 5th Assessment & Report on Climate Change (published by IPCC, the Intergovernmental Panel on Climate Change) suggests that building industry contributes to 5% of the total direct emission. The building industry has shown more awareness of the impact of GHG emissions with construction activities. Shield tunnels act as an important component of the infrastructure system, and have been the dominant way of utilizing the underground space, as well as a competitive alternative to passageway underneath rivers. To study the environmental effects of shield tunneling, there is a need to quantify the carbon emission of shield tunnel construction."

Jan 1, 2016

By Nick Barton

A recent analysis of 145 TBM tunnels of more than 1000km total length has helped to quantify the time dependence of utilization (U). In fact U = Tm, where T is time in hours and m is a negative gradient of deceleration. In poor quality ground, gradient m has a strong dependence on rock mass quality Q, for example m ˜ -0.5when Q = 0.1. Good investigation is critical for ensuring faster TBM tunneling then drill-and-blasting, which tends not to slow down (in m/hr) as the tunnel length increases. Anew design model called QTBM allows more reliable prognoses be made, and occasionally will disqualify the TBM solution.

Jan 1, 2001