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By Xin Wang, He Shao, Wenpu Li, Yiyi Zheng, Xi Chen, Yurong Gao

This study utilized experimental and numerical simulation methods to investigate and analyze the atomization characteristics of three internal air–water mixed atomizers under different operating conditions. By comparing the research results, the effective dust control working parameters for the application of the selected atomizer in the engineering field were determined. Firstly, the atomization characteristics of the three atomizers were studied using a customized experimental system. The results indicated that nozzle 2 had a wide atomization range, a small atomization distance, and small droplet size; nozzle 3 had a narrow atomization range, large droplet size, and fast atomization speed; and nozzle 1 not only had a large atomization range but also could produce droplets of dry mist size with fast atomization speed, meeting the dust reduction requirements of the Majiliang Coal Preparation Plant. Secondly, Fluent software was used to simulate the atomization process and particle size distribution of the three internal mixed atomizers, determining the working conditions of the atomizers, the required number of atomizers, and the application angle of the atomizers in the internal mixed dust removal system. Finally, the atomized dust control system was applied on-site, achieving a total dust removal efficiency of 90.72% and a respirable dust removal efficiency of 89.75%.

Mar 9, 2024

By M. K. Mohanty

A modified coal flotation characterization procedure, referred to as the Advanced Flotation Washability (AFW) technique, has been developed which, compared to traditional procedures, provides a more accurate prediction of the optimum separation performance achievable by a froth flotation process. The AFW procedure uses a vertically-baffled flotation column which provides enhanced selectivity among particles of varying degrees of hydrophobicity due to a plug-flow environment and an improved carrying-capacity environment. In fact, the separation performance of the traditional procedures was enhanced by increasing the possibility of operating under improved selectivity conditions. The separation performance provided by the AFW procedure was superior to that obtained from multiple cleaning stages using commercially-available flotation columns under both kinetic and carrying-capacity limiting conditions.

Jan 1, 1997

By BHAMIDIPATI S. SASTRY, ANMAYA NAIK, ASIF AHMAD, Srivatsan Jayaraman Sridharan, ADITYA PANDEY

Wet kata cooling power (WKCP) as measured by a kata thermometer is a well-known heat stress index used in the mining industry. Although, over the years, several researchers proposed different heat indices and indicated limitations of the kata thermometer, WKCP is used in the South African gold mining industry due to its simplicity and rapidity of assessment. This paper presents a comparative analysis of the newly developed empirical expression for the WKCP and some of the more commonly used empirical models. For this purpose, WKCP measurements are obtained based on experiments conducted in a low-speed wind tunnel. Based on a regression technique, the analysis presented aims to assess the disagreement between the empirical model predictions and actual measurements. The correlation is also presented between WKCP and the well-established thermoregulation models using parameters from the low-speed wind tunnel experiments, including dry-bulb temperature (Td), wet-bulb temperature (Tw), barometric pressure (P), and wind speed (v). It is found that the proposed empirical model for the WKCP represents the bioclimatic interaction quite well under the specific parameters that defines the harsh thermal environment and air condition, such as metabolic activity, clothing of the person, and the velocity of the ventilating air in which the person is working. The statistical analyses performed show that the empirical model proposed for the WKCP produces satisfactory estimates of the thermal stress experienced under lower air velocities, light clothing, and higher metabolic activity rates.

Sep 2, 2021

By T. B. Thompson

The Leadville District has been a prominent metal producer since its discovery in 1860. Veins and replacement bodies both have contributed to district production. The latter have been the major metal sources and are hosted within the Paleozoic Leadville, Dyer, and Manitou Dolomites. Igneous bodies representing eight separate events cut the sedimentary section. The main intrusive complex within the district occurs in the Breece Hill area and was the thermal center about which the vein and replacement ores exhibit mineralogical zoning. Precious metal-pyrite-quartz veins (quartz Th= 422 to 469°C; salinity < 4.2 wt. percent eNaCI) occur within or peripheral to the Breece Hill Intrusive Complex, whereas base metal veins and replacement bodies extend from the complex margins outward as much as 2 mi. Pre-ore and post-ore igneous bodies occur, but Fragmental Porphyry dikes immediately post-date the ore event. The Fragmental Porphyry grades downward from a heterolithic breccia with rock-flour matrix to one with a dark, glassy, sulfide- and phenocryst-bearing matrix, commonly with quartz-feldspar porphyry selvages on the dike. Two types of replacement bodies are recognized in the district: 1) the Leadville-type (LTM), massive sulfide (> 60% sulfides) bodies with recoverable Zn, Pb, Ag, and Au, and 2) the Sherman-type (STM), sulfide bodies (low total sulfide) with barite, galena, sphalerite, argentian tetra.hedrite, and minor pyrite. The latter type occurs only within the Leadville Dolomite and is found throughout the Mosquito Range and extending into the Alma District. The Leadville-type replacement bodies are zoned with a pyritic margin and base metal core. Wallrock alteration and trace Pb-Zn dispersion are strongly developed in igneous wallrocks but are weakly developed in carbonate wallrocks. Cu:Zn, Ag:Zn, and Au:Fe ratios increase outward from the center to the margins of LTM. Some of the sulfide bodies are localized on earlier-formed magnetite skarns. Pyrrhotite, pyrite, and marcasite are the earliest formed sulfide phases while chalcopyrite, marmatite, and galena developed later. Tetrahedrite and electrum occur in vugs and fine veinlets cutting the sulfides. Late-stage barite, dolomite, and fluorite occur as minor phases. Pressure-corrected Th for quartz (375-410°C), sphalerite (374-387°C), barite (320-360°C), and dolomite (310-314°C) fluid inclusions with salinities < 5.2 wt. percent eNaCI characterize the fluid responsible for the formation of the Leadville-type orebodies. These values clearly demonstrate the high temperature and low salinity of the ore fluids. Sulfur isotope analyses for galena and barite from LTM are - 1.9 to + 0.9%o and 7.8%o, respectively. Proximity to feeder veins and favorable dolomite hosts are the principal controls on ore localization. The Sherman-type bodies are not internally zoned but commonly have host rock silicification near the orebody margin or in the footwall rocks adjacent to fluid flowpaths along faults. Early quartz, pyrite, dolomite, and white barite precede base metal-silver minerals which are followed by late quartz and golden barite. It is not clear whether the early quartz and the late quartz and barite are part of the STM-forming process. Fluid inclusion analyses yield trapping temperatures as follows: early quartz, 316-341 °C; barite, 264-347°C; low-iron sphalerite, 215-265°C; and late quartz, 260-278°C. All inclusion fluids have salinities < 8.1 wt. percent eNaCI. Sulfur isotope values for barite and galena from STM range from 13.2 to 24.00/00 (avg: 18.4%o) and -6.8 to -3.8%o (avg: -5.5o/00), respectively. A hydrothermal fluid d34SSS of about 15%o is needed in order for galena and barite in equilibrium to exhibit the observed sulfur isotope compositions. Equilibrium sulfur isotope fractionation between barite and galena indicates a 300°C temperature of deposition. Two separate hydrothermal events appear to have taken place to form the distinctive Leadville-type orebodies and those of the Sherman-type assemblage. The STM is known to be older than the LTM. The latter is likely mid-Tertiary in age, post-dating emplacement of the Johnson Gulch Porphyry. LTM is clearly related to meteoric leaching of sulfur and lead (and other metals) from the upper portions of the Breece Hill Stock. Fluids were transmitted along faults, bedding planes, and contacts, and cooled away from the intrusive complex. Early ore fluids were weakly acidic and developed argillic assemblages in the igneous rocks adjacent to the fluid conduits. Reaction/replacement of carbonate rocks occurred where fluids encountered dolomite, but rapid neutralization prevented any wide-spread alteration beyond the ore-carbonate host contact. Pressures based on sphalerite geobarometry and stratigraphic reconstruction were 1.0-1.2 Kb. The high temperatures of vein and replacement ore fluids indicate that chloride complexing was more effective in metal transport than bisulfide complexes. Cooling, dilution of ore fluids, and reaction with carbonate rocks were the major factors in LTM ore deposition. STM formed over wide expanses of the Leadville Dolomite terrain adjacent to (and possibly capping) the Sawatch uplift. Sedimentary sulfur was derived from Pennsylvanian evaporite-bearing sequences adjacent to the uplift. Ore leads are strongly radiogenic (J-type) and are compatible with a crustal-leaching model. Temperatures of ore formation are higher, and ore-fluid salinities are lower than Mississippi Valley-type ore fluids. Superimposed upon dark-gray, diagenetic Leadville Dolomite are several stages of hydrothermal dolomite regionally distributed astride intrusive centers of the Colorado Mineral Belt. The presence of these later dolomites argues for dolomitization and later ore deposition in response to an abnormal thermal gradient caused by emplacement of Laramide batholiths and their generation of convective flow of meteoric fluids.

Jan 1, 2013

By J. R. Goode

The first part of this paper comprises a general discussion on refractory gold ores and their mineralogy processing methods now in use are reviewed and test procedures for the important methods are discussed. Factors determining the selection of a process are outlined. The paper includes a survey of production plants using pressure oxidation, roasting and biological oxidation to process refractory ore. The status of processes under development is briefly reviewed.

Jan 1, 1993

By D. R. Spears

As part of its mission to develop technology to assure a continuing supply of minerals, the US Bureau of Mines has investigated the flocculation of a Stillwater, MT, chromite ore. The ore was flocculated at different solids contents and at different stirring speeds to determine the importance and effect of hydrodynamic factors. In acidic and basic pH, the chromite ore was flocculated with high molecular weight polyacrylamides differing in the degree of hydrolysis. Polyacrylamides were found to bind to chromite ore particles through hydrogen bonding. The anionicity of the polymer and the pH affected the degree of polymer-particle interaction, which in turn affected polymer conformation at the surface. A polymer conformation with many loops and tails was used to explain high flocculation efficiency. It was found that such a conformation could compensate for poor hydrodynamic conditions.

Jan 1, 1992

By H. Reed

The precious metal mining industry in Nevada handles and generates a certain amount of hazardous materials and waste on a regular basis. These products range from processing material additives to wastes from laboratory testing, heap leaching, and hydrocarbon treatment and disposal. The volume of materials and wastes is dependent upon the amount of ore processed. Handling, treatment and disposal is dependent on the type of material handled and the waste generated. Owing to the health and safety concerns and due to the existing regulations that control handling and disposal of hazardous materials and wastes, the mining industry is obligated to comply with all applicable requirements for proper handling of these products. Plus, in an effort to minimize any impacts from this effort, the industry is continually looking for alternative methods to accomplish these requirements and to also minimize costs. This paper will discuss the general, and in some cases the specific conditions, by which the industry is coping with the issue and efforts to minimize any impacts from handling, treatment and disposal for hazardous materials and wastes. The subject of compliance with the Toxic Release Inventory (TRI) requirements and bio-treatment of wastes and other technologies will be discussed.

Jan 1, 2001

By Zhiguo Chang, QINGXIANG CAI, Ebelia Manda, IZHAR MITHAL JISKANI, XIANG LU, Wei Zhou, Saleem Raza Chalgri

The concept of mine safety is highlighted in the literature of sustainable mining but not extensively discussed. This study analyzes various aspects of underground and surface mine safety and emphasizes its importance in the context of sustainable mining. More specifically, this research attempts to find the relationship between mine hazards and demographic characteristics, examine and compare the perceptual difference among miners, and determine the impact of mine hazards on workplace safety and safety climate. Descriptive analysis, chi-square test, independent samples t test, and linear regression modeling were conducted to achieve study objectives. Results confirmed that mine hazards were significantly associated with age and experience. Miners perceived lower levels of management safety practices, followed by supervisor safety, coworker safety, and job safety. The analysis showed that underground miners reported lower safety scores than surface miners. There was a statistically significant difference between miners’ perception of safety climate (p < 0.05). The results showed that the higher prevalence of mine hazards predicts poor workplace safety and a low safety climate. The regression models revealed that mine hazards have a significant effect on workplace safety (p < 0.05) and safety climate (p < 0.05). In conclusion, the distinctive model of mine safety presented here contributes to the monitoring and design of comprehensive safety interventions and helps to better understand how certain factors interact on multiple levels to influence the overall safety of the industry. In this study, some suggestions are put forward to provide directions to develop a sustainable mine safety system.

Mar 27, 2020

By Chiranjibi Santi, Amit Kumar Gorai, VIVEK KUMAR HIMANSHU

Air overpressure (AOp) and peak particle velocity (PPV) are the most undesirable effects of blasting in mines. It is an urgent need to design a predictor model for AOp and PPV for universal applications to minimize environmental effects and damages that occur due to blasting. The present study attempts to design an artificial neural network (ANN) model for the prediction of AOp and PPV in different conditions. In this study, the blast design parameters (number of holes, depth of the blast hole, stemming length, spacing, burden, distance of vibration monitoring location from the blast site, charge weight per delay) of two active mines (coal and iron ore) are considered in four different conditions for training and testing of the model for the prediction of AOp and PPV. The model was trained and tested in four different combinations of data (trained using data of one mine and tested using data of another mine, trained and tested using data of coal mine, trained and tested using data of an iron ore mine, trained and tested using combined data of both the mines) for examining the applicability in different conditions. The results indicate that R2 values are ranged from 0.886 to 0.908 and 0.8728 to 0.8959, respectively, in the prediction of PPV and AOp. A comparative study of the performances of the developed model with the other empirical model is also demonstrated. For this, the site constants of different empirical models were estimated individually for both the mines. The study results indicated that the ANN model performs much better than all the empirical models. It can be inferred from the results that blast vibration cannot be accurately predicted only from charge per delay and distance from the blast hole. The ANN model was considered many other factors and thus can predict the vibration level more accurately.

Jul 30, 2021

Well designed and maintained haul roads are the key to minimizing truck haulage on-road hazards and costs, as well as increasing productivity. However, practically designing and managing a haul road for optimal performance is often difficult to achieve. Poorly designed and built roads exhibit high rolling resistance - a 1% increase in road rolling resistance can typically reduce speed on ramp by as much as 10% - and on the flat by up to 26%. In the current economic climate, investment and operating decisions come under scrutiny. In the long run, this scrutiny returns improved efficiencies and leaner, healthier operations. The focus of this evolving evaluation process should and will certainly fall on haulage operations ? simply by virtue of their contribution to overall cost of operations ? often in excess of 50% of total costs for deep open-pit mines. Whilst the end result - improved efficiency and reduced cost per ton hauled ? is not in itself problematic, it is the route, or process followed to achieve these savings that needs to be carefully managed. We can be guided on this journey by our understanding of how a road design is developed, and, critically, the interplay between a good design and safe, cost efficient haulage. This paper briefly summarizes the evolution of mine haul road design, from the seminal USBM work of Kaufman and Ault in 1977, through to current geometric, structural, functional and maintenance management design components. These augmented design and management guidelines have been developed over the past decade, both in response to the requirements of mine operators for more safe and efficient haulage systems, and the truck manufacturers? requirements for a more predictable and controlled operating environment. These developments have been paralleled by the need to minimize haulage hazards, both from a health and safety perspective. Whilst improved mine haul road design does indeed reduce haulage accidents, recognition also needs to be given to human factors which are a significant contributor to haulage accidents. The human factor is the most problematic to address in a road design. It is often easier break the link between the interactive effects which may lead to accidents than trying to predict and reduce human error. These human factor interactive effects include the geometric, structural and functional design components and to prevent an accident or reduce the severity of its consequences, a road should be more accommodating to human error. The more that is known about human error, the better a road can be designed to accommodate those actions or non-standard practices that would, on a poorly designed road, invariably escalate an error into an accident.

Jan 1, 2010

By Matthew S. Sanchez, Richard J. Lee, Matthew D. Zock, Drew R. Van Orden

"Current Environmental Protection Agency (EPA) risk models and asbestos fiber counting techniques for monitoring airborne exposures treat all fibers as being equivalent and ignore the effect of dimension on toxicity. While this may have been appropriate when modern analytical methods were not available, the measurement world is now fully capable of making the appropriate distinctions. The importance of width as a determinant of carcinogenicity has been recognized for nearly 30 years within the published literature. Stanton,1 in a landmark study of a suite of fibrous materials, found that durable mineral fibers with widths less than 0.25 mm and lengths longer than 8 mm were causally associated with the induction of tumors. Pott,2 in a later study, postulated a fiber toxicity model that agreed reasonably well with the Stanton findings, but extended the concept to include varying toxicity as a function of length and width. Wylie et al.3 reanalyzed samples used by Davis et al.4 and found that tumor generation was strongly and inversely correlated with fiber width. Crump5 testified increasing fiber length was correlated with disease occurrence. Lippman6 reviewed a number of studies and suggested that mesothelioma was closely associated with long, thin fibers. Berman et al.7 published a risk model, which found that disease was correlated almost exclusively with fibers longer than 40 mm and width less than 0.25 mm. Recently, Loomis et al.8 reanalyzed textile mill samples and found that aspect ratios greater than 40:1 were highly correlated with disease. Incorporation of width into risk models has been limited by the availability of data from operating asbestos plants and, in particular, the observation of an asbestos plant for which there is no observable mesothelioma. There have been only limited studies published on the dimensions of asbestos fibers, with a few serving as the primary references in other literature.9_13 A rare opportunity to collect detailed concentration and dimensional data of airborne crocidolite from an operating asbestos-cement plant using modern analytical procedures arose, providing a chance to supplement the existing literature on airborne fiber dimensions. The asbestos-cement plant is located in the eastern end of Cochabamba, Bolivia along Highway 4. Cochabamba is a relatively large city located in the Andes Mountains, approximately 250 km southeast of the capital La Paz. The city sits in a valley that runs east-west with mountains to the north and south. The crocidolite used in the products made at this facility is mined in central Bolivia, approximately 75 km northwest of Santa Cruz. The crocidolite is a fibrous magnesioriebeckite 14 (blue asbestos). Crocidolite fibers from Bolivia were the subject of prior reports suggesting the fibers are generally longer and thicker than crocidolite from Australia or South Africa.9 At the cement plant, the run-of-mine crocidolite was first pulverized using a hammer mill and then sieved on vibratory sieves to produce fibers of limited size ranges for use in the cement. The sieved crocidolite is mixed with other components, including recycled cement product, to produce a slurry that is vacuum filtered into sheet form. The sheets are then manually molded into a corrugated shape, air dried, and sawed (using circular saws) to accepted dimensions. The sawed sheets are cured in soaking pits for 28 days before being shipped to the consumer. Prior to shipping, the sheets are finished by a light hand sanding followed (at customer request) by applying one or more coats of paint. A detailed description of the cement plant and the industrial hygiene results can be found in Van Orden et al.15"

Jan 1, 2012

By Charles T. Ford

In 1971, Bituminous Coal Research, Inc~ established a program to provide the coal industry with the necessary information and technical capability to investigate and evaluate potential problems concerning trace elements in coal and coal-related materials. The initial efforts at BCR in developing or adapting analytical procedures for the precise determination of trace elements in the parts per million to parts per billion range were detailed in a report titled "The Development of Analytical Methods for Determining Trace Elements in Coal and Coal-related Products." A subsequent reports contained descriptions of reliable analytical methods refined by BCR for determining mercury in coal and coal ash and also in coal mine water. his paper reports initial progress in applying recently-acquired trace-element analytical capabilities to solving potential coal industry problems. In this case, the effect of a coal-cleaning process on the distribution and removal of potentially harmful trace elements in coal was evaluated. Coal cleaning offers the possibility of controlling potentially harmful emissions resulting from combustion of large tonnages of coal by removing the pollutants prior to combustion.

Jan 1, 1977

By M. A. Islam, H. Mischo, G. Barakos

Among the thirty-five declared critical raw materials (CRM) in the United States, there is no sustainable domestic production for the fourteen of them, while for some others domestic supply does not meet the national demand. Numerous potential critical raw material projects are in advanced exploration stages. However, the price uncertainties for many of these commodities put feasible future production into question and come into contrast with overly optimistic price forecasts published in all feasibility studies related to such exploration projects. Thus, in this work, a newly developed smart computational tool is used to evaluate the real perspectives of several CRM exploration projects implementing actual commodity prices, and to conduct reverse calculations in order to find the prices at which each project can be viable.

Mar 2, 2022

By Stanislaw Siewierski

One of the major problems in the exploitation of deep copper ore deposits in the Legnicko-Glogowski Copper Field is ground control and, in particular, roof control of the headings. The depth of copper deposits ranges from 600 to 1200 m. The parameters of ore-bearing rocks and the surrounding rocks show considerable variance of strength properties along the mining thickness (Fig. 1). The roof of the openings exploitation headings consists of dolomite-calciferous rocks. The roof strata consist of layers, the thickness of which vary from several centimeters to 0.6 m (sometimes to 1.0 m). These strata differ in strength and are characterized by igneous and sedimentary discontinuities. On the basis of studies in structure, properties and geological mining conditions of the roof strata in Polish copper mines, the method of roof classification has been developed. (1) This method uses the stability index "L" of the roof, calculated from [ ] The value of "t" ranges from 0, l to 0,8. Based on the value of "L", four classes of the roof (Table 1) corresponding to different degrees of fall hazard have been developed. The mining of copper ore deposit is carried out by a single lift room-and-pillar mining system or a two-stage room-and-pillar system with roof caving. (3, 4). The single lift room-and-pillar mining system is most often used. It consists in working of the deposit of 2.5 to 4.5 m mining thickness, 150-350 m long mining line, consisting of parallel room faces 6 m wide with pillars 5.7 or 16 m wide. As the mining line advances, cross-cuts joining individual rooms are made, thus forming support pillars 3x5, 7x7, 5x16, and 7x16 m (Fig. 2). The two-stage system (Fig. 3) mines the deposit with rooms 6 m wide into blocks 25 x 35 x 25 x 45 m. During the second step these pillars are worked with rooms and cross-cuts into pillars about 3 x 4 to 4 x 5 m (retreat mining). The pillars are crushed just before the fall of the roof. The maximum opening of workings in the two-step system is about 10 m, i.e. one belt entry and one row of bearing pillars. In single lift room-and-pillar systems it is about 35 m., i.e. three belt entries and three rows of bearing pillars. The support of the headings consists of expansion bolts 1.6-1.8 m installed in a bolting pattern 1.1 x 1.5 m. In both systems the fall step is about 10 m, i.e. the width of a belt and a bearing pillar. The Indications of Rock Mass Pressure Individual Dog Heading Individual dog headings are set wide apart from each other in the unmined ore deposit area where there is no interaction of headings. The indication of rock mass pressure are, in such cases, limited to the deformations and damage of side walls. Radiometric studies of rock mass loosening showed that the maximum range of lifts in side-walls immediately after web was 2 m (4,5). In the course of time the cracked side rocks fall off, thus widening the heading. The morphology of side-walls is influenced by the location of the heading in relation to clump layer/tarry. This layer is characterized by a weak strength and "lubricating" properties. The location of the heading in

Jan 1, 1982

By V. T. McLemore

"Production of industrial minerals remains important to the rural economy of New Mexico. In 2014, 226 active mines and mills were registered in New Mexico and included four coal, eight potash, 11 metal, 33 industrial mineral and 170 aggregate and stone operations. New Mexico leads U.S. domestic production of potash, perlite, zeolite and travertine. Other production includes aggregate, humate, pumice, gypsum, salt, common and fire clay, scoria, limestone, fly ash, cement, magnetite, silica and decorative stone. New Mexico also has the potential for additional production of industrial minerals. One company is exploring for garnet. Cretaceous black sandstones in the San Juan Basin have drawn interest for titanium, rare earth elements (REEs), niobium and zircon, and other REE deposits are being explored. REE-thoriumuranium veins have been found in the Gallinas, Capitan and Cornudas Mountains and Laughlin Peak-Chico Hills. Exploration for beryllium has occurred in the Ojo Caliente No. 2, Cuchillo Negro and Victorio mining districts. Companies also are examining high-calcium limestone and high-magnesium dolomite for potential development, while aggregate continues to be important in urban areas and along highways. IntroductionIndustrial minerals and rocks are literally the building blocks of our way of life. They are an exceptionally diverse and vital group of raw materials that underpin almost all aspects of human activity, infrastructure and standard of living. Industrial minerals and rocks are used in the manufacture of many products, from ceramics to plastics to refractories to paper. Although industrial minerals permeate nearly every aspect of daily life, their presence and their roles are typically invisible. A widely used definition of industrial minerals and rocks is “any rock, mineral, or other naturally occurring substance of economic value, exclusive of metal ores, mineral fuels, and gemstones: one of the nonmetallics” (Bates, 1975). This definition includes the important construction materials sector as well as specialized industrial minerals, but complex interactions between consumer industries produce a number of apparent anomalies to this definition. Some metals are included as industrial minerals because their use is industrial rather than as a metal. Sulfur is now predominantly extracted as a byproduct of cleaning natural gas, one of the world’s major energy fuels.Production of industrial minerals has been and remains important to the rural economy of New Mexico. Industrial minerals constitute nearly 41 percent of the more than $3.1 billion generated by mineral production in New Mexico in 2014 (Table 1). In 2014, 226 active mines and mills were registered in New Mexico and included four coal, eight potash, 11 metal, 33 industrial mineral and 170 aggregate and stone operations (New Mexico Mining and Minerals Division, 2015a). New Mexico leads U.S. domestic production in potash, perlite, zeolite and travertine. Other industrial minerals production from New Mexico includes aggregate, humate, pumice, gypsum, salt, common and fire clay, scoria, limestone, fly ash, cement, magnetite, silica and decorative stone. Additional production statistics can be found in Harben et al. (2008). Major industrial mineral districts are shown in Fig. 1."

Jan 6, 2017

By George M. Potter

Under contractural arrangements with the Bureau of Mines, Mountain States Research and Development, Inc. (MSRD) completed a technological investigation to determine the feasibility of in situ mining of metal commodities other than copper and uranium, The study was based upon available literature and experience. The selection of potential candidates for in situ mining was influenced by economic importance, probable amenability to in situ methods, and environmental considerations. Four metals (or metal pairs) were chosen for feasibility studies: aluminum (with a copper byproduct), gold-silver, and manganese were recommended for further study and action; cobalt-nickel was also recommended contingent upon preliminary laboratory leaching and recovery investigations and field geohydrological work. Mining and recovery plans and an economic evaluation are included. Other metals with potential for in situ leaching are lead/ zinc, molybdenum, and vanadium.

Jan 1, 1981

By J. Noll, D. Yantek, B. Kendall, J. A. Organiscak

"A self-tramming remotely controlled mobile Dry Scrubber (DS) was developed by J. H. Fletcher and Co. under a contract with the National Institute for Occupational Safety and Health’s Office of Mine Safety and Health Research (NIOSH OMSHR) to reduce exposure of miners to airborne dust. NIOSH OMSHR laboratory testing showed that the DS averaged greater than 95% dust removal efficiency with the disposable filters and averaged 88% and 90%, respectively, for the optional washable filters in their pre-washed and post-washed test conditions. Although the washable filters could be reused, washing them generated personal and downstream respirable dust concentrations of 1.2 and 8.3 mg/m3, respectively, for a 10-minute washing period. The DS’s velocity pressure regulated variable frequency drive (VFD) fan maintained a relatively consistent airflow near the targeted 1.43 and 4.25 m3/s (3000 and 9000 ft3/min) airflow rates during most of the laboratory dust testing until reaching its maximum 60 Hz fan motor frequency or horsepower rating at 2610 Pa (10.5 in. w.g.) of filter differential pressure and 3.97 m3/s (8420 ft3/min) of scrubber airflow quantity. Laboratory sound level measurements of the DS also showed that the outlet side of the scrubber was noisier and the loaded filters increased sound levels as compared to clean filters at the same airflow quantities. With loaded filters the scrubber reached a 90 dB(A) sound level at 2.83 m3/s (6000 ft3/min) of scrubber airflow, indicating that miners should not be overexposed in relation to MSHA’s permissible exposure level (PEL) of 90 dB(A) at or below this airflow quantity (1). The DS’s washable filters were not used during field testing because of their lower respirable dust removal efficiency and the airborne dust generated from filter washing. Field testing the DS with the disposable filters at two underground coal mine sections showed that it can clean a portion of the section return air and provide about a 50% dust reduction at the face area downstream of the continuous miner (CM) operation. INTRODUCTION Coal mine worker overexposure to coal and quartz dust continues to be a problem at underground coal mining operations in the U.S. The U.S. Mine Safety and Health Administration (MSHA) recently changed the standard for coal mine worker respirable dust exposure from 2.0 mg/m3 average during an eight-hour shift to 1.5 mg/m3 average over the actual working shift, effective as of August 1, 2016 (1). If more than 0.1 mg/m3 quartz mass is found in the coal mine worker dust sample, the applicable respirable dust standard is further reduced to the quotient of 10 divided by the percentage of the quartz in the sample (1). Over 90% of the mechanized mining units operating in U.S. underground coal mines are continuous mining machines (2). MSHA inspector dust samples from 2009 to 2012 showed that 3.7% of continuous miner operators exceeded the 2.0 mg/m3 dust standard, while 8.8% of these dust samples exceeded the new 1.5 mg/m3 dust standard and 9.7% of these samples exceeded the reduced quartz standard (3). Additionally, roof bolter dust samples at these mechanized mining units during this same period have exceeded the 2.0 mg/m3, 1.5 mg/m3, and reduced quartz levels at 1.1%, 3.7%, and 10.6%, respectively (3)."

Jan 1, 2016

By A. Robison, V. T. McLemore

"The San Juan Basin, New Mexico contains many heavy mineral beach-placer sandstone deposits of Cretaceous age. Beach-placer sandstone deposits are concentrations of heavy minerals that formed by mechanical concentrations (i.e. settling) of heavy minerals on beaches or in longshore bars in a marginal-marine environment. They have high concentrations of several elements, such as Ti, Zr, rare earth elements (REE), Sc, Y, U, Th, Nb, Ta and Fe. These elements are becoming increasingly more important to industry, because they are used in the manufacture of devices our society uses every day, i.e. cell phones, computers, and alternative energy devices, like solar panels. It is unlikely that any of the beach-placer sandstone deposits in the San Juan Basin will be mined in the near future because of small tonnage, low grades, high iron content, and distance to processing plants and markets. However, as the demand for some of these elements increases because of increased demand and short supplies, the dollar value per ton of ore rises, enhancing deposit economics. Current studies at the New Mexico Bureau of Geology and Mineral Resources are focused on the Apache Mesa (formerly Stinking Lake) deposit near Dulce, New Mexico. INTRODUCTION Beach-placer sandstone deposits are accumulations of heavy, resistant minerals (i.e. high specific gravity) that form on upper regions of beaches or in long-shore bars in a marginal-marine environment. They form by mechanical concentration (i.e. settling) of heavy minerals by the action of waves, currents, and winds (Fig. 1; Bryan et al., 2007). Modern examples are found along the Atlantic Coast, USA (Koch, 1986; Carpenter and Carpenter, 1991), southeastern Australia (Roy, 1999), and Andhra Pradesh, India (Rao et al., 2008), where they are mined for titanium, zircon, and monazite (a Ce-bearing rare earth, REE, mineral). Detrital heavy minerals comprise approximately 50-60% of these sandstones and typically consist of titanite, zircon, magnetite, ilmenite, monazite, apatite, rutile, xenotime, garnet, and allanite, among other minerals. Most of these minerals have a high specific gravity exceeding 4 and are dark colored, giving the sandstones a dark color, resulting in them being called black sandstones. Although beach-placer sandstone deposits are found in strata of all ages; the deposits in the San Juan Basin in New Mexico are restricted to Late Cretaceous rocks belonging to the Gallup, Dalton, Point Lookout, and Pictured Cliffs Sandstones (Fig. 2; Table 1; Chenoweth, 1957; Houston and Murphy, 1970, 1977). The beach-placer sandstones are black, dark gray, to olive-brown, resistant to erosion, and radioactive due to radioactive zircon, monazite, apatite, and thorium minerals. Anomalously high concentrations of Ti, Fe, Nb, Th, U, Zr, Sc, Y, and REE are characteristic of these deposits. Similar Upper Cretaceous heavy mineral, beach-placer sandstone deposits are found throughout Montana, Wyoming, Utah, Arizona, and Colorado (Dow and Batty, 1961; Houston and Murphy, 1970, 1977; Zech et al., 1994)."

Jan 1, 2016

By Raymond L. Lowrie

Deregulation, as authorized by the Energy Policy Act of 1992 (PL102-486) allows free-market competition in the electric-utility industry. As the act unfolds, though, uncertainties abound about the type, degree and direction of impacts throughout the affected economy — from fuel suppliers to electricity generators and from power distributors to energy consumers. Instead of having a familiar base of captive customers and electricity prices fixed by negotiation with state public utility commissions, utility companies are preparing for open, free-market competition. They are looking at all areas, including fuel supply, to cut costs to remain competitive. Humorous anecdotes are told about utility companies shunning insiders for senior executive positions. Instead, they are opting for people from the telephone or other industries with deregulation experience. And there are light-hearted stories about a trend away from traditional electric-company names, such as the name of a city or state followed by Edison or Power and Light, to space-age names, such as Ameren, Entergy, Illinova or Unicom. No one wants to be left behind or be perceived to be left behind.

Jan 1, 1996

By D. R. Wilburn

his summary of international mineral exploration activities for the year 2011 draws upon available information from industry sources, published literature and U.S. Geological Survey (USGS) specialists. The summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry and presents [ ] analyses of exploration activities performed by the mineral industry. Three sources of information are reported and analyzed in this annual review of international exploration: 1) budgetary statistics expressed in U.S. nominal dollars provided by Metals Economics Group (MEG) of Halifax, Nova Scotia; 2) regional and site-specific exploration activities that took place in 2011 as compiled by the USGS and 3) regional events including economic, social and political conditions that affected exploration activities, which were derived from published sources and unpublished discussions with USGS and industry specialists.

Jan 1, 2012