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By E. Ashworth

A thermistor probe has been developed to measure in situ temperature profiles underground. A full description of the probe is given. Data collected from the probe has been used to compare the actual profiles with those predicted from a finite element analysis using laboratory measured thermal properties of the different rock types. This comparison indicates the applicability of laboratory measured parameters in modeling the real conditions. Factors such as applied pressure, moisture content and anisotropy on laboratory measurements is discussed.

Jan 1, 1983

By Shailendra Chawla, Ashok Jaiswal, B. K. Shrivastva

The study aims to evaluate the pillar behavior during the depillaring operation by continuous miner (CM) technology. A panel with five headings developed as per the coal mine regulation of Indian coal mines [2] has been selected for the study. The depillaring operation has been carried out using CM technology after widening and heightening the original entries. An extensive field investigation has been carried out throughout the depillaring operation to access the mining conditions. Depillaring operation has been performed smoothly up to the middle of the panel (fourth row out of eight rows of four pillars each). Advanced blinking of the auto warning tell-tale (AWTT ) has also been observed on some of the instruments during the splitting of pillar no. 18. The panel shows extremely difficult mining conditions at this stage. The case has been numerically simulated using three-dimensional numerical techniques. The simulation result has indicated the high stress and yield condition on the working and the barrier pillar (surrounding goaf from both sides) after the extraction of pillar no. 18. The analysis has also indicated the marginal stability of the 2nd barrier pillar (namely “pillar B”). The failure of the barrier pillar could be the responsible for global instability of the panel as observed in the field. Understanding the importance of the barrier pillars, panel design has been modified by incorporating an additional row of barrier pillars. The stability of the modified panel has been evaluated. Both working and barrier pillars have been observed stable in the modified panel. This could be an alternative layout considering safety at the working face.

May 8, 2022

By H. -S. Yoon, C. -J. Kim, K. W. Chung

"With the final goal of ultrasonic application to ion exchange in a resin-in-pulp (RIP) system, the feasibility of an indirect ultrasonic application with a submersed ultrasonic probe was investigated first for the enhancement of ion exchange in the following resin-in-solution (RIS) system: Lewatit MonoPlus MP 600XL in an artificial solution with 106 ppm uranium. Ultrasonic radiation enhanced the ion exchange efficiency without mechanical degradation of resin. For 3.6 g/L of resin, the enhancement was 79 percent after 10 min of ion exchange and it gradually decreased to 11 percent at 60 min. In addition, a preliminary test of the mechanical stability of the resin in the RIP system showed little mechanical fracture of the resin due to ultrasound, which indicates that indirect ultrasonic application by a submersed ultrasonic probe is applicable for RIP systems. IntroductionIn uranium ore processing, the ion exchange process has been used on a commercial scale for preconcentration and purification (Gonzalez-Luque and Streat, 1984). The ion exchange process is divided into two processes: (1) a resin-in-column process with the uranium-bearing solutions passed through columns containing resins and (2) a resin-in-pulp (RIP) process with the leached ore pulp exposed to resins. The latter does not require the separation process of leach liquor and ore solids, which reduces process costs. This process, which has been developed commercially since 1955, has a certain drawback. The adsorption rate and efficiency in the RIP process are relatively low, so numerous contacts between resins and leached ore pulp are needed, which adds to the cost (Merritt, 1971). It is necessary to study methods to reduce process costs.Ultrasound can intensify mass transfer, increase the rate of chemical reactions, and change reaction pathways (Thompson and Doraiswamy, 1999; Luque de Castro and Priego-Capotem, 2007; Adewuyi, 2001; Luque-Garcia and Luque de Castro, 2003). It has great potential in chemistry and is especially considered to be a promising method for enhancing mass-transfer-limited processes, such as ion exchange. Enterzari and Tahmasbi (2009) reported the effect of ultrasound on water softening by ion exchange. Band et al. (1997) proposed a modulated ultrasound application to water desalination with ion-exchange hollow fibers. These reports revealed that ion exchange kinetics could be enhanced by the application of ultrasound. As for hydrometallurgy, Feng and Aldrich (2000) reported that the elution of an ion exchange resin was enhanced by the use of ultrasonication."

Jan 1, 2015

By Lina Ospino Ballesta, Oscar J. Restrepo Baena, Juan Diaz Martínez

Artisanal and small-scale underground gold mining in Colombia plays a significant role in the country’s economy, but it faces persistent occupational hazards that threaten worker safety. Despite mining economic contributions, outdated technologies, limited risk management practices, and insufficient regulatory enforcement have led to recurring workplace accidents, many of which have been fatal. This study presents a systematic review of mining-related accidents over the last decade. Through geo-referenced analysis, high-risk municipalities were identified, and the frequency of accidents was correlated with the mining legal status and operational practices of these municipalities. The findings underscore the urgent need for evidencebased interventions that are tailored to the country’s unique mining context. Ultimately, this research contributes to the global discourse on mining safety by highlighting practical pathways to reduce occupational risks and promote safer, healthier workplaces in resource-constrained environments.

Feb 22, 2026

By W. Clark Ashby

Productivity is a fascinating concept. Like motherhood or apple pie, we know it as a good thing. Just what it means is not so clear. To a coal miner we assume it means tons of coal hauled from the mine. To the company president it means profit after capital, labor, and other costs have also been reckoned. To the government economist it means output in a balance of payments. What does it mean to the biologist, and can reclamation really be productive? In this paper we discuss productivity from a biological viewpoint, give some yield data for various types of reclamation plantings, and discuss how our demand for or acceptance of differing kinds of productivity is tied up in bigger questions of land use, environmental stability, and resource allocation.

Jan 1, 1981

By Gary Peach, Khalid Saif Al-Khayareen, Vigil Fernandez, Furqan Hameed

The Musaimeer pump station and outfall project (MPSO) is in Doha Qatar. This technical paper will discuss and explain the three major stages of geotechnical investigation employed. Stage one the tender geotechnical data and how this was used to design the TBM and identify various areas of risk. Stage two was the selection of supplementary geotechnical investigation methodologies. Stage three was the geotechnical investigation by specialist equipment installed on the TBM and providing further data on a real time basis as the TBM was advancing. Analysis of all the data will be provided along with the lessons learned.

Jun 23, 2024

By N. J. Themelis

Autogenous grinding, broadly defined as the self-comminution of ore in a cylindrical tumbling mill without using auxiliary grinding media, was first applied in the early thirties in the so-called Hadsel mills (Figure 1) mainly used in gold mines on the U.S. West Coast. A number of these mills were built in sizes of 20 to 24 ft. in diameter and five-six feet in length but were later abandoned because of operating and maintenance problems. Further development of autogenous grinding led to the Hardinge wet grinding mill (Figure 2), the Aerofall dry grinding mill and others. A tabulation of all known autogenous and semi-autogenous installations around the world was sent recently to the authors by Hr. G. J. Kushner of the Koppers Mineral Processing Division. In the size range of 24 to 32-ft. in diameter, it lists a total of thirty mills used in the processing of copper ores. An additional 120 units are listed in the same size range for the processing of iron ores and other minerals. The largest mills in existence are 36-ft. dia X 15-ft. long mills in Minnesota, powered by 12,000 hp. motors and used in taconite beneficiation. It is indicative of the phenomenal growth of this technology that none of the above one hundred and fifty mills was in operation prior to 1964.

Jan 1, 1978

By George R. Stephans

The Climax Mine is a panel caving mine which has had a long history of incidents of severe ground control problems. The nature of the ore deposit, which lends itself to the caving meth- of of production, a1 so makes the mine susceptible to large scale stress concentrations which are referred to as ?weight? problems. These problems have increased with increased production and also with expansion to deeper mine levels. During the past twenty years the mine has had to learn to cope with these problems in order to remain in operation. A number of practical guidelines and useful techniques have emerged from these efforts. The purpose of this paper is to share a few of these ideas. The Mine is located near Leadville, Colorado on the continental divide at an elevation of 3450 meters. The ore body is a large low grade deposit of disseminated molybdenum sulfide. It measures about 1200 to 1600 meters in diameter and it had an original depth of about 660 mters. The Mine has been in operation since 1918 and the massive nature of the ore body together with its blocky, highly fractured condition made it natural for the caving system to have been adopted for production at an early date. Open pit mining was started in 1973. The total plant has a capacity of more than 50 thousand tons per day, and more than 400 million tons of reserves at an average grade of 0.310 percent molybdenum disulfide remain to be produced.

Jan 1, 1982

By William P. Shell

An important part of process control engineering is the implementation of the basic control system design through commissioning to routine operation. This is a period when basic concepts can be reviewed and improvements either implemented or recorded for application in future systems. The experience of commissioning the process control systems in the Homer City coal cleaning plant are described and discussed. The current level of operating control performance in individual sections and the overall system are also reported and discussed.

Jan 1, 1983

By Jaeheon Lee, Junmo Ahn, Jae-Yeon Kim, Yoo-Jin Kim, Jiajia Wu, Eun-Woo Kim, Jai-Won Byeon, Jun-Jae Lee

The surge in demand for battery materials, coupled with environmental challenges linked to battery disposal, underscores the need to recycle spent lithium-ion batteries (LIBs). Green recycling approaches, in particular, have garnered attention for battery recycling. In this study, a hydrometallurgical method using a synergetic organic lixiviant combining methanesulfonic acid (MSA) and citric acid (CA) as an alternative to inorganic mineral acids was introduced as a green approach to recycle cathode materials of LIBs. The conditions for leaching and recovery processes were optimized. Cathode materials were regenerated using the recovered materials. Moreover, the leaching performance and economic feasibility of this leaching system were compared with those of various other organic acids.

Feb 1, 2024

By W. K. Connor, O&apos

The Bureau of Mines is investigating the Co and Mn resource of the West-Central Arkansas District, including field investigations, mineralogical characterization, beneficiation, and hydrometallurgical tests. The deposits occur within the Ouachita Mountains and are con-trolled structurally, occurring along the axes of anticlines making up the mountain ridges. Brecciated novaculite is cemented with a mixture of Mn oxides, primarily cryptomelane and psilome-lane. Cobalt is concentrated within a particular Mn oxide phase, lithiophorite. Chemical analyses on head samples reported up to 25 pct Mn and 0.17 pct Co. Magnetic separation yielded products with up to 41 pct Mn and 0.22 pct Co at recoveries of 95 pct Mn and 93 pct Co.

Jan 1, 1991

By Giorgio De Tomi, Rondinelli Sousa

Whilst all public mineral reporting codes require classification of mineral resource and reserves according to the level of geological knowledge and confidence of the estimates, companies are not required to disclose how mineral estimates and associated cashflow projections respond probabilistically to the incorporation of different types of risk events. As the level of expectations and scrutiny of investors and stakeholders continue to increase over the years, it will be essential for companies to adopt an integrated framework for sensitivity analysis to increase corporate value through better capital allocation and reduce potential losses associated with poor investment decisions. Failure in fully capturing the impact of unexpected incidents in mineral estimates and financial modeling could be extremely harmful to the business, affecting the company’s reputation, and negatively impacting the relationship with stakeholders.

Feb 22, 2026

By J. Appleby

This paper reviews earlier in-plant testing at the Sidbec-Normines pelletizing plant at Port Cartier, Quebec, Canada. It describes the result of the more prolonged use of coke breeze during recent months and in addition, the effects of varying dolomite and coke additives upon the metallurgical properties of the pellet production have been studied. Mention is also made of some brief test work carried out to use peat moss as a carbonaceous additive to the pelletizing process and in particular the plans for future work in this respect. Earlier laboratory pot-grate test work had indicated that a production rate increase of between fifteen and twenty percent was a practical possibility, or alternatively that the plant could be run at design rating with significantly lower energy consumption. These energy reductions were of the order of ten to fifteen percent for fuel and main process fan power respectively. The physical and metallurgical pellet properties for both blast furnace and direct reduction furnace use were little affected by the production rate increases, and were actually somewhat improved when practicing maximum energy conservations. Pellet properties could be further improved by not extracting the maximum energy economy. Two phases of carefully controlled in-plant testing were run to assess the effect of energy conservation under plant conditions. These two phases of testing confirmed that an overall fuel saving of approximately fifteen percent could be realized, with a reduction in the Bunker C oil consumption of about forty-five percent, and a reduction in main process fan power of approximately ten to fifteen percent. The present scope of work is aimed at establishing the use of varying levels of coke addition up to about one percent under normal plant operating conditions.

Jan 1, 1980

By D. Marcus

A methodology was developed wherein. the increase in compressive strength, mineralogical changes and pore water composition were all studied simultaneously as a function, of moisturized spent shale curing time. From these results the relationship between the nature of cementation process and the composition of pore water was established. Heavy metals were entrapped in the cementing constituents and the pore water became mainly a solution of alkaline sulfates. While the specific data are applicable only to the material studied, the methodology and general conclusions are useful for evaluating the environmental factors in spent shale disposal and expected leachates composition.

Jan 1, 1984

By Michael F. Gleason

In 1986, Gold Fields began negotiations with a large Nevada electrical power utility to supply power for its Chimney Creek Mine In northern Nevada. After the long negotiations reached an impass over various costs associated with the power line, a decision was made by Gold Fields to generate its own power. Self-generation is not uncommon overseas, but it is rare for any but very large or very small operations in the United States. Surprisingly, under certain conditions a mine can generate its own power profitably and Gold Fields has found that the associated operating and maintenance problems are minimal. The following report details what factors went into this decision and how it works. Hopefully, it can serve as a guideline for those who may find themselves in a similar position.

Jan 1, 1990

By R. Maurice King

In the operation of today's large scale ore-processing mills, it is extremely important to have some way of making an objective evalu¬ation of the performance of the available flotation reagents. Attempts to do this may often result in inconclusive findings since the magnitude of the difference in the mill results for any two reagents is apt to be quite small compared to the variability introduced by the process and 'the analytical procedures used to measure them. In cases where two reagents give vastly; different mill results, evaluation becomes a simple matter and as such deserves no further attention here. A question of primary concern, however, is how a mill can go about evaluating the performance of two reagents which may, for example, give a difference of only 0.001% copper in the-tailings or of 0.2% in copper recovery. The casual observer may feel that such small differences may be of little importance, but in a mill-whose daily tonnage is between 30 and 40 thousand, these differences could mean a substantial savings. Before the presentation of an actual example of a reagent testing scheme designed for just this-purpose, perhaps a few minutes should be devoted to a review of some statistical methodology to be used later in the discussion.

Jan 1, 1964

By B. Hines

Grinding efficiency in a vertical stirred mill is affected by a wide range of process and mill configuration variables. Of these, the media fill, size, and intrinsic density have a significant effect on power draw and grinding performance. Media-related factors that influence grinding performance include, e.g.,a higher media filling providing additional particle breakage sites, or a lower bead density decreasing the running torque at a given media filling. It has been estimated that the grinding media can cause up to a 30% change in the specific energy required to grind. FLSmidth has generally recommended that the intrinsic density (specific gravity) of the grinding media be more than triple the slurry density. This density difference helps to ensure that sufficient stress intensity is generated in the mill to provide particle breakage. It also reduces the chance of media ?float? if there is a spike in either slurry density or slurry flow rate. The VXPmills have historically operated at slurry density values between 1.2 and 1.5 kg/L, which translates to nominal bead intrinsic density range between 3.6 and 4.5 kg/L. The current trend towards regrinding bulk flotation concentrates to even finer sizes, to improve recoveries of fine grained minerals, has provided motivation to consider closed-circuit operation of stirred media mills. The slurry density in this application is typically higher than in open-circuit operation due to the higher percent solids in cyclone underflows. An additional effect is that closed-circuit operation increases the potential for media float due to higher flow rates as slurry is recycled to the mill. The normal progression in extending the operating range of existing equipment is to carry out laboratory testing before pilot-scale and plant-scale trials. The results presented in this paper examine the media density to slurry density ratio and its effect on grinding performance.

Feb 23, 2014

By H Vigil, G. Peach

Long tunnels with only one access shaft pose many program problems for logistics, combine these with the requirement to drive directly out under the seabed for 10.2 km, and the program issues become even more challenging. The Musaimeer outfall tunnel was one such tunnel and to meet and eventually improve on the planned completion date required a complex and extensive management of all tunnel logistics required to support consistent tunneling for a two-year period. This technical paper will discuss the management issues and solutions implemented to meet the challenges of the Outfall tunnel construction.

Dec 1, 2022

By J. K. Hrica, T. J. Orr, J. Navoyski, B. Macdonald, C. L. Hoebbel, J. L. Bellanca, B. Demich

Haul truck fatal accidents and injuries continue to be a significant concern for the mining industry. However, the availability of high-quality training materials continues to be limited. Near-miss incident accounts, if packaged well, could help fill this gap, because for every fatality, there are hundreds of reportable accidents and thousands of undocumented near misses. Researchers from the National Institute for Occupational Safety and Health (NIOSH) collected detailed accounts of 21 near-miss incidents in virtual interviews with mineworkers at surface mining operations across the country. From these interviews, researchers created four simulation videos. The videos bring these events to life through first-person retelling and various visual perspectives of actual events. Each video exemplifies a critical safety message and a common haul truck hazard. This paper describes the process of taking narratives and turning them into impactful visual stories. NIOSH plans to co-release these simulation videos with the Mine Safety and Health Administration (MSHA) to the mining industry to raise awareness and ultimately help reduce haul truck-related accidents and fatalities in mining.

Feb 1, 2023

By L. J. Buchanan

The relationship between hydrothermal ore deposits and hot spring systems has received intensive study in recent years, particularly as a consequence of interest in the energy potential of geothermal systems. Base and precious metal deposition in surface pools and at shallow depths in modern geothermal systems has been recorded in numerous publications (1, 2, 3) Theoretical studies of hydrothermal fluid flow at depth, connected to surficial hot springs systems, have been presented by White and others (1), Cathles (2) , Henley and McNabb (3). As a result of these and additional studies, numerous hydrothermal ore deposits are thought to have originated as genetic parts of larger geothermal systems. In particular, it appears that metal precipitation is greatly enhanced in zones of boiling where volatiles and steam are escaping (4). High grade, near surface concentrations of base and precious metals, deposited as a result of partial vaporization of rising fluids, are such a common aspect of modern not spring systems that ore deposition models are becoming based on what may be called a geothermal model. In its most general terms, this model requires an anomalously high thermal gradient which acts as the driving force behind a convecting hydrothermal system. The water may be entirely meteoric or may be In part at least of other origins. The water migrates towards the higher temperature area, becomes heated, and picks up alkalies and metals by dissolving minerals along the fluid path. As water exits to the surface above the heat source, a mass balance requires the incoming hot water to rise to replace the lost water. As the water rises past the elevation where the hydrostatic pressure is insufficient to prevent boiling, then boiling will occur. Depending on the salinity and the temperature of the water, boiling can occur anywhere from great depths to near surface. Boiling results in a loss of volatiles, a pH rise in the fluid phase, cooling of the remaining fluid, a rise in oxygen fugacity, a concentration of salts in the remaining liquid, and precipitation of ore and gangue minerals.

Jan 1, 1980