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By D. C. Yang

A practical and economical flowsheet has been developed and demonstrated by integrating the packed column flotation with the GranuFlow process for fine coal recovery. Orimulsion, which was used as an additive, served a dual purpose: first in the flotation and second in the dewatering and granulation steps. The test results on the coal preparation effluent sample show that Orimulsion is flexible and compatible with fuel oil and various frothers used in the packed column. Clean coal with ash contents of 3.0, 3.7, 4.3 and 5.1% were produced from a head sample of 33% ash at combustible matter recoveries of 72.4, 81.1, 87.5, and 89.2%, respectively. Other advantages include high throughput, low moisture, improved handleability, and reduced dustiness of the dewatered coal, thus providing a very significant economic Incentive for the integrated process.

Jan 1, 1998

By U. Schoepf

Economic and at the same time environmentally acceptable mining of small vertical ore bodies and veins to great depths has always been a challenge for miners. The Bauer cutter system, widely used in civil engineering, has been further developed for applications in exploration and mining, to a sustainable system for selective mining with a focus on small vertical ore bodies and veins, as well as residual ore in open pit operations. Current situation of conventional mining of small ore bodies and vertical veins Small ore bodies and vertical or near-vertical ore veins often pose a challenge to the mining industry. The relatively small size of the ore deposit over great depths or lengths, with only limited exposure to the surface makes economical mining difficult. Open pit mining of such ore bodies must either be terminated early because of the high stripping ratio and the enormous environmental impact or is unprofitable from the very beginning. The required massive stripping of waste rock leads to high material hauling times and costs, intensive roadway and bench construction and maintenance, possible safety hazards due to heavy vehicle movement, pit wall stability risks, intensive surface water management and massive waste dump requirements. In addition, it can be assumed that increasingly extensive rehabilitation measures will be required in the future after mine closure. Particularly in vertically oriented magmatic and hydrothermal deposits the technical, economic and environmental limits for further pushbacks, to extend the open pit depth, can lead to an early end of mine life even if a significant quantity of residual ore is left behind. Going underground is only a viable option in a limited number of mines with very high ore values and volumes. The high development cost of an underground mine, as well as the higher underground mining costs, often prevent further mining to greater depths.

Feb 1, 2023

By L. Alan Weakly

The U.S. Department of Energy (DOE) has entered into a $l.5 million Cooperative Agreement with Alpine Equipment Corporation/Astro International Corporation ("Alpine") of State College, Pennsylvania, for the evaluation of water-jet-assisted (WJA) mechanical cutting of oil shale under actual mining conditions. A commercial-sized, heavy WJA mechanical miner is being assembled based upon the successful "factory testing" of a smaller prototype miner utilizing standard tungsten-carbide and Polycrystalline Diamond Composite (POC) bits in large oil shale boulders. Actual field testing of the machine will be conducted in an oil shale mine located in the Piceance Basin of Western Colorado. In-mine logistical support is being provided by several oil shale companies through the Colorado Mining Association (CMA) and the U.S. Bureau of Mines (USBM).

Jan 1, 1990

By G. L. Ploetz

The lanthanon compounds are becoming increasingly more important for ceramic and allied applications. As the supply increases and the cost decreases, further development of these interesting materials will undoubtedly lead to new applications and an increased demand. Recent improvements in separation processes have lead to high purity in the individual lanthanon oxides. This report includes short discussions on the mineralogy of the ores as raw materials, and on the separation processes required to produce the pure individual lanthanon oxides in useful quantities. To discuss the presently known applications of lanthanon oxides, this general review is divided into the following categories: A. Glasses, Glazes, and Porcelain Enamels. B. Refractories and Abrasives. C. Electronic Ceramics. D. Nuclear Ceramics.

Jan 1, 1960

By Gary W. Hudiburgh

The gangue in some magnetite ore bodies contains feldspar; the alkali content of the feldspar reduces the usefulness of these iron ores. One method of decreasing the feldspar content in magnetite concentrate is froth flotation. The amine flotation of feldspar from magnetite concentrate was investigated using zeta potential measurements, Hallimond tube flotation tests and laboratory-scale flotation tests. The zeta potential of various feldspars (microcline, albite, anorthite, oliqoclase and anorthoclase) were determined as a function of pH; the point of zero charge ranged from pH 1.4 to 2.5. Hallimond tube flotation tests using two amine reagents were conducted on the feldspars. Hallimond tube flotation tests using six amine flotation reagents were performed on the cobber tails (quartz, albite and microcline) from a magnetite concentrating plant; in all cases, over 85 percent flotation recovery was obtained at pH 8 and 10-5 to 10-4 [M] collector addition. Laboratory-scale (667 grams) flotation tests were performed on the magnetite concentrate in an attempt to float the feldspar which had reported to the concentrate. The effects of three different collectors, two levels of collector concentration, three pH levels, starch and HF acid were investigated.

Jan 1, 1975

By Yuting Xue, Alper Kirmaci, Taghi Sherizadeh, Dogukan Guner, Khaled Mohamed

Rib brows present a significant safety hazard in underground coal mines in the United States. To address this issue, researchers at the National Institute for Occupational Safety and Health (NIOSH) and Missouri University of Science and Technology (MST) are developing a practical tool to assess both the potential of rib brow formation and the stability of any formed brows. As part of this effort, a monitoring study was conducted to assess the potential for rib brow formation in coal pillar ribs. This study was conducted in a room-and-pillar coal mine where coal pillar ribs are prone to developing rib brows. Although no rib brows formed in the instrumented pillar, data from monitoring and visual observations provided valuable insights into the loading mechanisms impacting the instrumented pillar. These findings helped identify factors that may reduce rib brow formation, including the cavability of the roof in mined areas, the applied rib support, the strength of rock partings, and the overall integrity of the coal seam. The scientific findings published in the case study aid in assessing the potential of brow formation, offering additional evidence for the need to improve rib control methods in underground coal mines.

Feb 1, 2025

By Mathew Cook

Technological developments in Distributed Fiber Optic Sensing and improvements in both hardware and software have allowed fiber optic sensing systems to be deployed in a variety of applications such as pipeline leak detection, perimeter security monitoring, and power cable real time thermal rating. Recently, there has been a larger adoption of monitoring of conveyor belts in so called Conveyor Health Monitiring Systems (CHMS) within the mining and bulk material handling industries to identify idler conditions on an ongoing basis. Several attempts have been made to institute sensing capabilities into conveyors with mixed success. However, recent breakthroughs in modeling, installation methodology, and technology, as well as increased understanding of application and industry requirements, have allowed the technology to be deployed at both experimental and commercial scales. This paper summarizes the application conditions and requirements, design considerations, methodologies used, the outcomes achieved, the logistical and field considerations, and the future possibilities of the use of this technology in CHMS using Distributed Fiber Optic Sensing.

Feb 22, 2026

By E. L. Gillenwater

Coal mine planning has three distinct decision levels: (1) decisions made at the upper level of management that determine production requirements for specific mines, (2) decisions made at the middle management level, the mine level, that determine how the mine satisfies its production requirements, and (3) decisions made at the operating level of management, the sectional level, that determine the sequencing of machine movements at the face. In this paper, the underground production scheduling problem is formulated in multi-stages using the Hierarchical Production Planning (HPP) approach. Two linear programming HPP models for accomplishing decisions at the first two levels are developed. Both models address the aggregate production planning process. The Mine Production Scheduling (MPS) model permits determination of monthly production and inventory levels. The Section Production Scheduling (SPS) model incorporates a quality blending requirement into the determination of weekly sectional production and inventory levels.

Jan 1, 1995

By Jonathan Baggett, Nino Ripepi, Amin Abbasi, Richard Bishop, Juan Monsalve, John Hole

This work focuses on the operational and safety issues associated with karst voids in large opening underground mines. Issues include water inrush, structural instability, and engineering uncertainty in these environments. Coupled with the fracturing prevalent in folded sedimentary rocks, karst voids are complex and challenging ground-control risks. Traditional methods of predicting karst void locations, such as probe drilling, are impeded by the inconsistent spatial distribution and variable sizes of the features as reported by Li et al. (J Rock Mechan Geotech Eng:232–242, 2010) and Hassan et al. (Procedia Chem 19:737–742, 2016). Ground-penetrating radar (GPR) is a geophysical technique that transmits radio waves into a medium and subsequently detects reflected waves via a receiver. The travel time and energy of received signals are then processed and interpreted. The difference in conductivity and dielectric permittivity between limestone and open karst cavities causes strong reflections. GPR is frequently used as a geophysical surveying technique in several industries; however, there is a lack of published research on underground mining GPR applications as reported by Zhao et al. (2015a; Geophys J Int:62–71, 2015b) and Eskelinen and Pellinen (Constr Build Mater:888–898, 2018). The purpose of this work is to demonstrate the use of GPR in an underground stone mine and to discuss the importance of karst void detection ahead of mining.

By W. Szymanski

The United States contains one of the world's largest reserves of uranium. Domestic production and exploration activities, however, have declined since the early 1980s due to weaker-than-expected growth in nuclear power demand and to foreign competition. The main result has been that more costly and less productive conventional mines and mills have closed. Meanwhile, industry productivity as measured by uranium output per employee has increased threefold since 1980. At the end of 1992, only six plants, all nonconventional, were operating in the United States. Due to cost considerations and increased environmental awareness, any additions to existing capacity are expected to be met through nonconventional in situ leach plants.

Jan 1, 1994

By J. F. T. Agapito

Stability in Exxon's Colony Pilot Mine in the Piceance Creek Basin, Colorado has been monitored by periodic pillar stress-determinations End roof-to-floor convergence measurements since 1971. Pillar failure has caused marginal stability in some areas of the mine. Measurements taken during the process of failure provided valuable information on the in-situ pillar strength and long-term behavior of the mine structure. Four pillars were reinforced by 32 mm (1-1/4 in) diameter tensioned grouted bolts to increase long-term stability in the northern area of the mine. Stability of this area is necessary because future plans envision its use as an exit/access and ventilation exhaust. Computer analyses were performed to help evaluate the effect of pillar reinforcement on long-term stability. Results indicate that bolting is particularly useful in stabilizing failed pillars, but its effects are significant only in the immediate area of the pillar. The projected significant decrease in deformation of two extensively failed pillars near a main entry indicates that bolting reinforcement will assist the long-term stability of the opening.

Jan 1, 1985

By Kadri Dagdelen

The importance of factoring mining dilution into feasibility stage ore reserve estimates is discussed. An example that relates the issue of mining dilution to the size of smallest volumes that can be mined selectively is given. Relationship between the size of the selective mining units (SMU's) and the variance of their average grade is presented. The concept of variance reduction and its use in factoring mining dilution into geostatistical ore reserve estimation is described. An approach to estimate variance reduction factor by way of conditional simulation is introduced.

Jan 1, 1996

By Cesar A. Busnardo

The carbonatite orebody in Jacupiranga is situated some 230km (140-mi) southwest of Sao Paulo and is mined by Serrana S/A de Mineragao, producing an apatite concentrate for fertilizer production and a calcite tailing for cement manufacture (see Figure 1). The orebody (Table 1) is mined by open pit and the total production is 4.5 million mt/year of carbonatite ore with a further 2.2 million mt/year of overburden. The carbonatite low-grade ore (Table 2) is fed to the concentration plant at 460 mt/h , comprising of four parallel lines of grinding, by rod mills 2.7m x 4.5m (9 x 15-ft), operating in closed circuit with hydrocyclones. The grinding circuit product is deslimed in four stages using hydrocyclones and the deslimed product is conditioned with corn starch and subsequently floated, using fatty acids as collector to, recover the apatite.

Jan 1, 1985

By R. K. Clifford

The formation of elemental sulfur on the surface of sphalerite in aqueous systems was investigated. Hallimond tube flotation tests showed that unoxidized sphalerite did not float well without a collector. Flotation recoveries of greater than 95 percent were obtained without the use of a collector or frother after the sphalerite had been reacted with oxygen under pressure and water at pH 2.8 at room temperature. High flotation recoveries also resulted when sphalerite was reacted in acidic solutions in the presence of platinum sponge, titanium sponge, 316 stainless steel, copper turnings, or [10-5M++]. Conditions which produced high flotation recoveries of sphalerite yielded contact angles of 37° to 40° and also produced elemental sulfur. The increase in elemental sulfur on the surface of sphalerite was detected by elemental sulfur extraction with petroleum ether, electron spectroscopy for chemical analysis (ESCA), and the electron beam microprobe. The quantity of elemental sulfur formed was insufficient to be detected by infrared or Raman spectroscopy, or by the optical microscope or by the scanning electron microscope. An electrochemical type reaction for the production of elemental sulfur in acidic solutions was proposed. The cathodic reduction of oxygen was the slow step which needed to be catalyzed. A chemical type reaction which produced H2S rather than elemental sulfur was evident in non-oxidizing conditions.

Jan 1, 1974

By Biswajit Samanta, Pranjal Pathak

This article presents a customized genetic algorithms (GA) with new crossover and mutation operators to solve the short-term production scheduling problem of multi-mine mineral value chains (MVC). The preceding problem consists of determining the extraction sequence and destination allocation of blocks from all the mines collaboratively while closely meeting the quality and quantity requirements of the processing units subject to relevant technical and operational constraints. The short-term production scheduling is carried out at shorter scales wherein the operations are modeled in a great detail with large number of constraints. This makes the industry-scale instances of the problem computationally intractable for standard mixed-integer programming (MIP) solvers. Thus, a GA-based heuristic approach is developed to obtain nearoptimal solutions to the large-scale instances of the problem in a reasonable amount of computational time. Computational experiments show that the developed GA-based method is a promising way to handle industry-scale instances of the problem. Moreover, the sensitivity analysis on various parameter combinations of crossover and mutation operators indicates that the customized global mutation operator, when used in combination with the customized crossover operators, took on average 12.5% less time than the customized local mutation operator to converge to a solution.

May 21, 2022

By Jr. Hawk

The power generation industry may be required to reduce CO2 emissions if regulations related to global climate change are enacted. Coal-fired generation, which emits 82% of the power sector CO2, would be a likely target for CO2 reduction. Compliance with the Kyoto protocol will require a 30% reduction from the projected year 2012 emission level even with moderate load growth. This paper describes an analysis of power industry CO2 reduction options and their costs to assess how a generator would make compliance decisions under a mandatory CO2 emissions reduction program. Carbon sequestration, fuel switching and new plant construction are considered.

Jan 1, 1999

By Adil Jamali, Taufiq Hidayat, Imam Santoso, Zulfiadi Zulhan, Indah Suryani

The study investigates the segregation of iron and titanium in iron sand concentrate pellets reduced using coal under an isothermal-temperature gradient profile. The results show that metallic iron migrates to the surface while titanium and other oxides move to the center of the pellet. The study provides insights into the reduction process and the behavior of iron and titanium during heat treatment.

Mar 2, 2022

By J. R. Dyni

The lacustrine Green River Formation of Eocene age in the Green River Basin, southwest Wyoming, contains the world's large resource of natural sodium carbonate in bedded trona (Na2CO3? NaHCO3? 2H2O). In this study, 126 billion tons are estimated to be present in 22 beds, ranging from 4 to 36 feet in thickness. These 22 beds underlie areas of about 50 to more than 775 square miles at depths ranging from about 650 to more than 3,000 feet below the surface. The total resource of trona ore in the basin for which drilling information is available is estimated to be about 149 billion short tons. The undeveloped deeper trona beds in the southern part of the basin may be exploitable by solution mining. Additional unevaluated sodium carbonate resources are present in disseminated shortite in strata interbedded with the trona and in shallow sodium carbonate brines in the northeast part of the basin.

Jan 1, 1995

By L. B. Phelps

This paper focuses on the use of an integrated mine planing software package entitled "REMINE" which was constructed to provide a project evaluation tool for analysis of remining projects. Coal remining constitutes the affecting of sites which have had a past history of mining and have a pre-existing pollutional discharge. Such sites require a Best Professional Judgement (BPJ) analysis. The program was written to provide such an analysis with flexibility in the mine plans which can be analyzed. The process required for a BPJ analysis will be detailed and mine plan simulation performed to demonstrate the analysis.

Jan 1, 1990

By Y. C. Lo

This paper presents the development of ultrasonic grinding technology for material and mineral processing. The principles underlying this new technology, as well as their implementation in two laboratory scale devices are described in detail. Ultrasonic grinding experiment results are discussed with respect to operating variables and the achieved product sizes. Special attention has been given to the electrical energy consumption of the grinder, and an attempt to compare its efficiency with tumbling mills has been made. A mechanical system capable of measuring the specific grinding energy is also described.

Jan 1, 1991