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By Tassos Grammatikopoulos, Mike Johnson, Niels Verbaan

Seabed polymetallic nodules, which contain significant quantities of metals key to electrification (nickel, cobalt, copper, and manganese) can be processed using several different metallurgical processing options, including direct smelting and subsequent hydrometallurgical refining of the copper/nickel matte, ammoniacal leaching (gas reduction or Cuprion), and acid leaching (often reductive). Many of these approaches suffer from reduced cobalt extraction, difficult physical performance, or overall circuit complexity in general, leading to increased risk to the overall project. SGS has considered pressure acid leaching of nodules for further investigation, as publicly shared data on this processing route stems from the 1970s and 1980s and is not always easily accessible. This paper will detail the series of tests conducted and provide updated results obtained (high Ni/Co/Cu recovery with limited Mn/Fe), as well as comment on the potential treatment options on the product solution and residue.

Feb 1, 2025

By D. Wheeler

Similar to modern day petro-chemical processes, the flotation column is a complete break from the conventional manner of floating on a batch basis in cells. The column has a reputation of being only suited for cleaning applications, particularly that of molybdenum cleaning. The original column, invented and developed by Column Flotation Co. of Canada, Ltd., was developed as a Rougher-Scavenger. Only after proving its capability in this field was cleaning allowed. One rougher-scavenger column in closed circuit with a cleaner column produced better grade and recovery than a conventional cell plant consisting of one stage of roughing, two scavenging and four stages of cell cleaning. Three cleaner columns replaced 13 stages of conventional cell cleaning and resulted in higher grades and recoveries. The gentle countercurrent action of the column itself together with complete automatic control enable this machine to produce such results.

Jan 1, 1986

By J. Seiter, S. Cox, E. Kim

Mining has always been among the most hazardous of occupations, and with the increasing demand for coal and minerals, safety in mines assumes even greater importance. Worldwide, underground miners are being exposed to noise and respirable dust hazards associated with roof bolt drilling. These hazards are now being understood to cause irreparable damage to the health of miners. The objective of this research was to discover if a polycrystalline diamond compact (PDC) drill bit generates less respirable dust and hazardous noise than a competing tungsten carbide (WC) bit in dry vacuum drilling. In order to control the drill parameters the drilling tests were conducted in a laboratory setting. The results were obtained by determining the quantities of dust and noise generated using each drill bit and analyzing those levels, using monitoring devices and software to collect the data. This paper includes information on the experimental setup, equipment used, drilling parameters, and data collected. Our results indicate that PDC bits produce significantly less noise and dust than WC bits. Our findings can contribute to improving the working conditions of rock bolter operators by reducing noise and dust generation.

Jan 1, 2014

By R. Brown, A. J. S. Spearing, M. Treinen, M. Theisinger

The mining and use of coal creates a significant amount of waste material that needs to be safely disposed of. It is likely that in the medium term, the Environmental Protection Agency (EPA) in the U.S. will categorize all such products as a new category – special waste. This would make the materials subject to many of the requirements for handling toxic waste, which will complicate the disposal of such products and significantly increase the disposal costs. Underground disposal would, therefore, seem to be the obvious solution, especially if the placed material can have low or no permeability, so that water table pollution does not present a serious long-term issue after placement. Significant additional advantages could be derived from this backfilling, including the reduction or elimination of surface subsidence, increased extraction, reduced surface waste disposal footprint and the elimination of explosion-proof seals in worked out areas. The research using a specific coal waste product as a typical example proved that the method of placing the backfill at a high density with low permeability is technically viable, but it must be made more cost effective and the other potential benefits quantified and costed in order to present a true comparison.

Jan 1, 2010

By K. Deaton

"INTRODUCTION A packaged cooling system is being developed for refuge alternatives (RAs) that meets MSHA qualification guidelines for deployment in coal mines. This system will allow full occupancy ratings of deployed Refuge Alternatives (RAs) to be maintained by keeping the apparent temperature inside the RA from exceeding 95°F. Research investigations sponsored by NIOSH have shown that heat buildup caused by occupants in mobile RAs will result in apparent temperatures that exceed the 95°F limit established in 30 CFR 7.504. Figure 1 shows the temperature rise in an inflatable RA having an occupancy rating of 23 people at an 81°F mine air temperature. This plot shows the need for either heat mitigation or occupancy derating in warmer mines. The RAECS will be designed to provide enough heat mitigation to eliminate occupancy derating due to heat buildup over the 96 hour refuge period.This paper describes testing of a prototype cooling system that uses proven vapor compression technology powered by batteries to keep the RA interior below the 95° limit for a minimum of 96 hours. Testing of this prototype cooling system was conducted in December of 2015 and January of 2016 at the NIOSH test mine in Bruceton, PA. December testing was conducted at the prevailing mine ambient temperature – approximately 60°F. The January testing was done with the mine ambient temperature in the immediate vicinity of the RA artificially elevated to 85°F. Realistic heat gain from RA occupants was provided by human simulators developed by NIOSH. These simulators add sensible heat corresponding to human metabolic processes and latent heat generated by respiration and perspiration. Heat generated by CO2 scrubbers was also added. Results of cooling system performance using these simulated loads at the two ambient conditions are described. A comparison of the apparent temperature in the RA using two different control techniques is also presented. This work documents the ability of the cooling system to meet the established apparent temperature limit at the full occupancy rating of a six person RA. A new cooling system intended for use with existing RA deployments and having greater cooling capacity is currently in development and will be described."

Jan 1, 2017

By J. Y. Hwang

Coal cleaning with traditional magnetic separation usually yields unsatisfactory results because minerals associated with coal, such as quartz, clay, pyrite and calcite, are weak-or non-magnetic. Magnetic reagent technology is a new mineral processing technology with the capability to enhance the magnetic property of minerals selectively. This reagent can be adsorbed selectively on minerals through the control of surface chemistry and, thus, result in selective magnetic enhancement. The application of this technology on coal cleaning has been experimentally demonstrated. Good separation results can be obtained at low to medium magnetic field strength. Comparison with other processing technologies is included.

Jan 1, 1992

By N. Arbiter

Evidence for the floatability of sulphide minerals without collector is analyzed and it is shown that results obtained with ores, in contrast to those with single minerals or mineral mixtures, depend on many additional variables, some identified and others not. Because of the prevailing low levels and costs of collectors for most sulphide ores, it is unlikely that collectorless flotation will have commercial applications, so that continued research on the subject may be justifiable on theoretical but not on practical grounds.

Jan 1, 1993

By William G. Fischer

Basic laboratory tests initiated the. Rock Mechanics program. The stress-strain curve, modulus of elasticity, Poisson's ratio, the uniaxial rock strengths, Mohr's envelope, the stress at failure, and creep were investigated. A series of underground problems were then approached using this information; and various field measuring devices, most of which were developed by the Bureau of Mines. Initially, stress concentrations near mine openings were evaluated using the stress relief technique. This required an accurate determination of the pre-mining stress field. Later, stress concentrations associated with the cave line .sere studied. After about thirty stress reliefs over an appropriate time interval the effects of one type of mining could be compared against another. The microseismic technique was used to investigate a possible application of warning devices near the cave line. A study of mane reorientation was made Problems related to the shape and size of pillars and barriers were studied. Partial extraction mining systems were evaluated. The effectiveness of roof bolting patterns were examined. Control of roof stresses was attempted. A new system of mining in heavy ground has been developed using the information secured in the Rock Mechanics program without this system, mining in more than one instance would Nave been next to impossible. Indeed; from this one discovery alone, the Rock Mechanics program has paid off in improved safety as well as in dollars.

Jan 1, 1964

By Donald C. Violetta

During 1963 more than 200 million tons of coal was consumed by the public utility industry. Ash residual, from the burning of this coal has caused disposal problems. In order to prevent air pollution, dust collection systems have been installed to suppress the fine ash emitted from boilers before it is discharged into the atmosphere. The collected ash, called fly ash, must be removed from the dust collection facilities and disposed in some manner, usually at a substantial cost to the utility. Many years ago fly ash disposal was not a serious problem because the demand for power was relatively low and coarse coal was burned on stoker type traveling grate machines. The low burning rates utilized on these grates did not produce large quantities of air-borne coal ash while the mechanics of this system of burning resulted in a clinkered residue of cinders. Both of these conditions resulted in the production of only small quantities of fly ash. As the demand for electricity increased, a method of burning pulverized coal was developed and was introduced to the public utility industry in 1918 at Milwaukee, Wisconsin.1 This method of firing was considered a significant advance in steam electric generation as it (1) permitted the use of coals that could not be economically fired by other methods and (2) has generally resulted in improved efficiency, greater generating capacity and lower costs.2 The utilization of larger generating units using pulverized coal substantially increased the quantity of fly ash which resulted in a' more severe disposal problem.

Jan 1, 1966

This paper presents the results of column flotation of a fine feed sample of Florida phosphate. A central composite design is used to study the main and interaction effects of parameters affecting column efficiency. The statistical design is also used to determine the optimum conditions. The results indicate that, depending on the experimental conditions, it is possible to achieve a concentrate of high grade and recovery. A concentration of 15 ppm of non-ionic frother is found to be enough to maximize the recovery at the pH of 9.5.

Jan 1, 1999

By Eric Jacobs

"Building and operating tunnels has been a highstakes endeavor in terms of costs, complexity, safety and impact on contractors, owners and the public for a long time. There are many variables that need to be closely monitored and managed to construct a tunnel on-time, on-budget and safely. Once built, there are also many elements that need to be monitored and managed to operate a tunnel safely and efficiently.Fundamentally, the risks to the safe and efficient construction and operation of a tunnel are a function of the degree of harm and the likelihood of the harm occurring. From a cyber security perspective, risk assessments used to inform decision makers and support risk responses are typically based on identification of relevant threats; internal and external vulnerabilities; the impact that may occur given the potential for threats to exploit vulnerabilities and the likelihood that harm will occur. This article focuses on creating awareness of vulnerabilities associated with technology used in tunnel construction and operation and some of the challenges associated with remediation of these vulnerabilities. As we all know, technology has been evolving at an accelerating pace and infiltrating every aspect of our lives in new and often exciting ways. In the world of tunneling, sensors and systems that provide position and time have become accurate, rugged and cost-effective enough to come out of the research labs and into the equipment and systems used every day. There are many opportunities to employ connected computing devices and sensors to costeffectively capture, integrate and analyze key data with minimal latency to manage risk better, improve safety and avoid surprises."

Jun 1, 2019

Electronic detonators have been in commercial use for a decade, with an excellent safety record. This paper lists known incidents involving electronic detonators. Typical standards required by regulatory bodies for static electricity and electromagnetic fields are reviewed. The performance of some detonators is compared to these standards; in general the minimum standards are easily exceeded. The general resistance of electronic detonators to extraneous electrical energy that can be derived from the body of test results is compared to danger levels for exposure of humans to these energies; it is shown that electronic detonators can safely tolerate higher electrical energies than people can. This comparison includes comparable data for electric detonators, which are shown to be more vulnerable to extraneous electrical energy than people are. Electronic detonators also bring significant safety benefits in blasting due to their testability, two-way communications, reliability, programmability and precision. The links between these attributes and enhanced safety are discussed with examples from actual blasting. Although electronic detonators are usually more vulnerable to extraneous electricity than non-electric initiation systems, the paper shows that the net safety benefit in handling and blasting is in favor of electronic detonators, which are the safest initiation system that has ever been offered to the mining industry.

Jan 1, 2010

By S. C. Sethi

The WIPP (Waste Isolation Pilot Plant) Project near Carlsbad, New Mexico, is a research and development project sponsored by U.S. Department of Energy, designed to demonstrate the safe containment for disposal of radioactive waste. A mine (repository) is currently being developed 2150 feet below the surface, in a thick salt bed which will serve as the disposal medium. Provision of a proper ventilation system at the WIPP Project is a major priority of those responsible for its design, management, and operations. As an ongoing effort towards this goal, it was decided to simulate the mine's ventilation system using Dravo's MINEVENT computer program. Specifically, the work included the development of the following simulation models: 1. Simulation of the current ventilation system 2. Simulation of the designed ventilation system for the following modes: o Mine Construction mode/shift o Waste storage mode/shift o Fire or exhaust filtration mode These computer models are useful in solving complex ventilation problems likely to be encountered in an R&D project, like WIPP. They are particularly helpful for the development of contingency plans to incorporate during emergency situations, such as fires, fan stop- pages, radiation leaks, etc. Also, they can be utilized when considering expanding certain underground areas to ensure the availability of adequate ventilation.

Jan 1, 1986

By Zhongran Dai, Nan Hu, Jianhong Ma, Hui Zhang, Zhihua Zhong, Han Zhou, Feng Li, Yonggen Qiu, Yang Ding, Yingchun Yang, Dexin Ding

In the traditional chlorination roasting-water leaching-solvent extraction process for the extraction of rubidium-bearing ore, Rb leaching from the ore and calcium removing from the leachate are conducted separately, and this results in the complicated process and high energy consumption. In order to integrate the Rb leaching and calcium removing processes, Rb-bearing polymetallic ore was firstly treated by chlorination roasting, it was then leached in a micro-reactor with raffinate, and the calcium ions in the leachate were removed in the reactor as carbonate precipitates by passing CO2 at certain pressure into the reactor. The effects of raffinate alkalinity, CO2 pressure, and CO2 reaction time on Rb leaching rate and calcium removing rate were investigated. The experimental results show that when Rb-bearing polymetallic ore was leached for 90 min by stirring with raffinate with 1.125-mol/L alkalinity, and the pulp was made to react with CO2 at 0.8 MPa for 15 min, the Rb leaching rate and calcium removing rate amounted to 92% and 98.2%, respectively. This integrated process including Rb leaching from Rb-bearing polymetallic ore and calcium removing from leachate could simplify the process for the extraction of Rb-bearing ore and increase its economic benefits.

Sep 27, 2023

By John Murray, Ryan Smith, Daniel Ebin, Robert Gould, Thomas Hennings

The Atlanta Plane Train Tunnel West Extension was excavated at Hartsfield-Jackson Atlanta International Airport using Sequential Excavation Methods (SEM). At its shallowest point, tunnel cover to bottom of Domestic Terminal footings was limited to 6 feet in soft ground. To mitigate risk of excessive building movement due to tunneling-related activities, the columns near the alignment were directly underpinned. Underpinning was accomplished using a combination of grouted mini-piles, installed under low headroom conditions, that supported steel framing spanning over the tunnel excavations. This paper focuses on design and construction of the underpinning system used to mitigate risk from tunneling.

Jun 13, 2023

By Neall. George M.

No method of roof control yet devised has proven to be universally acceptable for the wide range of strata conditions experienced in U.S. coal mines. However, a relatively new innovation, the roof truss, has proven itself capable of preventing roof failures which both conventional and resin bolting could not. Presently, the economics of roof trusses are not favorable when compared to bolting due primarily to drilling and installation procedures, but this is expected to change with improved truss and equipment designs. To realize the full potential of this new method of roof control, design criteria are needed which can optimize the effect of the truss for varying strata conditions. A review of the literature reveals that some work has been conducted on the roof truss. 1 Gambrell and Haynes (1970) showed that the roof truss is superior to angled roofbolts installed through a header. Sheorey, Verma, and singh2 (1973) used statics to prove that the optimum angle of inclination should be greater than 450? However, to date, no systematic attempt has been made to establish design criteria. In this report, the problem was approached in three ways. First, model studies were performed to determine general trends of truss support as a function of a number of variables. This provided a better understanding of the support mechanism involved. Secondly, beam theory was employed to calculate the actual support capacity of a truss, realizing the many simplifications, assumptions, and shortcomings of this approach to such a complicated problem. Last, field testing will be utilized to test the hypotheses previously developed and provide hard data to further synthesize roof truss design criteria. Field testing has recently commenced and should be complete before mid 1977.

Jan 1, 1977

By C. Zhou, J. Srednicki

Electronic systems have been increasingly used in underground mines to improve mine safety. These electronic systems emit electromagnetic (EM) energy which can adversely impact the performance of other electronic systems nearby and thus should be characterized. Researchers at the National Institute for Occupational Safety and Health (NIOSH) characterized the magnetic fields emitted from devices that can potentially interfere with the performance of proximity detection systems (PDSs) and compared the emission levels of these devices to the susceptibility of PDSs. In this paper, we present our measurement results pertaining to this effort. Particularly, magnetic fields emitted from the different orientations of a powered air purifying respirator (PAPR) and two lite trackers are evaluated based on the RE101 protocol specified in the MIL-STD-461G standard. The results show that both devices emit strong magnetic fields which strongly depend on the orientation of the devices. At some frequencies, the maximum emission levels from the two devices exceed both the emission limit given in MIL-STD-461G and the maximum magnetic fields that a PDS can withstand without a failure. The results and findings in this paper can help the mining industry better understand electromagnetic interference (EMI) underground and provide critical scientific data that support mining-specific recommendations to address EMI-related challenges.

Feb 1, 2023

By Lok W. Home

HISTORICAL DEVELOPMENT At the beginning of the 1970 more than 90% of pro¬duction drilling in open-pit mining was obtained with the use of rotary drills. At the same time, the use of rotary drills underground was virtually nonexistent. Several progressive mines began questioning whether efficient rotary drilling could not be adapted to under¬ground applications. In the late 60s and early 70s at¬tempts to use rotary drilling were made by Inco, Ltd. and Meramac Mining, utilizing drill units designed as a combination of small diameter raise drills and rotary drills. These initial attempts were unsuccessful primarily due to the immobility of the equipment and low degree of dependability. At the same time, experiments con¬ducted by Inco and Meramac using large diameter in¬the-hole percussion drills produced immediate encourag¬ing results. The first serious attempt at utilizing rotary drilling underground was made by Texasgulf in 1971 at Kidd Creek mine in Canada. An experimental stope 15 m wide, 36 m long, and 30 m deep was drilled using 200-mm diam rotary drilled holes. The machine used was a Robbins' Model 11 D. The Model 11D is a rotary drill designed to drill drain and utility holes under¬ground. The results of this test revealed that large diameter blasthole stoping was feasible. The indications were that the major areas of concern-fragmentation and pillar damage-could be controlled and a new low-cost stoping method resulted. At this point Texasgulf and Robbins entered into a cost-sharing agreement to develop a rotary drilling unit specifically for this stoping method. Drilling of the trial stope required pouring a concrete pad at each drill hole plus anchoring the derrick to the pad by means of rock¬bolts. Utilization expressed in terms of drilling time to available time was less than 20%. It was obvious that the required unit had to be mobile, setup time had to be minimized, and rod handling had to be improved. The first attempt at an underground production-type rotary drill consisted of mounting the basic 11D on an air-powered Eimco 600 Series crawler. The crawler was equipped with four screw-type leveling jacks operated by an impact wrench; rod rack facilities for 60 m of 1.2-m long, 170-mm diam rods; a rod handling facility consisting of an air-lift swing boom and a pipe loader which automatically positioned the rod under the float¬ing drive box; a turnbuckle anchor system requiring in¬stallation of four rockbolts in the drill drift floor and placing turnbuckles from the rockbolts to the corners of the drill; and trailing power units containing the electrics and hydraulics required to operate the drilling unit. Operation of this unit revealed a vast improvement in drilling time but some problem areas remained. The anchoring system required secondary drilling and proved difficult to adapt to the localized irregular floor surface and the trailing power unit was difficult to maneuver and was causing unnecessary maintenance costs. Addi¬tional improvements resulted in the standard 11MD rotary blasthole drill. DESCRIPTION OF UNIT This standard model consists of the drill and the power unit integrally mounted on an air-powered crawler chassis (Fig. 1). The rod-handling and leveling¬jack systems are similar to those used on the prototype Texasgulf unit and remained relatively the same. The anchoring system has been replaced by the roof jack, initially screw type but now hydraulically actuated. The anchoring system is necessary as the drill exerts more thrust than the weight of the unit. During operation it is found that the two front jacks adequately anchor the machine. The complete unit's operational dimensions are: height, 3.2 m; width, 2.1 m; and length, 4.2 m requiring a 3.5- x 3-m drill drift. The derrick is pivot mounted and raised and lowered by a hydraulic cylinder reducing the transport height to 2.5 m. The derrick is also turnbuckle mounted to allow dip angle drilling from vertical to 0.52 rad (30°) off vertical. The drill derrick can be mounted to allow dip axis to be parallel or perpendicu¬lar to the long axis of the unit. The standard rods are 1.2 m in length and are contained in racks of 10 which can be removed for transportation. Drilling torque is produced by a 56-kW (75-hp) electric motor driving a double vane pump which in turn drives a Robbins high torque gear-type hydraulic mo¬tor. In addition to the hydraulic motor, the machine drive system has a 3.9:1 planetary gear reducer. This results in six speeds with the following minimum and maximum range: Maximum rpm 112 Torque 3725.5 J (380 kg m) Minimum rpm 10 Torque 14 706.0 J (1500 kg m) Drilling thrust is provided by two bootstrap cylin¬ders pressurized by a variable volume pump. This sys¬tem can produce from 0 to 267 231.2 N thrust in either direction. Bailing air (approximately 17 m3/min at 382.2 to 490.3 kPa) is introduced through a rotary swivel pass¬ing directly through the center of the drive system to keep efficiency and losses to a minimum. Hole annulus is also kept to a minimum by using 170-mm rod when drilling a 200-mm hole. A small amount of water is added to the air for dust suppression. The machine has to be supplied with air, water, and electrical power. It does not appear feasible to provide an integral air power supply with the rotary drill such as is done with open-pit rotary drills. Air is required and installed during the primary development of the drill drift. The machine can be adapted to drill hole diameters from 170 to 228 mm for blasthole operations. The drill string consists of the rotary bit, crossover stabilizer, roller stabilizers, and standard rods. The operator controls speed and thrust pressure from an operating console which can be mounted in a conve¬nient position. Mount Isa has made an adaption to the operating console to permit remote collaring of drill holes in an uncleared floor.

Jan 1, 1982

By Ronald E. Triplett, George K. Burke, Bernard H. Voor

To accommodate larger double-stack rail cars through a tunnel, the existing active tracks were to be lowered. The tunnel is an elliptical, horseshoe-shape with concrete base support, removal of which would jeopardize the tunnel integrity, particularly since the soils beneath part of the tunnel floor included soft, saturated silt overlying rock. Grouted bar anchors combined with a SuperJet soilcrete strut replaced the existing support in situ prior to floor lowering. Close cooperation and detailed timely engineering support provided a quality project. Project design and construction, ground improvement methods, and the performance of the work are described.

Jan 1, 2001

By M. William Lallman

Potash production from natural brines of the Bonneville Salt Flats has a comparatively long history dating back to the start of World War I. However, it vas sot until the late 1930's that a successful commercial potash operation was achieved by a firm known as Bonneville Ltd. While improvements in operating techniques, pond design and equipment have been incorporated as they became available it should he understood that the basic technology developed in the late 30's and early 1940's by Bonneville Ltd, for potash production has not been changed significantly. The purpose of this paper is to present a brief review of the history, geology and hydrology of the Bonneville Potash operations and discuss the cur¬rent methods employed for brine collection, solar evaporation and the recovery of potash and other brine chemicals. A detailed study of the hydrogeology of the Bonneville Salt Flats wan made by L. J. Turk,1 Ph.D. thesis for Stanford University in 1969, under the auspices, of Kaiser Chemicals the Industrial Chemicals Division of Kaiser Aluminum & Chemical Corporation. Turk's thesis furnished much of the information presented in this paper.

Jan 1, 1976