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By Serdar Aktaş, Özgün Küçükoğlu, Burcu Nilgün Çetiner, Mehmet Hakan Morcalı

This study compares the cementation performance of metallic iron, metallic aluminum, and metallic tin in terms of the reaction conditions and parameters in synthetic antimony chloride solutions. The effects on the antimony recovery (%) caused by the cementators’ types, stirring speed, reaction time, and temperatures were explored thoroughly. The cementation kinetics of antimony were also explored for each cementator. The activation energies were determined to be 10.99, 9.09, and 13.58 kJ mol– 1 for Al, Fe, and Sn, respectively. The results reveal that the reaction is diffusion controlled, and comparable results were obtained for each cementator. At 25 °C, 40 mg of iron powder was found to reduce all antimony ions (i.e., approx. 99% recovery), but even when 100 mg of Al and Sn cementators were used, the antimony recovery did not reach 100%. This result shows that iron is the best candidate to cement antimony out of the solution.

Jan 28, 2022

By Shani Engelbrecht, Belinda McFadzean, Avuyile Wali, Natalie Shackleton, Vratislav Malysiak

Frothers play a crucial role in sulphide and PGM ore flotation recovery, and AECI Mining Chemicals studies on PGM ores have shown significant flotation kinetic increases with the optimal frother-collector combinations. Using Senfroth 200 as the industry baseline, remarkable kinetic increases were observed with AECI Mining Chemicals developed frothers in the first concentrate. Even in the worst-case scenarios, 4E PGM recovery increased by 5% at a slightly higher concentrate grade. It is important not to limit frother dosage to a fixed value. Instead, enough frother should be added to maintain a stable bench float, measuring the dosages by frother volume before and after tests. Frothers can be specialized blends and their importance should not be underestimated. The results produced by formulating and innovating frothers to address specific industry challenges have been encouraging. Testing a frother on a plant scale does not have to be as daunting as with collectors, enabling the identification of the best frother-collector combinations at an industrial scale. AECI Mining Chemicals bench scale testwork has motivated plant-scale trials that have successfully transitioned to commercialization. This paper compares the results from metallurgical and froth stability tests and shows that occasionally frothers that have a less stable froth can have improved valuable mineral recoveries, while still exhibiting better drainage for reduced entrainment and mass pull. It was shown that caution should be used when relying only on simplified froth stability tests in the evaluation of new frothers.

Feb 1, 2025

By Hongqiang Wang, Qingliang Wang, Eming Hu, Zhiwu Lei, Fang Hu, Rui Zhang, Wei Hou

Pyrite, a mineral associated with uranium ore, is closely related to uranium leaching. In this study, Ozone micro-nano bubbles (OMNBs), as an environmentally friendly advanced oxidation technology, were used for the first time to oxidize pyrite under experimental conditions to improve the leaching rate of uranium. A laboratory-scale agitation leaching experiment of pyrite was carried out with a pH of 1.0–3.0, gas flow of 1–3 L/min, ozone generation rate of 0.55–2.22 mg/s, and pyrite concentration of 0.1–5.0 g/L for 1 h. By adding three different co-oxidant: Mn(II), Mn(IV), and Fe(III), it was found that only Mn(IV) increased the oxidation rate of pyrite by 21.7%. The results of the scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) show that the formation of Fe(III)-O film on the surface of the ore suppresses the oxidation rate of pyrite to a certain extent. Pyrite can be rapidly oxidized up to 57.6% by OMNBs, which is beneficial to uranium leaching. This method is expected to be used for in situ acid leaching of uranium with OMNBs injected into the ground.

Jan 3, 2022

By Dennis N. Poffenroth

One concern of the Mine Safety and Health Administration is the structural integrity of steel wire ropes used on mine personnel hoists and elevators. Failure of such ropes has resulted in loss of life and property. Although thorough and regular visual examinations are performed, hoist ropes may still fail from undetected internal wear, corrosion, and broken wires. To complement visual examinations, nondestructive rope inspection techniques have been developed to determine deterioration and removal criteria. The techniques use electromagnetic and permanent-magnet test instruments designed by a Canadian firm. This paper describes the operating principles, field and laboratory testing of these nondestructive testing instruments, and discusses the feasibility of using this type of testing as a supplement to visual examination and destructive tests.

Jan 1, 1983

By John L. Bolles

The Phelps Dodge Corporation's Morenci Concentrator includes facilities for coarse crushing, fine crushing, grinding, flotation, tailing, disposal, concentrate filtering, and drying. The Morenci Concentrator daily throughput is in excess of 60, 000 tons. The ore milled is mainly a medium-hard monzonite porphyry in which the principal sulfide minerals are chalcocite and pyrite. The ore is transported by rail from the Open Pit Mine to the primary crushing plant located at the concentrator site. Ore is side-dumped from 80¬ton railroad cars into a sixty-inch gyratory crusher. The ore is then conveyed to a. 12, 000 ton coarse ore storage bin. Fine crushing is accomplished by four parallel lines of conventionally stacked crushers in open circuit. Each unit consists of one seven-foot standard cone followed by two seven-foot shortheads. Ti% product of the fine crushing plant is distributed by two tripper cars across a fine ore storage bin. The crushed ore is then fed by variable speed belt feeders into thirty parallel, single stage, closed circuit grinding units. Each of the 30 grinding units consists of one 6' x 23' conditioning drum, one 10' x 10' ha l mill and two 54" duplex spiral classifiers as principal equipment. The dry ore is fed into the conditioning drum with water to dilute the ore to a slurry of approximately 78% solids by weight. An aqueous solution of ammonium sulfide is also added to the conditioning drum. The ammonium sulfide primarily acts as a sulfidizing agent. The ore slurry containing the naturally occurring sulfide copper minerals and the sulfidized copper minerals discharges into the feed scoop box of the ball mill, where milk of lime, collector and-.dilution water are added. The ball mill product slurry is gravity fed: to the classifier pool where water is added to obtain the desired classifier overflow product

Jan 1, 1977

By S. K. Sahoo, S. K. Sharma, A. Yadav, B. Behera, G. S. P. Singh

A field representative modeling of the gob behavior is critical for the understanding of the associated mechanics of strata behavior in longwall workings. The findings of theoretical models and laboratory tests on the simulated gob material have shown the strain hardening behavior of the gob material. The double-yield material model, which is a built-in constitutive model in FLAC3D, has significant potential to simulate the gob compaction process as it represents materials which undergo irreversible compaction in addition to shear yielding. Apart from this, several researchers have attempted using modified elastic model or applied nodal force in reaction to the strain in the gob area as per the well-known theoretical relations to meet this requirement. Although these models can simulate the mechanical response of the gob for subcritical and critical extraction widths, they do not apply to supercritical extraction width as the gob stress may exceed the in situ stress level in such cases. For overcoming these limitations, a standard approach has been developed and validated in this paper, which can be used for simulating the gob behavior in supercritical longwall workings as well. The complete study is divided into two stages wherein the laboratory scale compression test on the simulated gob material has been numerically replicated to develop preliminary confidence followed by a parametric study of the double-yield constitutive parameters for a rational estimation of their values in different conditions. The calibrated model has been used for verifying its results by plane strain modeling of two different longwall workings, using well-established empirical and analytical findings and field observations. The approach suggested in this study can be used for the efficient modeling of the gob behavior of longwall panels under varying geo-mining conditions without compromising the accuracy of the numerical model. The meticulously validated model can be helpful in rational estimation of stress redistributions around the gob area apart from load transfer on the barrier pillar.

By D. Einarson, B. Strickland

The decision to accelerate development of Stillwater Mining’s East Boulder Mine was made in March of 1998. It required the completion of conceptual designs by July of 1998. This was accomplished through teamwork and close cooperation of mine personnel, engineering firms and vendors, all working toward the common goal of developing an efficient and workable design. Early in the project, representatives of Stillwater Mining, Kilborn International, Parsons Brinckerhoff Transit and RailSystems, Continental Conveyor, and H.A. Simons met to develop methods to bring the mine into production at a highly accelerated rate and to solve potential bottlenecks, including the movement of personnel, materials, and muck through a 5.6 km(3-1/2 mile) adit. This interaction, including companies not normally associated with the mining industry, led to innovative approaches and designs produced by Kilborn Engineering and Stillwater Mining.

Jan 1, 1999

By V. Svalbonas

The process of grinding mill quality assurance brings with it associated truths and myths. When the mill quality assurance process took its first great steps forward in the late 1970s and early 1980s, they were in response to the conditions existing, in our industry, at those times. In the late 1990s, we are faced with different conditions, and problems, and need fresh solutions. Yet the system developed for the early 1980s has produced no new approaches for the late 1990s, becoming instead more hardened and entrenched. This lack of development and actual resistance to research is now costing the industry significant amounts of money in late start-ups and useless scrap loss.

Jan 1, 1999

"The adsorption of mixed cationic/anionic surfactants with different molar ratios onto quartz was investigated. The cationic surfactant used was dodecylamine bromide (DDA), and the anionic surfactant was sodium oleate (NaOL). The critical micelle concentration values for the individual surfactants and their corresponding mixtures were determined using a platinum plate. The adsorption mechanisms of mixed surfactants on quartz were studied using contact angle measurements, flotation tests and adsorption amount measurements. At alkaline condition, NaOL depresses DDA flotation of quartz without depressing the adsorption of DDA. The molar ratio of mixed surfactants is found to be a key factor in the orientation of alkyl chains and thereby the flotation response of quartz. A mixture of 1/2 or 1/3 DDA/NaOL forms on the surface of quartz when the concentration of NaOL is higher than that of DDA. The adsorption of the mixture decreases the wetting of quartz since the alkyl chains are in chaotically orientation with a conceivable number of head groups directing towards the solution phase. These results provide important insights into the adsorption of mixed surfactants onto quartz surface. INTRODUCTION Froth flotation is known as an effective method of separating mineral particles on the basis of their surface chemistry, specifically their hydrophobicity. [1]. The hydrophobic particles will attach to the bubbles and rise to the top of the containing vessel to form a froth that flows over the lip of the vessel. The hydrophilic particles remain in the liquid [2]. In the process, surfactant is often used as collectors for surface modification in order to change the wetting properties of mineral particles. The primary long chain alkyl ammonium salts are the most widely used as collectors for the flotation of oxide minerals, such as quartz, muscovite, hematite, phosphate and feldspar [3, 4]. Adsorption mechanism of alkyl ammonium salts on oxide minerals has been extensively analyzed [5, 6]. Generally, the ammonium salts are adsorbed through electrostatic interaction of the polar group of the molecules with the surface of these minerals [7]. Despite many obvious advantages of the ammonium salts in low temperature resistance and hard water resisting, however, their unavoidable drawbacks, such as high sensitivity and poor selectivity for slimes, relatively high cost, have limited their applications [8]. In recent years, mixed surfactants have drawn much attention due to their superior physicochemical and surface properties than single surfactants [1, 9-11]. They have been used in many industrial processes such as dispersion/flocculation, flotation, detergent, corrosion inhibition, cosmetics, foods, paints, chemical mechanical polishing, enhanced oil recovery, and nanolithography [12]. Most of the mixed surfactants have synergistic advantage in reduction of the surface tension and critical micelle concentration (CMC); therefore, they exhibit spurious properties, like excellent surface/interfacial activities, and are less expensive than single mixed surfactant systems [13, 14]."

Jan 1, 2016

By Dominick Mandalari, David Mast, Heather Ullinger, Juan Granja, Amanda Foote

The City of Akron will construct the Northside Interceptor Tunnel (NSIT) project to control and reduce combined sewer overflows. One component of the project a large diameter tunnel diversion / flow control structure that will facilitate tunnel storage, divert dry weather flow to the treatment plant, and divert large wet weather events that are greater than the tunnel capacity to the Cuyahoga River. The structure is designed to pass up to 1.2 billion gallons per day of flow and includes floatables screening. This paper will discuss project background, factors that influenced shaft location, and options evaluated to manage the large design flows.

Jun 23, 2024

By John L. Halls

Modern business practice dictates that in order to ensure the economic optimization of investment, the size of any investment venture must be such that every increment of capital invested in such a venture yields at least a corporate minimum acceptable rate of return. This practice is based on the premise that alternative investment opportunities capable of yielding the minimum corporate return are immediately available. If a mining corporation is to make the maximum use of its investment funds, any capital investment in a mining property must comply with the above practice. The most important parameter in estimating ore reserves is the cut-off grade which is used to separate material into ore or waste. The cut-off grade is calculated on the basis that material of cut-off grade produces sufficient revenue to cover the estimated costs of mining and processing through to sales, including depreciation and produce a pre-determined profit. Ore reserves so estimated are adequate for determining the magnitude of an orebody but do not provide a sound basis for determining plant size and therefore capital investment in a new property or for expansion consideration on an existing property. From a financial analysis of this one ore reserve it is impossible to ascertain whether each increment of capital investment is providing the minimum acceptable rate of return, Other difficulties associated with the calculation of a cut-off grade including the determination of depreciation and the amount of pre-determined profit to be included in the cut-off grade calculation are outlined in the text. The proposed solution to determine optimum ore reserves and plant size for new properties avoids the complication of calculating a cut-off grade by computing a series of ore inventories using arbitrarily selected cut-off grades. A comparison of the cash flows generated by production from such ore inventories using incremental financial analysis clearly indicates the ore reserve and plant size which will best serve the corporation's investment and metal production goals. Incremental financial analysis of a corporation's operating mines and prospects assists management in assessing the comparative expansion and investment possibilities of each property for increasing or maintaining metal production on a long term basis.

Jan 1, 1969

By Chee Theng

"Getting minerals out of ores is messy, but mineral processors learn to have fun with it. Celebrating the innate joys of the industry was the theme of this year’s Colorado MPD Conference. At the same time, attendees dug deeper for insights into problems that continue to dog the community, including tailings dam crises, water resource challenges, and a dwindling number of academics to teach and train the workforce (see box).Tailings dam crisesMatt Fuller of Tierra Group International Ltd. brought some of the audience to tears with his impassioned talk on “The Infamous Legacy of Upstream Tailings Dams,” which won the conference’s Lou Cope award for best paper. The talk was especially poignant coming on the heels of the January tailings dam failure in Vale S.A.’s Córrego do Feijão iron ore mine in Brazil, the latest in a series of catastrophic dam failures over the past decade that includes the Fundão dam failure in 2015.Noting that the two dams share a common characteristic — both are upstream tailing dams — Fuller explained the three basic dam construction methods and why certain upstream tailing dams are susceptible to failure (Fig. 1). The downstream, centerline and upstream methods denote the direction the centerline of the dam crest moves with each successive raise in elevation of the dam. With the downstream dam, the foundation for future raises is essentially the same as that of the starter dam, he explained. With the centerline dam, half of the dam is constructed on the same foundation as the starter dam, and with the upstream dam, each successive raise is built out over the top of the tailings.“Downstream dams are expensive to build because each successive raise is bigger, so the sustaining capex to build them keeps growing,” Fuller said. Many decades ago, mine owners realized they could construct a starter dam, put their tailings through a hydrocyclone, generate a coarse sand fraction and stack the sand over the top of the tailings to build the next raise. “Then, there is no sustaining capex, it all comes out of operations,” Fuller added. The footprint is smaller, and it is a favorable means of retaining the tailings."

Jul 1, 2019

By Donald J. Hill

To be successful, every organization within the mining industry must involve itself in researching and evaluating methods of loss control. The appraisal and evaluation of accidents and injuries is required to determine the costs of loss producing practices and conditions. This involves all of an organizations disciplines that concern themselves with a more efficient and cost effective organization. To come to know the cost of your safety program or how much is expended yearly for each employee on safety; to know what your safety costs are per man-hour or per ton-produced; to know what the health, medical and compensation costs are for any given incident are just a few of the important facts and figures that the safety management of a given organization needs to know to operate in the mining industry today.

Jan 1, 1984

By M. A. Trevits, G. W. Luxbacher, L. D. Patts

"It is almost a given that post-disaster mine conditions will have compromised the mine ventilation system, resulting in a hazardous atmosphere in portions of the mine, and often complicated travel through debris fields and roof falls. Robotic technologies provide the opportunity to gather valuable information to assist decision making or lessen exposure to dangerous conditions. MSHA's Mine Emergency Operations Division (MEO) has utilized a fully permissible mine robot, the V2, for a number of years, constantly updating the unit as new technologies became available. The National Institute for Occupational Safety and Health, as part of the MINER Act Extramural Contract Program, examined the need for additional robotic units and ultimately funded three different types of prototype technologies: two robots, the Snake Robot and the Gemini-Scout, and a mine rescue robotic assist vehicle known as the ""Mule"". The Snake Robot is designed to be lowered through a borehole and to conduct surveillance (gas monitoring, video and audio) in the immediate vicinity, while the Gemini-Scout, designed to be deployed in the mine opening, serves as a more mobile and agile exploratory tool as compared to the MSHA V2 robot. The Mule was developed in response to needs expressed by mine rescue teams for a versatile remotely operated support vehicle and it will move from prototype to MEO utilization in the near future. This paper describes the development of the robot prototypes and discusses their limitations in the prototype stage, possible enhancements and potential applications, as well as the utilization of the Mule. INTRODUCTION The conditions in a coal mine may be dramatically altered after a mine fire or explosion. For example, the ventilation system may not be functioning correctly as control devices may be compromised or damaged beyond repair. The visibility in the mine opening may be limited due to accumulated smoke and dust. Roof support systems may be damaged or no longer functional. Equipment and materials may be strewn about the mine opening. Debris fields, blocked openings, roof falls, flooded areas, gas accumulations and active burning make it very difficult or impossible for those managing the post-event emergency to permit mine rescue teams to enter the mine to conduct search and rescue operations. With the evolution of robots and robotic assist technology there has been a proliferation of purpose-built units for the military, police and law enforcement agencies, urban search and rescue and those contending with hazardous environmental conditions. In each case, the technology used is designed to limit human exposure to the unsafe conditions or to provide access to areas under difficult conditions. For example, a specially-designed marine robot has been deployed into the damaged core of the Japan’s Fukushima Daiichi Nuclear Power Plant to assess the conditions of the containment vessels, where melted fuel is believed to have accumulated. Human access to the area is prohibited due to dangerously elevated levels of radioactivity [1]. Multiple robots were deployed in Amatrice, Italy, to assist in the response after the 6.2-magnitude earthquake devastated the town. The robots were used to explore two medieval churches that were severely damaged and deemed too dangerous for human entry [2]. Tactical robots are regularly used by police and law enforcement agencies when the conditions of the emergency place intervening officers directly in harm's way [3]."

Jan 1, 2018

By B. K. Cantrell

A miner working in an underground coal mine with diesel equipment is exposed to a wide array of pollutants from the diesel exhaust. These include CO, CO2, NO, NO2, SO2, diesel-exhaust aerosol, and a variety of hydrocarbon compounds. A quantitative definition of the health risk resulting from these exposures remains elusive, but during the past several years, progress has been made in defining the problem. Results from epidemiological studies by Garshick, et al. (1988); animal inhalation studies by Mauderly, et al. (1986); Iwai, et al. (1986); and Brightwell, et al. (1986); and in vitro studies by Lewtas, et al. (1986), have provided sufficient data for the National Institute of Occupational Safety and Health (NIOSH) to recommend that "whole diesel exhaust be regarded as a 'potential occupational carcinogen,' as defined in the Cancer Policy of the Occupational Safety and Health Administration," NIOSH (1988). NIOSH further stated that "though the excess risk of cancer in diesel-exhaust-exposed workers has not been quantitatively estimated, it is logical to assume that reduction in exposure to diesel exhaust in the workplace would reduce the excess risk."

Jan 1, 1990

By A. D. Kalogeropoulos, T. N. Michalakopoulos

This paper deals with the numerical simulation of rock cutting laboratory tests using the discrete element method. The main objective is to provide a method for calibrating numerical DEM models of rock cutting in a systematic way so that realistic results are yielded. The numerical models are developed with the discrete element code Yade, which models rocks as a collection of bonded spheres. The models are calibrated in a four-step process based on the design of experiments method and optimization. The calibrated models are evaluated both quantitatively and qualitatively against actual laboratory cutting tests, in terms of the ratio of the simulated mean cutting force to the actual one and the cutting force time series, respectively. The fully calibrated models showed that the simulated cutting process matched qualitatively the actual cutting force recordings and underestimated the mean cutting force by approximately 3%. It is concluded that well-calibrated numerical simulations of the rock cutting process can provide not only a better understanding of the process itself but also quantitative data regarding the cutting force and energy requirements.

Dec 28, 2022

By M. L. Free, N. Dhawan, M. S. Safarzadeh, J. D. Miller, M. S. Moats

"The drum agglomeration of nickel laterite and gold ores has been optimized through the design of experiments (DOE) using a Taguchi L16 (45) orthogonal array to determine the optimum conditions for maximizing average agglomerate size and minimizing the amount of fines. The effects of controllable operating factors including moisture content (nickel laterite ore: 34-37%; gold ore: 7-10%), retention time (2-3.5 min), drum speed (15-45% critical speed), drum load (nickel laterite ore: 8-32 %; gold ore: 6-22%) and acid concentration (150-600 g/L) on the performance of the agglomeration process were studied.For nickel laterite ore, maximum average agglomerate size and minimum percent fines (-1 mm) occurred under the following conditions: drum load (23.7%), moisture (36.5%), time (3 min), drum speed (30% critical speed) and acid concentration (150 g/L). Under the studied nickel laterite ore conditions, the most effective parameters for maximizing average agglomerate size and minimizing the amount of fines were found to be drum load and acid concentration, respectively. Drum speed had a statistically significant effect on minimizing the amount of fines. Maximum average agglomerate size and minimum percent fines (-1 mm) for gold ore occurred under the following conditions: drum load (19.3%), moisture (8.5%), time (2 min 15 s) and drum speed (40% critical). The most significant factors for maximizing average agglomerate size and minimizing the amount of fines for gold ore were found to be drum load, time and moisture.IntroductionSeveral heap leach operations have experienced problems in terms of poor recovery due to percolation issues caused by low-grade complex ores, tailings and clayey deposits. Poor percolation can lead to low metal extraction due to solution channeling or the development of impermeable/dead zones within the heap (Dhawan et al., 2012; Kappes, 2005). Improper heap building practices such as the use of loose agglomerates and inadequate attention toward the presence of clay minerals have been among the main reasons for percolation issues. During the transport of ore material, severe segregation of the material can occur. To overcome percolation problems, a major improvement was made through the introduction of agglomeration prior to ore placement. If the ore particles and agglomerates are of similar size, segregation can be avoided to a great extent (Dhawan et al., 2013; Kinard and Schweizer, 1987; McClelland and van Zyl, 1988). Agglomeration improves the uniform percolation of solution through ore heaps and is applicable to many ores, wastes and milled tailings (Bouffard, 2005; Dhawan et al., 2013). Manning and Kappes (2005) reported agglomeration/ stacking accounts for ~14% of the total heap leaching operating cost. The cost of binder is a primary contributor toward the total cost. Also, the lack of consistent quality control tests for agglomerate often leads to operational problems. The details are mentioned elsewhere (Dhawan et al., 2013). Considering the significant contribution of the agglomeration/stacking step toward the total heap leach operating cost, it is appropriate to study the agglomeration behavior and its optimization for two different ores. The reason to study the same parameters for different ores is the fact that significant variability in the agglomeration behavior of different ores has been reported to exist in industrial operations."

Jan 1, 2015

By John F. Burst

For several generations now, the high alumina clayey sediments of Southeastern Alabama and Southwestern Georgia have supplied those regions with steady, mineral-based income although the impact of that income has been relatively minor until recently. Since World War II, mining activity has increased algebraically with over half of the total ore value in the Alabama area having been recovered since that time. The Georgia area production increases are even more dramatic. The trends are continuing and the next decade should see ore winning figures which will dwarf all previous production. It's time for the mining engineers to take note of this development as the mining methods, similar to the production, have developed rapidly and now offer challenges for the most competent professional. The development of mining techniques has followed a classic pattern. Beginning almost a hundred years or so ago, with the loading of weather-resistant surface boulders into mule-drawn wagons, mining methods have progressed to discovery of limited surface exposures in outcrop and eventually to stripping and development of non-obvious, subsurface deposits. Little by little, the overburden thickness of new pits has increased until, at present, pits with 100' -125' of overburden are being actively worked. Ground water problems in the Eufaula District are particularly challenging. At A. P. Green's J. W. Baker Pit, #l, in Barbour Co., Alabama, it is necessary to continually pump groundwater at the rate of about 400 gallons per minute from wells on the periphery of this large pit in order to keep the water table low enough to allow mining of the ore body.

Jan 1, 1972

By J. Fisher, M. Barish

Over the past several years, Somerset International has successfully installed over 20 patented Sub325® Fine Coal Recovery Systems in the United States, Australia, Canada and Russia. These installations recover between 5 TPH and 40 TPH for the host sites. In addition to the increased revenue from the direct recovery of a recirculating load (Screen Bowl “Insurance”, Direct Recovery vs. Indirect Recovery via Recycle, CPSA 2020), host sites have seen benefits ranging from improved operation of refuse equipment to a reduction in the solids content of the refuse streams. As Somerset has improved ultra-fine coal recovery through the introduction of Sub325® Effluent Flotation and, most recently, the Sub325® Effluent Settler™, the amount of coal that has been recovered from these systems has increased by up to as much as 25%. Many host sites have taken a sense of ownership in the Somerset system and consider it to be a critical circuit in the overall optimal performance of the plant. In the past year, Somerset has taken the initiative to expand upon the capabilities of the Sub325® Fine Coal Recovery System, primarily the Sub325® Solid Bowl Centrifuge, to include Refuse Tailings Dewatering to allow for co-mingled refuse disposal. As slurry ponds and boreholes are becoming difficult to impossible to permit and operate, there is a need for a reliable, low-maintenance, continuous operation that can produce a handleable refuse cake. Refuse tailings disposal applications are by no means limited to coal plants and impoundments. Somerset has successfully tested at iron ore and phosphate locations throughout the world and have begun commercial installations. The ability to dewater -325 mesh material, whether it be coal, coal refuse, iron ore tailings, or something else, is a vital piece of processing capability for the continued production of mining operations across the globe. This paper highlights the success that Somerset has had in the coal industry worldwide as well as the initial successes with phosphate, iron ore, and copper tailings (patent pending).

Mar 2, 2022

By Joel L. Morrison

The preparation of coal-water slurry fuel (CWSF) has the potential to be a commercially viable technology for the coal industry. The technology base required to prepare stable CWSF using grinding circuits has been developed over the past decade and is now being applied to the preparation of CWSF from wet coal fines which are generated during coal beneficiation. When preparing CWSF, the optimum CWSF formulation must be determined to ensure that the fuel will be stable while having acceptable atomization and combustion properties, and the production run must be monitored closely to ensure that the CWSF quality is maintained. This paper describes the CWSF formulation process, CWSF preparation circuits, and some of typical problems encountered in, and solutions to, the transportation and storage of CWSF.

Jan 1, 1993