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By Douglas W. Fuerstenau, Pradip Pradip

The design and development of selective flotation collectors has been the key to the remarkable success of flotation in beneficiating complex, difficult-to-process ores. It remains a challenging area of contemporary research in mineral processing.

By Taghi Sherizadeh, Kutay E. Karadeniz, Dogukan Guner, Samuel Nowak

Despite numerous empirical, numerical, and hybrid studies conducted on the subject of coal rib failure, mine fatalities related to rib failures continue to occur. To date, a standard methodology for the design of coal rib supports which can accommodate the wide range of unique conditions found in coal mines in the United States has not been developed, forcing mine operators to rely on the trial-and-error process or industrial legacy practices for the design of coal rib support patterns. In this study, to better understand the support systems' effectiveness, various rib bolting scenarios were investigated. A coal mass constitutive model is implemented to a Distinct Element Method (DEM) code, and rib factor-of-safety (RibFOS) analyses were performed by applying strength-reduction for the coal matrix and explicitly modeled face cleats. Ribs with various overburden depths and mining heights composed of solid Banded-Bright coal (BBC) were considered in this study. Different scenarios such as rib bolt length and the number of bolts were studied to quantify the effect of primary rib support density on rib stability. As a result of the unsupported coal rib analyses, a decaying exponential relationship is proposed between the mining height-overburden depth and the RibFOS. The developed coal rib models clearly show the coal-rib bolt interaction and illustrate how the addition of rib bolts restricts the movement of the coal rib. The results reveal that the strength reduction method in DEM code with the coal-mass model can aid in the development of practical primary support charts, which can help in the rib support design process. In addition, an unsupported RibFOS cutoff

By F. Ansheng

Though it becomes increasingly important with the valuable minerals in their deposits tending to be fine and poor, the solid and liquid separation remains difficult especially when the particles are of micrometer size and of low density. Almost of all conventional thickeners result in that fine particles lose into overflows which often costitutes a loss of potentially valuable resources as well as an environmental hazard. The addition of flocculations may improve the settling of solids but may also not work well for the final removal of fine particles from the overflows (Ref.1).

Jan 1, 1990

By F. A. Baczek

The Electroslurry TM electrowinning concept has been incorporated into a process flowsheet for recovering copper from smelter flue dusts. The process has averaged 96% recovery of the copper as high-grade electrowon while at the same time removing a majority of the impurities that degrade drawn copper as a result of recycling flue dust and liberator cathodes: The dust is processed through several stages consisting of leaching, copper precipitation, Electroslurry TM electrowinning and waste liquor treatment. The process may be integrated into a smelter operation and become an effective and feasible means of maintaining good product purity.

Jan 1, 1980

By P. M. Yavorsky

Using a mine roof simulator press capable of duplicating the expected magnitude of vertical and horizontal forces experienced by underground mine roof supports, load capabilities of some roof support cribbings were measured. Comparative ultimate vertical support strengths are reported for cribs of old and new timber and nonreinforced and steel-fiber-reinforced (SFR) concrete blocks. In terms of load- bearing capability, cribs of new hickory and nonreinforced concrete blocks have about equal strength, and SFR concrete blocks are three times as strong. Wood aged 2 years underground lost 43 pct of its support strength. These data were obtained during the course of the initial familiarization exercise of the complex press.

Jan 1, 1984

By D. L. McCain

The movement of solids by pipeline is an art dating back well over 100 years as evidenced by many references in the literature. Even though all of the early pipeline transport systems were based on trial and error and relied mainly upon the designer's experience, hydraulic transport offered distinct advantages in convenience or cost for the chemical, mining, and civil engineering industries. It became well established for in-plant process lines, dredging, waste disposal, and other uses almost exclusively for short distances. During more recent times, much research work has been done in an attempt to understand the underlying principles involved in transporting solids in a fluid. Design criteria for pumping slurries have evolved to the point where pipelines designed for distances of several miles to several hundred miles can be accomplished successfully. Consolidation Coal Company designed and built a 10-inch diameter 108-mile long line1 for transporting coal in the 1950's and operated it from 1957 to 1963 when it was placed in mothballs because of falling freight rates for rail shipment. More recently, the 273-mile Black Mesa Pipeline2 was built and is operating. There are other examples of long distance pipelines,3 but all are for specially prepared fine slurries which allow the pipeline to be operated more economically.

Jan 1, 1975

By K. Louk, E. Gilliland, N. Ripepi, M. Karmis

"Carbon dioxide (CO2) injection in deep unmineable coal seams can enhance coalbed methane (CBM) recovery as well as effectively and permanently store the CO2. Enhanced coalbed methane (ECBM) recovery and CO2 storage capacity can be improved by altering injection parameters including the injection well locations, number of injection wells, and the time and rate of the injection. A sensitivity study was performed with sixteen different injection scenarios on a coalbed methane field in Buchanan County, Virginia to understand the influence of the injection parameters on methane production, CO2 storage and the extent of the CO2 plume. History matching was done for the gas and water production period prior to injection based on field data from an active US Department of Energy funded pilot project. INTRODUCTION The coal structure is a combination of the coal matrix and cleats. In a CBM reservoir, the methane (CH4) is stored in the matrix under adsorption properties, not as a free gas. During CH4 production, the reservoir pressure is reduced and gas is released from the surface of the coal, diffuses through the matrix and transmits to fractures (man-made or natural) via the cleat network. Fractures and cleats are the major parameters that influence gas flow capacity because deliverability of the CH4 to the production well is controlled by the cleat permeability. As gas production continues over time, CH4 desorbs from coal, and coal matrix volume starts to decrease. This volume decrease in the matrix opens up the cleats, matrix shrinkage, which leads to a permeability increase. Several emprical (Harpalani and Schraufnagel 1990a, 1990b; Harpalani and Chen 1995, 1997; Harpalani and Mitra 2010; Pan et al. 2010; Liu et al. 2012; Mitra et al. 2012) and analytical (Palmer 2009; Liu and Harpalani 2013) studies have reported this relationship between pressure and permeability. Those studies showed that permeability is an important parameter in CH4 production performance. Furthermore, during gas production, water is produced through the cleat system as well, therefore gas-water relative permeability must be also considered in evaluating production performance (Gash et al., 1991). In the CO2 injection scenario the opposite occurs because CO2 has a higher adsorption affinity than CH4. CO2 replaces CH4 in the matrix of the coal and increases the volume of the coal matrix, matrix swelling, and results in a permeability decrease. Harpalani and Mitra (2010) concluded in their experimental study that swelling of the coal matrix due to the CO2 injection is two to three times more than the sorption of CH4, resulting in large permeability changes during CO2 injection."

Jan 1, 2016

By G. H. Harris

The flotation behavior of two high sulfur coals using a non-ionic surfactant as collector from two series of compounds containing oxygenated functional groups was studied in detail using a 2-liter Denver flotation cell. The performance of these reagents was compared with that of an oily collector, namely dodecane. The results showed that at the same coal recovery, a much lower dosage of these non-ionic surfactants was required as compared with that of dodecane. More import was the performance of these compounds as promoters for oxidized as well as un oxidized coal. Mechanisms of interaction of these compounds with the coal are suggested.

Jan 1, 1993

By Paul C. Lingo

The title of my talk today might lead you to two logical conclusions: The industry is faced with a problem that requires a solution and after discussing the problem I will offer a solution. The first conclusion is painfully accurate. One need only look at the accident statistics to be aware of the problem. During the eight-year period 1954 through 1962, the United States Bureau of Mines reports that falls of rock and coal accounted for 1,435 of the 2,516 fatal injuries that occurred in underground bituminous coal mines. Some improvement was made during 1962. For the first time since records have been kept, falls of rock and coal accounted for less than 50 per cent of the underground fatal injuries. The 105 deaths recorded in 1962 indicate that a great amount of work remains to be done in this area. As to the second conclusion, let me assure you at the outset that I have no panacean solution; however, I do propose to discuss some aspects of the problem and some possible methods of solution. What methods of solution are now, or have been employed in attempting to solve the problem? More specifically, what methods have you and your associates used? Has it been an orderly well thought out approach to the entire problem, or has it been a somewhat piecemeal approach which tackled the immediate problem and left the total problem for another day? Perhaps a new approach may be in order.

Jan 1, 1964

By Henry E. Swanson

In the early 1960's the Company, then named the United States Smelting Refining and Mining Company, was drilling the Continental ore body located near Fierro, New Mexico. Reserves of underground ore of sufficient quantity were indicated to build a mill. At the same time some ore from the Continental No. 1 mine was being milled at the Company's Bullfrog Mill, formerly a lead-zinc mill. The copper ore in comparison to the lead-zinc ores was very hard, abrasive, and heavy. These factors pointed out the possibility and attractiveness of autogenous grinding. While prior to this some study had been given to autogenous grinding, no large scale tests had been made. Such a program was carried out and from the pilot plant data the following was established: 1. Grinding of the ore by autogenous means could be accomplished. 2. This could be done in one stage; however, not at a satisfactory tonnage throughput rate. Thus, the use of a secondary unit has been employed. 3. Grinding in the secondary unit could be done by pebbles generated in the primary unit. This resulted in the scheme whereby the ore would be ground 100% autogenously. 4. Liberation of the copper minerals was excellent so that good recovery at a satisfactory concentrate grade would be obtainable.

Jan 1, 1976

By J. E. Sepulveda

Tar sand deposits in the. Stare of Utah contain more than 25 billion barrels of in-place bitumen, Although thirty times smaller than the well-known Athabasca tar sands, Utah tar sands do represent a significant domestic energy resource comparable to the national crude oil reserves (31.3 billion barrels), The term "tar sand" refers to a consolidated mixture of bitumen and sand, Based upon a detailed analysis of the physical and chemical properties of both the bitumen and the sand, a hot-water extraction process for Utah tar sands is currently being developed in our laboratories at the University of Utah. This process involves intense agitation of the tar sand in a hot caustic solution and subsequent separation of the bitumen by a modified froth flotation technique., Experimental results indicated that, for a given tar sand sample, percent solids and caustic concentration were the two most important variables controlling the performance of the digestion stage, These variables were identified by means of an experimental, factorial design, in which coefficients of separation greater than 0.90 were realized. Although preliminary in nature, the experimental evidence gathered in this investigation seems to indicate that a hot-water extraction process for Utah tar sands would allow for the efficient utilization of this important energy resource.

Jan 1, 1978

By R. R. Klimpel

The efficiencies of plant scale comminution processes are often evaluated by various indices that are calculated and/or measured somewhat independent of the performance of any associated downstream froth flotation processes. In order to compare some specific comminution factors such as energy utilization, media consumption, equipment utilization time, etc. comparisons of comminution efficiency independent of flotation behavior are appropriate. However, as more and more detailed plant level information is gathered on the joint and highly interactive nature of comminution and froth flotation, it is becoming increasingly obvious that knowing and using simple efficiency indices are not enough. What is needed are more performance related measures of the efficiencies of the combined size reduction -froth flotation system for effective plant level economic optimization to occur. The purpose of this paper is to present some examples of important interactions that influence the joint efficiencies of size reduction and froth flotation processes.

Jan 1, 1998

By Yang Ge, Yuzhu Pan, Mansheng Chu, Jue Tang, Cong Feng, Lihua Gao, Zhenggen Liu

Increasing attention is being paid to laterite nickel ore as an alternative to nickel sulfide ore to act as a feedstock for nickel metal production. While laterite nickel ore accounts for a lion’s share of global nickel resources at approximately 72 percent, it accounts for only 42 percent of the world’s nickel production. In addition, the processing of nickel sulfide ore is confronted with enormous challenges due to deeper drilling requirements, higher production costs and depleting reserves. The nickel content in the nickel laterite ore associated with hydrated iron oxides and silicate minerals limits the application of physical beneficiation methods for the removal of iron. Thus, magnetic reduction roasting followed by magnetic separation has been regarded as one of the attractive routes to concentrate and separate the valuable metals from the impurities. 

By S. J. Zagula

Improved desulfurization of Illinois coals is a widely Shared research goal. The development of a physical cleaning strategy and the results of a project to demonstrate technical and economic feasibility of producing a low sulfur compliance coal from the Illinois Basin are reported. Processing flowsheets to extend or retrofit existing preparation plants are considered. Comminution, conventional and micro-bubble flotation, and selective agglomeration technologies were investigated to maximize pyrite rejection while maintaining high product yield. Batch bench scale testing was followed by continuous pilot plant studies. Parameters included grind size, flow rates, pulp density, aeration, agitation, and reagent dose. An economic evaluation of targeted processes is included.

Jan 1, 1987

By Euclid P. Worden

In 1977, an article in World Mining (1) reported a total of 2726 rotary blast hole drills in service. This figure included only those machines produced by three of the manufacturers building drills of this type. The total, therefore, is much higher: Rotary drilling in the mining industry is big business to the manufacturers and suppliers involved, and a significant cost item, to mine operators. The time has come to take a hard look at rotary drilling technology with an eye to re¬ducing costs by increasing drilling efficiency. The efficiency of any rotary drilling operation is measured in terms of the rate of penetration achieved by the bit. In blast hole drilling, five factors affect the rate of penetration. They are: 1. Bit selection 2. Weight on the bit 3. Rotary speed 4. Hole cleaning 5. Formation properties Of these factors, all but one may be control¬led by the operator. Looking at any one in detail may reveal possible improvements in the system. Cleaning the hole is a good place to start. In order for a bit to perform at its maximum capability, each tooth or insert should strike fresh, clean rock as it falls into its drilling position. If the tooth or insert lands on previously drilled cuttings, a major portion of the energy delivered to the bit is absorbed in re drilling this broken material. A major portion of the interest, therefore, should be directed to the proper cleaning of the bottom of the hole.

Jan 1, 1979

By A. J. MacKellar

The economic viability of any project is generally assessed on an evaluation of the total capital constructed costs along with operating costs, owner's costs and market conditions. This paper will be directed to the role that Cost Engineering plays in the development of the capital costs and the cost control techniques applied thereto.

Jan 1, 1975

By M. R. Peterson

The U.S. Bureau of Mines (USBM) is investigating alternative methods to strip metal-loaded solvent extractants. Hydrolytic, precipitation, and hydrogen pressure stripping all recover metal or metal salts directly from the organic solvent extractant. Pure metals, metallic oxides, or metal salts can be formed, allowing direct production of value-added products. Aspects affecting commercial application are emphasized, including metal recovery from actual ore leach solutions, particle size control, organic modifier and diluent effects on stripping and metal recovery efficiencies, metal grade, seed addition, mixing intensity, recycling efficiency, and reactor plating. Metal separations from copper ore leach solutions and complex waste leach solutions were examined.

Jan 1, 1995

By Dae Young Kim, Sim Bo Kyung, Ebrahim Farrokh, Ki Chang Hyun

"TBM cutter life evaluation in abrasive granitic rocks is a very important issue, especially in pressurized face tunneling with mixshield TBM for which the planning of costly interventions becomes crucial. This paper presents an overview of methodologies for cutter life evaluation in rock. A comparative study is performed to indicate the predictability of cutter life evaluation methods based on detail data from the NS3 tunnel project in Singapore. A new model is developed based upon the cutter wear information of eight TBM tunnels from around the world. New methods are proposed to evaluate the optimum intervention interval length and the number of worn-out disc cutters for a tunnel project. Finally, two new laboratory tests in the evaluation of disc cutter abrasion, including a full-scale and a small-scale test, are introduced, and their test results are discussed. INTRODUCTION The issue of wear evaluation for hard rocks has been extensively studied in drilling and pavement industry. In this regard, several tests and evaluation methods have been proposed to estimate or evaluate the state of tool life (e.g. bit life for drilling). In the case of TBM tunneling, tool wear may depend on several factors such as mineral composition, strength, or type of cutting, but as the abrasion is usually the major mechanism for the tool wear in hard rock, the developed methods for cutter wear or cutter life evaluation are mostly based on the abrasion indices such as Cerchar Abrasivity Index (CAI). This paper attempts to review the major methodologies for disc cutter wear and life evaluation and to propose new methods to evaluate cutter life and intervention interval evaluation based on detail information of a mixshield tunnel project in Singapore as well as general information of some other projects from Iran, Italy, South Africa, and France. As the laboratory tests are crucial in the process of evaluation, two new lab tests are developed and used to inspect suitability of the new proposed model for disc cutter wear evaluation."

Jan 1, 2016

By Subhas G. Malghan

The response of feldspar flotation to tallow diamine dioleate collector in the presence of sulfuric acid is studied using batch flotation experiments. Application of this non-hydrofluoric acid (non-HF) reagent system in the flotation of mineralogically and chemically different feldspar ores is compared with that of the conventional hydrofluoric acid system. The dependence of flotation recovery and concentrate grade on feed particle size distribution, conditioning time, pulp density, and pH, combined variation of collector and acid addition rates, sodium hydroxide concentration in the collector solution, and initial pulp pH prior to conditioning is studied. The results have been discussed in relation to applicability of the non-HF system to plant trials, and the nature of the collector adsorption in the selective flotation of feldspar.

Jan 1, 1978

By J. D. Allen

The Concord Mine Coal Preparation Plant of United States Steel Corporation, located near Bessemer, Alabama, began operations in June, 1950. The basic cleaning circuit consisted of a Chance Cone for cleaning the 2-inch x 3/8-inch fraction and concentrating tables for cleaning the minus 3/8-inch coal fraction. Dewatering of the final product was accomplished with 35-mesh vibrating screens. However, because Concord coal is very friable (Figure 1), 85 per cent passing three mesh and 25 per cent passing 28 mesh, there was a considerable amount of fines passing through the dewatering screens. To recover these fines, the dewatering screen effluent was sent to two 70-foot diameter hydro-separators with the underflow returning to the dewatering screens and the overflow going to a 175-foot diameter thickener for water clarification, (Figure 2). As might be expected, there was a considerable amount of recirculation of the minus 35-mesh coal in this system. This degraded the coal and led to higher moistures. It also resulted in a fines bleed-off of plant water and thickener underflow to a fine-coal settling pond. In 1961, vacuum filters were installed to supplement the screens and to recover the fine coal lost in the bleed-off. The above system resulted in a product moisture of about 20 per cent. Further reduction to approximately 11 per cent was accomplished by drainage from railroad cars during transit to the coke plant. Control of the moisture at unloading was poor because of variations in operating levels and railroad car availability, but since the Concord coal constituted a smaller percentage of the coal previously used at the coke plant, the high moisture and fluctuations did not seriously hamper coking operations.

Jan 1, 1966