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By Y. M. Jiang

Many underground instabilities, such as excessive shield loading and roof falls, occur at longwall faces causing safety problems and production losses. Such instability problems are directly related to roof conditions which can be categorized using geological information. . However, most geologic information describing anomalies and variations of immediate and main roofs are not available before mining resulting in unexpected problems in a longwall face. It is apparent that the evaluation of these geologic anomalies provides a great benefit for longwall stability. The purpose of this study is to evaluate roof categories associated with geological anomalies employing fuzzy set theory. The evaluation is based on real-time monitoring information, such as shield leg pressure, developing load on shields, intervals of periodic weighting, and the ratio of developing loads during periodic to normal times. This paper introduces the application of fuzzy set theory for characterizing roof conditions and evaluating of roof similarities.

Jan 1, 1995

By Andrew Neale

ERIC GUTIERREZ: With that, we'll go ahead with the final speaker of the day, Andrew Neale. Andrew has a master's of science degree in mineral processing from the University of Alberta. He worked at the Falconbridge in Sudbury area, also at Brenda Mines, and then he became part of the Brenda Process Technology group in British Columbia. He joined Freeport in late 1993 in Indonesia, and was involved in process control and automation. He is now the senior manager of metallurgy in New Orleans. He's responsible for designing Freeport's new 100,000-ton-per-day expansion concentrator, which is currently being commissioned. Please welcome Andrew. ANDREW NEALE: With the ongoing explosion in digital computing power, there seems to be no limit to what can be modeled, simulated, and controlled in the mineral processing plant. However, at each stage of development of a control system, it is necessary to complete a cost-benefit analysis for justifying the move to a higher level of control. Incremental improvements in plant performance, while often significant, must be weighed against the costs of implementation and long-term maintenance. This presentation will provide examples of what the author believes are misplaced or misguided process control efforts and make a case for the KISS principle as applied to process control.

Jan 1, 1998

By D. PATIL, B. K. Parekh

Water is the mainstay for the beneficiation of fine-size coal and minerals, but it is also the least desirable constituent of the final product. The basic concept of the novel process described in this paper is based on the differential surface heat absorption capacity of the individual particles. When a differentially heated solid mixture is placed on a moving belt that has been coated with low-temperature melting resin, the hotter component of the mixture will stick to the belt while the relatively cooler component will stay free on the belt and fall off at the end of the belt run. Experiments were conducted with pyrite, coal and quartz particles of 6 × 18 mesh size. The goal of the test program was to find the optimum conditions at which there exists a required temperature difference between minerals and coal particles by controlling the operating and system variables. Preliminary test results show that there is a potential for separating mineral matter from coal using the thermo-adhesive separation technique.

By Bryant Fitch

This paper will review thickening theory, from the ( ) of the practicing engineer, with particular emphasis on ( ) uncertainty or disagreement. It will attempt to outline broadly what we know and what we don't know. This should serve two purpose First, it will warn the process engineer where he might get into trouble. At least it will alert him to the risk involved in uncritically accepting any of the recommended design procedures. Second, it will identify for researchers some areas in which further work might be fruitful. Not too many years ago there would have been little to write on such a subject. We had been designing thickeners for decades, using the classic Coe and Clevenger procedure. As far as we were generally aware, they all turned out to be about the right size. And so if there was anything we didn't know, It certainly wasn't hurting us much. Today we know better. While it is true that in most cases units designed by the Coe and Clevenger procedure (1) will perform satisfactorily, we now know of cases in which they don't. And during the past few years there have been many developments and advances in basic thickening theory. So there is now a lot more room for disagreement, and a whole lot more to be uncertain about. What is "thickening" "Thickening" means different things to different people. For this paper we define it to mean sedimentation behavior characterized by line settling. Solids subside with a clear line of demarcation between settling solids and supernatant. Although the supernatant will usually be clear, in some cases it may be turbid. Line settling must entail that all particles just below the pulp-supernatant interface have the same subsidence rate, so that

Jan 1, 1971

By O. J. R. Baena, N. J. Zapata

In Colombia, more than 15 regions and around 100 municipalities develop gold mining at different scales, and these operations generate mining waste composed of processing fluids and crushed rock with metals and high silica content. Cement production requires clinker, gypsum and other corrective additives. Clinker results from the partial fusion of some minerals including silica. In this study is proposed to evaluate the effect of the use of mining tailings sands from gold mining in the manufacture of clinker. The proposed methodology will allow the characterization of the sands to manufacture a cement specimen and measure its physical and fire properties

Mar 2, 2022

By Faruk Oksuz, Cary Hirner, Ray Brainard

"Key project participants, including owners, engineers, and contractors continually seek for sound and structured decision analysis on how to select the best contracting method for successful project delivery. In addition to being burdened with technical challenges, lack of resources, budget shortcomings, regulatory requirements, and bureaucratic and politically mandated obstacles, the project participants need a reliable decision analysis model on the best project delivery method. The pendulum of choice for contracting continually swings back and forth between traditional design-bid-build and alternative delivery options such as design-build, progressive design-build, construction manager at risk, and public-private-partnership. For large tunnel projects, the decision process is further complicated due to contract packaging options as well as risks in underground construction. Contracting strategies for large tunnels require thorough consideration of performance, risk, quality, operability, cost and schedule. This paper compiles an array of decision making criteria and tools for an unbiased and balanced evaluation and ranking system in the procurement of large tunneling projects. INTRODUCTION Successful project delivery hinges upon meeting the owners’ expectations and key performance indicators. Large tunneling programs benefit from a thorough understanding and successful implementation of project delivery options by key project participants including the owners, engineers and contractors. The key to success is a collaborative advancement of project as the key project participants knowledgably address the applicable management, performance, risk, quality, cost, operability and schedule considerations throughout a project realization cycle. PROJECT REALIZATION CYCLE All projects have customary planning, design, construction, commissioning and operation phases that may seem to be sequential but in reality that are well integrated and dependent on one another. A glitch in any phase of a project realization cycle could hinder a successful outcome and none of the project partners are immune to consequences whenever and wherever they may surface."

Jan 1, 2016

By Aixiang Wu, Minjie Zhang, Zhuen Ruan, Yiming Wang

 The paper combines theoretical and experimental analysis to improve the accuracy of predicting paste yield stress by slump flow. It derives an analytical model of slump flow for yield stress, providing a theoretical basis for quantifying the rheological properties of paste with slump flow. The study uses three different tailings-prepared pastes and constructs an empirical yield stress model, showing high accuracy and good generality.

Aug 1, 2023

By Donald J. Reining

The California Surface Mining and Reclamation Act (SMARA) is the nation's first legislation establishing a statewide mineral resource policy governing mining activities that recognizes regional needs and retains local autonomy. The Southern California Rock Products Association supported this proposed legislation. It was through our efforts that SMARA was passed in 1975. The local planning and zoning processes, which are so critical to the mining industry, have been significantly improved with implementation of SMARA. Recognition of the importance of the mining industry is now being developed by the State Mining and Geology Board and the California Division of Mines and Geology (CDMG).

Jan 1, 1984

The 25th Peruvian Mining Convention (Convención de Ingeneieros de-Minas del Perú) was held Sept. 10-14, 2001, in Arequipa, Peru. The biennual meeting, sponsored by the Peruvian Institute of Mining Engineers (Instituto de Ingeneiros de Minas del Peru), is designed to showcase the Peruvian mining industry and to ?promote progress in the national mining sector.? The convention consisted of technical sessions, forums, field trips and social activities. The technical sessions featured 80 papers selected from more than 200 papers submitted. The well-organized 2001 meeting was held at the Tecsup Institute of Technology of Arequipa. The meeting was held in conjunction with Exposición Technologica Minera (Extemin), a mining trade exhibition. The2001 Extemin had representatives from more than 400 companies in attendance. In addition to the many Peruvian companies present, the trade exhibition featured pavilions representing the United States, Canada, Germany, Australia and Chile. Registration at the 2001 meeting was about 3,300, a conference record. The theme for the 2001 meeting was Mining: Society and Development. Mario Brescia was chairman of the organizing committee. He said in his opening remarks that ?this year?s meeting seeks to emphasize the commitment on the part of the [mining] companies to treat our natural resources responsibly, controlling any adverse impacts and giving priority to group benefits.? Consistent with this theme, many of the technical papers stressed environmental and social responsibility. Many successful examples of environ-mental and social responsibility on the part of the mining industry were presented in the technical sessions.

Jan 1, 2001

By W. J. Kennedy

Energy management in industry has recently achieved notice as a way to reduce costs without decreasing production. The same approach used in industry can be used in mining, even though the processes are different. This approach is based upon a three phase system of data collection, implementation, and monitoring, all aimed at gathering and evaluating information in such a way as to have a maximum impact on energy costs. This approach has these advantages: (1) attention is directed toward the part of each mining system where the most energy is used, (2) input is collected systematically from all persons involved in the operation of each system, and (3) a means of monitoring the progress toward established goals is created. The mining systems considered are truck haulage, conveyor haulage, blasting and crushing, and lighting. After describing the general procedure, the authors have described a specific method for improving the efficiency (and hence the energy consumption) of round-trip truck haul age systems.

Jan 1, 1982

By N. J. Keys

This paper concerns the development and application of a high throughput multi-stream photometric sorting machine developed for the South African gold mines. It is now believed that this sorter and its progeny may be found suitable for a large proportion of all possible sorting applications. A laser light source and sensitive photomultiplier are employed in a scanning system to detect light reflected from the surfaces of rocks passing through the sorting zone. Electronic circuitry then analyzes the photomultiplier signal, which represents the varying intensity of the reflected light, and produces control signals to actuate the appropriate valves of an array of air blast rejection devices to remove from the feed certain particles selected by the analyzing process. Typical throughput per machine ranges from 50 tons/hour for a-2 ½? + 1 ¼? feed to 200 tons/hour for -6" +2 ¾ " material.

Jan 1, 1974

By R. J. Beltrame

The Cuyuna range, located in east-central Minnesota, consists of a sequence of argillite, siltstone, iron-formation, graywacke, slate, and quartzite of early Proterozoic age. Manganese-bearing materials occur within the iron-rich strata of the Trommald Formation and the Rabbit Lake Formation. Computer-assisted resource estimates, based on exploration drill hole information, indicate that the Cuyuna range contains a minimum of 176 million metric tons (Mt) of marginally economic manganiferous rock with an average grade of 10.50 weight percent manganese. The calculated 18.5 Mt of manganese on the Cuyuna range could supply this country's needs for this important and strategic metal for 16 years. An additional resource of 6.9 Mt of manganese metal is available in the lower grade deposits. The majority of these calculated resources are extractable by current surface mining techniques.

Jan 1, 1981

By J. Simmons, P. Ziemkiewicz

Acid-Base Accounting (ABA) is an analytical procedure that provides values to help assess the acid-producing and acid-neutralizing potential of overburden rocks prior to coal mining and other large-scale excavations. This procedure was developed by West Virginia University scientists during the 1960s. After the passage of laws requiring an assessment of surface mining on water quality, ABA became a preferred method to predict post-mining water quality,and permitting decisions for surface mines are largely based on thevalues determined by ABA. In order to predict the post-mining water quality, the amount of acid-producing rock is compared to the amount of acid-neutralizing rock, and a prediction of the water quality at the site (whether acid or alkaline) is obtained. We gathered geologic and geographic data for 56 mined sites in West Virginia, which allowed us to estimate total overburden amounts, and values for maximum potential acidity (MPA), neutralization potential (NP), net neutralization potential (NNP), and NP/MPA ratios for each site based on ABA. These values were correlated to post-mining water quality from springs or seeps on the mined property. Overburden mass was determined by three methods, with the method used by Pennsylvania researchers showing the most accurate results to actual overburden mass. A poor relationship existed between MPA and post-mining water quality, NP was intermediate, and NNP and the NP/MPA ratio showed the best prediction accuracy. In this study, NNP and the NP/MPA ratio gave identical water quality prediction results. Therefore using NP/MPA ratios, values were separated into categories: <1 should produce acid drainage, between 1 and 2 can produce either acid or alkaline water conditions, and >2 should produce alkaline water. On our 56 surface mined sites, NP/MPA ratios varied from 0.1 to 31, and six sites (11%) did not fit the expected pattern using this category approach. Two of eight sites with ratios <1 did not produce acid drainage as predicted (the drainage was neutral), and four of 40 sites with a ratio >2 produced acid drainage when they should not have. These latter four sites were either mined very slowly, had non-representative ABA data, received water from an adjacent underground mine, or had a surface mining practice that degraded the water. In general, an NP/MPA ratio of <1 produced acid or neutral drainage sites, between 1 and 2 produced mostly alkaline drainage sites, while NP/MPA ratios of >2 produced alkaline drainage with a few exceptions. ABA is a good tool to assess overburden quality before surface mining and to predict post-mining drainage quality after mining. The interpretation from ABA values was correct in 50 out of 52 cases (96%), excluding the four anomalous sites, which had acid water for reasons other than overburden quality.

Jan 1, 2003

By YUSONG MIAO, DI WU, XIANRONG YAN, YIPING ZHANG, JIE LIN, KEBIN LI

Rock fragmentation has been a concern in hard-rock mining for the mining industry. Rock fragmentation distribution is an important index to measure the blasting effect. It not only affects the cost of drilling and blasting, but also affects the efficiency of subsequent operations, such as loading, transportation and secondary crushing.

By W. Blake, J. Whyatt

Sixty years of rock bursting in the Coeur d&apos;Alene district has taught painful lessons and led to a number of practical advances in controlling rock-burst hazards. This paper summarizes these lessons, concentrating on practical measures that have been successfully adopted to reduce hazards. These lessons are explained in the context of district mining history and current understanding of rock-burst phenomena. Overall, the paper provides the practicing mine engineer with an appreciation of rock-burst hazards and an overview of practical measures that can be used to control these hazards in the context of Coeur d&apos;Alene district experience.

Jan 1, 2003

By H. F. King

In 1982, the result of a 3-year study was published as "A Guide to the Understanding of Ore Reserve Estimation". The principal conclusions were that computation formed only part, and perhaps not the most important part, of an estimate and that the estimate should recognize that geological, mining engineering and metallurgical judgements formed an essential part of the eventual result. Subsequent expectation/realization studies of several mines have produced case histories which form the principal basis of the paper. These imply that geology is even a larger factor than thought earlier.

Jan 1, 1985

By Madan M. Singh

It is estimated that through 1975, there were 1.69x109 m2 (418 000 acres) of urban land threatened by potential subsidence due to mining with a value of over $12 billion (19;3 dollars; USBM, 1979). With increased coal production to meet the energy needs of the nation, both these figures may be expected to increase. Hence greater attention to controlling surface damage due to subsidence is merited. In fact, the Surface `lining Control and Reclamation Act of 1977 (SMCRA) (Public Law 95-87) mandates that underground coal mining operators "adopt measures consistent with known technology in order to prevent subsidence causing material damage to the extent technologically and economically feasible, maximize mine stability, and maintain the value and reasonably foreseeable use of such surface lands, ..." The term "subsidence," as used in this paper, implies the total phenomenon of surface effects associated with the mining of minerals, and not only vertical displacement of the surface as is sometimes inferred in the literature.

Jan 1, 1984

By Terry I. Mudder

Metal complexed cyanides in wastewaters form as a result of interactions of free cyanide with metals present in the wastewater and exhibit varying degrees of stability, toxicity, and treatability. Thiocyanate, a pollutant commonly found in cyanide bearing wastewaters, is formed through the interaction of free cyanide with sulfur containing species (i. e. pyrrhotite) both present in the wastewater. In certain industrial processes, such as the beneficiation of gold and silver, cyanide is an essential reagent. Since free cyanide, complexed cyanides, and thiocyanate are potentially toxic to humans and aquatic organisms, these compounds must be removed from wastewaters prior to their discharge into surface or ground waters serving as potential potable water sources, marine or fresh water habitats

Jan 1, 1984

By W. J. Guay

Carbonaceous gold ores containing gold dispersed in sulfides are refractory to cyanidation because: ( 1) the carbonaceous materials adsorb gold during cyanidation; (2) a portion of the gold is so finely dispersed in the sulfide mineral lattice as to preclude contact with cyanide solution; and (3) a portion of the gold is chemically combined with carbonaceous material. Techniques which have been used to treat these ores are: (1) roasting or chemical oxidation to decompose sulfides and carbonaceous materials; (2) flotation to reject carbon; (3) the use of kerosene or other reagents to passivate the adsorptive carbon compounds; (4) carbon or resin in pulp; (5) flotation of a bulk concentrate which is treated by one of the above methods; and (6) the use of chelating agents which have a stronger affinity for gold than the activated carbon in the ore.

Jan 1, 1981

By James Withers, Dongbo An, Jinhong Zhang

A micro-scale investigation was carried out by applying an atomic force microscope (AFM) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy to study in situ the adsorption of three different collectors — oleic acid, octanohydroxamic acid (HA) and salicylhydroxamic acid (SHA) — on bastnaesite in aqueous solutions. The results show that all three collectors adsorb on bastnaesite. The hydroxamic acid collectors — HA and SHA — adsorb on bastnaesite mainly in the form of insoluble metal hydroxamate. Their specific adsorption mechanism indicates that high selectivity will be achieved with a hydroxamic acid collector for the flotation of bastnaesite.