Search Documents

By D. A. Karvonen

Although the economy in the Province of Saskatchewan has historically been agriculturally oriented, a major new source of wealth has been realized through natural resources such as petroleum and natural gas, coal and uranium and since the 1960's - potash. Potash or potassium chloride, in the form in which it is presently produced in Saskatchewan is used primarily as fertilizer, a source of potassium, one of three essential elements required for healthy plant growth with about 5 percent of production sold to the chemical industry for use in such products as soap and liquid detergent, glass and ceramics, textiles and some pharmaceuticals. Saskatchewan is estimated to have approximately 40 percent of known world potash reserves and its ten active mines account for some 25% of annual world production. The development of this resource was recognized to be important to the development of Saskathcewan. In an effort to guarantee a fair and lasting economic benefit to the Province of Saskatchewan the Potash Corporation of Saskatchewan (PCS) was created on February 4, 1975 through an Order-in-Council under the Crown Corporation's Act and later on April 1, 1976, the Potash Corporation Act provided for its continuation. PCS was given the mandate to acquire ownership of a significant portion of the potash mining capacity in Saskatchewan and to establish an organization capable of operating the facilities, marketing the product and conducting all of the other activities necessary for a successful corporation competing in the world potash industry.

Jan 1, 1983

By Roland C. Walker

Traditional headed rebar has existed in the mining industry as a ground support product for many years. The head of a rebar bolt is most commonly produced by hot upset die forging. Upset die forging produces a rugged, simple head that performs well. Certain elements of the head must comply with regulatory standards, such as ASTM F432-95, which offers a standard test procedure to ensure quality of the product. The head style produced by all major manufacturers has been optimized to reduce manufacturing costs, provide greater miner safety and provide an excellent performing product. Observations were made in some mines of heads failing under in-situ loading. These observations could not be replicated according to the ASTM testing method. This paper highlights the problem and how a solution was developed. The development includes pictures of in-situ failures from the underground operations, laboratory replication tests indicating how this loading occurs, and then the use of this calibrated test method to validate the new design created.

Jan 1, 2009

More than 410,000 visitors from 171 countries helped bauma ’04 set new attendance records at the world’s largest construction machinery and mining technology show. The show, held in Munich, Germany March 29-April 4, marked bauma’s 50th anniversary. At the last bauma show in 2001, attendance was about 406,000 people from 157 countries. At bauma ’04, international attendance increased to 31 percent from 27 percent in 2001. In addition to record-setting attendance, bauma ’04also attracted 2,801 exhibitors, up from 2,341 in 2001. Exhibitors came from the United States, Europe, China, Japan and the Middle East. Exhibitor space topped 500,000m2 (5.4 million sq ft), another record. And, for the first time, there were more foreign exhibitors than German exhibitors, show organizers said.

Jan 1, 2004

By D. Malhotra

The number of variables which can effect flotation of molybdenite is very large. This paper discusses the effect of two operating variables, namely, the degree of aeration and agitation, on the grade and recovery of molybdenite. A series of factorially designed flotation tests were carried out in a "Leeds Automatic Laboratory Flotation Cell." The analysis of flotation results indicate that molybdenite can be characterized into fast-floating and slow-floating components. The rates of fast-floating components, which do not create a problem in flotation, could be varied by changing agitation of airflow rates. However, the rate of slow-floating components was stable and was only a function of residence time in the float machine. The degree of aeration has a significant effect on the grade of MoS2 with only a slight effect on the recovery of MoS2. The degree of agitation has a slight effect on the grade, but does not effect the recovery of molybdenite. The implications of the results on the design of flotation cells and control and optimization of the existing circuits is subsequently discussed.

Jan 1, 1977

By Frank C. Schora

The Institute of Gas Technology for many years has dedicated a large portion of its research effort to the development of a practical solid-fuel-based gasification process to produce a synthetic natural gas equivalent. The work is being done to prepare for the day when supplemental gas will be needed. This program, initially supported by the American Gas Association, and now by both the Department of Interior's Office of Coal Research and the American Gas Association, has developed the IGT Hydrogasification Process. This process, now entering the pilot plant stage, is based on the high-temperature, high- pressure hydrogenation of coal with a hydrogen-steam bearing gas. Product gas from this step is cleaned and catalytically methanated to produce a high-Btu gas. Estimated production costs indicate the process will be competitive with natural gas in certain areas of the country when required.

Jan 1, 1969

By J. G. Groppo, A. E. Bland, B. K. Parekh, W. F. Stotts

Many coal preparation plants discard fine coal (generally minus 100 mesh) because it is difficult to beneficiate economically. At the Kentucky Energy Cabinet Laboratory (KECL), the waste streams from several Kentucky preparation plants were evaluated for cleaning with counter-current column flotation. A series of performance evaluations were conducted using a 0.05 m (2 in.) internal diameter (I.D.) 7.9 m (26 ft.) high laboratory column. The objectives of these tests were to assess the performance in terms of recovery and percent ash in clean coal and to optimize the operating parameters relative to combustible recovery and grade. Refuse streams containing 30-50 percent ash were upgraded to 2-8 percent ash with Btu recoveries of nearly 90 percent. A pilot scale column flotation cell was installed at the Bell County Coal preparation plant. This pilot plant utilized a 5.79 m (19 ft.) high and 0.15 m (6 in.) I.D. column to verify the performance data of the 0.05 m (2 in.) I.D. column for two different waste streams. Performance evaluation and pilot plant testing results related to scale-up are discussed.

Jan 1, 1988

By George R. Stephans

The Climax Mine is a panel caving mine which has had a long history of incidents of severe ground control problems. The nature of the ore deposit, which lends itself to the caving meth- of of production, a1 so makes the mine susceptible to large scale stress concentrations which are referred to as ?weight? problems. These problems have increased with increased production and also with expansion to deeper mine levels. During the past twenty years the mine has had to learn to cope with these problems in order to remain in operation. A number of practical guidelines and useful techniques have emerged from these efforts. The purpose of this paper is to share a few of these ideas. The Mine is located near Leadville, Colorado on the continental divide at an elevation of 3450 meters. The ore body is a large low grade deposit of disseminated molybdenum sulfide. It measures about 1200 to 1600 meters in diameter and it had an original depth of about 660 mters. The Mine has been in operation since 1918 and the massive nature of the ore body together with its blocky, highly fractured condition made it natural for the caving system to have been adopted for production at an early date. Open pit mining was started in 1973. The total plant has a capacity of more than 50 thousand tons per day, and more than 400 million tons of reserves at an average grade of 0.310 percent molybdenum disulfide remain to be produced.

Jan 1, 1982

By Aruna Mangalpady, Sandeep Kumar Jeripotula, Govinda Raj Mandela

Injuries due to work-related musculoskeletal disorders (WMSDs) are not uncommon in heavy industry like mining. Researchers acknowledged that occupational exposure to ergonomic risk factors is the chief causative factor in the development ofWMSDs. The aim of this study was to perform an ergonomic assessment of musculoskeletal disorders among surface mine workers in India. Standardized Nordic Questionnaire was used to collect subjective response from 500 workers. A stratified random sampling method according to surface mining work activity type was used to obtain the sample. Data was collected by means of a structured questionnaire, and the Statistical Package for Social Sciences (SPSS) was used to analyze data using descriptive and inferential statistical methods. A response rate of 85% was obtained out of 500 targeted groups. TheWMSDs prevalence for the 12-month period was estimated to be 44.23%. The mean and standard deviation of workers’ age were 41.31and 8.927, respectively. The study has shown that the operators of dumpers, dozers, and graders along with electricians were found to be the most susceptible to developWMSD problems. Among the most affected body parts, back disorder reported the highest. Further, it was found that working with static posture over the longer duration has a significant association with the lower back disorder (with p = 0.020) and bouncing and jarring has also significantly associated with the lower back disorder (with p = 0.023). Similarly, a significant association was found between repetitive work and neck pain (with p = 0.016). The study depicted a significant association between ergonomic hazards and WMSDs, like working with prolonged static posture, bouncing and jarring, and repetitive work.

Mar 13, 2020

By Zhiyuan Ma, Yong Liu, Xianjin Lyu, Jianfang Lyu, Jikui Zhou

A stable and continuous leaching process for niobium and tantalum extraction from ferrocolumbium tantalum (FT) was developed. The effects of initial concentration of HF and H2SO4, grinding fineness, leaching time, and temperature on the leaching rate of Ta, Nb, Fe, and Si were studied. Experimental results show that the leaching rates of Ta, Nb, Fe, and Si were enhanced by the increase of acid concentrate, fineness, leaching time, and leaching temperature. The optimum process conditions are HF initial concentration of 5 mol/L, H2SO4 initial concentration of 2.5 mol/L, − 74 μm percentage of 65%, leaching time of 20 min, and leaching temperature of 25 °C. Continuous leaching of FT was carried out by feeding ore and acid every 20 min. By leaching with HF − H2SO4 for 4 h, then adding appropriate amount of HNO3 into the solution and keeping for another 1 h, a high Nb extraction rate of 99.8% was achieved. The established method provides a promising technique for the high-efficiency separation of niobium and tantalum from FT.

Jun 5, 2022

By P. A. Cornejo

Blastings always generates induced vibrations through seismic wave, these are lost energy from the blasting and therefore causing the disturbance of slopes and structures near the blast source. Most of the components of an open pit mine have to reach a physical stability, especially during its closure process. Aiming to develop a vibration prediction model using the historical records from an open pit mine located on Peru, this research has two main focuses depending on the distance from the blast source to the structure: to protect the final slopes and to protect the villagers houses. Both are based on the Devine model of the Square Root Scaled Distance (SRSD) to predict the Peak Particle Velocity (PPV). The Mid field model, where is found mainly final slopes from the pit, limited by the failure criteria of McKenzie based on the geo mechanical properties of the rock mass. The Far field model ranges distances where are located the most community households, limited by the German rule DIN 4150 for highly sensitive structures. Both scenarios resulted on a distribution abacus to limit the weight of used explosives to get the best operational advantage and structure safety.

Mar 2, 2022

By J. A. Herbst

Mineral liberation modeling can be traced back to the early work 0fA.M. Gaudin up through more recent population balance modeling by R.p. King, J.A. Herbst and G.T. Adel. A more micro-scopic look was taken at the University of Utah in the form of the J.E. Sepulveda and J.D. Miller Pargen model which permits the creation of an arbitrary shape, multiphase particle made up of discrete grains. Recent work on image analysis and tomographic analysis by J.D. Miller and C.L. Lin have laid the experimental ground work for model validation, but until now it hasn't been possible to include the necessary physics of the particle stressing process to allow the development of a 'ffirstprinciples"mode1 which does not presuppose a "mode” of liberation (e.g., random or by detachment). Recent developments in discrete grain breakage (DGB) modeling now make a generalized physics based model feasible. This paper describes current work that is being done to develop a physics based discrete grain liberation (DGL) model. Two-dimensional and three dimensional simulation results exploring the effects of particle size, phase properties and loading type are presented. Relationships between energy based liberation efficiency, degree of random liberation and material properties are identified.

Jan 1, 2005

By Kirk Carlton

This paper deals with a group of subjects so familiar to all of us that we might question the need for discussion. Even so, nearly every day's business turns up expensive examples of differences in understanding, misdirected assumptions and incomplete technical purchase documents. As our international activities increase, so do these problem areas. Their expense in both money and embarrassment gives rise to this attempt to focus a little extra attention on technical criteria and specifications. The two terms ?criteria? and "specifications" are, we believe, worth separating with respect to meaning. They should not be used interchangeably, although they often are. Criteria are by definition "standards for judging", whereas specifications are "enumerations of particulars". In relation to plant or project engineering, the criteria are the general rules and data which apply to the whole project and the specifications are the further listing of detailed requirements for specific contractual items or pieces of equipment. We'll look a little more closely at specifications after we give another minute or two to this "criteria" subject,

Jan 1, 1973

By Robert C. Peddicord

Application of Quality Management philosophies and techniques commonly referred to as Managing for Continuous Improvement, Team Management , or Managing for Consistency is required in today's mining, manufacturing, and service industries in order to meet quality demands, beat competition, lower costs, optimize operations, effectively use personnel, improve morale, and enhance profitability. Most of these phiosophies and techniques are known to today's managers but either have fallen into disuse or were never allowed to surface in the corporate environment of the organization. Managers should review and adopt the philosophies and techniques of Quality Management and use them to revitalize their organizations and bring about a "paradigm" shift in the way we manage, thereby achieving the goals listed above.

Jan 1, 1991

By Ammar Henchiri

INTRODUCTION A current need of the phosphate industry is the development of process technology for treatment of high carbonate content ore. About 75 to 80 percent of the world phosphate reserves (1) are associated with carbonate gangue, which is not amenable to treatment by the existing techniques. Numerous laboratory and pilot plant studies have been devoted to carbonate-phosphate separation. Different techniques were involved (washing, sieving, attrition, flotation, calcination, and leaching). For technical and economical considerations, flotation appears to be an efficient process for this problem. Separation of carbonates (calcite and dolomite) from igneous phosphate is applied in industrial plants in Brazil, Finland, and South Africa. But, for sedimentary phosphate, no industrial realization exists at this time, with the possible exception of some plants in China. The main problems with sedimentary phosphates are: • high substitution by CO3-2 and F- for P04 -3 in the apatite lattice. • larger surface area of the phosphate particles because their surface is porous and irregular. • tendency of sedimentary minerals to produce more slimes in conditioning than the crystalline minerals, hence, larger dosages of collectors are required for sedimentary minerals. Investigations reported in the literature indicate that most processes developed for sedimentary carbonate-phosphate separation involved inverse flotation of carbonates using fatty acids as collectors (2), (3) associated with phosphoric acid (4), monosodium phosphate (5), F- (6), or SiF6 -2 (7) as phosphate depressants. Later investigations, conducted by A. Henchiri and G. Baudet (8), (9), (10), (11), (12), (13) in the BRGM technology department, of phosphoric esters revealed that these reagents are selective collectors for carbonate-phosphate separation. The above investigators developed a process which used phosphoric esters to collect carbonate minerals and sulfuric acid or sodium fluorosilicate as depressants for phosphate. Extensive comparative tests for different processes on the same phosphate sample show that the process developed at BRGM is one of the most promising methods proposed for sedimentary phosphate-carbonate separation. It should be pointed out, however, that phosphoric esters make abundant froths. The handling of these excessive froths will be a problem in an industrial-scale plant. This paper outlines test work performed in order to optimize and to improve the efficiency of the flotation process on a sedimentary phosphate ore selected from the Sra Ouertane orebody. The Sra Ouertane flotation process, illustrated on Figure 1, first removes carbonate minerals by inverse flotation and then recovers phosphate as a froth product, leaving quartz as a cell product.

Jan 1, 1993

By JUAN DIAZ, Kray Luxbacher, Steven Schafrik, Dionissios T. Hristopulos, Zach Agioutantis

Methane gas is emitted during both underground and surface coal mining. Underground coal mines need to monitor methane gas emissions to ensure adequate ventilation is provided to guarantee that methane concentrations remain low under different production and environmental conditions. Prediction of methane concentrations in underground mines can also contribute towards the successful management of methane gas emissions. The main objective of this research is to develop a forecasting methodology for methane gas emissions based on time series analysis. Methane time series data were retrieved from atmospheric monitoring systems (AMS) of three underground coal mines in the USA. The AMS data were stored and pre-processed using an Atmospheric Monitoring Analysis and Database Management system. Furthermore, different statistical dependence measures such as cross-correlation, autocorrelation, cross-covariance, and variograms were implemented to investigate the potential autocorrelations of methane gas as well as its association with auxiliary variables (barometric pressure and coal production). The autoregressive integrated moving average (ARIMA) time series model which is based on auto-correlations of the methane gas is investigated. It is established that ARIMA used in the one-step-ahead forecasting mode provides accurate estimates that match the direction (increase/decrease) of the methane gas emission data.

Aug 2, 2022

By S. K. Samal, B. Mishra, M. K. Mohanty, S. C. Mishra

Steelmaking industries consume the majority of chromium and manganese ferroalloys to impart several properties in steel and also for other purposes. The quality of ore governs the process kinetics as well as the process economy of the ferroalloy industry. The present study demonstrates the thermal transformation behavior of chromite and manganese ores with varying compositions. Simultaneous thermal analysis (DTA/TG) is employed for such ore samples where the transformation of mineral phases is correlated with the thermogram characteristics and quantified. Phase, microstructure, and compositional analysis results of individual ores corroborated with thermal analysis are in good agreement. Chromite samples are ferruginous with goethite and gibbsite contents, whereas manganese ores vary in composition and also exhibit multiple and/or overlapping transformations.

Jan 21, 2021

By N. K. Dumakor-Dupey, G. B. Sakyi-Addo, K. J. Bansah

"Artisanal and small-scale mining (ASM) occurs in many countries around the world, and provides a source of livelihood to many impoverished local people in areas where it occurs. This paper reports the role of female participants and reasons why they engage in ASM. Field visits were made to 12 ASM sites located in the Tarkwa Mining District of Ghana to conduct interviews with male diggers and female participants. It was observed that over 100 women between the ages of 18 and 50 participate in ASM for survival. They engage in ASM largely because they have no alternative employable skills and income sources. These female participants depend on ASM to sustain the lives of their dependents. INTRODUCTION Artisanal and small-scale mining (ASM) conventionally involves use of rudimentary tools (such as picks, shovels, chisels and hammers) to exploit precious minerals and metals from the ground. It has been a major source of livelihood to many impoverished local people for more than a century. In many instances, it is the only source of income to indigenous people who have no alternative employable skills. The World Bank estimated that more than 100 million people around the world benefit from ASM which largely occurs in developing countries in Asia, Africa, Oceania, and South and Central America (World Bank, 2013). Cobalt, which is used in lithium-ion batteries to power cellphones, laptop computers, and electric vehicles, is largely produced by artisanal miners in Congo (The Washington Post, 2016). In Sudan, ASM is a significant contributor to the national economy, accounting for about 85% of total gold extracted yearly from 2010 to 2015 (Ibrahim, 2015). Also, according to the Embassy of Sierra Leone in Washington DC, USA, 90% of mineral export in Sierra Leone can be attributed to thriving artisanal diamond mining in the country (Sierra Leone Embassy, 2016). In Ghana, the ASM sector was recognized by government as a multimillion industrial activity, and through a series of initiatives, it was legalized by promulgating the Small Scale Gold Mining Law of 1989 (PNDCL 218). Presently, artisanal mining is widely practiced in two forms: licensed (registered), sometimes referred to as formal ASM, and unregistered (informal or illegal) operations, popularly called “galamsey”, a name believed to have been derived from “gather and sell” by ancient miners who could not communicate in the English language with European/British miners. The ASM sector in Ghana, like other countries, has seen a rise in female participation over the years. A report by the International Labour Organization (ILO) indicated that women account for about 15% of total workforce in ASM in Ghana, and up to 50% in Africa (ILO, 1999). Other researchers have also estimated women participants in ASM to be between 30 and 70% in Africa (Hinton et al., 2003a; Hinton et al. 2003b; Hilson, 2002). Presently, there is no reliable data from Ghanaian authorities on number of females engaged in ASM. However, data obtained from 15 ASM sites suggest that at least 40% of the employees are women. It is expected that a similar trend exists across ASM operations in Ghana."

Jan 1, 2017

By D. A. Huggins

Column flotation is finding increasing use in the flotation of copper, molybdenum and other heavy metals and coal. Columns have proven operational, cost and metallurgical advantages which caused us to investigate their use in the proposed Escondida flowsheet. A comparative pilot plant test with 35 tons of ore showed that one column can replace three stages of cleaning and result in a significantly higher concentrate grade with no loss in recovery.

Jan 1, 1987

By Herbert H. Einstein

Swelling ground is one of the most feared problem in tunneling. Although usually not causing sudden failures during construction, the very large and long- lasting deformations give contractors and designers the impression of facing an inevitable phenomenon against which there is no technical defense. Examples are concrete liners of up to 1 m that have been cracked or crushed, tunnel inverts that are heaving at a rate of 0.1 m per week during construction and continue to heave during decades. This author (Einstein (1979). Einstein et al. (1972) (1975)) and others (Huller (19761, Grob (1972) (1976). Golta (1967), tienke (19761, Krause (1976). Lee et al. (1976)) have described many cases of swelling tunnels that illustrate the significance and magnitude of the problem. This paper intends to show that tunnels in swelling rock can be built to perform satisfactorily. . For this purpose the tunnel builder needs to know how to determine the existence and specific behavior of swelling ground, how to select appropriate structural characteristics of the tunnel and predict its performance under the specific ground conditions, and finally how to construct the tunnel such that the anticipated performance will be achieved. This concept of a design-construction procedure is the same as that for tunneling in general; it is mentioned here for NO reasons: 1. To point out that design and construction cannot and should not be separated. The way in which the tunnel will be built has to be an integral part of the design. 2. This paper will be structured corresponding to the procedural concept.

Jan 1, 1981

By R. Q. Honaker

Recent studies conducted at Virginia Tech have shown that ultrafine coal particles can be selectively coagulated and separated from mineral matter without the use of traditional agglomerants or flocculating agents. This technique utilizes hydrophobic interaction forces to induce coagulation of coal particles, while particles of mineral matter are dispersed using pH control. After selective coagulation, the coal coagula can be recovered by a sedimentation technique. In the present work, factors such as pH, particle size, and solids concentration have been examined. A wide range of coal samples have been successfully upgraded using this technique.

Jan 1, 1991