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By W. J. Kennedy, John D. Gardner

Introduction During the past 10 years, energy costs in mining have risen from about 4% to as much as 25% of total production cost. When combined with declining ore grades, these costs exert inordinate stress on mine productivity. Industrial engineering techniques have traditionally been aimed at improving manufacturing facilities productivity, but they have been applied to mining as pressure for productivity improvement has increased. These techniques can perform four useful functions for mining operations by improving methods, equipment selection procedures, energy use through scheduling, and managing energy costs rather than being managed by them. This article discusses some of the standard techniques for productivity improvement, and how they can be adapted to perform these four functions. Pre-Production The best time to seek high productivity is when a mine is being planned. During pre-production, when most options are still open, an optimum mine design is achievable. At this time, major equipment selections are made, the layout, material handling systems, and processes are designed, and critical energy source decisions are made. By including explicit energy cost projections, decisions can be made that will save significant amounts of money per ton of ore over the life of the mine. Attention can also be given to often overlooked details such as lighting. Some of the same tools used in new mine planning are applicable to productivity improvements at an existing plant. These tools are the charting and modeling methods that have been developed by industrial engineers over the past 75 years. Energy Consumption Before any analysis of energy consumption can be performed, preliminary work is necessary to find the kind of energy used, how much it costs the plant, and when electrical peaks occur. Past bills should be examined to determine the monthly consumption rate and the cost of each energy type. These data should be adjusted to remove effects caused by production fluctuations or weather. Knowing when electrical peak demands occur is necessary because these determine either the electrical capacity needed or the amount that must be bought. At $500-$800 per kW for construction or $5-$15 per kW per month for purchase, they represent a significant cost. By the time these data are collected, planners should be aware of the importance of energy in the total cost of mine operation, and should have the most crucial time data for electrical peak demand. Flow Process Chart Reducing costs can be accomplished by a thorough look at mine systems and how altering one system causes changes in others. By developing and exercising models of production processes outward to the transportation of the final product, otherwise obscured weaknesses may become apparent. There are tools available for analyzing the mine and its associated systems; one of the most useful is the flow process chart. The flow process chart gives a system analysis of a production procedure by classifying all actions into one of five types: operations, inspections, transportation, delays without paperwork, and delays with paperwork. Operation: In an operation, the nature of something is changed. Examples are blasting, washing coal, and processing matter. Denoted by 0. Inspection: Examining an object for identification or to measure some attribute. Examples are determining whether a drill hole is deep enough, deciding how far to cut under an unsupported roof when operating a continuous miner, or checking the lubricant level on a truck. Denoted bye. Transportation: Moving an object from one place to another. Examples are transporting overburden, moving coal on a conveyor belt, and pumping water. Denoted by =>. Delay without paperwork: A delay that is an inherent part of the system. Examples include idle time of a continuous miner while waiting for shuttle cars or for roof bolting, crushed ore in a storage area waiting for grinding and flotation, and people from one craft waiting for another craft to finish. Denoted by D. Delay with paperwork: A delay that can be terminated only by some written authorization. Examples are coal that cannot be removed until authorized by a bill of sale and transportation orders, personnel records, maintenance, or spare parts. Denoted by V. In practice, the flow process chart is completed after data collection and a detailed examination of the process. Data collection is needed to answer questions on distance, quantity, and time for each of the operations. As the analysis is being performed, each step of the process is subjected to these questions: • Why is the step necessary? • What is being moved? • When does the step take place, and why?

Jan 11, 1983

By Ning Wang, Tengfei Guo, Wanyan Li, Hanjie Wen, Hannian Gu, Zehai Li

Red mud has been reported as a potential resource for lithium. To investigate the leaching behavior of lithium, a lithium-rich red mud was neutralized with hydrochloric or oxalic acid and then leached with acetic acid. When red mud was neutralized using dilute hydrochloric acid, about 58 to 60 percent of lithium was leached with 25 percent acetic acid at 95 °C for 60 min, while more than 95 percent of sodium and 85 percent of calcium were dissolved in the leachate solution. When oxalic acid was used to neutralize red mud prior to acetic acid leaching, lower lithium leaching efficiencies of about 42 to 47 percent were observed. Nevertheless, these leaching efficiencies of lithium were close to that of calcium and much higher than those of sodium under the same conditions. In this study, 25 percent (v/v) of acetic acid at 85 °C for 60 min was demonstrated to be the optimum conditions for lithium extraction from oxalic acid-neutralized red mud using acetic acid. The results are useful and of interest for lithium recovery and purification from red mud.

By M. J. Virnig, Christopher A. Fleming

THE CIP PROCESS "IN THE RIGHT PLACE AT THE RIGHT TIME? After its tentative introduction to the precious metals mining industry in the earlier part of this century, the carbon in pulp (CIP) process has now come of age, and is the process of choice on all new gold mills. Well over 50 percent of all gold that is mined each year is recovered by adsorption on activated carbon, and the percentage will increase in the years ahead, when old mills using Merrill Crowe technology come to the end of their lives, and as the proportion of world gold production from low-grade resources increases. The pioneering process development work in this field, which was mainly concerned with carbon elution, was carried out by Zadra and his colleagues at the United States Bureau of Mines in the early 1950's (Zadra et al., 1950, 1952), and led to the commissioning of the first large-scale, industrial CIP plant, at the Homestake Mine in South Dakota, in 1973 (Hall et al., 1974). From there, the process spread rapidly, firstly in South Africa in the late 1970's. and then throughout the rest of the gold producing world in the 1980's. There were several factors that led to the meteoric (by gold industry standards) acceptance and successful implementation of this new technology into gold processing operations worldwide. Firstly, and perhaps most fortuitously, the development of the technology closely paralleled the 1968 release of the gold price from the rigid constraints of the $35/oz. gold standard. With the value of the metal allowed, for the first time in modern history, to fluctuate in response to free market supply and demand forces, the gold industry witnessed an unprecedented boom as the price of their commodity increased ten-fold in a remarkably short period of time. This had several important spin-offs as far as new process developments were concerned: The profits realized by established gold-mining companies increased enormously and, consequently, there was more to spend on research and development and exploration for new deposits.

Jan 1, 1993

By Yuemin Zhao, Daniel Tao, Rick Honaker, Maoming Fan

"Froth flotation is the most widely used method of separating fine coal, especially coal with coking properties. However, froth flotation is not efficient for treating ultrafine coal and coarse coal particles. Our previous fundamental test results demonstrated that cavitation-generated nanobubbles around 700 nm in diameter can significantly improve coal and phosphate flotation performance over a wide particle size range. In this study, the effect of nanobubbles on the flotation performance of different particle size fractions of coal was investigated using a bank of 10-L flotation cells, a specially designed 50-mm inside diameter column and a 152-mm inside diameter column. It was found that nanobubbles that were either directly formed on or subsequently attached to the surface of coal particles during the froth flotation process improved flotation efficiency. The use of nanobubbles in a bank of mechanical cells flotation and column flotation significantly increased the flotation recovery at a given product grade. Nanobubbles increased the flotation rate constants of different coal particle sizes. The presence of nanobubbles in flotation slurry could extend the lower and the upper particle size limits for effective coal flotation.IntroductionFor minus 0.6 mm fine coal or minus 0.15 mm ultrafine coal particles, froth flotation is known to be the most efficient and the most cost-effective separation technique. However, flotation efficiency decreases sharply with ultrafine and relatively coarse coal particles. Studies have shown that the low flotation efficiency of ultrafine particles is mainly due to the low probability of bubble-particle collision (Yoon et al., 1989; Ralston and Dukhin, 1999). Enhanced flotation of fine and ultrafine coal can be achieved by increasing collision and attachment probabilities.The top size of particles that can be recovered by flotation depends on the combination of mineral properties and flotation devices. Turbulence in flotation devices is an important factor that affects the stability of bubble-particle aggregates. Even in the flotation of fine particles, bubble-particle detachment can significantly influence the kinetics of flotation taking place in mechanical cells, which provide intensive turbulent agitation (Deglon et al., 1999). Coarse particle flotation is more difficult, because increased agitation is required to maintain particles in suspension and coarse particles are more likely to detach under turbulent conditions (Mankosa and Kohmuench, 2002; Soto and Barbery, 1991). More efficient attachment of particles and improved flotation rate has been observed when tiny bubbles coexist with conventional-sized flotation bubbles (Attalla et al., 2000; Tao et al., 2010; Fan et al., 2010a, b, c, d; Fan et al., 2012)."

Jan 1, 2015

By David G. Adam

Introduction Syncrude Canada Ltd. is the operating company for a consortium of industry and government participants that produce synthetic crude oil from their leases in the Athabasca Oil Sands. Production from the $2.3 billion (1978) integrated mining, extraction, and bitumen upgrading and utility complex started in September 1978. Production is currently about 6.4 Mm3/a (40 million bbl per year) of high quality synthetic crude oil. This is done by upgrading the extracted bitumen from the oil sands mined. Plans are to increase the production to 8 Mm3/a (50 million bbl pier year) by 1989. At that time, the mining operation will be required to deliver 100 Mt/a (110 million stpy) of oil sand (ore) to the extraction plants, and handle quantities of waste ranging from 50 to 75 Mt/a (55 to 83 million stpy). The Syncrude plant is located at Mildred Lake, 40 km (25 miles) north of Fort McMurray and 480 km (300 miles) north of Edmonton, Alberta. Climate, particularly winter, is therefore a major factor affecting the design and operation of all the Syncrude production facilities. Bitumen production, consisting of overburden removal, oil/sand mining, bitumen extraction, and tailings disposal, account for about half the total SCO production costs. Considerable research and development, therefore, continues to be applied to improve both material handling and bitumen recovery methods. Potential applications for feeder breakers were identified in the material handling aspects of both overburden and oil sand mining to reduce cost and to attain planned production increments. Overburden removal Overburden materials on the leases comprise thin Pleistocene sands, gravel and fill, and sands, silts and clays of the thicker Clearwater Formation with the silt to clay components predominating. The latter contains multiple leases of hard siltstone with unconfined compressive strengths up to 148 MPa and thicknesses up 0.1 to 0.9 m (1 to 3ft). Characteristics of the overburden as well as the climatic environment and scale of operation present unique problems for the efficient removal of the material. In a bucketwheel/conveyor system, the weak silty clay formations require relatively flat working slopes for safe operation, while the siltstone lenses and frozen overburden require blasting or selective removal by other equipment. These factors, combined with the normal bucketwheel/conveyor design parameters, lead to high capital investment and relatively inefficient use of that capital. Hydraulic mining alternatives, including dredging, are constrained by severe clay settling problems in the waste disposal

Jan 6, 1986

By J. Lorosch

Improvement of current leaching technology was found necessary when processing ores which are more difficult to leach because they generate highly viscous, air-rejective pulps. Cyanidation of these pulps has to run at low oxygen concentrations if the conventional aeration technique with compressed air is used. Since the dissolution rate of precious metals mainly depends on the concentration of dissolved oxygen in the pulp [1, 4, 5], the kinetics of the gold extraction become slow in such cases, which in turn often leads to a significant decrease in the overall gold output within the conventional leaching time of up to 48 hours.

Jan 1, 1988

By Steve Kral

For an industry that provides more than half of the nation’s energy needs, the U.S. coal industry still attracts negative publicity. However, the nation’s energy appetite continues to increase. And political leaders and the public are beginning to understand that alternative fuels will not be enough to keep up with that appetite. Does that mean the nation will now embrace the coal industry? No, according to speakers at the Rocky Mountain Coal Mining Institute (RMCMI) meeting. The industry still needs to sell the public on coal’s advantages over other fuels. And the industry must continue to develop technology that will allow coal to meet and exceed strict clean air and clean water regulations.

Jan 1, 2002

By Ernest M. Spokes

Starting in 1980, a committee of the National Research Council studied the question of why some underground coal mines are safer than others and what could be done to improve the ones with poorer performance. The results indicated that safety is improved by management commitment to safety, by cooperation between labor and management on safety matters, and by quality training of employees and managers. Younger mines have higher accident frequencies, but are less likely to be killed or permanently disabled by a lost-time accident. Methods for improving safety performance are proposed.

Jan 1, 1983

By M. K. Gangal, E. D. Dainty, G. Kunchur

This paper presents a validation of C02 as a single surrogate measurement for other diesel-emitted pollutants in multi-diesel-machine operations typical of small underground mines. This means that the simple measurement of C02 alone can be used to estimate the concentrations of other components of diesel exhaust in the mine environment. The linear relationship of C02 concentration with other diesel-emitted pollutants was indicated by the results of simultaneous real-time monitoring of C02 with CO, NO, NO2, SO2, Respirable Combustible Dust (RCD), and Air Quality Index (AQI) in several small underground mines. The SO2 was not directly measured but calculated from the measured C02 concentration and diesel fuel analysis for carbon, hydrogen and sulphur. The measurements were made in the return air drift under various mining conditions involving a number of diesel LHDs and haulage trucks. The statistical analysis and mathematical representation of the several components of diesel pollutants with C02 are presented. Regression analysis shows that at the 1 percent level of significance there is a strong linear relationship of these diesel pollutants with C02. This relationship is discussed in detail, concluding that C02 measurement alone is a good indicator of overall mine air quality and can be used as a control parameter.

Jan 1, 1991

By James H. Barks

Exploration for ore deposits in southeastern Missouri in the 1950's resulted in the important discovery of lead, zinc, copper and silver in 1955. Further discoveries in the area led to the naming of the Viburnum trend. It has sometimes been referred to as the "New Lead belt" to distinguish it from older lead-producing areas to the east. As presently developed, the "trend" is 35 miles long, running north and south about 50 miles west of the Lead belt. Galena (lead) is the principal ore mined, with lesser quantities of sphalerite (zinc), chalcopyrite (copper) and silver recovered as economic by-products. The ore body is as much as 140 feet thick and 1,200 feet wide, and is found in the Bonneterre Dolomite (Upper Cambrian) at depths ranging from 700 to 1,200 feet. Since its discovery many companies have engaged in exploration and several major companies have developed new mines and constructed mills and a smelter in the area. The first mine in the Viburnum trend came on stream in 1960, but as more mines came on stream and others reached capacity, lead production increased to the point that the Southeast Missouri Lead district produced 432,576 tons of lead in 1970 to become the world's largest lead-producing region (Missouri Geological Survey and Water Resources, 1971). The Viburnum trend area with its rolling, heavily forested hills and numerous clear running streams is in the Clark National Forest of the Missouri Ozarks. Until the recent development of its mineral resources, the area was sparsely populated and nearly unmarked by the activities of man. Industrial development is almost certain to be accompanied by environmental changes. In a day of growing awareness of the need to preserve the quality of the

Jan 1, 1971

By K. Oraee

Mining Ventures are considered as high risk projects and therefore managing the risks is inevitable. Risk assessment is an important part of the complex process of risk management, hence applying appropriated and practical methods for ranking the risks associated with projects, can help to perform a better risk management. In this research the applicability of using Techniques for Order Preference by Similarity to Ideal Solution (TOPSIS) method for risk ranking in an underground mine, extracting by block caving method, was studied. Via this method, the risk associated with reserve estimation ranked as the first while in conventional method (P-I Matrix method) located in the sixteenth. Also there were significant differences in ranks of the other risks. Considering the more criteria, with different weights, in comparison with conventional methods, the results comprised from TOPSIS method are more reliable. By implementing this method risks are ranked better and more realistic and consequently then will be managed more efficient.

Jan 1, 2011

By A. Kalmes, B. Dehler, D. Kopp

Nutrien has six potash mines in Saskatchewan and has been proactive in maintaining the integrity of their tailings facilities through ongoing assessment, design, operation, inspection, and monitoring. Nutrien commissioned a system inventory and semi-quantitative risk analysis (SQRA) of all dikes to further environmental stewardship at their potash facilities. The inventory assessed nearly 100 dikes; each dike was rated according to a probability and consequence factor and assigned a risk score. The risk scores were used to develop a risk matrix for each of the six sites and risk-response actions for each dike and segment. The inventories and SQRAs will help each site assess priorities for investigation and risk mitigation, if necessary. The study results will also help Nutrien refine corporate wide tailings governance standards and demonstrate compliance with various governance regulatory obligations.

Mar 2, 2022

By Robert G. Lundguist

REAM is a unique and promising method of rock breaking using high energy, inert projectiles to impart mechanical energy to the rock. This paper describes a demonstration of the application of this new technology to two specific problems in open pit mining: secondary breakage and the scaling of loose material from pit walls. Under previous government contracts, Physics International Company developed the projectile impact method for a large variety of commercial and military rock excavation tasks. A 4 meter (13 foot) diameter by 16.8 meters (55 foot) long tunnel was driven at the Hope Valley Mine in the Sierra Nevada mountains of California in 1972 and 1973. An average of 1100 kg (1 ¼ tons) of a 172 MN/m2 (25,000-psi) granodiorite formation was broken by each of 590 shots used to drive the tunnel.l Based on these results it is estimated that REAM can drive over 60 meters (200 feet) of tunnel per day at about 88 percent of the cost of drilling and blasting. In addition, repeated axial impact by high energy projectiles was used to drill a 0.4 meter (16 inch) diameter horizontal hole in the same granodiorite formation. Each shot advanced the hole an average of 0.2 meter (8 inches).

Jan 1, 1976

By A. P. Massmann

Design for economical operation, minimum operating labor and minimum maintenance for labor and supplies are virtually inseparable. Each consideration has a vital bearing on the other. Let us assume that we have the design complete for the most economical operation with a minimum of operating personnel. This means, in addition, that we have the fewest number of operating units consistent with the product requirements for a team or metallurgical coal which we are called on to produce. The number of units will vary greatly, being influenced by design, washability characteristics, tonnage and degree of quality control necessary by reason of producing a product for metallurgical, steam or domestic use. The units involved most ordinarily for any type coal preparation plant will number as a minimum the following: 1. Hoppering R.O.M. Coal 2. Feeding

Jan 1, 1959

By Charles S. Spirakis

The consistent occurrence of organic carbon early in the paragenesis of Mississippi Valley-type sulfide deposits suggests a genetic link between organic carbon and the sulfide ores. Reduction of sulfate in the mineralizing solution by organic carbon at the sites of mineralization is commonly proposed as the precipitation mechanism for these deposits, but inorganic sulfate reduction is too slow to be important to the chemistry of the ore zone, and bacteria, which catalyze sulfate reduction at low temperatures, are not known to survive at the temperatures of mineralization. Sulfate reduction with or without bacteria is not consistent with the sulfur Isotope evidence. Sulfur isotope studies also indicate that the derivation of sulfur from hydrocarbon at the sites of mineralization is unlikely. Organometallic complexing may be involved in the transport of metals, but no plausible mechanism for breaking these complexes at the sites of mineralization has been proposed. Reduction of partly oxidized sulfur species in the mineralizing solution by organic carbon at the sites of mineralization is a possibility which deserves further scrutiny.

Jan 1, 2013

By PAITIP THIRAVETYAN, KANJANA KUDPENG

The aim of this study is to compare amino acids and organic acids in the extraction of gold from silicate ore. Amino acids were found to have higher efficiency of gold extraction than organic acids at the same acid concentration, which is likely due to amino acids having both carboxylic and amine groups in their structure, while organic acids only have carboxylic groups. Five amino acids (glycine, aspartic acid, glutamic acid, lysine and tryptophan) and seven organic acids (citric, malic, tataric, fumaric, oxalic, succinic and ascorbic acids) were selected to investigate gold extraction efficiency. Aspartic acid was found to have greater capacity to extract gold than succinic acid. The optimal gold to aspartic acid molar ratio was 1:6, and low concentrations of aspartic acid extracted 35 to 42 percent of gold from silicate ore within 15 days. Further studies are needed to increase gold leaching and reduce incubation time. The results imply that aspartic acid can be used as an alternative reagent to traditional methods for extracting gold from ore. This method is nontoxic to humans, is environmentally friendly and can have real applications.

By A. V. Castelli

Weighting materials as we know them today were first recognized in 1922 by B. K. Stroud1. Stroud, who was supervisor or the Mineral Division of the Louisiana Department of Conservation, tested galena, cement and hematite as weighting materials and successfully used hematite to make a "heavy mud". The first use of barite was in the fall of 19222 . The process of adding heavy minerals in mud was patented in 1926 by Stroud and National Pigments and Chemical Company, a subsidiary of National Lead Company now NL Industries, Inc. The ground barite was marketed as BAROIDR barite.

Jan 1, 1983

By D. Rahal

All ores have an economic optimum particle size (Wills and Napier-Munn, 2006). This optimum value is often a compromise between the need to achieve adequate liberation for the efficient separation and recovery of valuable minerals and the energy consumed by the crushing and grinding process. It has been recognized for nearly three decades that grinding is the most expensive and least efficient stage in mineral processing (El-shall and Somasundaran, 1984). At that time it was estimated that grinding consumed between 25 and 70% of the total power required in mineral processing. This recognition drove the development of new stirred mill fine grinding technology in the 1990s (Jankovic et.al, 2003; Enderle et. al., 1997; Massey, 2008). These milling technologies have a reduced energy consumption compared to traditional fine grinding using ball mills. In the ?coarser? fine grinding applications this improvement is approximately 30%. The benefits increase to above 50% in ultrafine grinding applications (Lichter and Davey, 2006). Despite these gains, the US Department of Energy reported that an additional energy savings of up to 37% is possible in the minerals industry. They identified continuing research and development and implementing best practices in both grinding and materials handling as the primary avenues for the additional reduction (BCS, 2007).

Jan 1, 2011

By Y. J. Wang

In the mathematical analysis of electrical networks, the electrical devices are often modeled using idealized network elements such as current sources, voltage sources, and resistors. An analogous approach is outlined here for the modeling of mine ventilation networks, which can be considered nonlinear resistive networks. The modeling technique proposed uses five basic (non-reducible) elements: the H element, the Q element, the D element, the R element, and the N element. These elements are characterized by their (a) pressure gain or loss, (b) air quantity, and (c) pressure-versus-quantity relationship, each of which may be known or unknown. In addition to the definition of the basic elements, the necessary conditions for which there exists a unique solution are discussed. This is performed using theoretical developments derived from electrical circuit theory and illustrated in example networks. The proposed procedures are useful in the solution and characterization of mine ventilation networks.

Jan 1, 1996

By Steve Kral

The Northwest Mining Association (NWMA) has been an advocate for the U.S. mining industry since 1895. For several decades, the organization has represented mining members located mostly in the Northwest and some southwestern Canadian provinces. Today, though, the NWMA?s membership is located in 42 states and seven provinces and has become a national voice for the mining industry. So, during the association?s 119th and final meeting as the NWMA, a name change was announced. The organization is now called the American Exploration and Mining Association (AEMA). But that?s not all that has changed, according to the association. The new name reflects more closely the diversity and location of the AEMA?s membership. It will still be an advocate for the mining industry, dealing with land, environmental and community issues on state and federal levels. The conference, held in December 2013 in Reno, NV, attracted about 2,500 attendees. And the accompanying exhibit included 230 equipment and service suppliers in 246 booths. Technical programming ran the gamut of mining industry issues and technologies, including surface and underground mining; high technology systems and automation in mining, metallurgy and exploration; along with social issues, finance and safety. The following is a sample of some of the sessions.

Mar 1, 2014