Search Documents

By David Harrison

Exxon Minerals Company uses geostatistical techniques for ore resource evaluation of its mineral projects. These techniques provide the most reliable estimates of recoverable tonnage and grade and uniform and realistic confidence limits. A schema has been developed which categorizes the company's successive evaluation phases. Clear separation is intended between geostatistical estimates and other factors in project evaluation such as mining, metallurgy, and economics. Company management seeks consistent and reliable estimates for investment decision-making and to meet growing demands for disclosure of mineral assets.

Jan 1, 1983

By I. Loomis, D. Rachmad, I. Duckworth

During the past two years the Underground Mine Ventilation Group at PT Freeport Indonesia has undertaken to upgrade their Hygiene Laboratory. This process has included upgrading equipment for dust sampling and gas monitoring, as well as procurement of an OCEC analyzer for Diesel Particulate Matter analysis. While the laboratory equipment represents one factor, these changes have also required re-evaluation of the sampling protocols and the burden of ventilation monitoring personnel. This paper provides a review of these experiences.

Jan 1, 2006

By M. S. Klima, A. Simard, M. L. Turek

Laboratory testing was carried out to evaluate several devices for recovering clean coal from bituminous coal refuse material. The bulk of the testing focused on using a dense-medium cyclone to process -0.6-mm refuse material. A hindered-settling column and a spiral concentrator were also used to process 1.2x0.15-mm material. Product yields and ash contents were obtained for all tests, while partition curves were generated for selected tests from which the characteristic performance parameters (relative density of separation and probable error) were determined. The results indicated that the dense-medium cyclone was capable of cleaning down to 0.037 mm, while the other devices were effective to 0.15 mm.

Jan 1, 2002

By S. Mukusha

Electronic spreadsheets are the most common and readily available software applications for analyzing and modeling quantitative problems. Spreadsheets can offer a vast array of opportunities for the analysis and modeling exercises encountered in the field of geomechanics. This study explores the potential for using spreadsheets of in the practice geomechanical engineering. The study also examines some of the barriers to widespread use of spreadsheets. Best practices and guidelines for overcoming potential pitfalls are discussed and highlighted through a case study.

Jan 1, 2000

By P. S. Baker

CRU estimates that the global supply of metallurgical grade alumina (MGA) grew by 5 percent during 2005 to a little more than 61 Mt (67 million st). About 30.7 Mt (33.8 million st), or 50.3 percent, of that originated from Oceania (principally due to the commissioning of the CAR refinery in Australia) and Latin America. In this context, Chinese production surged by 20.5 percent year-on-year to 7.7 Mt (8.5 million st) on the crest of a 17-percent rise in that country’s primary aluminium production. Meanwhile, on the demand side, there was a 6.7 percent climb year-on-year in global consumption to 62.3 Mt (68.6 million st). This reflected a healthy demand for primary metal from aerospace, construction, packaging and passenger transportation (to a lesser degree) in the United States, China, Brazil, South Korea and India. So there was an overall supply deficit of more than 1.2 Mt (1.3 million st). This, combined with an 18.3-percent diminution in closing stocks (down to 35 days of requirement), lifted the average spot price of MGA by 17.6 percent year-on-year to US$448/t (US$406/st).

Jan 1, 2006

By P. Mills

More than 95 percent of all the barite mined and produced is used in the petroleum industry as “drillers mud.” The remaining barite is used in the industrial and medical markets. Therefore, the amount of drilling activity is a good indicator of the health and growth of the barite industry. The four major barite-producing countries in the world are China, the United States, India and Morocco. In 2005, the average number of drilling rigs exploring for oil and gas increased by about 15 percent over the average number in 2004. This increase in oil and gas exploration has resulted in a higher demand for barite and an increase in barite production.

Jan 1, 2006

By S. Dixon

The Peñasquito deposit in Mexico is one of the largest grassroots precious metal discoveries developed in recent years. Goldcorp Inc. acquired the gold-silver-lead-zinc property with the acquisition of Glamis in 2006. The Peñasquito property is located in the northeast corner of Zacatecas state, Mexico. The elevation of the property averages 1,900 m (6,200 ft) above sea level. It is situated in a wide east-west valley. Minera Peñasquito, S.A. de C.V., wholly owned subsidiary of Goldcorp Inc. has operated twin SABC-flotation lines since June 2010. Each line is capable of processing 50,000 tonne per day using a SABC grinding circuit followed by flotation to produce lead and zinc concentrates. The addition of a Polysius Polycom HPGR 2417 with dual 3,000 kW drives to reduce the crushed pebbles produced by the SAG mills was planned to increase production to 65,000 tonne per day per line. The production has been limited to 100,000 tpd due to operating issues in the grinding circuit. The operating issue has been the amount of pebbles generated by the SAG mills is significantly less than originally planned. This paper describes the planned installation of a crushed augmented feed to maximize utilization of the HPGR capacity. This coupled with full utilization of the SAG and Ball Mill available energies there is the potential to achieve a 50% total capacity increase from the grinding circuit.

Jan 1, 2012

By Ray Brainard

Treated effluent from the Clean Water Coalition (CWC) member agencies is currently discharged at an annual average rate of 6,570 l/s into the Las Vegas Wash, and is increasing annually. As the effluent flow increases, the nutrient loading of the treated effluent will approach the maximum limits allowed under the current regulations. To manage this flow while maintaining water quality in Lake Mead, the CWC is implementing a 44-km-long conveyance system. This paper discusses the geological and geotechnical aspects of the 13.4-km-long tunneled section through the River Mountains and their effect on design. The tunnel alignment traverses a heterogeneous package of volcanic and sedimentary rocks exhibiting widely variable rock conditions.

Jan 1, 2008

By M. J. Ramos

Without an exclusive definition of administration in business, we could propose to define it as performance by management to adopt or implement established business formulas. Administration could also be defined as a universal process that organizes people, and achieves, through efficiency, common objectives and goals. Humanity developed some form of this process from the beginning of civilization. To imply that something is new in administration might be considered specious or naïve. Moreover, what is new in management? Administration of business is not new to the world. To prove this statement, we need only ask this question: Does the architecture and monumental workmanship of the past civilizations of ancient Egypt, Rome, and the Incas demonstrate management without administration and without definition of objectives? The answer must be a resounding ?NO!? In spite of this acknowledgment and for the purposes of this presentation, I will use the word ?new? in business and hope that the reader will follow my reasoning. The mining industry has unique characteristics in respect to other industries. It is multi-disciplinary, has a single purpose (majority for one metal), has two players (man and nature), and it involves high risks for generating environmental imbalance. Mining exploits non-renewable and finite resources, creates an unstable job market (work hard to have no work) and a speculative economic market with unpredictable prices ? a one-time payment for a finite resource with multiple recycling. On top of all that, the industry still operates within obsolete petroleum-based technology, utilizing practices that were designed two centuries ago. Today, we confront the challenges of the millennium with outmoded practices and management. Ordinarily, several styles of administration are standardized into a FRAGMENTED vertical system of organization. Mining has rigid objectives in production, with profitability as the focus from the beginning to the end. Citing the concept of safety, as an important facet of production is bombastic since, in truth, mining is an experimental industry that consistently reports high numbers of fatal accidents. In mining, we designed a process to work according to our objectives, demanding attention and supervision of all levels of management with a halo of parameters that are not assimilated into the design. We continue to perform a rigid style of management in an industry that is still not responsive to variations of the market ? losses in particular. The existing design process generates loss without capitalization and without response to said loss. This perception is reflected in a mindset that is only too ready to ignore mining liabilities. The reality of the enterprise has created an immense pressure from top to bottom in the hierarchy to do more with less. It is for all of these reasons that I propose to set forth a new essence for administration that encompasses an alternative vision and style in mining: Management by Loss. MANAGEMENT BY LOSS Management by Loss (MBL) is a systematic, integral process organized to quality control operation and the human profitability within the industry. It permits focus on achievable goals by utilizing the best practices (Mining Open-closing). Identification and characterization of loss in the process determine how objectives are defined, controlling the time limits to execute based on constant balance of mass, energy, water, and ?wastes? in each stage of the industry, in order to reach final objectives. The concept of loss can be defined by various criteria. Generally, it is the mass that could not make or arrive at its destination from a designed process or simply, it could not maintain balance. Otherwise, the design of the process describes the final point of the resource. However, those resources could not make their destination because of failure to use the best design, resources and TIME. The loss has typical characteristics such as Identifiable, classifiable, measurable, manageable, controllable, valuables, negotiable, avoidable, reportable, and monitoring. In the traditional scheme, these losses are not registered; they are made exclusions. We are trapped within a system, which was designed to obtain objectives of the industry in a specific timeframe. In the present style of administration, the focus is total - our emphasis in this treatise is in the loss. The current traditional report form contains only the most positive achievement of objectives, only the best of the exercise, humanizing numbers, without touching what we left behind or what we were waiting for to assimilate as a ?surprise account?(new account of liabilities). Management by loss is a method that redefines the concept of waste (waste zero) for controlling the mine operation under the equilibrium of the ecosystems. This method confronts the problems that impact our industry in this millennium. Understanding and quantifying losses (reserves, resources, time, energy, water, soil, materials, equipment, tasks, labor, ecosystems, etc) is a priority mandate for the industry and demands the application of a ?new ? style of administration by seeking to maintain balance instead of the disequilibrium that mining now creates in nature. It is necessary to answer questions such as: How can we minimize loss? How can the loss be assimilated during the life of the mine? What is the vision of mining in respect to the generation of waste? How can we convert liabilities into assets? In addition, the control of loss is determined in the achievement of the plan. Loss occurs because of a failure of the process in the original plan. Still we do not plan to fail but we fail to plan appropriately. It is a remarkable thing to accomplish and compel those objectives described in the original plan when that plan is designed with a determined budget. If not, we lose time and, of course, capital. Moreover, in Management by Loss (MBL), we can find answers to the following questions: What is the multiplier of productivity in mining? What are the influences of identification and characterization of loss and what is the level of efficiency of energy in order to achieve waste zero (effective cut off grade)? The challenges of mining in this millennium validate this new style of administration. Finally, it is important to point out that mining is entering into an era that has different rules, but the industry is still run by companies functioning with objectives from two centuries ago. They are trying to confront issues with concepts that are not designed for new tasks. Therefore, I ask you to consider this new style of administration of business under a vision of how the industry should be organized and managed, with an attitude of balance toward nature and social responsibility.

Jan 1, 2009

By Sabina Brady

Nearly a decade and a half after the US and China established formal diplomatic relations, and two decades after the two countries signed the Shanghai Communique and established commercial ties, the world, and perhaps China itself, has discovered that a wealth of natural mineral and energy resources lie beneath China's soil and directly off its coast. The country's coal reserves and oil and gas potential are well known. Its ferrous and nonferrous metal reserves are respectable and in a number of instances pre-eminent. According to 1981 Minerals Yearbook estimates - more often than not below those now being claimed by China - the country's aluminous metal reserves are about 907 Mt (1 billion st); iron ore reserves are 40 Gt (44 billion st); and copper reserves are about 46 Mt (54.4 million st) of contained metal. In addition, the country has about 10.7 Gt (11.8 billion st) of phosphate reserves, the fourth largest in the world, and 3 Gt (3.3 billion st) of pyrite. China's national Sixth Five Year Plan promulgated in late 1982 ended a stringent three-year retrenchment or readjustment period in which a number of major development projects involving foreign participation initiated in the late 1970s were shelved. The new Five Year Plan is a signal both within and outside of China that things are now moving again, and that major industrial and service sectors are receiving the kind of funding and flexibility they need for expansion, construction and modernization. The new plan's strategy for growth is measured and much less grandiose and frenetic than it was five years ago when China flung open its doors to foreign companies and invited participation in large-scale development projects. Now, the country's reticence to spend foreign exchange to purchase key equipment, technology, and services -a reaction to these projects and the spending they entailed - is clearly on the wane. In China's effort to quadruple its GNP by the year 2000, there is a new willingness to use some of its substantial foreign reserves. In fact, it is projected that 1983 will witness a $1.9 billion deficit, with a $2-3 billion deficit in 1984 and 1985. The following article discusses implications the Sixth Five-Year Plan has for nonferrous metal development in China. It is the first in a series of three articles on Chinese mineral resource development to be published in Mining Engineering over the next few months. The second article will identify specific nonferrous projects underway, while the third in the series will focus on trade and development opportunities for phosphate and potash producers in China. China's Ambitious Plans In the last few months, the exploitation of China's nonferrous resources and development of its industrial processing capabilities have begun to receive increasing attention on both provincial and central levels. Unlike the earlier modernization drive of 1978 when China's ferrous sector - best typified in the Baoshan iron and steel project - got the lion's share of the Ministry of Metallurgical Industry's (MMI) energy and resources, it now appears that in some respects the nonferrous and industrial sectors are finally moving out from beneath the dominating shadow of ferrous and getting their own day in the sun. Separation of Nonferrous from Ferrous One clear demonstration of this is the establishment in April 1983 of the China Nonferrous Metals Industry Corporation (CNFMIC). The corporation is composed of 819 enterprises with over a million workers, and also includes 12 nonferrous metal construction companies, eight design institutes, and three prospecting companies. Of ministerial rank, CNFMIC is responsible for the development of both the country's nonferrous resources and its processing facilities. Although closely tied to the parent ministry from which it sprang (i.e. MMI), CNFMIC, at least theoretically, is separate and independent from it. One strong indication that this independence is, or soon will become a reality, can be seen from the fact that the new corporation is not headed by the former MMI officials, not even those who made up the ministry's now defunct nonferrous bureau. Instead, its president Qiu Chunfu is formerly of the State Economic Commission and the China International Trust and Investment Corp. Its general manager Fei Ziwen, an engineer in his early 50s, is from the Jiangxi Province Copper Corp. The new nonferrous corporation appears to be powerful

Jan 7, 1983

By S. Watkins, D. Apel, B. Gray, R. Moss

Currently, there are several techniques and technologies available which are used by mining industry in its attempts to remotely monitor the ground movements both at surface and underground mines. The currently available remote distance meters and distance change monitors mainly use phase change and time-of-flight techniques. The described monitor uses triangulation technique to track position of an optical spot projection and then image processing to measure mine wall movements. The system can be easily automated and poses no obstruction to mine traffic. The position of an off-normal laser spot will shift as the target wall moves. The described ground movement monitoring system has potential for superior accuracy and target monitoring can be made through air (gaseous) or other transparent media. The theoretical accuracy and range of this system depends solely on the resolution and focal length of the camera being used. The remote capabilities of the system make it uniquely suited to applications where monitoring is required in high-traffic, inaccessible, or unstable and dangerous areas of a mine.

Jan 1, 2007

By W. X. Wang

In the mining and quarry industries, rock fragments are often transported by conveyor belt. To estimate the qualities of the rock fragments (i.e., size distribution and shape), an operator must take samples from the conveyor and manually perform a sieve analysis, which is time-consuming and tedious. Alternatively, an image-analysis system can be used to monitor the fragment quality on a fast moving conveyor belt. However, images of fragments on a fast moving belt vary to such a degree that the quality of any two successive images are not the same, and some of the images are of such poor quality that they are unrecognizable by human eyes. If poor-quality images are directly analyzed by a segmentation algorithm, the analysis will not be satisfactory. To resolve this problem, it is necessary to use an image-classification pro-gram for the automatic selection of fragment images with good quality. Because of this need, an image-classification program was developed and tested both in the laboratory and in the field. Testing of the system on different types of fragments showed that the system works reasonably well.

Jan 1, 1996

By T. Arthur Palm, Stephen L. Bessinger

San Juan Coal Co. (SJCC) operates an underground coal mine near Farmington, NM. Continuous miners and a longwall produce 6.3 to 7.2 Mt/a (7 million to 8 million stpy). SJCC is owned and operated by BHP Billiton. The coal seam at SJCC has been shown to have a propensity for spontaneous combustion. As such, during the feasibility study for this project, it was elected to use a bleederless ventilation system on the longwall. Due to the combination of spontaneous combustion, methane liberation and, to a lesser extent, hydrogen sulfide, a typical wraparound ventilation system would not be appropriate. Three-entry gate roads are developed, and the longwall gob is sealed as mining progresses. SJCC uses a nitrogen injection system to continuously inertize the gob.

Jan 1, 2007

By Harvey Parker

This is part two of an article on the prominent role that the United States and its industry leaders have played on the International Tunnelling and Underground Space Association (ITA), which represents the underground construction and underground space industries worldwide. The U.S. is officially represented in ITA by UCA of SME. (Part one is in T&UC, June 2007, pp 39-42) Tunnel advances in 1960s and 1970s The 1960s and 1970s were active and productive times for the U.S. tunneling industry. During that time, federal programs, sponsored by the Federal Railroad Administration (FRA), the Office of High Speed Ground Transportation (OHSGT) and the Advanced Research Projects Administration (ARPA), stimulated tunnel research and development. Also, the American Society of Civil Engineers (ASCE) and SME collaborated to create the Underground Construction Research Council (UCRC) and the Rapid Excavation and Tunneling Conference (RETC) series.

Jan 1, 2007

By P. Amelunxen

This paper presents the authors? personal experiences in the design and operation of moly separation circuits in copper-moly concentrators. Topics discussed include column cells versus mechanical cells; use of nitrogen; use of CO2 and sulfuric acid for pH modification; and general equipment selection and sizing. A benchmarking of main operating parameters for industrial plants is presented. Upgrading curves for commercial column and mechanical cleaning circuits are also presented, showing that with average flotation kinetics and rougher concentrate grades, technical grade concentrates can be easily achieved with five column cells operating in counter-current configuration.

Jan 1, 2009

The speed and internal accuracy of today's electronic calculators can be utilized to write an efficient slurry calculation program. The calculator's input/output printing feature offers additional benefits for data organizing and record keeping. This program allows slurry calculations to be performed without the urgency of immediately transferring a calculated result onto a process flowsheet or specification sheet. The number of flowsheets required for some hvdrometallurgical processes means the number of process stream blocks or ladder diagram entries can become substantial. Slurry calculations for such projects tend to become repetitious and tedious, and the chances for errors increase both in calculation and data entry onto process documents. Using this program has minimized both types of errors. Checking process flowsheets is particularly expedient with the program because you may "walk" through the flowsheet on a weight basis, i.e., solids rate and solids density, and have the program verify and/or correct the volume entries, gallons, and specific gravities. The program was initially used on a beneficiation project to check some 500 data entry values on ladder diagrams covering seven process flowsheets. Numerous hand calculation errors were determined and corrected, and the time for completely checking and correcting the flowsheet ladder diagrams was substantially reduced.

Jan 4, 1981

By T. R. Ellis

Considerable movement is afoot internationally to rationalize standards and regulations relating to valuations and the qualifications for valuation professionals. In July 2000 the International Valuation Standards Committee released expanded standards, and additional important improvements are planned by 2003. Possible updates to the International Accounting Standards (IAS) and potential adoption of IAS by the U.S. could significantly impact minerals appraisers. Standards designed specifically for mineral asset valuation are under development in Canada and the U.S., with Australia’s internationally respected VALMIN Code providing the benchmark. In the U.S., the all-encompassing Uniform Standards of Professional Appraisal Practice (USPAP) is annually modified and continues to gain deeper acceptance, while the SEC holds fast to its antiquated rule prohibiting reporting of a quantitative estimate and value for non-reserve mineralization. Some important international trade agreements are driving actions to free the trade in professional services. In July 2000, an international workshop was held to initiate discussion on minimum qualifications for appraisers to work internationally. Pressure for uniform minimum qualifications and rules for professionals internationally will continue to build. The U.S. is historically among the slowest countries to implement such initiatives, with its state level licensure barriers having the potential to cause some of its professionals to be stranded in an international backwater. Structural change is needed in Australia’s VALMIN Code to remove conflict with the latest International Valuation Standards. The mineral valuation standards developers of Australia, Canada and the U.S. should work jointly on updating VALMIN for global use.

Jan 1, 2001

By K. S. Gritton

The implementation of advance control systems brings with it the expectation of improvements in process performance and controllability. Specifically, expectations include a shift in the mean value of the gross measure of process performance, and/or a decrease in process variability. When determining statistically-defensible measures of these benefits care must be taken to preclude process parameters from biasing the determination. Specifically, the effects of ore type, shift personnel, water availability, etc., must all be separated from the effect on performance of the advanced control system. Methods are presented for separating the effects of process control from other process parameters. Examples of the required data analyses are also presented.

Jan 1, 2001

By P. Roghanchi

The Rock Mass Rating (RMR) system is an internationally recognized classification system that can be used for preliminary ground control design. The RMR system assigns quantifiable values to predefined classified parameters of a rock mass. Assigning a single value rather than a range to each parameter is a source of uncertainty, however, assigning a single value can be useful for further studies related to RMR ratings. Fuzzy systems are being used in an increasing number of application areas where linguistic rules are used to describe the system. In past decades, fuzzy systems have been successfully used in geotechnical and mining engineering problems to cope with uncertain data as well as with vagueness. In such scenarios, linguistic rules and rating-based classification of rock masses have always been questionable. The objective of this study is to apply fuzzy set theory to the RMR classification system. The fuzzy system proposed in this study is specified for weak and very weak rock masses (RMR<50) based on data collected from Nevada gold mines where 68% of RMR data is in the ?poor? and ?very poor? classes. In this approach, a Mamdani fuzzy algorithm has been constructed to evaluate basic RMR89 rating for the ?wet condition.? Comparison between basic RMR89 and fuzzy RMR shows the fuzzy RMR system is valid to predict RMR from the discrete rating of each input parameter.

Feb 27, 2013

By H. Seguin, J. A. Le Gac, S. Bernhard, P. R. ZETTWOOG

The "Service de Protection Technique"of the "Institut de Protection et de Sûreté Nucléaire" was asked by the Commission of European Communities to conduct measurement campaigns which would make it possible to evaluate, on an experimental basis, the collective risk to miners exposed to radon in underground, non-uranium mines located in countries within the European Community. 1. METHODOLOGY USED TO CONDUCT THE CAMPAIGNS This campaign is original in that direct measurements of the individual monthly exposure to potential [a]-energy from short-lived radon daughters are made using personal [a]-dosimeters described previously (1). We call this type of dosimetry "personal dosimetry". The workers who wear the personal [a]-dosimeters were selected taking into account the various categories of workers and their work assignments in the various areas of the mine. Another way of finding out the occupational exposure of these miners consists in making numerous measurements of the radon concentration at the various work places, taking into account the time spent at each place by each worker. This procedure is too complex for an evaluation of the collective risk as requested by the Commission of European Communities and was therefore rejected. Additional data was gathered during these measurements campaigns using the following techniques (table 1). [ ] (1) Current [a]-dosimetry as practiced in France - SPT international report N° 234 - February, 1981 - P. ZETTWOOG The mines were chosen to include a larger variety of types of ore, of geological situations, and of mining methods. 2. RESULTS OF THE RADON DATA-GATHERING CAMPAIGNS 2.1 – [Uranium content of the surrounding rocks and ore] The samples taken during the campaigns make it possible to establish the U content in the rocks of the mines selected. These values, from 2 to 15 ppm, are slightly higher than those usually found (2 to 5 ppm) (table 2). [ ]

Jan 1, 1981