Search Documents

The prime objective of geometallurgy is to improve the profitability of mines through the use of spatial models of rock properties that have a significant impact on value. Although a key property is the grade of the component of interest, because it directly influences the revenue from saleable material, increasingly attention is being focused on other attributes. These 'non-grade' variables may have a less direct, but equally profound impact on value, either by reducing potential revenue (eg lowering recovery, deleterious elements, etc) or increasing mining or treatment costs (eg comminution, grindability, throughput, reagent use, etc). Collectively, these variables have been described as 'geometallurgical'. There are three main areas of activity required to realise the value of geometallurgy: 1. acquisition of appropriate data through sampling and measurement, 2. building spatial models of geometallurgical variables, and 3. using these models to optimise value. Each of these is built on the foundation of the preceding step. In building reliable spatial models, it is critical that the amount of error introduced to data by the sampling and measurement processes is understood and quantified, in order that the inherent variability of the component of interest can also be properly understood. Management of the quality of grade variables is now applied (with different levels of diligence and success) across nearly all sectors of the mining industry, not least because of the necessity to adhere to Codes of practice (eg JORC, 2004). The necessity for quality management and at least the broad framework of what to do in practice is reasonably understood by many relevant professionals. There are also a number of tools, including software products, statistical analyses and presentation formats, available for those managing grade data. It is also abundantly clear, that in many cases people have little understanding of why they are doing particular quality control activities, or how to sensibly interpret the results. The same is not true for many geometallurgical variables. In almost all instances the authors have seen, the magnitude of sampling and analytical/measurement error variance embedded in geometallurgical test data is untested and unknown. This is partly because until relatively recently, metallurgical data has mainly been collected for the purpose of process and mill design, with few, expensive tests carried out on 'average' samples of the orebody. Increasingly however, there is a move towards collection of much larger data sets from spatially distributed sampling, and thus a growing necessity to understand the errors inherent in both sampling and analysis of these types of variables, and how to manage them. In order to understand how the quality management practices applied to grade variables can be extended to geometallurgical variables, it is essential to understand the theoretical foundation that supports these practices. This requires an analysis of the concepts that underpin the 'principles of additivity' (Matheron, 1963), the 'theory of sampling' (Gy, 1982, Pitard, 1993), and 'statistical process control' (Shewhart, 1930). Relevant concepts are then integrated to form a foundation to develop methods to improve the quality management of geometallurgical variables. Application of this framework will significantly increase the integrity of geometallurgical data, the reliability of geometallurgical models and ultimately the value derived from implementing geometallurgy. This is an ABSTRACT ONLY no paper was prepared for this presentation.

Mar 1, 2010

By M. Polat

A combined heavy medium-flotation process which incorporates the advantages of two widely employed cleaning methods, namely, heavy medium separation and flotation was used to achieve improved separation of coal from ash at fine sizes and to recover the heavy medium as a substantially recyclable product. The investigation was carried out in two successive phases. In the first phase, tests were performed to deter-mine the effect of different variables such as the medium density, flotation time, magnetite type, etc. on the efficiency of the process using in-plant samples from Homer City Coal Preparation Plant. In the second phase, the optimum conditions determined in the first phase were employed to determine the applicability of the process to a few Central Pennsylvania coals. It was observed that the process was very effective in recovering the magnetite. In most of the cases investigated, the magnetite was separated from the non-magnetic material at approximate-1 to 99 % recovery with a grade ranging from 95 to 99 %. The grade of magnetite decreased with increase in ash content of coal and with decrease in size of magnetite.

Jan 1, 1992

By Thomas J. Peters

In 1984, at the request of the Bureau of Land Management, the Bureau of Mines studied 7,000 acres of the 9,240-acre Little Blitzen Gorge Wilderness Study Area in Harney County, OR, to evaluate its mineral resources. The study area is dominated by a 1,500-ft-deep canyon that was carved by Pleistocene glaciers in gently westward-dipping homoclinal flows of Miocene Steens Basalt. The Bureau reviewed pertinent literature and county mining records During the field investigations, 18 rock samples were collected from basalt dikes, breccia, fractured or porphyritic flows, and 20 alluvial samples from gravel accumulations. Mercury anomalies from sampling by the Oregon Department of Geology and Mineral Industries could not be verified. The mercury might have originated -From the Pike Creek Formation, a known mercury-producing unit that may extend into the study area beneath the Steens Basalt. Any epithermal deposit at depth would be expensive to explore and develop.

Jan 1, 1986

By J. A. Dos Santos

High angle conveyor (HAC®) systems in open pit mining offer many advantages over the traditional, truck only, haulage systems, including: (1) superior energy efficiency, (2) less dependency on petroleum products, (3) less sensitivity to inflation, (4) less labor, (5) less excavation for the amount of ore recovered, and (6) less ramp construction and maintenance costs. Previous studies had revealed the technical and economic feasibility of high angle conveyors. This paper presents the Sandwich Belt HAC® as the vital link to optimization of in-pit conveying systems. HAC development to date is discussed, beginning with studies in 1979, to the first large scale prototype in 1983, to the first commercial unit in 1984, into "the latest commercial installations. Discussion continues with the HAC systems to suit the various open pit mining operations and the corresponding characteristics of the system components, particularly the high angle conveyor. The range of HAC systems from the low capacity (up to 1,814 t/h), low lift (10.7 to 36.6M), highly mobile to the moderate capacity (1,814 to 3,629 t/h), moderate lift (36.6 to 76.2M), intermittently mobile to the high capacity (greater than 3,629 t/h), high lift (greater than 76.2M), semi-mobile, are discussed along with some possible combinations of these.

Jan 1, 1989

Since the comprehensive review of the Persian fields presented by Sir John Cadman last year, operations have proceeded normally. No developments of especial importance fall to be recorded and it remains only to bring up to date the full information given at the beginning of 1933. Controlled production from the Masjid-i-Sulaiman and Haft Kel fields has been maintained at slightly higher rates than during 1932. The figures for the past five years are as follows: These represent crude oil and products piped to the coast but exclude products reinjected into the reservoir, a process that has been in continuous operation at Masjid-i-Sulaiman during the period under review. The systematic delimitation of the Haft Kel field has been continued during the past year and results have been sufficiently encouraging to justify the inception of a wider scheme for distribution of production. Drilling has been resumed recently in the Persian sector of the Naft Khaneh field, and preliminary survey work is in progress for the selection of a site for a refinery at Kermanshah arid the construction of a connecting pipe line. Investigations in connection with the scientific control of reservoir were dealt with in considerable detail in last year's review. This work has been steadily pursued during 1933 and certain of the investigations have been the subject of papers presented to the World Petroleum Congress held in London in July of last year.

Jan 1, 1934

By Terry J. Close

In 1986 and 1987, at the request of the U.S. Bureau of Land Management, U.S. Bureau of Mines personnel studied 7,040 acres of the 7,240-acre Sheep Mountain Wilderness Study Area (OR-006-003) in order to evaluate its identified mineral resources. The area studied is along the divide between the Snake River and Pine Creek about 1.5 mi south of the village of Oxbow in Baker County, OR. No mineral resources or mineral-related activities were identified in the Sheep Mountain study area. The basalt covering most of the study area has no known mineralized sites. However, it contains common agate and opal that is of limited interest to mineral collectors. This basalt (stone) could be used locally as construction material (crushed stone or fill); however, suitable material is wide spread in the region and more accessible to possible markets.

Jan 1, 1987

Provide the technology to remotely reset circuit breakers on continuous mining machines used in extended cuts.

Jan 1, 1994

By W. M. Hart

Business Process Improvement (“BPI”) Change to Survive “It is not the strongest of species that survive, nor the most intelligent, but the one most responsive to change.” [Charles Darwin] “If you want to understand something, try to change it.” [Kurt Lewin, social scientist] Many companies have tried one or more process management initiatives. Each effort may help develop a culture that is more receptive to change. Executive Management needs to be unwavering in support of change with systems and structures, staffing, development of people, measures, with incentives and rewards. General Electric developed principles for quality change management that are necessary for effective, continuing Business Process Improvement (BPI). Change Acceleration Process (“CAP”) One of the tools General Electric developed has been used successfully by companies around the world in a wide variety of industries. This tool, named Change Acceleration Process (“CAP”), is designed to improve acceptance of change. Acceptance is the method by which the creative energies of the workforce can be fully tapped. Over time, every employee receives CAP training at least once, and in many instances three (3) or four (4) times, and will work on one or more High Performance Teams. Thus, BPI can achieve and maintain its goals. The CAP tool focuses on: • Leading Change • Creating a Shared Need • Shaping a Vision • Mobilizing Communication • Making Change Last • Monitoring Progress • Changing Systems and Structures

Jan 1, 2006

Improve the dust-control effectiveness of the Rotoclone1 dry-dust collection systems used on surface coal mine drills.

Jan 1, 1994

By Ernst Lindemann

The SMS group has developed the ultrasound technology “HD scan” for inspection of the internal quality of as-cast products. This method of sample analysis requires less preparation work and is safer than the current, most common technique of etching and/or sulphur printing. Furthermore, this technology offers a three-dimensional view into the sample of the cast product and thus more representative information for a better quality evaluation. The internal quality evaluation can be performed automatically and objectively by software based on clear statistical methods. A quantitative centerline segregation rating can be assigned to each sample, based on the size and distribution of segregates detected by the unit. Internal crack statistic (length, position, orientation, etc.) and narrow side profile can also be measured. Grain macrostructure can also be visualized which allows for a potential optimization of casting parameters like strand cooling, soft reduction or electromagnetic stirring. The accuracy of the new method was proven by parallel metallographic investigations of more than 100 samples of different steel grades and sample shapes. Automatic defect evaluation and classification was compared against macroetching results. It was found that HD scan identified more defects and the visualization of the macro structure could be performed in more cases than with macro etching. All tests, comparisons, further developments and analyses for various steel producers and steel treatment companies have been conducted at the HD scan unit, located at the SMS group headquarters in Düsseldorf, Germany (Figure 1). Based on the results, SMS group has designed a unit which can be used in industrial scale.

Aug 17, 2017

By George S. Dulikravich

An advanced semi-stochastic algorithm for constrained multi-objective optimization has been adapted and combined with experimental testing and verification to determine optimum concentrations of aJ10ying elements in heat-resistant and corrosion-resistant H-Series austenitic stainless steel alloys. The objective was to simultaneously maximize a number of alloy's mechanical properties. This research will result in a rigorous tool for the design of high-strength H-Series steels and other types of alloys unattainable by any means existing at the present time. Such a material-by-design tool will also be able to reduce or minimize the need for the addition of expensive elements such as Cr, Ni, Co, Nb, Ti, V, etc. and still obtain the optimum properties of an aJ1oy.

Jan 1, 2003

By C. D. Iles

The philosophy used in designing and writing Duval's Sierrita mine design programs is discussed. The Sierrita Incremental Design system (SID) is reviewed with emphasis on Pushback Extraction Design (PED). FED is a method by which predesigned pushbacks are sequenced into an optimized period-by-period design that can be directly utilized in daily operations as well as intermediate and long range planning. The advantage of SID is that it provides a practical, mineable open pit design. PED is not a theoretical design system; it is in operational use.

Jan 1, 1981

By S. J. Aresco

The Bureau of Mines has been active in promoting the purchase of coal for Government use under specificetiona that define the requirements in terms of heating value of the coal, expressed in British thermal units, and the composition as shown by proximate analyses. To these, when required, are added the fusing temperature of ash and the free-swelling index. Under most of these specification contracts the bidders guarantee the quality of the coal, end that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled in accordance with instructions3/ issued by the Bureau; the samples are analyzed in the Bureau's laboratory to determine whether the coal is of the quality guaranteed by the contractor and, if it is not, a price adjustment is made. Analyses of the delivered coal and "tipple" samples (samples collected at mine tipples as coal is being loaded into railroad cars or trucks) provide valuable data for use in evaluating future bids. In addition, the continuous sampling of coal as delivered 1s a check on the practical results obtained in burning the coal.

Jan 1, 1953

By S. Whinery

In these times of sharp rivalry, both as to price and quality, among the makers and venders of engineering explosives, it is often desirable to be able to determine the relative energy or value of the various explosives offered for sale, in order to purchase intelligently ; or, having contracted for a large amount of an explosive of a certain standard quality, to be able to ascertain if the manufacturer keeps his product up to the specified standard. The simple and inexpensive apparatus described below was devised by the writer while engaged on the improvement of the Tennessee River, at MuscleShoals, under the direction of' Major W. R. King, U. S. Engineers, in the summer of 1879. It answered the purpose so well that it is thought that a brief account of it may be of interest to other engineers. It consisted, essentially, of an old blacksmith's anvil and a common striking hammer, such as is used for driving rock-drills. The anvil was placed face downward on solid, level ground. In what was then the top of it, a vertical hole, one and one-fourth inch in diameter and about one arid three-fourths inch deep, was made with a ratchetdrill. The surface of the anvil immediately around the drill-hole was made as true and smooth as possible with a file. Next, a new striking-hammer, weighing nine pounds, with a turned and true face, was selected ; and a handle, eleven feet long and about one and a half inches in diameter, was fitted into it so that it

Jan 1, 1886

By William A. Faust

La Colorada Mine was begun in 1993 as a small heap leach mine and was the first operation for Eldorado Gold Corporation. 'This paper describes the growth of the mine to annual production levels near 60,000 ounces of gold and highlights recent improvements that were made to maintain a profitable operation by efficiency gains and cost containment programs.

Jan 1, 1998

By M. Moys

The use of temperature measurements for unusual applications in the analysis and control of column flotation and milling is discussed. This is followed by a review of some of the authors current research in the application of the discrete element method to the modelling of particulate processes, specifically milling, fluidized beds and chute flow.

Jan 1, 2005

By Jan Luca Grunow, Ansgar Bendiek, Klaus Böde

According to the Markowitz portfolio theory the value of a diversified portfolio is higher than the sum of the parts of a portfolio, which is an important consideration for the correct valuation. This is valid for real estate portfolios as well as for mining assets (or enterprises). This paper analyses the application of the portfolio theory to a diversified portfolio of assets in the real estate industry and draws conclusions on further research work to be done in the minerals industry. The volume of real estate transactions is increasing over recent years. As such, the nature of those transactions is constantly changing and in some cases portfolios become more heterogeneous as they are composed of different property categories, e.g. locations and types of use. This makes their economic evaluation more difficult. This paper focuses on the acquisition of a fairly heterogeneous real estate property portfolio purchased by “Commerz Real” in Germany in Q4 2019. For economic evaluation the widely used Markowitz portfolio theory (Markowitz, 1952) was applied. It was investigated whether diversification effects could achieve added value in the form of a reduction in risk compared to the sum of their individual components. As a result the findings of this research could be applied to other heterogeneous real estate transactions and even to mine property portfolio or PPP1 project portfolio transactions.

Jun 25, 2023

By Girnau G

The necessity of effective dust suppression measures during excavation work is just as uncontroversial in tunnelling as it is in mining. In many respects, in fact, the applied technology is comparable. Notwith- standing, given more careful appraisal, it becomes evident that very different starting conditions exist in both these fields: In mining, there are for instance, well organised firms, which in many cases have been active for several decades, carrying out the required drivage and winning operations - and although there are also experienced firms in tunnelling, these generally speaking form a joint venture in order to accomplish a certain project. These "tunnelling firms" which are formed for a short term, normally only exist for a period of two-to three years. They con- stantly reorganise themselves: from the site supervising engineers by way of the foremen and shift overseers to the gangs working on site. The "firm's headquarters" are also re- located when a new project is started up. Then of course, there is often pronounced fluctua- tion among the crews of a single tunnelling project. Seen from this point of view, a safety expert in tunnelling has a far more difficult task than one in mining. He has not the advantage of knowing every corner of the mine for years if not decades on end, of being familiar with the overall organisation of the enterprise let alone knowing many of the men at the face. This ideal prerequisite for effec- tive decisions pertaining to suitable measures for industrial safety and accident prevention taking all weaknesses into consideration given the interplay of the most varied system com- ponents, can practically only be arrived at in mining.

Jan 1, 1987

By W. H. Liu

The stability of floors of large drydocks and wagon tipper sheds at coal terminals is an important matter but quite difficult to solve. Anchors can be used to join floors to foundations thus ensuring the stability of floors by the self-weight of floors and the pull of anchors. In this paper, the author describes the structures and types of the anchors used in the floors of the drydock in Beihai Shipyard and the wagon tipper shed at Shijiu Port, both in Shandong Province China, the determination of bearing capacity of anchors in rock bed of highly weathered granite, the comparison between prestressed anchors and non-prestressed anchors, the construction technology of anchors and the analysis of field experimental data.

Jan 1, 2010

If you are to be and remain competitive in the mining industry, it is vital that your company management systems are efficient. An integral part of today's competition in a ruthless market is to keep internal costs to a minimum. Integrating our core and parallel management systems is becoming an essential strategy to ensure efficiencies are maintained to the highest level, allowing the maximisation of profits, and to maintain that leadership status within our industry. The uniquely designed Integrated Management Process provides the path to develop, implement, and monitor an Integrated Management System in a simple but highly efficient and effective manner.

Jan 1, 1997