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By Jonathan S. Jackson, Bruce P. Ream

Leach water management is one of the few areas in dump leaching subject to operator control. As such, it is of considerable importance. Theoretical considerations indicate that high leach solution application rates are inefficient in washing solubilized copper from dumps. The high rates cause unnecessary dilution of copper values, raising unit recovery costs. Use of excessive amounts of leach solution also cools dumps, resulting in reduced leaching rates. This paper reviews leach solution application methods and details the results of field tests run to determine the benefits and feasibility of low versus high application rate techniques of applying water to dump surfaces.

Jan 1, 1980

By Ronald D. Mariani, Gregory E. Mahoski

BACKGROUND The steel and iron ore industry has had a long history of an adversarial relationship with its union and workforce. The Empire Mine during its first 40 years of existence was no exception. The "we-they" mentality went hand-in-hand with the normal by-product of an adversarial relationship, grievances and arbitration. This relationship was considered the norm and it was not until the late 1970s that consideration was given to changing this relationship. At this time the industry was involved in a fight for existence and the economic pressure demanded increasing productivity to lower cost. The challenge to survive highlighted the fact that an adversarial relationship was not conducive to attaining the needed gains in productivity. The first formal attempt to change the way we worked came in the 1980 Labor Agreement which provided for the opportunity to utilize Labor Management Participation Teams (LMPTs). LMPTs were established at the Empire Mine and they functioned for a couple of years. The teams spent most of their time working on creature-comfort issues and steered clear of dealing with productivity issues. Mine shutdowns had occurred in Michigan resulting in large layoffs, and the union was trying to add jobs and was not supporting teams that could increase productivity and eliminate jobs. When the 1986 labor negotiations began, the local union pulled their support of the LMPT process. Other initiatives were negotiated over the years to foster a change in the culture but, as with the LMPT program, they did not produce the desired culture change. It became abundantly clear: you cannot negotiate a culture change.

Jan 1, 2004

The writer had the pleasure of several months' laboratory tests on a metallurgical process for copper ores devised by Mr. W. H. Corbould, Consulting Engineer, North Queensland. Mr. Corbould's research work in this direction commenced somesix years ago, and he eventually succeeded in obtaining a good extraction of copper and a resulting solution practically free from iron and other impurities. The commercial operation of the process was investigated and special machines with novel features were designed. OUTLINE OF THE PROCESS.The process described in detail in the following pages, required for successful application that the ores contain at least the minimum ratio of sulphur to copper, consistent with the production of sulphadising roasting conditions.

Jan 1, 1921

By J Kleynhans, D Vermeulen, V Cogho

A number of rehabilitated open cast coalmines in SA are already decanting. The paper focuses on the situation at one of these mines where the following information exist: monthly decant rates and rainfall; sulfate concentrations of the decanting water; water level measurements inside the mine prior to decanting; ABA analyses; information about the rehabilitation (drainage slope, vegetation, soil used). A 2D-model was constructed for the mine and calibrated against six years of flow data. About 85 per cent of the decant outflow rate comes from direct recharge on top of the rehabilitated mine while the other 15 per cent is derived from lateral groundwater inflows. The estimated recharge value was 17 per cent of the rainfall. Measured sulfate values showed that the sulfate generation rate for the mine was in the order of 7 kg/ha/d. Conclusions from the study are:most of the water decanting from rehabilitated open cast coal mines is derived from recharge via rainfall; given a specific sulfate generation rate, then: the lower the recharge the less the decant rate but the higher the sulfate concentration of the decanting water and vice versa; future prediction of the decant rate must be stochastic according to expected percentile monthly rainfall values; and as a first assessment of the predicted sulfate concentration of decant water from rehabilitated open case mines, the 7 kg/ha/d sulfate generation rate can be used.

Jan 1, 2003

By Freddy Syvertsen, Ali Riza Tarakcilar, Engin Tan, Derya Dispinar

"It has been shown that the disturbance of the advancing liquid front in the mould cavity may lead to surface entrained defects known as bifilms. These defects can deteriorate the mechanical properties significantly. The developments in the simulation of castings aid many casters. It is quick and economical. Therefore in this work, the aim was targeted to optimise the mould filling of a tensile test pattern design that is used for aluminium alloys. Several different designs, gatings and runner systems were investigated with Vulcan Casting Simulation Software. In addition to the achievement of non-turbulent and quiescent mould filling; other parameters such as temperature profile, porosity and feeding were investigated to optimise the process.IntroductionConsiderable effort has gone into understanding and controlling defects that are formed in aluminium and its alloys during casting. The conventional approach was the elimination of porosity by eliminating hydrogen in the melt simply due to the following reaction:"

Jan 1, 2012

By Charles Catlett

An examination of the census reports' for 1880, which contain a large number of complete analyses of typical American iron-ores, indicates that the existence of barium sulphate in intimate association with iron-ore is rather unusual. Of 94 analyses reported there, but four show any barium sulphate, and the maximum content amounts to 3.04 per cent. The note of the occurrence of considerable quantities of barite in connection with certain iron-ores found in the Pinar del Rio Province of Cuba may be of interest. These deposits are found near the little village of Francisco, about 25 miles west of the city of Pinar del Rio on the Western Railroad of Havana. The principal ridges are anticlines, and consist of very thick deposits of sandy shales and slates containing a large number of little veins of white quartz, which, by the gradual disintegration of the mass of the material, is left covering the surface. This quartz occasionally shows sulphide, but is generally barren of any such indication. At times lenticular masses of a more or less pure limestone mere observed in these slates. The shales, which are of light color, are occasionally talcose. The formation would tentatively be classed as the Lower Cambrian, arid the heavy ridges of comparatively horizontal limestone found in the anticlinal valleys as the Upper Cambrian. Along the crest of these slaty ridges deposits of iron-ore are found which are apparently in place, and were probably formed by replacement of masses of limestone similar to those noted elsewhere. The ready disintegration of the slates, arid the

Jan 1, 1908

By R. W. Jenkins

TRACKLESS equipment is being used by the Coplay Cement Manufacturing Co. to develop a folded limestone deposit economically and safely with inexperienced men. Cost and quality of development stone results in a saving when it is used in- stead of outside sources of limestone. This favorable cost has been attained by following a methods development and training program described in this paper. It is expected that further savings in favor of the mined stone will be made when stopes now being prepared are in production. The present equipment will be used for loading from stope draw points. The limestone is blended with quarried cement rock to serve as raw material for Portland cement, first produced in this country by Coplay Cement Manufacturing Co. from a process developed by its president, David 0. Saylor, in 1873. For many years the cement rock alone or with a small amount of added limestone was used for raw materials. Later as specifications were raised and the richer portions of quarries were depleted, limestone from outside sources was required in increasing amounts. In 1925 D. J. Uhle, the general manager, began to prospect company property for limestone.

Jan 1, 1954

By W. J. Babyak, F. N. Rhines

It has long been supposed that, regardless of the mechanism by which grain boundaries increase the hardness of a ductile metal, the effect should be linearly proportional to the grain boundary area. At the present time two methods for determining grain boundary area in an isotropic aggregate are available. The first, derived by Angus and Summers,' presumes that the grain boundary area is equal to 3vn, where n is the number of grains per sq mm in a random section through the metal. This estimate is based upon the assumption that the grains are equivalent to cubes whose faces correspond with the grains as observed in the micro-section. Measurements on copper, bronze, and a brass showed that a nearly linear relation exists between 3vn and hardness. This is illustrated, for the case of brass, in Fig. 1. The second method, developed independently by Smith and Guttman2 and by Duff in, Meussner, and Rhines,3 is absolute and employs a simple linear intercept count for measuring grain boundary area. It involves no assumptions with respect to the shape and distribution of the grain boundaries. The total surface in unit volume is 2 NL , where NL is the number of intercepts between grain boundary and unit length of a test line passed randomly through the sample. In practice, NL,, the average number of grain boundaries intercepted by unit length of traverse across a prepared microsection, is ob-

Jan 1, 1961

By Jianliang Li, Xi Peng, Guorong Lu

This paper describes a wind tunnel modelling study on airflow and pollutant concentration in a large open pit mine located in southern China. A 1:1000 scale model of the surface mine was fabricated and placed in a wind tunnel. Airflow velocity in the test section of the wind tunnel can be continuously adjusted from 0.3 m/s to 6.0 m/s. In this study, both the present pit condition and the projected final pit condition were modelled. Airflow direction and velocity profiles were obtained. The impact of wind direction and velocity on airflow was also studied. The pollutant concentration distribution in the open pit was simulated using smoke, and a distribution profile was obtained. Respirable dust concentrations at the mine site were measured, then its concentrations at the projected final pit condition were estimated using the obtained pollutant concentration distribution profile. Under normal meteorological conditions, it is expected that the respirable dust concentration for the final pit should not exceed the government standard. Key Words: wind tunnel modelling, open pit, surface mining, scale model, mine ventilation, airflow profile, point source.

Jan 1, 1993

By R. Binning

"Economic high density mineral reclamation and subsequent transportation of solids through a pipeline presents many formidable engineering problems.Mineral reclamation system design by theoretical formulas is almost impossible because solids composition, ie. concentration, velocity, moisture content, solid size, etc. can only be controlled within a broad pumping range.Traditionally this has restricted pumping to relatively dilute slurries whereas it is usually preferred, because of economic considerations to reclaim as high a concentration as possible.At Toyo/De-Velde Corp. we recognized these pumping limitations and began to develop and manufacture a range of standard and auxiliary equipment that would exceed these technical restrictions.MATERIAL RECLAMATION & PIPELINE INJECTIONTo minimize fluid usage and increase material reclamation efficiency we designed a submersible dredge mixing pump that uses most of its energy to pick up material from rest, mix it with fluid into a highly concentrated slurry then push it firmly into a pipeline.Where material is too compacted to be mined by the standard submersible mixer pump, auxiliary high torque self contained submersible excavators can be fitted around the periphery of the mixer pump. This is to facilitate excavation and break up of the compacted material into a slurry.High flexibility of this system can be achieved by combining the many equipment variations available into the most efficient format to fit individual site requirements.Whatever combination of equipment is selected, torque is nullified by counter rotating excavators against each other. This increases effective excavator/material bite torque but also allows mixer/excavator rig suspension by cable for deep water material recovery."

Jan 1, 1985

The writers of these notes, having conducted some tests on the steam consumption of air compressors under varying conditions, believe that the detailed results of such tests will be of interest to the members of the Institute, and may lead to the contribution of further and more valuable information, of benefit both to manufacturers and users of this class of machinery-to the manufacturer in that he frequently has the opportunity of giving a very thorough test to the machine in the shop, and-tothe user or purchaser by making clear to him what may be reasonably demanded of a high-class machine. It must be remembered that, though of the highest importance, a low steam consumption is but one of the many features of a high-classmachine; for the present, however, it has been considered advisable to confine the paper chiefly to the first-mentioned aspect, with such information concerning the air ends as is obtained along with the steam consumption tests. Unfortunately, too few of these tests are conducted, and but few results are published, therefore the writers feel that no apology is needed in bringing their results before the members.Some nine months ago the Brilliant Extended G. M. Co. was supplied with a compressor by Messrs. Thompson and Co., of Castlemaine, and with the object of testing its actual performance.

Jan 1, 1907

By G. F. Revey

Most commercial explosives contain from 70% to 94% (by weight) ammonium nitrate. When some of the explosives end up in shot rock and ore, through either spillage or incomplete detonation, ammonia and nitrates can leach into the ground water. In recent years, state and federal regulators have applied more stringent water-quality standards, particularly at new mines and development projects. When mining conditions permit, bulk ANFO, a mixture of ammonium nitrate and fuel oil, is the explosive of choice. ANFO is less costly than other explosives but it dissolves readily in water. Several case histories in the United States and Canada show a clear connection between uncontrolled losses of bulk explosives and high nitrate levels in mine effluents. Mining companies have tried several approaches to reduce ammonia and nitrate levels in groundwater. These approaches range from controlling explosive losses to treating the mine effluents. In this paper, controlling explosive losses is addressed For both packaged and bulk explosives, guidelines to limit losses during storage, handling and use are described in detail.

Jan 1, 1997

The ever-increasing power (and decreasing cost) of computers has opened up substantial oppor¬tunities for 'Vision'-based systems in both on-line and off-line control. This paper reviews image analysis applications in use at the Julius Kruttschnitt Mineral Research Centre (JKMRC) for: •blast and mill feed size monitoring; •AG/SAG mill model-based control; •mineral liberation; and •froth flotation control. The SPLIT™ image analysis system is being used to estimate muck pile and ROM feed sizings. AG/SAG mill feed sizing is being used in a dynamic model for mill control. A new generation mineral liberation analyzer has been developed with Philips Electron Optics. The Philips-JKMRC mineral liberation analyzer offers a substantial improvement in resolution and speed over previous developments. While on-line liberation control continues to be something of a pipe dream, measuring liberation "one shift behind" is now feasible. A robust instrument has been developed to measure flotation froth bubble size and velocity. The instrument also derives a parameter that allows different froth textures to be distinguished. The instrument has been used for on-line control in coal and sulfide flotation. For coal froth, an online ash estimate has been achieved at one site and is being tested at other sites. Overall, image analysis is finding many applications in mineral processing and control.

Jan 1, 2000

By Albert G. Funk, Gary M. Thornley

The available energy of aluminized ANFO and aluminized slurry blasting agents has been measured by seismic methods, calculated theoretically, and compared. With aluminized ANFO it is concluded that aluminum concentrations should be restricted to less than 10 percent because of diminished energy yields at high aluminum concentrations. However, with aluminized slurry it is concluded that efficient use of aluminum can be made at aluminum concert"rations up to 18 percent. It is further concluded that the difference in efficiency of use of aluminum by these two classes of blasting agents results from a higher contribution to useful work from the condensed detonation products of the relatively higher density aluminized slurry blasting agent.

Jan 1, 1981

By A. Suzue, T. H. Okabe, Y. Taninouchi

Methods for the physical separation and enrichment of platinum group metals (PGMs) from autocatalyst scrap were studied in order to develop an environmentally friendly and efficient recycling process. In general, an autocatalyst has a honeycomb-structured ceramic substrate that is coated with a catalyst layer containing platinum (Pt), palladium (Pd), and rhodium (Rh). Therefore, physical separation of the PGM-containing catalyst layer directly from the ceramic substrate is favorable for upgrading the autocatalyst scrap. In this paper, the authors present a scrap-upgrade process consisting of electroless iron plating and magnetic separation techniques. Iron was plated on the surface of a catalyst sample used to represent an autocatalyst, which was then crushed and magnetically separated. The Pd in the catalyst sample was successfully extracted and concentrated in the magnetic powder. Under certain conditions, the process increased the Pd concentration by a factor of 4 and recovered 89% of the Pd in the autocatalyst sample.

Jan 1, 2014

By David G. Dixon

From its first implementation for the recovery of gold from low-grade ores by cyanidation in the early 1970s, heap leaching has developed into a key hydrometallurgical technology, in conjunction with solvent extraction and electrowinning, for the recovery of base metals, including most notably copper from both oxides and secondary sulphides, and more recently, nickel and zinc. And, given recent advances in bioleaching with thermophilic microbes, the successful application of heap leaching technology to low-grade primary copper ores seems only a matter of time. However, with each new development, it becomes increasingly apparent that the successful application of heap leaching technology will ultimately depend on our having an ever more complete understanding of the fundamental processes underlying it. Much work has been done toward the development of this understanding, on many different fronts. In this paper, a critical overview of heap leach modeling work to date is presented in terms of the most important phenomena which occur during heap leaching, and potential directions for future work are discussed.

Jan 1, 2003

By Jan Nemcik

Among other products steel mesh has been used successfully for many years to support strata and minimise loose material from falling into the mine opening. Installation of steel mesh has proven to be difficult to automate and many other products, such as Thin Spray-on Liners (TSL), have been proposed as a replacement. Ideally, the mechanical properties of these products should be superior to those of the steel mesh, however, most TSL trialled in mines to date have been weak and in addition have had slow cure times, as a result none of these materials can seriously compete with steel mesh. Now a new polymer product that cures in seconds and forms a stiff strata binder that surpasses the properties of steel mesh is under development at the University of Wollongong. To enable selection of a suitable polymer material for roadway skin reinforcement several numerical models were constructed to investigate the role of interface roughness and the influence of polymer stiffness on load transfer along the rock-polymer interface. Laboratory tests indicate that the shear adhesion of the rock-polymer interface can be substantial while the tensile adhesion can be much lower. The models indicate that the natural stone roughness and surface waviness plays a major role in shear adhesion while the elastic properties of polymer liner can significantly influence the polymer ability to resist fracture opening.

Oct 1, 2009

By Santhanam Ramesh

"The shell (exoskeleton) waste of shellfish such as shrimps and crabs is the raw material in the extraction of chitosan, a polymer. Chitosan has several medicinal values such as reduction in cholesterol, urea and creatine in the blood. It is estimated that about 40000 tonnes of chitosan may be obtained from all chitin yielding invertebrate sources of India and a foreign exchange of 600 million US$ could be earned annually. Awareness has to be created among sea food processors to put up plants to convert shellfish wastes into chitosan. Similarly pharmaceutical industries may use chitosan in the development of new drugs. Types of training and awareness programmes to be organized for entrepreneurs, sea food processors and pharamacists are discussed in this paper.IntroductionIndia earns annually foreign exchange to the tune of 0.8 million US$ by exporting processed marine crustacean shellfish resources such as shrimps, crabs and lobsters (Figure 1) through 300 sea food processing industries. At present, only a small quantity of shell wastes (exoskeleton) generated from the above is utilized as an ingredient in fish feeds and hence much of the wastes are disposed off either as land fill or by direct dumping in sea. These wastes containing primarily chitin could be the major raw material for the production of a proteinaceous byproduct viz. chitosan, a highly valued pharmaceutically important source"

Jan 1, 2008

The twenty-eighth regular meeting of the Rocky Mountain Coal Mining Institute, which was held jointly with the Utah Section of the American Institute of Mining and Metallurgical Engineers, was called to order at eleven o'clock A. M., Monday, March 11, 1929, President Otto Herres presiding. Introductory remarks were made by John M. Boutwell, Chairman of the Utah Section of the American Institute of Mining and Metallurgical Engineers, who outlined the intent and purpose of the joint meeting, and its co-operative program. He spoke of the in- creased recognition being given to men in the engineering profession by the public, which has recently been manifested by the election of President Hoover, an engineer of outstanding ability, and the re-election of Governor Dern to the Governorship of the State of Utah. He then introduced Governor Dern, a fellow member, to make the address of welcome. Governor Dern assured the meeting a hearty welcome. He spoke of Utah as one of the important mining states of the Union, particularly in metal mining; the magnitude of Utah as a coal mining state being limited only by its market; of the enormous coal resources of Utah, and the problems of the coal mining industry.

Jan 1, 1929

By Davies L, Jeffreys J

The Broken Hill Proprietary Company Limited (BHP) has been successfully using mini computers in its open cut strip and pit coal planning for the past six years. A recent development within the computerised Seam deposit User oriented Mine Planning System (SUMPS) provides the facility for the generation, evaluation, and simulation of colliery workings.Existing computer programs for collieries were studied, but none met the requirements of BHP's underground mine planners.Consequently, it was decided to develop programs, based on those existing within BHP for open cut strip and open cut pit mine planning. The new planning facility was designed to enable any number of proposed colliery developments and operating plans to be evaluated against optimistic, most likely and pessimistic geological lease area interpretations.In mine planning, sensitivity studies should be conducted to determine the likely effects on production, development costs and colliery economics of changes in mine design and budgeted equipment productivity. By automating the manual calculations involved, the computer programs provide the ability to conduct numerous and extensive sensitivity studies. Hence an optimum mine design for budgeting purposes can be derived quickly with an improved degree of confidence in the long term viability of the proposed development.

Jan 1, 1982