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By P. Tsang, S. S. Peng

The stability of longwall chain pillars depends not only on the mechanical properties of the coal and surrounding rocks but also on geological and mining conditions. To evaluate the effects of each variable, orthogonal experimental design was employed in a significance analysis. The study concluded that the stability of longwall chain pillars is mainly controlled by the ratio of pillar stress to pillar strength, the ratio of the Young's moduli of roof to coal and floor to coal, entry width, pillar width and the internal friction angle of coal. Additionally, horizontal stress, panel width and mining height also play a significant role.

Jan 1, 1996

By D. Lenartowicz, K. R. Alexander, M Collings

Cosmo Howley is a gold deposit in the Northern Territory of Australia. The geology is complex and the input of geological data is an important part of the grade control process. As the geology of the deposit has become better understood, grade control and mining techniques have evolved to meet the changing circumstances. Present grade control depends on the use of angled blast holes, 21/2 benches and selective mining. Data is processed on site using 2 386 PC's running Surpac software. An environmental protection programme is employed, including soil stripping and stockpiling, sulphide waste containment and water quality monitoring.

Jan 1, 1989

By Nelson R. Shaffer

Secondary minerals, amorphous materials, and biologic entities that form on building stone can cause aesthetically unflattering changes in color and may even result in stone decay. Techniques to determine causes of such changes generally have entailed destructive sampling and often required chemical, thin section, X-ray, or other relatively slow, expensive measurements. We have found that a rapid leach of in-place stone using small volumes (50-100 ml) of very pure distilled, deionized water provides recovery of sufficient dissolved material to help diagnose stone anomalies. Water is sprayed onto the stone and collected in a nonwetting plastic pan. Ion chromatograph analysis of waters thus collected from more than 160 sites showed wide variations in concentration of anions F, Cl, NO3, and SO4. Anion analyses were made in minutes for less than $20 per sample. Cations Ca, Mg, Fe, and Sr also were detected, and analyses might be used to determine mineral sources using equilibrium computer models. Solid particles filtered from the samples can be examined microscopically to provide further information about atmospheric agents affecting the stone. The collected water can even be evaporated to precipitate dissolved minerals. Chloride values in samples rinsed from stone ran as high as up to 17,000 ppm, nitrate to 100 ppm, and sulfate to 1,000 ppm. Limited data also indicate that measurable amounts of fluoride were found in some of the rinse waters. Chlorides were most abundant in areas where the stone has become dimpled or spalled. Nitrates were generally higher near ground level, and sulfate tended to be more abundant in samples taken from higher sites or from sheltered sites. Dark-stained limestone tended to yield less soluble material than clean-looking stone. Leachable elements were higher in samples from urban areas. Most of our data are from limestone buildings, but the technique works on other types of dimension stone, man-made construction materials, and even natural outcrops of rocks. Longitudinal studies show that soluble materials vary through time and are affected by climate. This rapid, in situ leach technique, although still being perfected, shows great promise in the diagnosis of stone alteration and in the evaluation of stone treatments because it is completely nondestructive.

Jan 1, 1999

By C. I. Wilmot, A. Sass, J. VanDeBeuken

Introduction This chapter addresses the need for operation manuals, presents an outline as a guide for writing the manual, discusses who should write the manual, suggests how it is implemented and gives tips to potential manual writers. Theory & Purpose of Operating Manuals The primary objective of the operating manual is to provide every operator the benefit of a uniform minimum level of training. This training is not only critical to the safety and efficiency of every employee, but also provides a basis for incorporating future operational improvements into standard and emergency procedures. The manual promotes safety through- out and additionally has a special section devoted to safety. The operator should be able to find information on chemical and physical hazards as well as be exposed to safety procedures for such items as motor lockouts and tank entries. The operating manual will usually reference a separate safety manual or incorporate parts of the safety manual. Safety is also promoted through standardized procedures for operation of equipment. Standardized operation is the second most important reason for the writing of manuals. If equipment is started, operated, and shut down in a consistent manner, then operational efficiency should be maximized. If it is not, then the procedure is adjusted until it is. The experience of many can be condensed into set responses for start up, shutdown, steady state operations, and upsets. Implicit with the standardized operation objective is a minimum level of training the operator will receive by thorough familiarization with the manual. The ability to know the contents of the manual is a basic requirement for operator status. The operating manual serves as a basis for a training program both at the start of the new plant and as new operators are hired or promoted into the job. The operating manual is a collection of at least part of the knowledge that "key people" own and will cushion the loss of key personnel for whatever reason. The manual can only fulfill these lofty goals by being a dynamic document. Manuals must change as equipment is modified and superior techniques evolve. To be effective they must be periodically updated, so word processors and reproduction

Jan 1, 1986

By Malcolm Roberts

Extensive personal experience in the USA and Australia has shown that Australians working in suitable work environments are capable of world class performance. To build such work environments, mining leaders need to ditch two common management approaches that have not succeeded. Firstly, stop relying on traditional methods of trying to change people's behaviour simply by using communication alone to change attitudes and then change behaviour. Analysis of human behaviour explains why this approach fails in all industries. Secondly, stop trying to improve productivity by just running harder and increasing capital investment. Understanding work processes explains why this approach has limited success. These two approaches underlie problems commonly mentioned by many Australian mining executives: • negative or inadequate attitudes prevailing among Australian miners and managers including the lack of ownership of business goals among people at many levels • inadequate development of managers and accountability • lack of a competitive advantage in an industry in which labour costs are around 50% of mine site cash costs at many mines, and, • logical, emotional and physical barriers to change.

Jan 1, 1995

By O. Ofor

Finely-ground hematitic ore, too high in silica (quartz) to be commercially viable, was treated by emulsion flotation. A three-component emulsion mixture was used at temperatures ranging from ambient (22° C) to 30° C, 40° C, 49 °C, 59° C and 68° C. The optimal emulsion dosage and composition at ambient temperature were used to determine that dosage for higher-temperature flotation tests. The crushed ore (100%, -8 mesh) was repeatedly washed with tap water, and the filtrate's ionic content was analyzed. The separation efficiency values (a measure of the selective separation and concentration of hematite from gangue minerals) demonstrated temperature dependence, with marked increases at temperatures above ambient. The optimal separation efficiency occurred within the range from 30° C to 60° C. The improved separation efficiencies at temperatures exceeding ambient are explained by quartz depression. This depression is attributed to: • the precipitation of quartz-activating cations, principally calcium and magnesium, at increasing temperature; and • temperature's effect on the collector's solubility and attachment to the aqueous hematite surface.

Jan 1, 1993

By J. Shibata

Separation of rare earth, especially Nd and Sm, was investigated by batch and column methods with a solvent impregnated resin. The solvent impregnated resin was prepared by impregnation of organo- phosphorous extractant whose trade name was PC-88A into a macro porous resin. The adsorption behavior of rare earth with a solvent impregnated resin in a batch method is the same as that with solvent extraction. In a column method to separate Nd and Sm, the effective separation in both adsorption and elution processes can be attained by setting suitable conditions, such as bed height, flow rate and concentration of eluent. Neodymium which is a lighter rare earth is separated from Sm an adsorption step, while Sm in which is a heavier rare earth is recovered in an elution step. From the integration of breakthrough and elution curves, yield of Nd and Sm is calculated in the condition of 100% purity. It was found from the results of life test of the resin that the solvent impregnated resin can be repeatedly utilized at least 20 times.

Jan 1, 1995

By Todd A. Duex

The Richmond Hill Mine has recently completed a reclamation plan to mitigate Acid Rock Drainage (ARD) which was identified at the toe of the former waste rock pile in 1992. Reclamation activities began in 1994 with the removal of ARD material from the waste rock pile and placement of this material in the former pit. This material was then isolated from the near surface environment by a low permeability capping system designed to minimize water and oxygen flow into the material. The capping system consists of, from bottom to top, six inches of limestone, 18 inches of low permeability clay liner, 4 and one-half feet of thermal barrier/drain layer, and six inches of topsoil. This capping system was completed in 1995. An extensive program is in place to monitor the effectiveness of the reclamation plan, and includes measurements on moisture content movement, temperature, oxygen content, and groundwater impacts. Monitoring has been ongoing since the completion of reclamation. This monitoring plan is demonstrating the success in isolating the material from the near surface environment and minimizing the impacts to the surrounding environment.

Jan 1, 2000

By David J. Dyet

Computer applications in the past five to seven years have become a typical and necessary practice in most modern geological offices. Manual calculations, interpretations and plotting of data can be, at times, quite tedious, inefficient and lacking in ac- curacy. The introduction of geostatistical and geological software can eliminate these problems. Computer applications in the uranium industry are not new; however, they are constantly being developed. A variety of soft- ware programs are available. Generally, these programs support most geological and geostatiscal applications in uranium mines. The Rabbit Lake Operation - Eagle Point mine in Northern Saskatchewan is a high grade mine, as one such case. Computer applications at the Eagle Point mine have been a mainstay in the geology department, since the mine's collaring in 1991. This paper presents a discussion on descriptions of programs, operations and applications of computers. It also explains and de- scribes the radiometric equipment used at Eagle Point. This pa- per will demonstrate how, by using computer systems, mine site information flows reliably with the involvement of computers.

Jan 1, 1996

By B. Kendall

"ISSUES ASSOCIATED WITH HAND DRILLING/JACKLEGS In coal mines, hand held air, electric, and hydraulic powered drills are used along belt conveyors, in single entry development, in entries where there are obstructions, and in long wall recovering bolting. In hard rock mines pneumatically powered “jack leg” drills are typically used in narrow vein mining. Drilling and bolting in narrow confines has traditionally been performed with pneumatically or hydraulically powered hand-held drills or newer electrically powered hand held hammer due to their low cost, simplicity of operation, and extreme flexibility due to their small size. Mechanized equipment has typically been too large, too expensive, inefficient due to the confined space, and too restrictive due to lack of flexibility for use in narrow confines. Although the hand-held equipment is effective, it requires operator exposure to certain inherent hazardous conditions in use. These include falling rock from the roof, rib, and face; tripping hazards; bending twisting lifting hazards; high noise levels; and chemical fumes from the pneumatic exhaust. The operation of the hand held equipment can adversely affect the long-term health of the operator – continual jackleg operation frequently results in long term damage to hearing, shoulders, arm and wrist joints, and back injuries. This results in a reduction in life style for the operator and higher personnel turnover rates for the mining company. Hand held drills also typically have limited thrust and torque capability which limits their ability to push long resin bolts, inadequate torque to properly install resin bolts, or to properly torque mechanical or tensioned rebar bolts. Hand held drills do not offer any type of protection for the operator from roof or rib falls. They do not offer any means for handling roof or rib mesh. Since the operator stands on the ground the maximum safe drilling height without use of a ladder or “riding the drill” is limited to 8’ (2.44M)."

Jan 1, 2015

By Gordon V. lewis

The Penjom gold mine treats highly preg-robbing carbonaceous ore by using relatively inexpensive gravity and hydrometallurgical methods. The mine is a joint venture between Avocet Gold Limited, a subsidiary of Avocet Mining PLC, a U.K listed mining company with interests in gold and tungsten, and the Pahang State Development Corporation (PKNP) who receive a 2% royalty. The operating team at Penjom embarked on a programme of innovation during 1998 following a realisation that almost all of the primary ore in the gold deposit was highly carbonaceous in nature. Earlier attempts at desliming and leaching the deslimed product through a normal CIL circuit had failed, and through shear necessity, the team turned to new technologies which were considered most suited to the ore characteristics indicated from pre­feasibility testwork. Between April and September, 1998, the mine introduced three key processes, which combined represent the elements of "The Penjom Process". The gravity circuit was boosted to maximise the capture of leachable sulphide and free gold from the relatively carbon free cyclone underflow stream, kerosene and diesel blanking was introduced to treat the cyclone overflow and RIL (resin-in­leach) technology utilised to replace the existing CIL (carbon-in-leach) circuit. Further experimentation with selective resin in partnership with Mintek of South Africa yielded a significant improvement to the process during 1999. Minix­Dowex resin was introduced mid year to replace a non-gold selective resin, which had been used in a flotation/batch leaching circuit for about nine months. Lower carbon levels in the feed at that stage led to the abandonment of flotation and the introduction of continuous RIL, which has been adopted as the major chemical process at the Penjom gold mine since September, 1999. Given the proven performance of the circuit to date, this process may be considered as a low cost option for the treatment of highly carbonaceous ores, particularly those which are not refractory and contain a reasonable percentage of free gold.

Jan 1, 2000

By J. E. Rourke, O&apos

This paper describes the use of rock index property testing to obtain rock properties that a.re useful in the design and construction planning of an underground development for civil engineering or mining projects. The index properties discussed include (1) point load; (2) Schmidt hammer hardness; (3) abrasion hardness; and (4) total hardness. The first two index properties correlate to uniaxial compressive strength and Young's modulus. Discussions are given on the relationship to rock mass properties and the integrated use with semi-empirical, geotechnical design methods. The latter two properties correlate to construction performance parameters and some experience is cited. Examples of data are presented from an index testing program carried out on siltstone, sandstone and limestone rock core samples from a deep borehole drilled in the Paradox Basin of Utah for a nuclear waste repository site investigation.

Jan 1, 1988

By Wolfgang Baum

The objective of this presentation is to demonstrate the utilization of process mineralogy to improve the plant performance of a large gold-silver operation. From raw ore to tailings, from concentrate to off-gases, nearly all aspects of the recovery process have benefited from the mineralogical work. The involvement of a process-oriented mineralogist on a routine basis permitted the plant to "unlock" the reasons for process problems and to take corrective measures such as adjusting and modifying the mill circuit and the process parameters. Process mineralogy has also been of substantial value for the selection and operation of equipment. This resulted in a more cost-effective operation with improved precious metals recovery and better by-product quality. Specific modifications made in recent years are largely related to mineralogical factors, particularly the inherent precious metals mineralogy and alteration characteristics of the ore.

Jan 1, 1998

By Luis Elu, Andy Bolland, Jack Simmons

The gold refinery at Barrick Goldstrike Mines has increased production to more than 2,000,000 ounces poured per year while reducing the labor requirement. Safety and health has not been compromised with this increased production and in fact incident rates and exposures have reduced over the past five years. Streamlining procedures, improving ergonomics and the wise use of unique innovations has accomplished this significant achievement.

Jan 1, 1998

By J. M. Gambogi

Demand for titanium minerals and pigments was nearly unchanged in 1996 compared with 1995. However, through mine expansions and process optimization by the TiO, pigment industry, the available supply of titanium minerals and pigments increased moderately. At the end of 1996, exploration, development and expansion programs were ongoing in the mining sector. But expansion projects in the pigment sector were delayed pending increased demand.

Jan 1, 1997

By Chen Ziming, A. Burkert, A. L. Mular

A mechanism has been proposed for autogenous grinding that involves three distinct types of breakage: self impact breakage, media breakage and abrasion. Based on this analysis a mathematical model and an autogenous grinding simulator have been developed. Using pilot plant data fitted to the model, the simulator was tested and employed to examine both the scale-up problem and the effect of feed size distribution on performance.

Jan 1, 1995

By Howard R. Postovit, Bonnie C. Postovit

Raptors are birds of prey. In recent years, these birds have become highly regarded and have been given protection under various state and federal statutes. Surface coal mining can have both negative and positive impacts on raptors. Mitigation strategies and enhancement techniques can be implemented to alleviate negative impacts. The success of habitat reclamation will determine the long-range impact of mining on raptors.

Jan 1, 1989

By P. M. May, J. S. Solis, G. T. Hefter

Chemical speciation plays a critical role in many areas of gold processing. These include the formation of HCN in plant liquors, interference by copper in the extraction efficiency of gold, the recovery of adsorbed gold, and the behaviour of plant effluents in the environment. Thermodynamic modelling provides a cost-efficient method of rationalizing and even predicting of chemical behaviour. Unfortunately, because thermodynamic data for cyanide complexes are of poor quality and few are known under hydrometallurgical conditions. Such models are currently of limited use. This paper describes recent work on the thermodynamics of cyanide complexes of a range of metal ions. Data will be presented on the stabilities and enthal­pies (heats) and entropies of formation of a variety of metal ion species determined by potentiometry and calorimetry. Particular emphasis will be placed on the Cu(I)/CN- system.

Jan 1, 1995

By C. A. Fleming, C. J. Ferron, I. Dymov

An oxidized gold/silver ore from Mexico has been evaluated at Lakefield Research in order to develop an economically viable treatment flowsheet for the recovery of gold and silver. Initial cyanidation test results indicated that at least 20 kg/t cyanide was required for maximum gold and silver extractions, due to high cyanide consumption by an oxidized zinc mineral present in the ore. A process was developed for the recovery and recirculation of the cyanide from the leach liquors. The proposed flowsheet included direct cyanidation, CCD and Merrill-Crowe, followed by precipitation of the zinc associated with cyanide with sodium sulphide and recycling of the regenerated cyanide liquor to the leach circuit. The process was demonstrated during a continuous pilot plant. A mill has been erected recently in Mexico and has been operating using this flowsheet.

Jan 1, 1997

By V. Fred Swanson, J. Patrick Glynn

The environment for process engineers today is very different from 20 years ago. The ideas and mathematical description of models for a multitude of different unit operations is an ongoing development. The computer tools to deal with the mathematics are readily available and specialist companies have developed, tested and verified their models. The challenge for the process engineer is to know which package to use and to know whether a particular application is the most accurate for the specific process. Metallurgical simulation programs today are well known and proven. Certain programs are specialized while others are broader based. The needs of each user are dependent on the application. Typically, most users require the following operations: • Comminution • Flotation • Hydrometallurgy • Pyrometallurgy • Additional requirements could be defined as: • Thermodynamic capabilities for solids, phases, and gases • Dynamic simulation • Data analysis tools • Coal oriented operations • Diamond oriented operations

Jan 1, 1997