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By Christopher Haycocks

Successful ground control is an essential part of all viable underground mining operations. To a large extent ground conditions influence the choice of mining methods, percentage and cost of extraction, and often the degree of safety that can be achieved. Utilizing the computer for ground-control planning offers great potential under many diverse conditions as not only are computations facilitated, but also details of the often complex geologic and structural framework of the mine can be readily stored and retrieved. Two basic approaches have been developed for applying the computer in solving ground-control problems. The first uses an analytical method, such as the finite element technique, for solving a specific problem. The second is more general and involves storage of geologic data and application of general design equations. The latter has found wide application in stratified deposits. It is the purpose of this chapter to describe both approaches as they are used for improving the ground-control aspects of mine planning.

Jan 1, 1979

By Andrew T. MacKenzie, Paul A. Rantala

Predictive pastefill rheology (flow characteristic), models have long challenged pastefill practitioners. While the methodology and practicality of recipe formulation is attainable in most locals, the remaining challenge has been to devise a predictive mathematical or empirical model of paste flow characteristics. Flow phenomenon can now be assigned mathematical and physical basis. The authors herein disclose physical and mathematical methods that demonstrate how operators could proceed when designing reliable pastefill systems. Knowledge presented will allow users flexibility in adjusting flow-rates. Laboratory data shows stiff pastefill delivery design can be derived through mathematical relationships of particle size, material characteristics and pipe diameter.

Jan 1, 2001

One of the major objectives of cost analysis is to enable the manager to predict the financial outcomes of decisions. To accomplish this, the future costs and benefits of alternative courses of action must be determined. If care- fully used, information about past financial performance can be helpful in this analysis despite the fact that, by definition, financial reporting information is historical. In many cases, both revenues and costs need to be estimated for decision- making. For the production manager, additional revenue is a result of increased throughput or recovery of valuable material from the stream of mined material. A reduction in operating cost, although similar to a revenue increase in its financial impact, is estimated using slightly different techniques. Generally, the estimation of cost is more difficult than the estimation of revenue. Most cost estimates have two components: an estimate of fixed costs and an estimate of variable costs. As discussed in chapter 5, the total cost of an activity during a specified period can be expressed as: Total cost = (Variable cost per unit of activity) x (Units of activity) + Fixed cost or TC = VX+F

Jan 1, 1999

By P. Somasundaran, Bruno Lartiges

Two different groups of mechanisms have been considered in the past to explain the effects of chemical additives on grinding. While one group of explanations is based upon alterations of surface and mechanical properties of the individual particles, the other group depends mainly on the arrangement of particles and their flow in suspensions. In this paper some of the past work on grinding aids is reviewed and attrition grinding of a commercially important ceramic material, zirconia (stabilized with yttria) with polyaaylic acid as grinding aid, is studied in order to determine the effect of the aid on the ground product itself. It was observed that even though polyaaylic acid did cause a drastic decrease in the viscosity of the pulp, it did not have any major effect on the grinding of zirconia at least up to 2000 ppm and only minor detrimental effect above it. Importantly, complexation by the polymer was found to cause extraction of yttrium into solution with possibly significant changes in the surface chemical composition of the product.

Jan 1, 1992

By E. V. Manlapig, B. K. Gorain, N. W. Johnson, K. Ward

A flotation model developed at the Julius Kruttschnitt Mineral Research Centre was used to predict the performance of copper rougher and scavenger circuits at the copper concentrator at Mount Isa Mines. The model describes the kinetic response of an ore in a flotation cell in terms of ore floatability, cell characteristics and froth recovery. The floatability parameters of the rougher feed ore were obtained directly from a detailed plant survey. Flotation analysis was carried out for twenty different size-by-liberation classes to account for the effects of particle size and liberation on flotation. This paper investigates the capability of the model to predict the flotation behavior of 20 different size-by liberation classes in the rougher and the scavenger banks.

Jan 1, 2000

By N. Finkelstein, D. A. Hinckfuss

The large and compact but simple Bougainville Copper Limited flotation circuit has been in operation for 3-1/2 years. Discussion of problem areas encountered since start-up and remedies that have been implemented or proposed, form the main basis of this paper. Full cur- rent operational data is also provided.

Jan 1, 1976

By Rudolf E. Greuer, Xintan Chang

Mine fires have always been of great concern to mining engineers and their behavior has been studied for a long time. Although an abundance of observations exist, no satisfactory mathematical model for their interpretation and extrapolation has become known. The paper presented here tries to close this gap, making use of the laws of chemical kinetics, energy and momentum conservation. To overcome the mathematical difficulties, the fire zone is axially divided into segments and radially into sections, each one with an extension of only a few inches. Conditions in segments and sections are updated in time intervals of one second or less. To solve the large number of resulting equations, a numerical solution is performed. The model has so far been tried on timber fires. It confirms experimental observations on the ignition phases and equilibria of these fires.

Jan 1, 1987

By Cathleen J. Webb, Arden D. Davis

Begun in 1992, an abandoned and inactive mine inventory in the Black Hills National Forest has resulted in a hazard ranking of the most severely affected sites. For purposes of the inventory, the Black Hills were divided into three main regions: the northern Black Hills, with primarily gold mines; the central Black Hills, with pegmatite mines and some gold mines; and the southern Black Hills, with primarily uranium mines. A computerized data base has been developed along with standard forms for field crews. The forms were designed to provide maximum compatibility with other abandoned mine inventories on various federal and state lands. Measures recommended for the most hazardous and heavily affected sites include regrading of unstable slopes, fencing of open shafts, and remediation of the most severe acidic mine drainage problems. Specific examples are illustrated where remediation and safety measures were recommended or have been implemented. The vast majority of the sites, however, needed little or no remedial action.

Jan 1, 1995

By Takashi Sakaguchi, Akira Nakajima

Some attempts were made to recover and remove heavy metal elements, such as uranium, copper and chromium, from aqueous systems by using several phosphate compounds. The phosphorylated derivatives of polysaccharides, chitin phosphate, chitosan phosphate and cellulose phosphate, have high abilities to accumulate heavy metals, such as uranium, copper, manganese, cobalt, cadmium, zinc, nickel and chromium, compared with non-phosphorylated polysaccharides. In order to obtain basic information on the recovery and removal of uranium that may be present in industrial effluents, mine waste water and seawater, the adsorption of uranium by chitin phosphate and chitosan phosphate was investigated in details. The adsorption of uranium by chitin phosphate and chitosan phosphate was much greater than copper, cadmium, manganese, zinc, cobalt, nickel, magnesium and calcium. The adsorption of uranium was very rapid and was affected by pH of the solution, temperature. granule radius and co-existence of carbonate ion. The amounts of uranium adsorbed on the adsorbents increased linearly as the external uranium concentration increased. Uranium adsorbed on chitin phosphate easily desorbed with diluted sodium carbonate solution. On the other hand, uranyl and cobalt ions were separated from each other by using chitin phosphate. Along with these fundamental research, some attempts were made to recover uranium from seawater.

Jan 1, 1993

By Bruce E. Nesbitt, Paul G. Lhotka

At Lupin mine gold is spatially and genetically linked to zones of hydrothermal alteration in iron-formation which are symmetrically developed adjacent to late Archean quartz veins. Immediately adjacent to the veins, coarse grained, typically gold- and sulfide-poor, calc-silicate rocks are often present. These rocks comprise hedenbergite + quartz ± grossular garnet ± epidote ± scheelite ± calcite. Sulfides (pyrrhotite, arsenopyrite and loellingite) and gold are concentrated in the next zone and occur with hornblende-rich rocks comprised of hornblende, quartz, hedenbergite and grunerite. Furthest from the veins are gold- and sulfide-poor, grunerite-rich iron formation comprising grunerite, quartz, hornblende and sometimes magnetite. Although the alteration assemblages have similarities with skarns, they develop in iron formation, and are at best indirectly related to intrusive igneous rocks. Geological and geochemical data clearly indicate the calc-silicate rocks are metasomatic in origin.

Jan 1, 1990

By E. M. J. A. Pallone, F. N. Cunha, W. S. Resende, R. M. Stoll, R. C. Bradt

Utilization of the magnesium aluminate spinel in refractor' applications is briefly reviewed. The synthesis of a magnesia aluminate spinet aggregate from natural raw materials is considered in terms of the crystal chemistry of the spinet structure and expected impurities. Principles for the formation of this spinet refractory aggregate from different natural raw materials are presented. The basic concepts were then applied to the reaction of a bauxitic clay with a natural magnesite. This combination of raw materials has the potential to produce a low-cost refractor' aggregate that is a composite of spinel and forsterite. Experimental results are reported to produce a spinel refractor.' aggregate containing a small amount of forsterite. It possesses low apparent porosity and high bulk density suitable for industrial refractor' applications, including steelmaking, aluminum and copper foundries and cement production.

Jan 1, 2002

By Adrian Smith, Debra W. Struhsacker

There is now overwhelming evidence that, despite concerns to the contrary, natural degradation of cyanide and cyanide attenuation by hydrogeochemical processes are capable of minimizing or eliminating potential water qua1ity impacts from heap leach systems. A1 though there was some recognition of these data by the regulatory authorities, for example the initial USEPA modification of cyanide standards to an advisory level, many states have codified standards inappropriate to the clearly site specific nature of heap leach operations. As an overview to this problem, this paper will integrate the theoretical chemical data on cyanide with the observed geochemical behavior of cyanide in the decommissioned heap leach environment. The cyanide species that are likely to exist within an abandoned heap leach system will be identified, and the relative toxicity and potential environment effect of these cyanide species will be discussed. These data will then be used to evaluate cyanide detoxification regulations for decommissioned heap leach projects in 14 states.

Jan 1, 1987

By G. H. Roybal, J. M. Barker

Humate mining in New Mexico is a small industry [455 m3 (16,079 cu yd) valued at $395,894 for 1983] with three mines active in 1985. Either humate (carbonaceous claystones rich in organic matter) or weathered coal ("leonardite") high in humic acid are mined. The humic acid content needed to meet consumer specifications determines which type is mined. The humate and "leonardite" now mined in New Mexico are used primarily as soil conditioners or as drilling mud additives. The potential resource for both are very extensive within the coal-bearing formations of the San Juan Basin in northwest New Mexico.

Jan 1, 1987

By K. A. Natarajan, J. M. Modak, P. Anand

A microbial survey of Jamnagar bauxite mines in Gujarat, India, revealed the indigenous presence of a variety of autotrophic and heterotrophic bacteria and fungi associated with the ore body and water ponds in the vicinity. Among these, bacteria belonging to the genera Thiobacillus, Bacillus and Pseudomonas are implicated in the weathering of aluminosilicates; the precipitation of iron oxyhydroxides; the dissolution and conversion of alkaline metal species; and the formation of alumina, silica and calcite minerals. Fungi belonging to the genus Cladosporium can reduce ferric iron and dissolve alumina silicates. Biogenesis thus plays a significant role in bauxite mineralization. Various types of bacteria and fungi, such as Bacillus polymyxa, Bacillus coagulans and Aspergillus niger, were found to be efficient in significant calcium solubilization and partial iron removal from bauxite ore. Probable mechanisms in the biobeneficiation process are analyzed. Biobeneficiation is shown to be an effective technique for the removal of iron and calcium from bauxite ores for use in refractories and ceramics.

Jan 1, 1998

By William Petruk

Performance assessments are carried out to monitor operations, to evaluate performance and to identify processing problems. The assessment involves collecting and analyzing representative samples from critical points in a flowsheet and interpreting the data. Sample analysis techniques include chemical analyses, mineralogical investigations, mineralogical analyses, and materials balancing. Chemical analyses provide the lowest cost assessment and should be used liberally, particularly in monitoring a process. Materials balances performed on chemical assays for a suite of samples are used as a first step in evaluating a process. Mineralogical investigations are more expensive than chemical analyses but need to be used only at the beginning of mining and metallurgical operations and as a second step in assessing processing problems. Quantitative mineralogical analyses combined with materials balancing provide the most complete performance assessment, but the procedure is expensive. On the other hand, the assessment has the potential of a large payback when carried out where warranted.

Jan 1, 1991

By Graeme Lyall, Oy Leuangthong, Clayton V. Deutsch

There are many variables to consider in the evaluation of nickel laterite deposits including the concentrations of nickel, iron, silica, and magnesia. These variables show complex relationships with each other such as mineralogical constraints, non-linear correlation, and heteroscedasticity. The complex multivariate relationship between the variables cannot be reproduced by conventional Gaussian or indicator geostatistical techniques. We introduce the stepwise conditional transformation method as a pre- and post-processing multivariate transform for the stochastic simulation of a nickel laterite deposit. Transformed data are multiGaussian and independent at h = 0; thus, cosimulation can be avoided after verification that variables are independent at all lag distances. Back transformation restores the features of the input multivariate distribution to the simulated realizations. The complex multivariate correlations are reproduced and sensitivity issues are addressed.

Jan 1, 2002

The visible portion of accounting-record keeping and preparation of financial statements-suggests a lack of sophistication and imagination. In reality, accounting is based on a large body of theory. Accountants philosophize, theorize, judge, create, and deliberate as a significant part of their professional practice. The subjective aspects that are so critical to current accounting practice, such as searching for truth and fact, judging what is fair presentation, and considering the behavior induced by presentations, are often overshadowed by the appearance of exactitude, precision, and objectivity that accompanies the use of numbers to express the financial results of the enterprise. * Fundamental accounting principles are hypothesized in the same manner as mathematical principles. These principles are justified by acceptability and intuition. Accounting theory is built upon these hypotheses, resulting in a coherent set of standards and rules. Although it does not specifically address every situation that may be encountered, this conceptual frame- work enables the manager or analyst to resolve specific situations. This framework also aids in the understanding and confidence in financial statements and ensures comparability between statements from different companies. This framework is referred to as "generally accepted accounting principles," or GAAP.

Jan 1, 1999

By A. M. Marabini, V. Alesse, Belardi. G.

An alternative flowsheet was designed for the flotation treatment of a complex sulfide ore from the Sotiel Mine in Spain. The ore contains 0.71% Cu, 2.24% Pb and 5.63% Zn. Two specially developed synthetic collectors, methyl-mercapto-benzoxazole (MMBO) and 6n-propoxy-mercapto-benzo-thiazole (PMBT), were examined. MMBO exerts a specific action on copper and zinc minerals after treatment with copper sulfate, and PMBT exerts a specific action on Pb minerals. Flotation operating variables (pH, frother type, frother quantity and feed particle size) were examined by means of rougher flotation tests to determine the optimum conditions for the new collectors. Once the optimum conditions were determined, a series of open flotation circuits were run on feeds of various particle sizes (obtained by different types of grinding). The objective was to obtain high-grade Cu and Zn concentrates. The results of the open-circuit tests demonstrated that a Cu concentrate grading from 18% to 23% Cu and a Zn concentrate grading from 40% to 48% Zn can be produced.

Jan 1, 1996

By A. D. Davis, C. J. Webb, T. V. Durkin

This project took a watershed approach in the evaluation of water-quality impacts from past mining activities and current restoration projects in the Bear Butte Creek basin, a small and well-defined drainage in a heavily mined area of the northern Black Hills. The basin contains numerous inactive and abandoned mines, as well as a heap-leach surface gold mine. Bear Butte Creek normally loses all of its discharge to sinkholes in the Madison Limestone aquifer. Thus, it can affect the water quality of this regionally important water resource. Water-quality data were analyzed, stream surveys were conducted and two abandoned-mine restoration projects were monitored to evaluate the effectiveness of the watershed approach and to identify practical remediation techniques that could be applied to other watersheds. A geographic information system (GIS) was developed to organize information on stream quality, abandoned mine locations, and other geologic and hydrologic data. The watershed approach toward assessing and reclaiming abandoned mines appears to be effective when compared to a point-source approach that might improve water quality at specific sites but not result in significant overall improvement to the watershed because of adjacent sources.

Jan 1, 2000

By Robin J. Batterham, Stephen H. Algie

It is often stated that innovation is central to the economic survival of mining and mineral processing in the face of global competition, and yet technology is often far from a core strategy in our industry - hence the concerns that are often voiced about the apparent slow rate at which new technology is applied. Much of the discussion stems from a lack of understanding of the role of technology in innovation, and of the role of R&D within the innovation process. To a large extent this has all been said, however, the messages are clear and deserve repetition. This paper expresses the personal views of the authors, based on experience in government-funded (CSIRO and universities) research, and in CRA Ltd, a large mining and mineral processing company. Further than this, it explains how our own development unit within the CRA Group has come to see its key roles as including the transfer of technology, and the training of technologists to move into the operating business units. We conclude that these critical tasks are the keys to creating the environment that will allow us to maximise the contribution of technology.

Jan 1, 1995