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By Louis W. Cope

INTRODUCTION Various methods for sampling placer deposits have been mentioned by Wojcik in Chapter 2. Here, a brief description and comparison of these methods will be given as related to bulk versus drill sampling. The advantages and disadvantages inherent to each will also be given. The means of sampling can be grouped into bulk or drill samples. As a generality, drill samples over a five-foot length will run from I/,, to 1 /, cubic yard, depending on the diameter of the drive shoe on the drill casing. Bulk samples can be expected to be in the range from one to many cubic yards each. SAMPLE METHODS Bulk Bulldozer-dug trenches and dozer or front-end loader pits are two methods to excavate large bulk samples. Smaller bulk samples can be obtained by digging small dimension shafts through the deposit, by hand or caisson-like drills. It is not recommended to split samples by alternate bucket-loads or by other means, as the effect of a nugget falling into one or the other fraction will seriously alter the sample.

Jan 1, 1992

By V. V. Ershov

Mining geometrical graphic documentation is employed on a large scale in designing and planning of mining operations at all the stages of exploitation. Mining geometrical modelling of mineral grade distribution presents an independent type of mathematical (graphic) modelling. The idea of functional relationship between geological indices being observed, and spicier coordinates is the basis of traditional mining geometrical modelling. Graphic presentation of three independent variables P =f (x,y,z) is confined to obtaining the series of two independent variables functions. Independent variables are presented as topographic surfaces corresponding to plane cross-sections of a deposit. During exploitation of certain parts of a deposit the most reliable geological information is obtained, characterizing regularities of ore distribution in the entrails. This information is, though, not taken into account in goemetrization of the new areas. In this connection dynamic modelling of deposits in the process of exploitation is necessary, i.e. geometrization of the deposits should be dynamic.

Jan 1, 1986

Sewage sludge contains heavy metals, pathogens and bears annoying characteristics that limit its land application. For the sewage to be applicable on land, several stabilization methods can be used. Stabilization with lime (CaO) is used to raise pH and temperature and therefore, according to ASTM standards, reduce pathogen levels and achieve compliance with regulatory requirements. Although the process results in the production of a stabilized material, its direct application to soils is rather limited mainly due to the improper product texture. Inert materials can be further added to sewage sludge stabilized with lime to tackle this problem. The objective of this study is to investigate the potential use of dried bauxite residues as an inert material together with lime for the stabilization of sewage sludge from a municipal water treatment plant. It was indicated that the addition of bauxite residues and lime to sewage sludge apart from meeting the requirements of ASTM standards, it further reduces moisture content, improves material texture and eliminates odors. It was also found that although some elements leachability increased due to the treatment with lime, it further decreased when bauxite residues were also added.

Jan 1, 2006

By R. J. Snow, S. N. Bhattacharya, D. D. Patil

Electrokinetics involves the movement of charged particles or water molecules in an applied dc field. Applications in particle fluid systems include the dewatering of soils, the densification of mill tailings and the treatment of coal wastes. In this paper, a novel application of this technique is discussed, wherein an electric field is applied to a coal-water slurry flowing through a pipe, resulting in lower pressure losses in the system. A unique experimental setup was designed and built to study the effect of an electric field (dc) on the wall shear stress for the flow of coal-water slurry through the pipe. The effect of solids concentration, current strength and pH on drag reduction across the system was quantified.

Jan 1, 2002

By J. J. Davis, D. G. Osborne

The Australian coal industry is characterised by efficient fines recovery, and the climate does not dictate the use of thermal drying. With the increasing trend to underground mining and hence finer ROM coal, and market pressures for reduced product moistures, dewatering issues are assuming increasing importance in the Australian coal industry. The greatest potential gains in dewatering performance undoubtedly lie in the treatment of finely sized material. This paper examines the dewatering issues which have been recognised by the Australian coal industry, and describes current Australian research in this field.

Jan 1, 1995

By Yongping Hu, Dianchen Cai, Congya Zhang

China is a rich in stromite mineral resource. Unfortunately, the resource is very difficult to separate by using conventional flotation method because stromite and gangue minerals are very fine disseminated, the average size of them is about 10 µm or below, and the content of clay minerals such as illite is 19% or even more. In this paper, the aggregation floatation behavior of ultrafine (-10 µm) stromite, illite, ablbite and quartz using anion collector were studied. The result show that, Oxidized paraffin (O.P) is a good collector and has better selectivity for stromite particles flotation. The salted sodium silicate depressed illite gangues minerals effectively. The separation of mineral mixtures was carried on successfully at one stage flotation by the technique. The mechanism of O.P. and salted sodium silicate were studied and discussed by using IR and Zeta- potential measurements.

Jan 1, 1995

By T. Malterer, R. Adams

Peat has unique physical, chemical and biological properties. These include high porosity and water retention, high absorption and adsorption properties, and high buffering capacity. In addition, peat is a rich medium for microorganism activity. Peat has traditionally been used for horticultural purposes. However, in recent years, peat is increasingly being used for waste- treatment purposes. This paper reviews North American literature on the use of peat for waste-treatment applications. The literature indicated that peat has potential for use in the treatment of municipal and on-site effluents, for the removal of low concentrations of heavy metals and for the adsorption of liquid and gaseous hydrocarbon pollutants.

Jan 1, 1997

By Ross W. Smith, D. L. Taylor, K. A. Altman

Traditional sensitivity analysis of metallurgical data has the potential to overestimate the value of mining projects. Such analyses provide no information about the probability of the results. Simulations that rely on the input of statistical information provide more realistic predictions of the value of future projects and offer additional information regarding the probability of the outcome.

Jan 1, 2003

By L. W. Saperstein, M. C. Radomsky, D. L. Passmore, J. D. Bennett

About 60 small surface coal mines in Pennsylvania participated in a program designed to improve safety performance in the workplace. The method involved the use of safety sampling and observation to assess the degree of safety exhibited by workplace behavior and conditions. Data were collected through the use of on-site safety instruments covering seven major occupational positions typical of small surface mines. Workplace events observed (acts and conditions) were assigned a hazard classification. Feedback was initiated to improve safety performance in areas failing to conform to appropriate safety standards. Results suggest that the variety of unsafe acts and conditions associated with the companies observed are extensive. Further, the experiences drawn from this pilot project have proven the need to pursue this behavioral approach. Future research should concentrate on subjecting the present approach to a strict experimental design involving randomly selected “poor risk” mines.

Jan 1, 1987

By S. K. Kawatra

Various types of mathematical descriptions of the flotation process are used in the design of a full scale flotation circuit. Mechanistic descriptions developed under controlled laboratory conditions establish theoretical residence time requirements. Empirical models, describing flotation performance as a function of full scale operating variables, are established from one flotation system and applied to another hypothetical system. Problems of design by mechanistic modeling, such as scale up factors, can be alleviated if the model is developed from a full scale flotation circuit. However, the numerous uncontrollable variables encountered in a full scale operation would preclude the practical application of such a model. Incorporating empirical relations into the full scale mechanistic model will facilitate its effective use as a guide for flotation circuit design. A semi-empirical model has been developed that promises to offer a more effective means of flotation circuit design.

Jan 1, 1982

By Robert F. Jones

INTRODUCTION Upflow Solids Contact Clarification is a process long employed in the treatment of potable water, wastewater and municipal sewage. This process incorporated in a fiberglass conical structure seems to offer an economical solution to problems encountered in reduction of particulates in uranium effuents. CONCEPT OF UPFLOW CLARIFICATION Use of suspended solids contact units date back to the 1930's. These types of units produced by Infilco and the Permutit Company, among others, were used in the Lime-Soda softening process to precipitate calcium and magnesium salts from hard water. In general, the process operated as follows: (a) Raw water entered a central chamber where it was mixed with chemicals. The chamber had provisions for agitating and circulating the chemicals so that mixing and reaction zones were formed. (b) The water, precipitated chemicals, floc and turbidity flows to a clarification chamber (the Permutit precipitator used a truncated cone). In most cases the influent then passes upward through a blanket of suspended floc and other solids before it leaves the chamber at effluent weirs or launders.

Jan 1, 1984

The long-term goal of the Collaborative Research Centre 525 is the identification of options for the resource-sensitive supply and utilization of metallic raw materials. In order to address these issues, an integrated resource management system for metallic raw materials was developed and tested. Simulations were carried out, using the tools and methodical approaches developed in this system, in order to compare alternative operating scenarios for aluminium and copper. However, before these alternative operating scenarios could be formulated and assessed, it was necessary to develop a consistent set of indicators to monitor progress towards sustainable development in the processing and utilization of metallic raw materials. The primary objective of the centre is to develop a set of indicators, which adopt a holistic approach to resource management, thereby enabling the assessment of different operating scenarios within the broadest possible context. The target audience for this research consists of decision-makers in the realms of politics, business and industry, as well as NGO?s.

Jan 1, 2003

By Stephen Day, Maria Falutsu, Gary Coulter

Open-pit mining began at Red Dog in 1989. Mining is expected to continue past 2030 but closure planning is an ongoing process. Geochemical studies of rock and tailings were begun in 1996 as part of development of closure plans to address leaching of metals and ARD. The deposit has many different primary and secondary sulfur minerals in amounts that preclude the use of conventional geochemical characterization methods. This paper will describe development of a specific chemical method to estimate the speciation of sulfur and classify wastes according to reactivity.

Jan 1, 2000

By G. E. McKelvey

A group of gold deposits in southeastern Ecuador, near the town of Zamora, have become the focus of intensive mining activity, due to their extremely high gold grade (unconfirmed reports of about 50 g/t or 1.4 oz per st, or more). The deposits at Nambija and other prospects in the district are hosted by a sequence of sedimentary and volcanic rocks that are present within a large xenolith orpendant within alkalic phases of the Jurassic Zamora Batholith. The xenolith, unknown in size, is composed of various island arc lithologies (limestones, shales, sandstones, tuffs and flows). All have been altered to some degree by skarn-hornfelde alteration assemblages. Mineralized areas appear to be localized within a linear zone containing tectonic and intrusion breccias that cross-cut a complex calcic skarn assemblage developed within the xenolith. Although the nature of the host rocks appears to have exerted some control on mineralization, the high-grade ore is concentrated along north-northeast trending breccias, faults and dikes that crosscut the flat-lying stratigraphy and skarn alteration as suggested by the strong linear trend of workings in the district.

Jan 1, 1991

By M. Z. Dogan, M. S. Celik, G. Onal, O. Ozcan, I. Yildirim

A fluorite ore (51.85 % CaF2) containing high contents of calcite, quartz and iron oxides was upgraded by flotation using a new reagent, oleoyl sarcosine (OS). In addition, quebracho and sodium silicate were used as depressants for calcite and quartz, respectively. The effect of pH, collector and depressants concentrations on grade and recovery was determined with the aim of optimizing the flotation conditions. Application of the two-stage cleaning achieved a concentrate assaying 92.17 % CaF2 with 80.1 % recovery. The Si02 content (0.76 %) was below the required level of 1 % SiO2. The mechanism of interaction between OS and fluorite, as compared to oleic acid, is also elucidated based on the zeta potential measurements.

Jan 1, 1993

By E. F. Divers, R. A. Jankowski

In response to a request from the Mine Safety and Health Administration (MSHA), the US Bureau of Mines completed a respirable dust survey of 18 US coal preparation plants. Of these, three were essentially free of dust problems. Respirable dust exposure to workers in the remaining plants depended on the time spent in the dusty areas. In five of the plants surveyed, Bureau tests showed that in some areas worker exposures could exceed Federal dust limits in less than two hours. Cooperative studies were arranged with coal preparation plants using three different dust control techniques. These included a standard baghouse-type dust collector, two types of scrubbers, and an electrostatic precipitator. Results of these evaluations are presented. Various types of ventilation systems used during summer and winter conditions were also evaluated. Results showed that appropriate ventilation can provide a highly cost-effective method for controlling coal preparation plant dust.

Jan 1, 1987

By J. Duarte Neto, V. M. Torres, A. Viana, G. S. P. Pereira, P. M. Andrade

There are technical and commercial limitations to using high fluorine copper concentrates in industrial copper smelters. The presence of more than 1,000-ppm fluorine affects the sulfuric acid units generally integrated to copper smelters. Price penalties are normally applied to copper concentrates with high fluorine contents. Several process alternatives to resolve this issue were studied at the Companhia Vale do Rio Doce (CVRD) Technology Center, Santa Luzia, Brazil. These alternatives included modifications to conventional sulfuric acid plants so that they can use high fluorine concentrates; removal of fluorine-containing minerals by flotation using depressants; selective leaching of fluorine minerals; and sulfuric acid leaching of the copper concentrates. As a result of this research, a hydro¬metallurgical process to remove fluorine and upgrade copper concentrates was developed by the CVRD.

Jan 1, 1999

By George S. Koch

Today, after about 30 years of development, computer-based analysis of geoscience data has reached a mature phase. From the tentative early beginnings recorded in the proceedings of the APCOM meetings, geoscientists are now able to emphasize the need for both pertinent mathematical/statistical models and computer hardware and software. From those models that are well understood in the disciplines of statistics and mathematics and for which effective computational methods are available, practitioners select and develop methodology for their particular purposes. Computer hardware is typically assembled from off-the- shelf components now readily available, with particular emphasis, whenever feasible, on microcomputers for reasons of economy and control by the scientific or engineering user rather than by a bureaucratic computer center. Computer software may be written by the user in high level languages such as Pascal, FORTRAN, or LISP. However, more often today geoscientists use routines available in spreadsheets, data bases, or statistical packages. In so doing, they save time and, programming costs and take advantage of routines written and maintained by large, well- established organizations, while losing the flexibility in specifying exact input/output afforded by writing in a high level language.

Jan 1, 1989

By D. S. Bird

Kennecott Utah Copper began a modernization program in 1986 that was aimed at expanding and updating mining and ore process facilities at the company’s Bingham Canyon copper mine and concentrator near Salt Lake City, UT. Major components of the project included installation of an in-pit crusher, a transfer conveying system and a new ore concentrator with a design capacity of 70 kt/d (77,000 stpd). The Copperton concentrator was commissioned in February 1988. The grinding circuit is one of its principal features. It consists of three identical lines, each with a 10.4-m- (34-ft-) diam x 4.6-m- (15-ft-) long semiautogenous grinding (SAG) mill and two 5.5-m- (18-ft-) diam x 8.6- (28-ft-) long ball mills. The SAG mills are driven by two 4.5-MW (each) (6000-hp) variable- speed dc motors through a clutch-pinion gear-ring gear assembly. The ball mills are driven by 4.1-MW (5500-hp) synchronous motors coupled through a typical clutch-pinion gear-ring gear system.

Jan 1, 1995

By M. Spangler

FirstMiss Gold installed a supervisory control system that is based on Pavilion Technology's Process Insights neural-network software and Oil System's PI data historian. The first successful control loop involved controlling the limestone feed rate to the neutralization circuit. The resulting improvements in the control of the circuit resulted in savings of $31,000 per month. Although it was the primary goal of the system, supervisory control of the preconditioning circuit was not achieved. However, information gained during the modeling suggested process modifications that resulted in cost savings of $54,000 per month in the preconditioning circuit.

Jan 1, 1997