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By L. Spiers

Motorized Conveyor Pulleys contain all the traditional conveyor belt drive components inside the pulley. Light duty airport check in, grocery stores and food processing conveyors; requiring compactness, elimination of guarding and component containment have been using them for years. Portable Aggregate Processing Equipment require these features but with higher belt pulls and severe duty beyond the capacity of traditional components in a limited space. New materials, design technologies and automation; converging with safety issues, higher energy and operating costs; have created a pressing need. The challenge is to integrate new technologies and traditional components into a reliable, compact, conveyor belt drive system.

Jan 1, 2003

By J. D. Miller

Fluid flow phenomena and therefore the flotation efficiency of air-sparged hydrocyclone (ASH) flotation are strongly dependent on the operating and design variables such as air flow rate, slurry flow rate, underflow and overflow opening areas, percent solids in the feed, reagent levels, particle size, ASH length, etc. Time-averaged multiphase flow characteristics, as deter-mined by x-ray CT and described in a previous publication, are used to understand and explain the steady-state ASH flotation of quartz. A detailed parametric study of quartz flotation by a nominal 2-inch diameter air-sparged hydrocyclone (ASH-2C) revealed the influence of these variables on the flotation response which is discussed in terms of the multiphase flow characteristics. Thus, a phenomenological description of quartz flotation has been established to assist in the further development and utilization of the ASH technology.

Jan 1, 1995

A nuclear technique utilising the gamma-ray resonance scattering process is used at Isa Mine for the determination of copper in drill core and bulk mineral samples. The Copper Bulk Analyser (CBA) provides quick and accurate non-destructive copper analysis of drill core at costs two to three times cheaper than conventional chemical techniques.The almost immediate availability of sample results enhances the efficiency of the mine geologist in the duties of grade control, design of diamond drilling programmes, and input to planning. The unit has proven to be a reliable and accurate production tool requiring a minimum of technical support.

Jan 1, 1990

By Wilbert J. Huff

The work of the Explosives Division, Bureau of Mines, United States Department of the Interior, for the fiscal year ended June 30, 1939, is described in the following pages. This paper is the fourth of a series of annual reports covering the activities of the division since July l, 1936.

Jan 1, 1940

By R. S. Das, A. K. Sinha

Modern mine ventilation systems have grown rapidly in recent years both in terms of complexity and value for human health and safety. Although computer models are now available to help the design and operation of mine ventilation systems, considerable differences often exist between the computer-based predictions and practical results. Research conducted to compare computer results with practical measurements made in ventilation circuits simulated in a physical model seems to confirm such differences. It is concluded that although a mine ventilation computer model is a very powerful tool, it can be utilized to its full potential only if reliable input data are provided.

Jan 1, 1987

Careful monitoring of the position of the cave front is essential for well-managed block cave mining. Seismic monitoring systems yield 3-D information about the location of fracturing ahead of the cave. However, because the a seismic gap between cave surface and seismogenic zone is of unknown extent, the cluster of micro-seismicity can only yield an upper bound for the cave height. The large velocity contrast between the fractured rock in the aseismic gap and the broken loose material within the cave can be used by an inversion procedure to find a few simple geometric parameters (such as height of the top of the cave) if a simple 3-D shape?for example a paraboloid?is assumed for the cave. Ray-tracing must be used as the large velocity contrasts cause seismic waves to bend around the cave, but the inversion takes the form of a minimization problem in only a few dimensions and so the computational time is feasible. This technique has been successfully tested on realistic synthetic data.

Jan 1, 2007

A newly developed damage model was used in the study of rock fragmentation mechanisms involved in crater blasting. Simulations show that at the detonation of the explosive charge, a crushed zone around the explosive charge is formed due to compressive failure and then a strong pressure wave is sent out forming a pressurized ring that propagates at the dilatation wave velocity. As the pressurized ring leaves the crushed zone, two tensile stress components perpendicular to the radial stress are developed in response to the action of the radial pressure, causing tensile failure and forming a damage zone around the charge. The formation of this damage zone is quite independent of the depth of the explosive charge provided there is no interference by the reflection from the free face. When the pressurized ring reaches the free face, it is reflected there and causes rock failure on the ground surface that forms another damage zone. Under the simulation conditions, it is revealed that the depth of charge is a factor controlling the relationship between the two damage zones. At a depth smaller than the optimum, the two damage zones coalesce into one and there is excessive rock breakage; otherwise, the two damage zones tend to isolate from each other with the increase in the depth of charge. Calculations of fragmentation indicate that the average fragment size increases and the uniformity of fragments decreases when the depth of charge increases as observed in practical blasting.

Jan 1, 1998

By A. E. M. Warner, A. Vahed, P. J. Mackey

"Since early 2015, the price of nickel has dropped from the region of US$6/pound to current levels of around US$4.60/pound (March 2017), reflecting several market factors, but principally due to lower demand from China. Under such conditions, nickel companies have been under pressure to contain operating costs. In addition, labor and energy costs will continue to rise, while nickel ore grades will likely continue to drop. All major companies now accept the need for climate change action and consequently efforts are being made towards lowering carbon-based emissions. Nevertheless, meeting these challenges can also contribute to higher operating costs without parallel innovative developments - which at the same time, under current conditions, major companies are tending to curtail. In this paper, several productivity improvement opportunities to reduce unit operating costs at nickel sulphide and nickel laterite plants are reviewed. Opportunities include: (a) process technology and energy-type selection, production capability, optimization of process intensity and implementation of newer technologies; (b) improved productivity, equipment availability including maintenance best practice; (c) energy savings and recovery opportunities and use of energy surveys and, (d) process modeling and improved scheduling. Such improvements along with an uptick seen in nickel demand going forward should better position the world nickel industry.INTRODUCTION Nickel is an essential metal to modern society, primarily through its use as an important ingredient in stainless steel. Thus, stainless steel finds vital applications in food preparation facilities, as well as important uses in transportation and industrial applications. Canada has always played an important role in nickel production and nickel metallurgy. In the 1940s and 1950s, Canada supplied over 90% of the world’s nickel. However, this proportion has declined considerably to around 10% of the world nickel supply today. Still, Canada remains an important nickel supplier and contributor to nickel extractive technology. Due to the importance of nickel to society, nickel demand is expected to continually rise. On the other hand, nickel companies have been under pressure to contain production costs amid languishing nickel prices. While demand projections show nickel growth, there are uncertainties in actual levels of future market growth. Ore grades are dropping, while labour and energy costs, which are key cost contributors are rising, hence efforts to lower production costs will generally require innovative approaches."

Jan 1, 2017

By C. F. Starr

This paper deals with the various types of cable in use in mines, with special attention paid to their construction. There will be a few comments regarding the different insulants, jacketing materials and armouring used, depending on their application. Governing standards and the differences therein will also be discussed.

Jan 1, 1969

By M. J. Voigt, R. A. Govender, A. Mainza, L. Bbosa

"Mineral texture is a critical factor which controls ore variability and is an important attribute in geometallurgy. In relation to downstream processes, it affects the fracture pattern during breakage, where rock strength is inherently a function of mineral texture. Because of the subjective nature of mineral texture, it has not been easy to quantify, especially in the context of a measurement suitable for use in geometallurgical programmes. The aim of this paper is to present the first steps in developing a 3D mineral texture quantification method for drill core and to assess its sensitivity to differences in rock strength using a case study. The methodology includes classifying the textural information using the 3D grey level co-occurrence matrices (GLCM) and X-ray computed tomography (XCT) coupled method. Rock strength tests were performed using the split Hopkinson pressure bar (SHPB). The case study investigates a heterogeneous polymetallic sulphide deposit and a homogeneous shale subdivided into three ’mineral textural types’. The variability is largely captured by the GLCM matrices, and preliminary trends can be observed where the shale is finer grained and has a higher yield strength in comparison with the coarser grained polymetallic sulphide ore. IntroductionModern mining requires the exploitation of lower grade and more complex, heterogeneous orebodies to address the growing industry demands. Historically, processing plants were designed and built based on average ore characteristics and therefore are relatively inflexible when facing the full spectrum of ore variability in heterogeneous orebodies (Lamberg, 2011; Lotter, 2011; Schouwstra et al., 2013). The practice of geometallurgy represents an opportunity to manage ore variability in the mining industry (Powell 2013; Baum, 2014; Yildirim et al., 2014; Nguyen, 2013). It focuses on quantifying the relationships between ore characteristics and their downstream mining and processing responses, often starting with small-scale laboratory testing. The purpose of geometallurgy is linked to maximizing the net present value (NPV) of an orebody by minimizing technical and operational risk – where ‘ore variability’ is considered one of the most significant technical risks."

Apr 1, 2019

By W. E. Anable

The Bureau of Mines studied the purification of commercially available vanadium in the 100-kw electron-beam furnace. Purification studies were conducted on a 100-gram button scale by melting and holding the liquid vanadium at temperatures ranging from 2,060° to 2,080° C at pressure of 5(10)-5 torr for periods ranging from 5 to 20 minutes. The effect of doping vanadium with carbon and metallic additions was determined. This study demonstrated that hydrogen was readily removed to 3 ppm or less, oxygen and carbon were reduced to less than 100 ppm each, and the metallic impurities were reduced Co the range of 10 to 500 ppm. The nitrogen content was not reduced in any of the buttons; rather, the nitrogen concentration generally increased as samples were held for successively longer periods. Oxygen was removed much faster and more completely when vanadium was doped with small carbon additions or one of several dopes prior to melting.

Jan 1, 1967

By Young C. Kim

Introduction and Objective of This Paper Computerized open pit mine models* are more and more used today for feasi¬bility studies as well as for long range mine planning. In fact, using these models is becoming an enforced practice due to various reasons. One main reason is its capacity to evaluate several designs in a fraction of time required by manual effort. Another reason is the necessity to evaluate several. pit designs due to ever decreasing grade of the orebody and increasing financial risk due to smaller profitability margin. In spite of today's accepted use of computer models, very little guidelines are available which the average practitioner can follow either to choose or to build the type of model best suited for his need. Consequently, the objectives of this paper are: 1. To review the current state of the art in the computerized open pit mine models. 2. To provide some suggestions for model selection. 3. To share our experiences in developing a model for a highly irregular copper ore deposit (see Appendix).

Jan 1, 1977

By Paul Dean Proctor

The known northern ore zones of the New Lead Belt of Southeast Missouri extend to the drainage divide between the Meramec River draining north and east and that of the Black River draining southward. Intensive geochemical studies related to the environmental impact of the new mining area have been carried out in the vicinity of some of the newly developed mines, mills and smelter complexes (Bolter,1970; Gale, et al, 1973; Wixson, et al, 1969, 1977). Other investigations have related to fringe studies of the Northern New Lead Belt and the possible additions of heavy metals to the surface waters, stream sediments and selected aquatic life (Proctor, et al, 1975, 1976). Similar studies have been completed in the Joplin area in the Tri-State district, and in the fringe area near Springfield, Missouri (Proctor, et al, 1974). A surface geochemical study is currently underway on the lead-zinc-copper-cobalt-nickel province near Fredericktown, Missouri (Proctor and Sinha, 1977). This report summarizes some of the distribution patterns of heavy metals in the waters, stream sediments and selected aquatic life in the Upper Meramec River drainage basin just north and west of the known northern portions of the New Lead Belt of Southeast Missouri. The region studied includes the site of the proposed and somewhat controversial Meramec Dam and the reservoir site behind it. Some 3905 km2 (1508 mi2) are included within the drainage basin of the Upper Meramec River. Six distinct drainage areas are included within the drainage basin; 1) a combined, lightly industrialized and farm area around Rolla and Salem, Missouri representing the Dry Fork drainage; 2) a primitive, mostly forested area with some farms and cattle rancheseast and north of Salem, Missouri comprising the Upper Meramec River

Jan 1, 1977

By George A. Morrison

This paper describing the methods of mining and crushing limestone at the West Winfield, Pa., limestone mine of the West Penn Cement Co., is one of a series being prepared by the Bureau of Mines on mining practices, methods, and coats in the various nonmetallic mining districts. HISTORY The limestone deposits of western Pennsylvania have been exploited for many years and have been quarried extensively at West Winfield in Winfield. Township, which lies in the southeastern corner of Butler County.

Jan 1, 1931

By Kevin Telmer, Daniel Merino, Scott Smith

El Aglomerado de Carbón y Aceite (COA) es un método práctico, eficiente y fácil de utilizar para la recuperación de oro libre; el método destaca por el bajo costo y fácil acceso a los insumos utilizados, por eso es considerado una alternativa limpia para el beneficio del oro sin uso de mercurio. El método se basa en la formación de aglomerados o pellets compuestos por carbón, agua y aceite, los cuales capturan partículas de oro libre. Esto ocurre gracias a las propiedades hidrófobas/oleófilas que tiene el oro, que permite adherirse a los aglomerados; el aceite actúa como líquido puente entre el carbón y las partículas de oro, facilitando su unión.

Sep 29, 2023

By Richard L. Rains

During this study in 1983, the U.S. Bureau of Mines examined one mine and five prospects in the Greenwater Valley Wilderness Study Area (WSA). No mineral resources were identified within the WSA. Principal mineral commodities in the WSA are gold and silver with minor lead, and zinc. Two properties have significance; sample analyses indicate the Salsberry Prospect may have gold-silver-lead-zinc resources, and the Graham Jem Mine may have gold resources. The likelihood for development is greatest at the Salsberry Prospect, although the only recorded production from the study area was from the Graham Jem Mine; in 1908 less than 1 ton of gold-bearing ore valued at $25,000 per ton was produced. Gold, silver, lead, zinc, and copper minerals in the WSA are associated with rhyolite dikes and quartz veins in Precambrian gneissic rocks, commonly concentrated in sheared zones along the dikes and veins. Although known to contain silver-lead deposits elsewhere, Precambrian Noonday Dolomite sampled inside the WSA contained no significant mineral values. Much of the WSA is covered by relatively unmineralized Tertiary and Quaternary volcanic rocks. The Bureau collected 140 rock samples at four adits, nine shafts, four trenches, and 33 prospect pits in the WSA. In 1983, 14 lone claims and one millsite within the study area were current. No patented claims, placer claims, or coal, mineral, oil and gas, or geothermal leases were in the WSA.

Jan 1, 1985

By Fremont T. Johnson

Credited with production of more than 164,000 flasks Of quicksilver from 1876 to 1944, the Oat Hill mine has ranked third in output in the United States. During World War II, when the demand for mercury was high, this property was selected for diamond drill with the purpose of increasing ore reserves so that production could be maintained or, if necessary, increased. Although the existence of marginal-grade ore (fill material) left in the stapes and possibly of virgin ore of good grade had suspected in certain parts of the Oat Hill mine, no factual information to tonnage, grade, or location was available. In close cooperation with the Federal Geological Survey, the Bureau of Mines studied old records and the few available incomplete maps. Diamond drilling began in November 1943 and was completed in December 1944. Twenty-eight holes aggregating 8,121 feet were drilled, in only parts of the promising areas disclosed by the study of the data available. Detailed data on the work done by the Bureau as well as a brief history of the property and some operating details are described in this report.

Jan 1, 1949

By C. I. Godwin

"The relative-value (R-value), discrimination-factor (D-factor), and vector-ratio (V-ratio) method (RDVM) provides a geological knowledge-based statistical and geological-genetic interpretation scheme for geochemical data that enhances discovery in geochemical exploration. The practical advantage of RDVM is that it synthesizes geochemical features geologically related to ore-deposit discovery in three steps: reclassifying element concentrations using log-probability plots into R-values; calculating geologically defined D-factors from R-values; and determining V-ratios. D-factors are the sum of R-values, divided by the number of R-values summed. Based on the analyses selected, D-factors mimic rock or mineral deposit signatures. V-ratios refine interpretations of rock type and vector to orebody locations.RÉSUMÉ La méthode de la valeur relative (valeur R), du facteur de discrimination (facteur D) et du rapport de vecteurs (rapport V) (RDVM), fournit un schéma d’interprétation des données géochimiques basé sur les statistiques et les connaissances géologiques et la génétique géologique; ce schéma contribue aux découvertes en exploration géochimique. L’avantage pratique de la RDVM est qu’elle fait la synthèse des caractéristiques géochimiques reliées géologiquement à des découvertes de gisements de minerais en trois étapes : une reclassification des concentrations des éléments au moyen de courbes de probabilité logarithmique en valeurs R; un calcul des facteurs D définis géologiquement à partir des valeurs R et la détermination des rapports V. Les facteurs D sont la somme des valeurs R divisés par le nombre de valeurs R additionnées. Selon les analyses choisies, les facteurs D imitent les signatures de la roche ou des gisements minéraux. Les rapports V peaufinent les interprétations des types de roches et dirigent vers des emplacements de gisements."

Jan 1, 2016

By A. R. Sorta, D. C. Sego

ABSTRACT The settling, shear strength, and index properties of oil sands fines-sand mixture tailings (FSMT) for a wide range of solids and fines content are investigated. Results indicate that the liquid limit of FSMT obeys a linear mixture law. The fines-water ratio (FWR) governs the permeability of composite tailings (CT) and CT with comparable geotechnical behaviour can be produced from the same initial FWR mixtures. A phosphogypsum (PG) dosage > 900 mg/kg does not improve the dewatering behaviour of CT. The undrained shear strength of FSMT at the liquid limit is approximately 2.4 kPa, but is dependent on fines content at the plastic limit.

Jan 1, 2013

By S. Annavarapu

"Fragment size distributions play an important part in the design and planning of block cave mining operations. Though several methods have been proposed for estimating fragment size distributions in advance of mining, the calibration of these estimating procedures to field measurements has been a challenge. The Block Size Estimator (BSE) program was developed for providing an assessment of primary fragmentation expected in a block cave mine using drill-core piece length data and joint characteristics from the exploration and geotechnical evaluation programmes. In order to validate the results from the BSE program, the drill-core piece length data and the joint characteristics in different rock types from the DOZ block cave mine in Indonesia were used to help generate fragment size distributions in different areas of the mine. The predicted fragment size distributions were compared with the fragmentation observed at the drawpoints during operation of the mine.This paper presents the details of the validation of the fragment size estimates by the BSE program using fragment size distribution data from the drawpoints at the extraction level at the DOZ block cave mine, and the challenges encountered in developing reasonable correlations between the estimated and measured fragment size distributions. IntroductionThe assessment of fragmentation is an important aspect of the design and planning of the block cave mining method, and forms an integral part of the design of the excavations at the extraction level and the selection of material handling systems for transporting the ore to the processing stations. Secondary blasting requirements can also be estimated based on the fragment size distributions developed for the block cave (Laubscher, 1994).Several methods of estimating fragment size distributions in block cave mines have been developed based on joint set parameters estimated from structural data from oriented core drilling campaigns and mapping of available excavations and outcrops. The BCF program (Esterhuizen, 1999) estimates the fragmentation using a combination of empirical, analytical, and rational methods to model the behaviour of materials during the primary and secondary fragmentation processes. The program JKFrag uses advanced tessellation of joint traces to create rock blocks and then generate fragment size distributions (Brown, 2002). Nickson, Coulson and Hussey (2000) presented the details of processing of the geotechnical data from the Mont Porphyre project, including an assessment of block sizes from the data collected on the core logging sheet. The distance between natural fractures was used to create distributions of block lengths, and a distribution of potential block sizes was estimated assuming that the blocks had equal dimensions in all directions. The results agreed closely with the results of the BCF program. Hadjigeorgiou, Grennon, and Nickson (2002) demonstrated the use of oriented borehole data to provide characteristic block size distributions for a mining project using a software package called Stereoblock, which generates a three-dimensional joint network for a given volume and calculates the volumes of blocks created by the intersections of these joints, simulated as circular planes. The distributions of joint orientation and joint spacing generated from statistical analysis of the oriented core data are used for the creation of the Stereoblock model. The diameter of the circular planes representing the joints is determined based on the mean and standard deviation of the joint trace length obtained from scan-line mapping."

May 1, 2019