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By Michael J. Fiannaca

Disseminated epithermal gold metallization occurs within a breccia unit interpreted to be a submarine debris flow. Cold is associated with oxidized pyrite, fluorite, and jasperoidal silica. A minimum of 9 million tons of open-pittable mining reserves will be cyanide heap leached as run-of-mine ore at a rate of 1.0 million tons per year. Careful evaluation of the combined results of successive sampling projects has established the pit plan, mineable reserves, and process metallurgy of the operation. The sampling procedure utilized for a given test depended upon geological interpretation as well as the procedures, successes, and failures of previous tests. This paper summarizes the sampling and testing procedures of the development effort in light of the project goals and attendant problems in achieving them.

Jan 1, 1984

By T. Lee

Ongoing economic success for mining companies is dramatically enhanced when they really know what they are harvesting, such that they can accurately forecast their head grades for any time period in excess of a month. This is an uncommon experience. It is a very common scenario for resource/reserve estimates to overstate the concentration (grade). Grade is a critical input of revenue, and hence, it is to cashflow projections. With the current direction being taken by the legal climate, it is no longer adequate for directors to accept the resource/reserve estimates of experts at face value. This is because resource/reserve estimates are the foundation of primary mineral economic decisions. Directors of mining assets need to undertake their own due diligence analysis of these estimates, in the best interest of themselves, and the company's shareholders. In the light of the industry's past achievements, this is quite a challenge. This paper suggests a set of new objective tools for directors to undertake an overview of the unique commodity concentration pattern and assess associated economic dynamics of each mineralization. These tools allow the examination of global graphical trends that can be helpful to directors and others in undertaking due diligence of resource/reserve statements. Ensure that it smells right.

Jan 1, 1995

By F. M. Doyle, S. M. El-Raghy, M. F. El-Demerdash, E. Peters

The Activity Distribution Diagrams (ADD) developed by the authors are computed for Cu-S-H2O and Mo-S-H2O systems. The distributions of metal and sulfur between all species are estimated against pH at different potential levels. Both M-H2O and S-H2O distributions are compared to the M-S-H2O distributions to estimate the changes occurring due to the presence of sulfur. The method of computation follows the Activity Term Criterion, taking into consideration the multi-equilibrium interrelations and conservation of mass. Results are analyzed in terms of dividing a distribution curve into three basic segments. These segments are formation, stability, and dissolution.

Jan 1, 1993

By J. A. Marts, R. C. Gilmore, S. Saki, J. F. Brune

Computational fluid dynamics (CFD) modeling involves the creation of a computation domain called a mesh or grid to solve the equations defining the physics of fluid flow. This process often comprises the majority of time spent in modeling efforts. In a project sponsored by the U.S. National Institute for Occupational Safety and Health (NIOSH), researchers at the Colorado School of Mines used an innovative meshing approach, allowing easy adaptation of the CFD model to adjust to a variety of longwall bleeder-ventilated and progressively sealed (often referred to as bleederless in the United States) mining geometries, with gob porosity and permeability scalable over a wide range. This paper presents the methodology of the meshing and scaling approach along with recommendations for using CFD modeling in longwall gob ventilation applications. The new meshing technique was utilized to evaluate the function of a back return in a progressively sealed gob and a bleeder-ventilated gob.

Jan 1, 2014

By P. W. King

The performance of the versatile McNally Wedag horizontal vibratory centrifuge for dewatering ultra fine 0.5 x 0.15 mm (28 x 100 mesh) material has proven to be success¬ful and the results presented herein will examine its capabilities in terms of capacity, solids capture, product moisture, effluent solids, and size analysis. Centrifugal dewatering of fine refuse has proven t to be another application for which this unit has performed exceptionally well.

Jan 1, 1985

By H. C. Harrell

The Tennessee Valley Authority began employing geophysical well logging for foundation investigations in October 1973. Since that time more than 3,000 holes have been evaluated for engineering purposes. The Tennessee Valley Authority has not actively used geo-physical well logging for exploration of construction materials, but we feel that much of the information derived from geophysical logs for foundation exploration is applicable to the construction materials industry. This paper will then discuss geophysical logging as applied to foundation engineering and, by implication, the feasibility of use in construction materials exploration. The use of geophysical logging and percussion drilling instead of coring has greatly expanded TVA's data acquisition capabilities and has also resulted in substantial savings in time and money. Economical boreholes are obtained through the use of large percussion track drills (Figure 1). This equipment is capable of drilling through the overburden, setting steel casing on the top of rock, and drilling the rock beneath the casing. Holes as deep as 400 feet (121.9 m) have been drilled by this method.

Jan 1, 1977

By Stephen F. Munsell

The development of transportation systems for mined materials has historically been characterized by steadily increasing sizes in basic hauling units. This is especially true for open pit mines for which success is dependent upon the economical transportation of vast quantities of material. The depletion of high grade ore reserves has mandated a tremendous increase in the size and complexity of the ore haulage systems necessary for open pit mines, These increased demands were served by rail haulage systems in the early large open pit copper mines while later developed properties opted for the flexibility and lower initial costs of truck haulage. Now, we find the trucks being displaced as large overland belt conveyors tackle the problem of handling these ever larger quantities of low-grade ores with accompanying overburden ratios that can run as high as 10:1 or even 15:1. The basic development of large conveyors with shiftable sections and modular belts has generally taken place overseas, during the last few decades. The coal fields of central Europe proved an ideal testing ground for conveyor innovation because the low density and natural friability of the material created an ideal medium for transporting by belt conveyor. Now these proven ideas are being considered for and implemented into both the soft and hard rock mining industries of the United States.

Jan 1, 1978

By William Gleason

While a fleet of 100 t (110 st) haul trucks were busy removing overburden from the open pit mine in the distance, a host of dignitaries, including congressmen and California state representatives, gathered for Molycorp?s official groundbreaking ceremony at the Mountain Pass Mine on April 20. The mine, recognized as arguably one of the richest rare earths deposits in the world, is at the center of Molycorps? strategic ?Mine to Magnets? plan. It aims to secure America?s future supply of rare-earth-dependent technologies by developing a strong domestic rare earth industry. Molycorp identifies rare-earth-dependent technologies as those that cannot be produced without rare earth materials. The list of these technologies is long and growing. It encompasses everything from personal electronics and batteries for hybrid cars to permanent magnet generator wind turbines and national defense applications.

Jan 1, 2011

By Susan G. Bilhorn

A number of studies have been conducted in active and inactive mine environments using continuous monitoring and data acquisition systems to detect various parameters. In addition to the information obtained for research purposes, these monitoring systems can provide a means to remotely collect required information (such as radon daughter concentrations and air velocity) and control various conditions (such as fan operation and air door position) in numerous working sections of an active mine. Selection of detector locations and placement, which are critical to obtain the information and control desired while not inhibiting mine operations and influencing the detector readings, are covered in this paper.

Jan 1, 1984

By M. G. Mudrey

Considerable potential for metallic mineral resources in the lower Proterozoic rock of the Lake Superior region exists (Mudrey and Kalliokoski, in press). Most of the identified resources occur within a 2.0- to 1.9-b.y.-old lithotectonic assemblage characterized by extensive sedimentary strata in the north and thick volcanic se- quences in the south, all deposited on a two-terrane, composite basement of Archean age (DeMattis, 1989). Since the late 1960s, measured resources of nearly 90 Mt (100 million st) of typical volcanogenic massive sulfide at eight localities in Wisconsin have been discovered. The largest of these, near Crandon, contains about 61 Mt (67 million st) of ore averaging 5.6% zinc, 1.1 % copper, and 0.5% lead. Although none of these properties are in production, estimates by Mudrey (1978) suggest that Wisconsin could become a major contributor of newly mined zinc and copper in the United States. These discoveries and uranium and gold discoveries in the Canadian Precambrian are what have led to in- creased metallic mineral exploration throughout the northern half of Wisconsin (Fig. 1). In this chapter, we discuss the geology and legal framework in which the Proterozoic volcanogenic massive sulfide deposits were found. Exploration activities for other metals have generally been negative, and have been background noise for the legislative activities related to the massive sulfide discoveries. Uranium exploration has been consistently negative, although several different environments have been assessed. Other metal discoveries. such as titanium/vanadium, have been subeconomic.

Jan 1, 1991

By John Hayden

The nation runs on energy. It is essential for the economic growth and national security of the United States that the nation has an adequate, sustainable, environmentally acceptable and economically viable balanced supply of energy sources, (e.g., coal, petroleum, nuclear, natural gas, solar, wind, geothermal, biomass, hydroelectric power). Therefore, the allocation of mineral raw materials to the energy-producing sector of the economy must be a top priority that requires the total demand for energy-related materials be judged in terms of domestic supply (Fig. 1).

Jan 1, 2012

By S. S. Sephton

Sintering as applied to agglomeration of ferrous fines has shown little growth in the United States in recent years. The general concensus was that most of the existing facilities would remain in production at a reduced tonnage to dispose of and recover solid waste from steel plants. Further growth for ferrous sintering technology was not in sight in the United States and in the early sixties expansion came to a virtual standstill, however, we witnessed a rapid emergence of a tremendous pelletizing industry. On other continents, due to different raw materials supply and capital structure, sintering technology continued to grow, with a more cautious development of pelletizing installations. In the U.S. the diminishing supply of good quality, high grade coarse ore resulted in eventual disappearance of high grade ore fines for sintering. The finely divided concentrates produced from lower grade ores were not amenable to this type of agglomeration, but were more suitable for pelletizing. Furthermore, pellets seemed to possess all the features of an ideal blast furnace feed; namely pellets are free flowing, uniform in size, strong, with extremely uniform chemical composition and good reducibility. Importance and demand for such well stabilized furnace feed further increased as size of newly installed blast furnaces continued to grow. The in- creasing demand for a uniform, stabilized burden coincided with the effort to produce a fully beneficiated burden for smelting, thus reverting the blast furnace to its primary function of smelting.

Jan 1, 1973

By Per-Martin Sandgren

LKAB's ores have specific mineralogical properties that make them especially suitable for the production of super-grade concentrates. Conditions are particularly good for this purpose at Malmberget, where a concentrate for high-purity sponge iron production has been produced for many years. Until 1978 the approximate assay was 71.2 % Fe and 0.45 % SiO2. Since then the assays have been improved by process modifications to approximately 71.5 % Fe and 0.20 % SiO2. Scope exists for still further improvement. In recent years the production of fractioned concentrates has been started. The material lies within the size range 74-125 µm and the approximate chemical analysis is 71.6 % Fe and 0.30 % SiO2. Other special products are under discussion. The Malmberget ores are also suitable for the production of high-purity direct reduction pellets with a SiO2 content below 1 %.

Jan 1, 1981

By Wenming Wang, Edgar E. Vidal, Scott A. Shuey, Patrick R. Taylor, Judith C. Gomez

Introduction In modern society, vanadium is defined as a strategic metal. Some 90% of the global consumption is used as an alloying agent for carbon steels, tool steels, and high-strength low-alloy steels (particularly for pipelines). Advanced titanium-aluminum-vanadium alloys are seeing application in the aerospace industry. Small but ever growing amounts are finding application as catalysts or in electronics. New uses are continually being discovered for this metal. One example of a new application is the vanadium-redox battery for use in generation plants and back-up power sources. Vanadium is found in a large number of minerals, of which the most important are carnotite, roscoelite, vanadinite, mottramite, and patronite. Just over a third of the world's vanadium is produced as a primary product; the balance is a by-product of the iron and steel, oil refining, power generation and uranium enrichment industries. Vanadium can also be sourced by recycling spent catalysts from the petrochemical industry and ash produced by the combustion of oil emulsion in power stations. However, recycling activities are believed to account for only a small amount of total world supply. Vanadium is recovered from these ores largely as the pentoxide (V2O5) [1]. The major sources of vanadium-bearing magnetite ores are scattered throughout Australia, China, Russia, and South Africa. Current estimates of world’s Proven & Probable vanadium reserves are of the order of 41.3 million tones [2, 3]. Commercial vanadium-bearing titaniferous magnetite deposits can be found in Kachkanar, Russia; Pan Zhihua, China; Bushveld, South Africa; and Windimurra, Western Australia [4]. Other deposits have been found in New Zealand, Canada, and India, among other countries. Vanadium consumption in the steel sector has increased some 7% per ton of steel over the last 10 years as new alloying applications have been found to improve steel's strength-to-weight ratio. Future demand from the aerospace and nuclear industries for non-ferrous vanadium alloys such as titanium and super-alloys is also likely to grow. Vanadium is usually added in the form of ferrovanadium, a vanadium-iron alloy. Vanadium compounds, especially the pentoxide form, are used in the ceramics, glass, and dye industries, and are also important as catalysts in the chemical industry. While established approaches may be used at an industrial scale to treat vanadium-bearing titaniferous magnetite ores in several countries, new alternatives are being developed worldwide. This review will give short overview of the treatment of vanadium-bearing titaniferous magnetite ores, an overview of direct reduction and direct smelting processes and an approach to determine technical alternatives for the property.

Jan 1, 2005

By Quispe Mamani, Mayra Casas Azañero

The research is located within Asuncion and Cospan districts, which according to their geological features in contrast with previous studies pointing out Au, Mo and Pb anomalies create an environment of prospective interest. The objective is to use ASTER Satellite Images to identify ore-bearing hydrothermal alteration zones. To do this, processing techniques such as the combination of bands by RGB 943 and 461, band ratio 4/6, 4/5, 5/8 and 2/1 to identify advanced argillic, argillic to phyllic and propylitic alterations. In addition, indices defined by Ninomiya were used as a third technique in order to reinforce the data obtained from the previous techniques. The results in the study area are confirmed by the SAM spectral mapping technique using spectral signatures from the USGS library. Identifying kaolinite, alunite and pyrophyllite, assemblages of the advanced argillic alteration. Concluding in 3 areas of interest with the band ratios, 5 areas with the Ninomiya indexes and 9 areas validated with SAM, which were contrasted in 13 areas of prospective interest with well-marked argillic alteration.

Feb 1, 2025

By P. Zhang, D. W. H. Su, M. Van Dyke, H. Dougherty

To provide critical scientific data and engineering guidelines to federal and state regulatory agencies as well as the coal and gas industries, the National Institute for Occupational Safety and Health (NIOSH) initiated a Gas Well Stability Research Program in 2016. This paper summarizes the critical scientific data acquisition, interpretation, and modeling by NIOSH regarding the stability of unconventional shale gas wells influenced by longwall mining. Currently, NIOSH is the only organization in the U.S. conducting such fundamental and impactoriented research, which receives input and collaborations from MSHA, PADEP, WVDMS, OHDNR, the coal industry, and the gas industry. Results from the NIOSH field instrumentation programs—which include surface, subsurface, and underground instrumentation—and the parallel three-dimensional numerical modeling programs indicate that, under shallow and medium covers, the measured horizontal displacements within the abutment pillar are one order of magnitude higher than those measured under deep cover. Casing couplers are found to play an important role in longwall-induced casing deformations. Cementing alternatives are found to have significant impact on longwall-induced casing stresses and deformations. Measured 60-arm caliper logging results are in good agreement with three-dimensional computer simulation results. Engineering guidelines on longwall-induced deformations, casing and cementing alternatives, gas well setback distances, as well as risk assessment strategy are proposed.

Mar 2, 2022

By Dmitriy A. Malovichko

The general theory for the description of seismic sources is briefly discussed. The effect of excavations on seismic radiation is considered. Expressions for seismic source mechanisms in terms of the geometrical and mechanical parameters of source processes are provided for the following cases: fault slip and shear failure in a confined environment, dynamic stress fracturing around a tunnel, rock fall, landslide and sudden subsidence. A classification of seismic events in mines based on source mechanisms is introduced. The classification separates blast-, slip- and crush-type events. Various approaches of analysis of source mechanisms involving forward modelling and inversion are discussed. The following examples demonstrating the utility of source mechanisms in mining are presented: forensic analysis of damaging seismic events, assessment of the increase in the depth of failure for dynamic stress fracturing around tunnels and its duration, examination of the rockmass deformation regime, assessment of deformation around tunnels using crush-type events, identification and parameterisation of weak geological structures, stress inversion from slip-type events. Finally, the requirements for seismic data to ensure high quality source mechanism solutions are briefly reviewed and future challenges in the interpretation and utilisation of seismic source mechanisms in mines are speculated on.

Apr 26, 2022

By D. Hodouin

Abstract. Dynamic experiments were performed in a continuous open-circuit 40x40 cm ball mill using a pseudo-random binary sequence of the feed rate and measuring the variations of the discharge particle-size distribution. The impulse response is calculated by a cross-correlation technique. Then a model involving a discrete transfer function and a time-series stochastic equation is calibrated using maximum likelihood methods. Based on this empirical model. a minimum variance controller with constrained input is designed and its performances are compared. by simulation, to the performances of a conventional PID regulator.

Jan 1, 1987

By A. Ghosh

Commonly used predictors of ground vibration from blasting, being linear in log-log plot, do not model the underlying physics of wave attenuation. Amplitude of the wave decays with distance due to geometrical spreading and inelastic attenuation producing a nonlinear carve in log-log scale. The nolinear decay of seismic waves has also been observed from non-explosive sources, such as, pile driving, drop hammer, traffic, etc. The improved predictors, by explicitly taking these two mechanisms into consideration, model the data trend extremely well at all distance ranges. Actual field data from different studies have been used to validate the improved models.

Jan 1, 1991

By R. C. Schmidt

The Mont Klahoyo magnetite deposit is located about 600 km northwest of Abidjan, Ivory Coast. During an exploration period ending in 1977 an international joint venture group investigated the deposit and proved reserves of 670 million tons grading 36% iron. The deposit, occurring at the northeast end of the Baoubly-Kiriao chain of Precambrian iron formations, is associated with amphibolites, pyroxenites and gneisses of the Liberian Shield. At Mont Klahoyo occur two separate iron formations of which the lower member is the ore body. This lower member consists of a highly metamorphosed - banded quartz-magnetite iron formation in which iron silicate bands alternate with beds of quartz-magnetite. mphibolite-pyroxenites and sillimanite-cordierite-garnet gneisses form hanging and footwall rocks. The iron formation has been folded into an elongated overturned "Z" shaped major drag fold with axes trending and plunging approximately northeast. Beds are vertical or dip steeply to the southeast. The ore zone has an average thickness of 130 m and outcrops intermittently over a distance of approximately 5.5 km. Based upon detailed studies of drill cores and the results of ore dressing test work, eight stratigraphic units, identified as K-1 to K-8, are recognizable in the iron formation. Four interbedded units are low grade silicate zones (silicate facies) with the remaining quartz-magnetite units (oxide facies) repre¬senting the important ore zones of the Mont Klahoyo deposit. The ore-bearing "K" units are subdivided further, based upon their specific lithologies, iron content and concentration characteristics, into eleven ore types. The identification of these ore types is considered particularly important to mine planning and flowsheet design. A cap of oxidized materials overlies the primary quartz-magnetite iron formation but no enrichment has occurred. It is proposed that the Mont Kalhoyo iron formations were deposited, possibly chemically, in a volcanic environment as a siliceous iron formation with volcanism providing the primary source of iron and silica. Metamorphism converted the siliceous iron formation to a relatively coarse-grained quartz-magnetite-silicate iron formation.

Jan 1, 1979