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By R. W. Lai

Cyclic voltammetry (CV), flotation response, evolved-gas analysis (EGA), and X-ray photoelectron spectroscopy (XPS) were employed to evaluate the major differences in the surface property and surface reactivity of coal pyrite and mineral pyrite.

Jan 1, 1989

A portable electronic instrument was developed which will measure change of longitudinal wave velocity with change of uniaxial stress in rock columns. The instrument is a solid-state device powered by nickel-cadmium batteries. It uses a probe of two piezo-electric crystals spaced inches apart to send and receive a pulse through a stressed rock. A one-inch cathode ray oscilloscope visually displays the longitudinal wave. A reference chart is used to find the stress. Laboratory results have indicated that the average stress on a sandstone column can be found to within 35 psi. The feasibility of using this instrument to determine stresses in mine pillars is to be studied. The instrument may be used to investigate physical properties of rock.

Jan 1, 1970

By M. Frenzel, D. Ebert, K. Bachmann, A. D. Renno, R. Möckel, J. Gutzmer, J. Krause

With the increasing demand for metalliferous and mineral raw materials, and consequent depletion of the global natural resource base, the possible utilization of secondary raw material sources is receiving more and more attention. In the present study, we present results from a detailed vanadium deportment study of three basic oxygen furnace slag (BOS) samples known to containing elevated bulk concentrations of vanadium (V). Complementary analytical methods that were used to quantify the abundance and composition of V-containing phases include SEM-based automated mineralogy, Xray fluorescence (XRF) analysis, and X-ray powder diffraction as well as electron probe microanalysis. The vanadium deportment was quantified using Monte-Carlo simulations of the data obtained from automated mineralogy and electron microprobe analysis. The total V concentrations identified by XRF are between 1.7 and 2.2 weight percent V. The most important hosts of vanadium are larnite-, brownmillerite- and portlandite-solid solutions. In two samples, calcium carbonates also significantly contribute to the V deportment, while wuestite, lime and native iron do not contribute significantly to the vanadium deportment. A thorough consistency check identifies considerable uncertainties in the density of the Vbearing phases as the most likely reason to explain remaining discrepancies between measured and calculated V values.

Aug 1, 2024

By T. J. Jr. Corwin

This paper will cover the problems confronting an owner when planning and estimating the cost of a proposed tunnel. Three factors are known: the length, size and the time allocated for the completion of the work. In general the difficulties encountered when driving a tunnel in California are the greatest at the lower elevations and in the Coast Range and are minimal in the Sierra Nevada mountains particularly in granitic formation. The writer will discuss the experience gained from observing the driving of about 120 miles of tunnel in California as well as the repairs of some tunnels. SIZE OF TUNNELS It is known that a small tunnel may be more costly to drive than one of somewhat larger dimensions. This fact was found to be true when a tunnel about 4,000 feet long was constructed to eliminate 7 miles of canal. The formation was lava so it was anticipated the ground would be self supporting because of the small bore. Actually the tunnel required support for most of its length and working conditions were poor. It became apparent that a larger size could have been driven at no additional cost and probably in less time. On another unlined tunnel, to be driven in granitic formation, the contractor was given the option of using

Jan 1, 1974

By S. B. Castor

Although production generally satisfies demand for rare earths, new markets may make undeveloped resources, particularly those rich in yttrium, more interesting. A Precambrian carbonalite orebody at Mountain Pass, California, has been the world's largest rare earth producer. Minor rare earth production comes from titanium placer mining in Florida and uranium mining in Canada. Prior to operations at Mountain Pass, North American production was mostly from placer deposits that constitute large, low-grade rare earth resources. Newly discovered North American rare metal resources in peralkaline igneous rocks are potential yttrium producers. Most of these resources are in a continent-wide belt of anorogenic magmatic rocks approximately coeval with mineralization at Mountain Pass. Other untapped rare each resources in North America are generally light rare earth-dominated and small or of low grade.

Jan 1, 1991

By John S. Lagarias

When ore bodies are faulted or mill feed turns refractory, mining managers and engineers act vigorously to convert imminent failure into eventual success. The recent proliferation of onerous "environmental" regulations and restraints is likewise a threat to successful mining enterprise, in some ways more insidious and dangerous than the problems presented by natural obstacles. The regulatory burden has become so heavy that a pall of pessimism covers much of the mining enterprise. In this paper we frankly recommend a Pollyanna approach, making not just "the best of it" but directing the whole environmental process: first, to improve our planning, engineering, and operating procedures; and, second, to demonstrate the need for modification of laws and regulations which are intolerably burden-some to both the mining industry and the public. It is customary for government officials and environmentalists to point out how great are the new environmental regulations and how successfully these have improved the natural environment in particular and the quality of life in general.

Jan 1, 1978

By S. M. Alvarez

The Moon Creek Reclamation Project provides a case study in the development of creative cleanup solutions for an abandoned lead and zinc mine and mill site located in northern Idaho. Innovative design features include construction of a 88,000 cubic yard combined waste containment facility on soft in-situ tailings, water-balance cap, limestone gravel drains, a geocell mattress for stability, and a below-grade scour protection berm. The stream, including a wetlands buffer, will be relocated within an existing road alignment and rehabilitated to provide trout habitat. These elements allow for the integration of reclamation and stabilization measures into an effective site design.

Jan 1, 1999

By T. W. Peterson

There are two approaches to developing a minicomputer based application for an industrial grinding circuit. Usually, the control program is coded and compilation-debugged on a large-scale scientific computing system or the minicomputer itself if the machine is available. Final debugging and testing must wait for installation and checkout of the entire minicomputer system. Two immediate disadvantages of this approach are the need to obtain, install and check out the hardware before the final debugging stages of program development can begin, and interference with normal mill operation during such final testing. This work reports on an alternative to the usual procedure. Here both compilation and execution bugs are eliminated from the application program before hardware installation by testing the control program against a reasonable dynamic simulation of the entire process. Thus, software development can be completed before the target mini is installed. Such off-line development requires a reasonably accurate mathematical model for the entire process system as well as a suitable simulation package for communication between the simulated environment and the minicomputer application program. Specific data describing the design configurations and dimensions of the mills, cyclones, sumps, pump characteristics and analog controller configuration were supplied by ANAMAX for a grinding division consisting of a rod mill followed by two ball mills in parallel. This information was used to set up a plausible model structure. Steady state ANAMAX data on particle size analysis at various points in the circuit and corresponding values of flow rates, pump speeds, sump heights and slurry densities were used for model parameterization. The preferred operating control strategy - "best grind at operator-set rod mill feed rate" - was set by ANAMAX. An inferential particle size analysis technique using the cyclone cluster as an on-line particle size sensor was used in a novel control strategy_ to achieve the stated objective. Two disturbances common in the ANAMAX circuits - rod mill scoop pluggage and shut down/start up of one of the ball mills - were studied in detail. This report out- lines the steps in system development and testing and the results obtained.

Jan 1, 1974

By Feng Dingwu, Chen Jin, Sun Zhongyuan, Peng Shiying

The recent development of rare-earth permanent magnets has impacted the field of magnetic separation. The permanent magnets technology led to the advent of various magnetic separators particularly designed for application in mineral processing. In this paper, a new type of rare-earth PHGMS possessing a higher magnetic field strength in the working zone was developed using finite element analysis techniques. The NdFeB permanent magnets used had properties of 38 MGOe stored energy, and magnetic material flux levels exceed 1.2 T, The combination of scientific and engineering design and suitable matrices can offer an effective separation of industrial minerals, such as kaolin, feldspar, etc. Compared with conventional high intensity electromagnetic separators, the equipment can reduce electrical energy over 80% with lower operation and maintenance costs, and less installation space.

Jan 1, 1995

By T. M. Plouf, G. A. Lang

INTRODUCTION The finding or acquisition of ore bodies containing 200,000 opt gold and greater is becoming more difficult. There are more investors and small heap leach operators who have or can raise the capital to make the investments in the large ore bodies. Echo Bay Mines' approach has been to regionally develop small ore bodies, two or three in the same geographic location, which when considered together contain over 200,000 opt gold. CONCEPT The "world class" ore body syndrome, which many large gold producing companies maintain, can restrict company growth if the finding or acquisition of these large ore bodies is not forthcoming. Another approach has been taken by Echo Bay Mines. The concept is to regionally develop two or three small ore bodies suitable for processing with portable equipment. The systematic scheduling of mining, processing with a single flexible processing plant using the same management/ operator team can reduce your overall investment. The initial selection of mining and crushing equipment suitable for sun11 open pit operations is essential. A very viable option in the mining sequence is to use contract mining/crushing/screening/agglomerating and stacking. This option also lowers your initial capital investment and increases the flexibility in mining as you move from one mining operation to another. LOCATION AND SEQUENCING One single small ore body of itself is not attractive enough for the large producer. The recovery of the initial capital investment, although very rapid, does not make a viable project. The only alternative is to find two or more small ore bodies close enough geographically to each other so that the same management/operator team can be used to run the operations as each is put into operation. Echo Bay Mines has regionally located several ore bodies ranging in recoverable ounces up to 100,000 oz. These small separate ore bodies, located within a 30-mile radius of each other, for planning purposes have been considered as one single ore body. The first small ore body has the initial burden to recover the capital invested in the office, laboratory, power plant and processing plant. Other capital investments such as water supply, access and haul road, fencing, septic system, pads and ponds are reoccurring at each mine site. The first small ore body must recover the initial capital investment in the movable structures as well as the reoccurring capital investment in the fixed structures very rapidly. A total capital recovery time of 6 to 9 months should be used as an economic decision point for both choosing which small ore body should be processed first, and what the plant design capability should be. The sequencing of the small mines is very critical. All the fixed structures mentioned above must be installed at the second mine site before the first mine has been mined out. The ideal sequencing will allow for only one month between shutdown of the first small mine and production from the second. SPECIFIC OPERATION Echo Bay Mines has completed the construction of the Illipah Mine located in White Pine County, Nevada, with this small mine sequence approach. The Illipah Mine is a 40,000 ounce recoverable gold ore body. This ore body met all the necessary requirements. The Illipah project could support the capital investment in the movable structures which will

Jan 1, 1987

By D. A. Knight

The property is located in the Porgera Valley 600 Km North West of Port Moresby. The remote location is 2500 m above sea level. The mine area has 3,600 mm of annual rainfall and a temperate climate with temperatures ranging from 10" C to 22° C throughout the year. Alluvial gold was reported in the Porgera area in 1938 and has been an important source of revenue for the area for many years. Intermittent exploration was carried out until the 1960's when Placer (PNG) Pty. Ltd. with Mt. Isa Mines commenced an extensive exploration program. The property was brought to production in 1990 by the Porgera Joint Venture group consisting of Mount Isa Mines Ltd, Rennison Goldfield Consolidated Ltd. and Placer Dome Inc, each with a 30% ownership and the Government of Papua New Guinea with a 10% share. Placer Dome Inc. is the manager of the property with construction under the direction of the Placer Dome Technical Services group.

Jan 1, 1992

By V. Nasri, P. Jarast, M. Bakhshi

The Montreal metro Blue Line Extension toward the northeast consists of the construction of five new underground stations. The project includes 6 kilometers of the tunnel which will be constructed using a Tunnel Boring Machine (TBM). In line with the commitment to integrating sustainability best practices, Envision verification is pursued this project. The Envision reference framework was developed to cover all the sustainable development aspects of an infrastructure project and each phase of its life cycle (planning, design, construction, operations and maintenance, and end-of-life). As a part of this endeavor, low-carbon concrete and shotcrete mixtures are proposed for the linings of TBM and SEM tunnels as well as stations and auxiliary structures. The CO2 emission of the low-carbon concrete and shotcrete mixtures were compared with their typical mixtures and the total CO2 emissions reduction related to the tunnel lining is determined. The study is of strategic significance for achieving emission reduction in the tunnel industry.

Jun 13, 2023

By F. L. Kadey

A discussion of fillers would not be complete without allotting adequate time to that unique and different mineral material, diatomaceous silica. Historical references to its use challenge the aesthetic aspect of man's curiosity; whereas modern scientific tools have provided a dimension of measurement that has motivated many of its more recent applications. A brief review of what is already known is in order. The diatom is a unicellular, plant-like, microscopic organism, related to the algae1. Its natural function appears to be that of a food for other marine or lacustrine organisms, The diatom's "claim to fame" from an industrial viewpoint is dependent on the fact that it secretes an opaline siliceous skeleton that must survive, chemically and structurally, the geologic processes that caused its formation in the first place; its subsequent demise, burial, consolidation, and alteration; and finally, its ultimate exploitation by man--in somewhat that order. In addition to its siliceous nature, the skeletal structure of the diatom possesses a variety of shapes, patterns, and sizes that have not only been the intrigue of microscopists for decades, but have served to set diatomite apart as an industrial mineral; and have reserved for it applications that cannot be satisfied by any other material. Its chemical inertness, its intricate structure, and its intrinsic hardness-coupled with fineness and friability-- are generally known and have accounted for its application in a wide range of filtration and filler uses. The increasing use of the electron microscope has considerably expanded our knowledge of heretofore unseen secondary and tertiary structure of submicron dimension in the diatom valve. The development of electro-sensing methods of particle size measurement which seem to supersede sedimentation and microscopic techniques has portrayed size distribution in a more realistic light. Interest in the surface chemistry of these silica structures has further strengthened our understanding for certain uses. Thus, new tools and ideas have made possible the introduction of diatomite into such sophisticated technologies as that of chromatographic supports, its improved utility in paint applications for the control of gloss and sheen, and its usefulness in the entirely new concept of "Dry Acid Concentrates." Each of these applications has been discussed elsewhere before people particularly interested in analytical chemistry, in paint, and in liquid handling, respectively, where the diatom has been a means to an end. The emphasis here, before the mining fraternity, however is on diatomite as a raw material with reference to the uses mentioned above. It is therefore toward an awareness and understanding of diatomite properties pertinent to these newer filler applications that this paper is directed.

Jan 1, 1967

By Konstantinos Komnitsas, Evangelos Petrakis, Emmanouil Varouchakis

The paper discusses the limitations of population balance modeling (PBM) in predicting particle size distribution in grinding systems. It introduces a nonlinear framework that transforms the batch grinding equation into the Rosin-Rammler distribution, providing more accurate analysis under different operating conditions. The study uses marble as test material and investigates the adaptability of the nonlinear model with different media sizes.

Oct 1, 2023

By A. Kalmes, B. Dehler, D. Kopp

Nutrien has six potash mines in Saskatchewan and has been proactive in maintaining the integrity of their tailings facilities through ongoing assessment, design, operation, inspection, and monitoring. Nutrien commissioned a system inventory and semi-quantitative risk analysis (SQRA) of all dikes to further environmental stewardship at their potash facilities. The inventory assessed nearly 100 dikes; each dike was rated according to a probability and consequence factor and assigned a risk score. The risk scores were used to develop a risk matrix for each of the six sites and risk-response actions for each dike and segment. The inventories and SQRAs will help each site assess priorities for investigation and risk mitigation, if necessary. The study results will also help Nutrien refine corporate wide tailings governance standards and demonstrate compliance with various governance regulatory obligations.

Mar 2, 2022

By D. F. Scott

Spokane Research Center personnel have been investigating the use of seismic tomography to monitor the behavior of a rock mass, detect hazardous ground conditions, and assess the mechanical integrity of a rock mass affected by mining. Seismic tomography can be a valuable tool for determining relative stress in deep (> 1220 m) underground pillars. If high-stress areas are detected, they can be destressed prior to development or avoided. High-stress areas can be monitored with successive seismic surveys to determine if stress decreases to a level where development can be initiated safely. There are several benefits to using seismic tomography to identify high stress in deep underground pillars. The technique is reliable, cost-effective, efficient, and non-invasive. Also, investigators can monitor large rock masses, as well as monitor pillars during the mining cycle. By identifying areas of high stress, engineers will be able to assure that miners are working in a safer environment.

Jan 1, 1997

By Alexandru Corneliu Stematiu, Catalin Popescu, Radu Sarghiuta

"The tunnel sector is excavated into a rock mass heavily affected by tectonics, defined as a regional fault. The rock around the tunnel support undertakes the non – elastic deformation and gradually detaches from the rest of the non affected rock mass, moving inside of the excavated area and tending to fill up the whole space. The initial solution of using stiff support consisting in double steel ribs I12 with circular shape in the upper part and straight vertical pillars in the lower part has proved to be inadequate. Based on the calculations of the subsidence phenomena and a mathematical model, the proposed alternative support was provided by special circular steel ribs – SG-23 –that allows a limited rib deformation (by relative slip between the arch segments) in order to mobilize the contact between the rock contour and the inner face of the rib - not only for the deformed rib but also for the neighboring ribs. 1. INTRODUCTION Hydropower development of Jiu river in Romania, in the narrow gorge sector includes two diversion HPP and a small hydro plant that provides the minimum required flow downstream: CHE Dumitra , CHE Bumbesti and MHC Livezeni (Table 1. Hydropower parameters).The Livezeni intake reservoir is provided by a gated dam located 1250 m downstream of merging point between Jiul de Vest river and Jiul de Est river. The dam is equipped with three radial gates with flap gates with a span of 12 m each and the height of (6 + 3) m. The longitudinal profile of Dumitra head and the location of the gallery zone that is the subject of the paper are presented in Figure 2. Longitudinal Profile – Dumitra Head."

Jan 1, 2016

By R. M. White

Abstract. Gulf Coast Salt Domes are being considered for radioactive waste disposal and this paper describes the geophysical techniques currently being used and those being considered for later phases of the program. Detailed gravity work utilizing a modification of the Talwani-Ewing modeling technique, shallow high resolution reflection seismic surveys using the mini-sosie concept, surface electrical resistivity and down-hole geophysical logging to add a third dimension to all of the surface techniques and to allow inverse modeling of the surface data sets are being utilized. The logic of the combined geophysical surveys will be discussed as well as their relative economics and their relationship to the overall exploration effort.

Jan 1, 1980

By R. D. Kelsey

The theory, definition and practical application of cutoff grades have evolved over a long period. This evolution is reflected in the continuing flow of papers on this and other related matters though the rate has varied as new ideas and theories have become understood and applied in practice. Papers by Lane(l) in 1964 and Taylor(-2)- in 1972 provided landmarks in the understanding and general communication of cutoff grade theory and its application. The reasons for the continuing interest in cutoff grades are obvious. Too high a cutoff can reduce the mineral recovered and possibly the life of a deposit. Too low a cutoff would reduce the average grade (and hence profit) below acceptable levels. This paper provides a brief overview of existing cutoff grade theory and some particular aspects of its application.

Jan 1, 1979

By J. M. Mutmansky, Y. J. Wang

The method usually used to predict the direction of flow in a connecting airway is to conduct a survey of the two existing nodes to be connected by the new pressure airway. It is then assumed that the air will flow from the node with the measured higher pressure to the node with measured lower pressure. This paper examines this direction-of-flow problem using properties of the system characteristic curve for a two-terminal network and specifies some conditions that will ensure that the air will flow in the direction anticipated. It was concluded that the only requirement is that all characteristic curves of the fans in the network should be strictly decreasing. Five numerical examples illustrate some important proper- ties of the direction-of-flow problem.

Jan 1, 2000