Search Documents

By Yong-Moo Cheong

When the zirconium pressure tube(PT) is in contact with the calandria tube(CT) in the pressurized heavy water reactor(PHWR), the temperature gradient between the inner and outer wall of the PT results in a thermal diffusion of hydrogen(deuterium) and hydride blisters are formed on the outer surface of the PT. Since Zr-2.5Nb pressure tubes have a high risk for the formation of blisters during their operation in a PHWR, there is a strong incentive to develop a method for the non-destructive detection of the blisters grown on the tube surfaces. However, because there is little mismatch in an acoustic impedance between the hydride blisters and zirconium matrix, it is not easy to distinguish the boundary between the blister and the zirconium matrix with the conventional ultrasonic methods. This study has focused on the development of an ultrasonic method to detect the hydride blisters formed on Zr-2.5Nb pressure tubes. Hydride blisters were grown on the outer surface of a Zr-2.5Nb pressure tube using a cold finger attached to steady state thermal diffusion equipment. Ultrasonic velocity ratio method as well as conventional ultrasonic parameters with an immersion technique was developed to detect small hydride blisters on the Zr-2.5Nb pressure tubes.

Jan 1, 2006

By Steven M. Shope

An essential element of the Bureau of Mines electromagnetic location and communication system for trapped miners is a quantitative knowledge of the surface and above-surface electromagnetic fields created by an underground transmitter. The field solutions given in this report use approximations in which the displacement currents are negligible for low frequencies. The earth is represented by a homogeneous half-space model in which a dipole source is immersed. The vertical magnetic field equipotential contours at and above the surface are graphically mapped. The volumes of the regions bounded by these contours are directly related to the geometrical zones of signal detectability. Knowledge of the detectability zones will enable the proper search strategies to be developed for airborne detection of trapped miners.

Jan 1, 1983

By A. S. Macfarlane

Mineral resource management (MRM) practice has developed in South Africa over the course of the last ten years, with the purpose of integrating previously isolated technical functions into a value chain aligned, process organization, responsible for mine planning and optimization. The implementation of MRM within various companies has met with varying degrees of success, often resulting in incremental improvements in the planning process and, conversely, often becoming the scapegoat for poor delivery on plans and projects. The reason for this has been, amongst others, a lack of a suitable metric to define the success rate of MRM in the business at hand, in terms of its contribution to the bottom line. This paper is the result of extensive research by the author into this subject, which has resulted in the conclusion that economic value added is an appropriate measure that will lead to real optimization and value creation in mining companies, if applied within a new, holistic model

Jan 1, 2006

By N McIntyre, J Smart, J Ossa-Moreno, D Rivera

Hydro-economics is a field of research that analyses water resources from a multi-disciplinary approach (Harou et al., 2009). These models generally include one component that describes the water resources of the catchment being analysed (e.g. the physical behaviour of water), an economic component that describes users’ water demand function (changes of willingness to pay relative to availability) and a coupling methodology. These models go beyond calculating cash flows for water investments and analyse the economic behaviour of users when facing water shortages or surplus. In other words, water demand curves are defined for each water user (e.g. urban, agriculture, mining, environmental and hydropower), and they are used to retrofit the water resources component. As a result, the model approximates the catchment scale response to droughts and wet periods, including the effects of water markets, restrictions, recycling, water sharing and any cooperative efforts by users to adjust to changing climate conditions.These models are usually focused on agriculture and urban users, the main water consumers in most catchments, but they have sometimes included environmental, industrial and hydropower users (Bekchanov, Sood, & Jeuland, 2015). Nevertheless, although a relevant user of water in several catchments, the mining industry has been rarely included. This paper is part of an ongoing project that addresses this gap by developing a hydro-economic model in the upper section of the Aconcagua River in Chile. The aim of the paper is to analyse the sensitivity of the outputs of the model to changes in input data, both hydrological and economic, and to develop insight on usefulness of such models for reducing water conflicts in mining regions.CITATION:Ossa-Moreno, J, McIntyre, N, Smart, J and Rivera, D, 2018. Sensitivity of a hydro-economic model in a mining region to changes in hydrological and economic inputs, in Proceedings Life-of-Mine 2018, pp 52–55 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By W. A. Dixon Edwards

Industrial mineral production in Alberta, worth $468 million in 1997, comes from a dozen types of industrial minerals, mined by about 400 producers. Cement and lime from Paleozoic limestone formations exposed along the Rocky Mountains account for the greatest production value. Sand andgravel is the primary source ofmineral aggregate. Almost two-thirds of this aggregate is consumed in the Edmonton and Calgary regions. Sulphur produced at 48 sour gas processing plants and two oil sands plants was valued at $84.8 million in 1997 and accounted for 80% ofCanadian sulphur production. Four companies solution mine the Elk Point salt beds to produce chlor-alkali chemicals, industrial salt and sodium chlorate. Natural brine is also produced as a dust control product. Al $22 million, peat moss is a major industrial mineral product in Alberta. Other minerals with noteworthy production include shale, stone, silica and ammolite. The commodities with the greatest development potential are diamond, silica and oil sands tailings by-product minerals.

Jan 1, 2001

By Brian W. Mackenzie

"This paper briefly outlines the characteristics which should be considered in assessing the economics of mineral exploration, and illustrates such an assessment by using data from the Canadian base metal sector. Implications for the sector are found to include the following:(1) base metal exploration has the potential to create a substantial amount of new wealth;(2) investment incentive for exploration under current conditions is not unattractive over-all;(3) because of existing taxation policies, there is much more incentive for large companies to explore than for smaller enterprises;(4) succesful exploration is sensitive to the size, financial resources and organizational structure of the exploration entity;(5) the general level of recent exploration expenditures should be adequate to maintain the current rate of production and perhaps to support very modest growth; and(6) there is an important opportunity for growth in the sector.The findings of the study suggest that government policies should be made more flexible, in order to take into account the risks associated with exploration and with price fluctuations in the base metal sector. Recommendations are also made concerning improvements in provincial regulations for disclosure of exploration information."

Jan 1, 1981

By T. A. Grammatikopoulos, B. Vasily, A. H. Clark

"The St. Lawrence deposit is a large wollastonite skarn (ca. 9 Mt @ 41.3% wollastonite) adjoining the gabbroic-to-syenitic Leo Lake pluton in the granulite facies Frontenac Terrane of the Grenvillian Central Metasedimentary Belt. It occurs within a horseshoeshaped horizon of quartzite, open to the east. The skarn extends over 1.2 km2, and comprises wollastonite-dominant, wollastonite-clinopyroxene, and diverse quartz-feldspar-sulphide (-titanite) layers, interbanded with, and strongly folded within, the quartzite. As in the world-class wollastonite deposits of the Willsboro district, New York, no carbonate protolith is preserved, and calcite is a negligible constituent of the mineralized zones. Wollastonite development is nonetheless ascribed to metasomatism of a metacarbonate unit by magmatogene, silica-rich, CO2-poor (XCO2 < 0.05) fluids, at P = 350 MPa and ca. 560°C, or, alternatively, 550 MPa and ca. 630°C.Several high-grade zones, averaging >40% but locally exceeding 80%, of translucent, white, tabular wollastonite grains, with lengths of 0.2 cm to 5 cm, have been delimited by drilling. Preliminary beneficiation studies yield high aspect-ratio and high-purity (low Fe and Mn) concentrates.St. Lawrence compares favourably to other known prospects and operating wollastonite deposits: having good chemical and physical properties, low iron content, and high aspect ratios (>20:1). In addition, the deposit has a favourable size and location, and will benefit from a low Canadian dollar. Canada currently has no wollastonite production."

Jan 1, 2003

By EDWARAD A. SIVEDENBORMG

REPORTS have been made at different times on the progress of water encroachment in the Frontier sands in the Salt. Creek oil field, Natrona county, Wyoming. All previous reports have, -however, been largely based on the position of water in the sands as determined by various physical tests. Subsequent information has been secured through a preliminary investigation of the porosity, grain size and degree of saturation of the Frontier sands. Also, a closer differentiation has been made between the waters encountered incident to the production of oil by means of chemical analysis. In view of the more recent developments there has been a need of a water encroachment map of the first Wall Creek based on a field survey and additional information acquired since the water encroachment map of the sand of 1926, by J. S. Ross and E. W. Henderson, petroleum engineers of the U. S. Geological Survey. The present report is confined to a study of the first Wall Creek sand and was written in connection with the preparation of the map, showing water encroachment in this sand. The first Wall Creek sand was the discovery sand in the field, the first well having been drilled in 1908. Its thickness averages 120 ft. and, varies between 90 and 160 ft. The sand is in the Colorado group of the Upper Cretaceous series and is further considered as a part of the Frontier formation found in other parts of Wyoming.

Jan 1, 1930

By J. F. Childs

Montana consists of an Archean crystalline basement overlain by Proterozoic through Cenozoic sedimentary rocks. Igneous rocks range in age from Archean to Pleistocene; the most voluminous magmatism and volcanism occurred during the Late Cretaceous and early Tertiary. The state can be divided into three tectonic provinces whose deformational styles are a function of different bedrock responses to Late Cretaceous-early Eocene compressional tectonism. Several long-lived structural zones have been periodically reactivated since the Precambrian, and were the sites of recurrent magmatism. Regional gold distributions are strongly influenced by the tectonic provinces and structural zones. Lode gold systems in Montana occur in diverse geologic settings resulting from a complex interaction between structure, magmatism, and sedimentary depositional processes. Reserves or resources are known for 19 significant lode gold systems, and additional unannounced discoveries have been made recently. Mineralization ranges in age from Archean to Tertiary. The influence of long-lived structures is apparent at both the regional and deposit scale, and in some cases multiple mineralizing events have been superimposed upon one another. Most Montana gold systems have a direct spatial and genetic association with Late Cretaceous through Oligocene igneous rocks. However, the importance of sedimentary rocks and associated depositional processes should not be underestimated.

Jan 1, 1993

Innovative mining technology came to Texas in the form of bucket wheel excavator/cross-pit spreader systems. Texas Utilities Mining Company put the first system to work at its Big Brown Mine in December 1985. The second such system was put into operation at the Monticello Mine in February 1991. The cross-pit spreader systems are mobile, electrically powered, excavation and conveyor systems, the principal components of which include bucket wheel excavators (BVE) and an across-the-pit conveyor (spreader). These crawler mounted machines operate as a unit; the BVE&apos;s excavate overburden, feed it via conveyors to the spreader which in turn conveys the material across the open pit and onto the developing spoil bank. The system at the Big Brown Mine is composed of 2 BVE&apos;s and an across-the-pit conveyor while the Monticello system is made up of 1 BVE and a spreader. The BVE&apos;s prestrip overburden preparing a dragline bench for the final removal of overburden. Numerous evaluations, including lignite production requirements, economics, overburden characteristics, rehandle reduction, spoil stability, and the compatibility with dragline operations, led to the selection of the cross-pit spreader system at the Big Brown Mine. The system has proven itself as a viable and economical means of prestripping. The system&apos;s success at the Big Brown Mine led to the development of a second such system at Monticello. The advent of the cross-pit spreader system is viewed by Texas Utilities Mining Company as a viable solution to recovering deeper lignite reserves in a safe and economical manner.

Jan 1, 1993

By R Soong

The Wharekirauponga (WKP) epithermal gold-silver deposit is located about 10 km north of Waihi in the Hauraki Goldfield east of Auckland. WKP is notable for its sheeted to stockwork quartz veins hosted in rhyolitic rocks, that have attracted exploration interest as a low grade, bulk tonnage exploration target. Exploration between 1978 and 1993 included 23 diamond drill holes totalling 5505 m. The mineralisation occurs in a rhyolite dome complex (Miocene), consisting of flow-banded rhyolite and rhyolitic pyroclastic rocks, with minor andesite. Fifty four drill core samples were collected from six exploration drill holes and analysed by semiquantitative XRD techniques. Hydrothermal alteration of the rhyolitic and andesitic rocks has developed secondary mineral assemblages of quartz, adularia, albite, chlorite, illite, sericite, interlayered illite-smectite, carbonate, halloysite and pyrite. The main zone of mineralisation is characterised by quartzadularia alteration, which grades oiItward to quartz-clay (illite, local halloysite and/or interlayered illite-smectite) alteration. Propylitic alteration is present at the southern end of the drilled area of the prospect. Depth-related changes in mineralogy include a decrease in illite and appearance and increase in quantity of chlorite with increasing depth, and the localisation of halloysite and interlayered illite-smectite in the shallow parts of some drill holes.

Jan 1, 2001

By Frederick R. Cosgrave

Blasting near buried Natural Gas pipelines has always been an area of great concern. Given the many variables that the blaster must contend with in determining how to break the rock while trying to keep the vibration low and doing so while not compromising the pipeline.

Jan 1, 1995

By Tommy Wilson

OIL well drilling fluids have become a vital part of the drilling industry during the past 25 years. From chance usage of drilling mud at the fabulous Splindletop field in 1901, drilling fluid control has become an extremely technical and exacting science. Drilling for oil today involves exploration at depths ranging to 21,000 ft, nearly 4 miles. Geological formations encountered at these depths offer a tremendous challenge to the production, research, and service facilities of any drilling mud company.

Jan 5, 1954

By D. A. Salinas G., A. H. Castillejos E.

Pachuca tanks are commonly used in the hydrometallurgical industry to carry out leaching operations. The fluidynamic characteristics of the liquid phase, resulting from the injection of gas into the draft tube, are important to achieve the complete suspension of the mineral particles and has a decisive influence in the mass transfer processes occurring in this reactor. This study investigated the effect of different design and operating characteristics on the liquid velocity field. using a laboratory-scale Pachuca tank. The transparent model was filled with water, and air was injected through the bottom in the absence of mineral particles. The liquid velocities over the whole reactor were measured under several experimental conditions using particle image velocimetry (PIV). This technique allowed to obtain a very detailed picture of the liquid motion even in the draft tube, as long as bubbles were absent from the measured field of view. The experiments have shown that the liquid velocities increase with increasing the draft tube to tank diameters ratio, the distance from the conical bottom to the draft tube entrance, or the gas superficial velocity. On the other hand, an increase in the water level with respect to the draft tube outlet caused a decrease. A mathematical model, which used the no-slip model, to calculate the variation of axial effective density along the two-phase region, was found to predict liquid velocity fields which agree very satisfactory with the experimental results obtained under all the conditions studied.

Jan 1, 1999

By A. J. Potgieter, C. Hill, A. Humpel, D. S. Magudulela, V. Scholtz, A. Coetzee

Keywords: Pyrometallurgy, long steel products, coke, sinter, blast furnace, steel plant Located in Northern KwaZulu Natal, Mittal Steel South Africa Newcastle works produces roughly 1.8 million tons per annum, supplying long steel products, locally and overseas. The great extent of local raw material availability and low conversion cost ensures that Mittal Steel South Africa is among the lowest cost, high quality producers of steel. MSSA Newcastle works can be subdivided into two main sections: The iron making side, comprising the coke ovens, sinter plant and blast furnace, and the steel making side, comprising the basic oxygen furnace, ladle furnace, continuous casters, and the medium, rod, and bar mills.

Jan 1, 2006

By B. McLaughlin

"The Penna shaft is the deepest single-lift shaft in North America. Agnico-Eagle started sinking the Penna shaft in 1995 with a hoisting plant capable of hoisting 1800 t/d from a 2240-m deep shaft. Exploration success at depth led to the replacement of the existing double drum hoist by another double drum hoist capable of hoisting 7000 t/d. The use of another double drum hoist, instead of a Blair multi-rope winder, to hoist 24.5 t skips was only made possible by lowering the safety factor.This paper describes recent experiences at Penna and in South Africa, and examines the possibility of extending the double drum hoisting system to a depth of 3 km. IntroductionThe original Penna production hoist was a 4.88 m (16 ft) diameter double drum and single clutch machine. Béliveau (1996) and Scott (1996) have described this hoisting plant. In 1998, a decision was made to increase mining capacity from 1800 t to 4500 t of ore per day from the shaft bottom. Final capacity had to include an allowance of 1800 t of waste per day for future capital projects. While daily capacity was to be 6300 t, it would, by taking into account the different rock densities, be equivalent to hoisting 7000 t of ore.The steps taken to lower the safety factor were presented by McLaughlin and Scott"

Jan 1, 2004

By Adam Bedell, Brad Crenshaw

Tunnel project contract documents often present groundwater infiltration requirements for components of the underground portions of the project. All too often these documents require quantifiable target inflows for these components, but only refer to them in subjective terms such as “dry,” “manageable,” etc. The Contractor’s definition of these terms will inevitably differ from the Engineer’s definition of these terms. The purpose of this paper is to look at common subjective terms used in documents and provide suggestions for reasonable quantifiable language. Additionally, the paper will provide information and recommendations on relative levels of cost and effort increase needed to provide increasing levels of water cutoff (i.e., achieve “dryness”?).

Dec 1, 2022

By C. Dorfling, C. A. Snyders

South Africa has extensive mineral processing and extractive metallurgy capacity and infrastructure for metal production from natural resources. Decreasing ore grades, increasing labor costs, and more stringent legislation have made economic metal production from primary resources challenging. Opportunities exist for metal production from secondary resources such as mining wastes and end-of-life consumer goods. The objectives of this study were to evaluate the current status of metal production from secondary resources in South Africa and to identify potential opportunities for further development. Two main classes of secondary resources, namely mining waste and electronic waste, were considered. Primary metal producers are dominating metal production from mining wastes; several of the gold, platinum and chrome producers operate low risk and low cost tailings retreatment facilities that contribute significantly to their overall production. Further opportunities exist in, for example, the treatment of more than 450 estimated gold tailings dumps in Gauteng, as well as metal recovery from slags and furnace dust. The majority of companies involved with electronic waste recycling in South Africa focus on collecting and disassembling; only a few perform preliminary physical processing, with the recovered fractions then being sent overseas for metal recovery. Projections are that the rate of waste generation will increase significantly and that treatment will become critical to comply with more stringent environmental legislation. Projects related to process development, techno-economic evaluations and environmental impact studies for metal recovery from batteries, printed circuit boards, and fluorescent lamps are underway. South Africa is ideally positioned to further explore opportunities for synergistic relations between metal recyclers and primary metal producers. Processing of electronic waste for production of technology metals, for which limited natural resources exist in South Africa, would be a key enabler for local manufacturing industries and expansion of the value chain.

Jan 1, 2018

By A. L. Murray

First -aid training as an adjunct to safety is receiving more wide spread recognition in the industries every year . Moreover , the adoption of a program for giving firstaid training to practically all employees at a mine or plant is based upon the experience gained and good results obtained from standard first -aid instruction during the past two decades . In the near future industries that desire to maintain a low accident rate , to decrease compensation costs , to reduce lost time , and to build up an efficient , loyal working force , will recognize that training in first aid is one way of attaining these results with little expenditure of time and effort . Progressive organizations will require every man from the superintendent down to take first - aid training and not , as heretofore , only a small percentage of the working force . When employees learn that first - aid training can be applied not only at their daily tasks but in their homes and on tthhee highways ,, they will welcome the opportunity of learning how to care for injuries and perhaps save lives . In a limited way first - aid instruction was given to miners as early as 1899 . Later , in 1904 , a few of the companies in the Pennsylvania anthracite district inaugurated the distribution of first - aid packets to their employees and instructed them in the use of the contents . It remained , however , for a branch of the United States Government to grasp the real significance of widespread first - aid training as an effective means of saving life and minimizing suffering from the large number of accidents among workers in the mineral industries . The United States , owing to its vast resources , both natural and human , for

Jan 1, 1930

By A. J. Miller

Estimates of interstitial water saturation derived from capillary pres-sure data are compared with residual water saturations found by the analysis of cores out in oil-base drilling fluid. A theoretical explanation for the high-rate of water production from the Bellshill Lake Field is proposed, based on the interpretation of the capillary pressure data.

Jan 1, 1960