Search Documents

The Lead-Line Update held in conjunction with the 1977 SME-AIME Fall Meeting in St. Louis provided sessions on mining, mineral processing, extractive metallurgy, and economies to brief the record on the industry's activities and developments since the 1970 World Symposium on Lead and Line convened, also in St. Louis. Changes in the industry since 1970 have not been profound, notes the program committee, consisting of D. O. Rausch, F. M. Stephens, and B.C. Mariacher, cochairmen; and H. L. Clifford, S. C. Fall), and M. Snedeker. However, various environmental and conservation factors have had a direct impact on process consideration and operating practice; the result has been new mines, improved technology, and changing market opportunities. The general consensus of the participants is that the future for the Lead-zinc industry looks promising as new applications are found and new products resulting from intensive research reach the marketplace. The highlights of the HS technical papers presented at the 1977 session follows.

Jan 11, 1977

By D Baas, J Le, R Braun, R Chandramohan, K Hollis, G Lane

The Phu Kham Copper-Gold Operation (Phu Kham) is located in northern Laos, approximately 140 kilometres from the capital, Vientiane. The operation is a producing asset for Australian-based copper and gold producer, PanAust Limited (PanAust) and is operated by Lao-registered company, Phu Bia Mining Limited (Phu Bia Mining). PanAust holds a 90 % interest in Phu Bia Mining. The Government of Laos owns the remaining 10 %.The Phu Kham Operation has recently undergone a series of process improvements to treat the anticipated competent ores scheduled for 2017 and 2018. The operation’s comminution circuit, which comprises a semi-autogenous (SAG) mill and two ball mills, each with 13 megawatts (MW) of installed power, was expected to be SAG mill limited when treating competent basement rock. Ausenco Services Pty Ltd (Ausenco), was engaged to help optimise and enhance the productivity of the Phu Kham comminution circuit over an eight-month period. The work involved participating in and overseeing the redesign of the SAG mill liner systems and developing operational strategies for maximising throughput through to the end of mine life. Ausenco’s comminution optimisation tool, Ausgrind, was used to benchmark and analyse plant data with empirical models, predict circuit performance for varying ore characteristics and evaluate liner wear and predict the life for varying operating parameters. Variances between the actual and the predicted values were assessed in detail to identify missed opportunities, and guiding operating parameters were redefined to maximise throughput and productivity. In combination with the redesigned liner system, optimised process controls for varying ore competencies, and improved operational practices and troubleshooting strategies, increased Phu Kham overall production, exceeding the milling capacity when treating competent ores. CITATION:Chandramohan, R, Braun, R, Lane, G, Hollis, K, Le, J and Baas, D, 2018. SAG mill optimisation and increasing throughput at the Phu Kham Copper-Gold Operation – a success story, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 113–128 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By L. C. Raymond

Good afternoon. I have entitled my talk "Investment for Progress," implying thereby a spark of friendly competition by private enterprise with such government-inspired foreign aid and investment programs as the Alliance for Progress. While the subject of foreign investment is hardly a new one, the perpetual flux of the political and economic surface of this earth we inhabit makes it forever timely and forever interesting. Especially do tremendous opportunities for international investment constantly present themselves to the mineral industry, and just as often must the industry approach these opportunities with a great deal of investigation and caution. This is not to say that the mineral industry--no less than any other industry--should be unenthusiastic about the foreign scene, but like everyone who proposes to put his money where his hope is, it should consider all the factors and weigh the possible disappointments as well as the rewards.

Jan 1, 1964

By R. J. Mitchell

"The use of hydraulically delivered classified tailings sands to provide ground support in large mining operations is still widespread despite recent developments of alternate backfilling methods and materials. The major disadvantages of the use of hydraulic fill are the costs and risks associated with slurry delivery. The main risk is that of bulkhead failure resulting from sand liquefaction due to insufficient operational control or due to dynamic loading from earthquake or rockburst. That risk may be eliminated by the pouring of a stiff cemented sand plug in the base of each stope prior to continuous fill pouring in that stope. An additional advantage of cemented plugs is that massive bulkheads are not needed. Instead, a temporary (removable and reusable) bulkhead can be used for plug forming.Physical model studies of fill pressures on a temporary bulkhead were carried out in a 3 m radius centrifuge facility. Fill pouring in-flight was carried out in order to model prototype stress paths. The results indicate that the average bulkhead pressure is likely to be less than 10 kPa under normal operating conditions and less than 20 kPa under the poorest anticipated operating conditions which include smooth walls, high slimes content and high water-content slurries. A portable bulkhead consisting of a central core and a surrounding sealing bladder was modelled and found to be effective. The use of different sizes of cores allowed the stress distribution adjacent to these bulkheads to be evaluated."

Jan 1, 1992

By Floyd G. Anderson

This report reviews and summarizes information on prevention and suppression of dust in mining, tunneling, and quarrying published in the United States from 1961 through 1967. Unpublished pertinent data developed or assembled by the Bureau of Mines during this period also are included.

Jan 1, 1969

By Thomas J. Neil, O&apos

Mine land reclamation is a comparatively new science-Although some mining companies point with pride to reclamation efforts of 20 to 30 years ago these were the exception rather than the rule. In the last ten years the skyrocket of environmental awareness has been awesome to behold. Future shock gripped mine operators everywhere as they struggled to cope with rapidly changing and escalating demands. The initial result was that two divergent points of view became dominant. Environmentalists said, "Put it back the way it was," and the miners responded, "Let's grow some weeds and hide it." These views are not surprising as they represent rather obvious alternative responses, albeit at opposite ends of the decision spectrum. The former case has prevailed more often than the latter, as most state and federal legislation -- both proposed and passed -- has required drastic alteration of the post-mining landscape so that evidence of prior mining is largely obliterated. An exception to this has been in porphyry copper country where the infrequent abandonment of mines has given emphasis to the second philosophy -establishing vegetative cover on mine waste materials. Now, it should come as no revelation to most mining people that both of these approaches to mine reclamation suffer from serious drawbacks when applied to open pit copper mines. First, whereas waste dumps and tailings dams can be vegetated with some aesthetic benefit, the massive presence of copper mining operations remains very prominent. It is difficult to conceal an open pit copper mine. Second, returning open pit copper mines lands to their original topography and productivity is simply not a reasonable alternative.

Jan 1, 1976

By Marreros D. Oscar

La perforación y la voladura son mecanismos que suministran material adecuadamente roto al equipo de carguío. La efectividad de ambos depende de la evaluación de la perforadora y de los explosivos a utilizar. En esta perspectiva, el presente trabajo describe los parámetros necesarios para evaluar los requerimientos de perforadoras en una mina nueva. El proceso de selección y evaluación conlleva una optimización económica del equipo de perforación para cumplir el plan de minado, asegurando la producción t reduciendo los riesgos financieros. Asimismo, se presenta el análisis de inversión con la técnica de flujo de caja descontado.

Aug 26, 1988

By Suguru Kohno, Yoshihiro Momose, Masakazu Honma, Tokirou Kamosawa

Copper metal surfaces have been examined by an extremely sensitive surface analysis technique called temperature programmed photoelectron emission (TPPE). The surfaces were ultrasonically cleaned and subsequently abraded by a screw in organic solvents and water. The TPPE apparatus is composed of a Geiger counter with Q gas (He+ iso-C4H10). The curve of photoelectron emission (PE) intensity vs. wavelength from 300 to 170 nm, termed PE spectrum, was repeatedly measured at different temperatures in the temperature- increase process from 25 to 350°C. The number of emitted electrons in a PE spectrum (PE total count) increased, reached a maximum at-250°C, and decreased with increasing temperature. With the surfaces cleaned alone in the liquids the maximum PE total count decreased in the order C3H70H > (CH3) 2CHOH > C2HpH > CHPH > H2O. With the mechanically abraded surfaces in the liquids the maximum PE total count changed as a function of the abrasion period and the maximum tended to appear at higher temperature with increasing abrasion period; the maximum value at 10-min abrasion decreased in the order H2O > CHpH > C2HPH > (CH3) 2CHOH > n-C3HpH. It was suggested that the TPPE behavior can be related to the acid-base interaction between the alcohols and the abraded metal surfaces and the presence of a contaminant over layer on the surface. From the XPS analysis of the 01 s spectra it was suggested that the chemical change of the adsorbed oxygen to oxide oxygen with temperature plays a substantial role in the appearance of the maximum PE total count.

Jan 1, 2000

By G. Roy Chaudhury

Adsorption techniques are comparatively low cost and effective for treatment of arsenic contaminated drinking water. Various adsorbents such as alumina, ferrihydrite and manganese ores have been used, but there has been little investigation of modifying the structure of ferrihydrite to improve its adsorptive efficiency of As(III) and As(V). In the present study the incorporation of manganese oxide into the ferrihydrite structure was carried out and the prepared materials used in arsenic adsorption experiments. The compounds were X-ray amorphous, but TGA/DTA and FTIR analysis showed some structural characteristics. Sorption studies reported in this paper indicate the excellent arsenic removal properties of the manganese/iron compounds with a loading capacity of 0.3 mmol/g. Adsorption follows first order kinetics and the results fitted to adsorption and mass transfer models. Arsenic levels in water containing 1 mg/L As(V) were reduced by 50% in 20 minutes and 90% in 60 minutes using 1 g/L manganic ferric oxyhydroxide.

Jan 1, 2003

By John K. Hammes

INTRODUCTION This introductory paper presents a description and definition of what the finance function is and what it specifically means for the mining industry. In its simplest terms, finance is, "management of money matters". As an area within the discipline of business administration it draws heavily on the related fields of economics and accounting, and to a lesser extent on marketing and production. MINING FINANCE DEFINED In preparing to write about what finance means to the mining industry, I asked a number of mining people the question, "What does mining finance mean to you?" Most responded that mining finance was "How a company borrowed money for mine development", and perhaps half those questioned included "raising equity" in the definition. It is not surprising that the mining industry concept of finance is the providing of funds needed for the objectives of the business, for that was once a view shared by authorities in the field of business administration. Further, it is certainly the area where much of the emphasis has been placed in the past ten to fifteen years as the industry struggled with the development of more remote and more refractory or lower-grade orebodies while profitability and internal cash flow were below expectations. No wonder project finance became such a popular topic. Twenty years ago it is probable that the emphasis would have been on mine valuation, for that subject was the area of finance then most often examined in industry publications. Papers concerning the pros and cons of payback, internal rate of return, and discounted cash flow appeared regularly. Let's examine the following situations, each the result of a financial decision: - Funding the exploration program in a developing country was accomplished by buying the next six-months budget needs in local currency. One week later the currency devalued 30 percent. If the purchase had been delayed or the local currency borrowed short term, a substantial saving would have been made in funding the program. - A major mining company borrows heavily to finance both expansion of its primary mining business and its entry into several new industry segments. When markets for all of the commodities it produces turn down for a prolonged period, there is concern over the adequacy of cashflow to cover debt service in addition to other company needs. The company's financial officers, however, had arranged very large committed credit facilities from numerous financial institutions which assured the availability of funds for several years. This enabled the company to implement a strategy to conserve cash, sell assets and survive until conditions improved. Further, short term suppliers of credit also were comfortable with the assurance that longer term credit was there to support them. -A medium size mining company financed several mines independently with limited obligations on the part of the parent company. The company decided to refinance the operations under one agreement. More flexible terms, lower interest cost and a longer tenor financing were achieved in return for assuming the risk as a direct obligor. - The exploration and development group of a large mining company proposes to develop a new mine in a country in which the company does not presently operate. When the investment is rejected they are advised that one reason was that the reinvestment assumption inherent in the discounted

Jan 1, 1985

By George H. Holmes

This paper is one of a series being prepared by the Minerals Division of the Bureau of Mines on mining and milling methods and practices at various mines in the United States. It describes such methods at the Caselton mine of the Combined Metals Reduction Co. The Caselton mine and mill are in secs. 28 and 29, T. 1 N., R. 67 E., M. D. B. & M., Lincoln County, Nev., about 10 miles by paved highway south- west of Pioche, Nev. (fig. 1). the history of the district and company This circular summarizos operations, describes physical features, labor and living conditions, the geology, ore deposits, and the ore. Prospecting and exploration methods are outlined, and shaft sinking, drifting and crosscutting, and raising are covered under development methods. In the soction on mining mothods, stoping and slushing are discussed, following which are descriptions of underground transportation, hoisting, ventilation, drainage and sampling, and surveying. The surface and crushing plants are described, and milling practices are presented in dotail with explanation of the filter plant and assay office. Safoty practices and the company organization are described in the concluding sections of the circular.

Nov 1, 1950

By P. N. Anyalebechi

"The effects of solidification rate, initial melt hydrogen concentration, and grain refining on porosity formation in aluminum alloy 2024 have been investigated with unidirectionally cooled laboratory-size ingots. The ingots were prepared from melts containing hydrogen concentration of 0.059-0.27 cm3/100 g and solidified at 0.2-37 °C/s. As expected, the amount of porosity, average pore size, and pore number density increased with increase in melt hydrogen concentration and decrease in solidification rate. However, the effect of solidification rate was greater at the very low melt hydrogen concentration (0.059 cm3/100 g). These results are consistent with reported effects of solidification rate and melt hydrogen content on porosity formation in other aluminum alloys. Interestingly, addition of grain refiner slightly increased the amount of porosity and the average pore size, especially at solidification rates above 1°C/s. IntroductionIn shaped castings and wrought products fabricated from ingots, billets, bars, or slabs of aluminum and its alloys porosity formation is a problem. This is because it compromises their tensile strength, fracture toughness, and fatigue properties [ 1-18]. The pores are usually the crack initiation and propagation sites [6,8,9] and the largest pores tend to dictate the fatigue life of the aluminum products [9,10,14]. Porous regions within an aluminum product probably yield first due to the reduced tensile load bearing capacity, causing the concentration of the strain near the voids which subsequently results in premature fracture. In aluminum alloy ingots, billets, bars and slabs porosity formation is particularly problematic because of its persistence through fabrication and potential for reappearance or exacerbation during subsequent thermal treatment processes before and/or after fabrication [19]. In fact, persistence of microporosity is a serious problem in large thick plates of wrought aluminum alloy products that must be rolled from correspondingly large direct-chill or electromagnetic cast ingots. Some of these thick plate products are machined into large aircraft components that are required in service to withstand multi-directional stresses and to possess high fatigue strength, fracture toughness, resistance to stress corrosion cracking, and strength in the short-transverse direction [1,20]."

Jan 1, 2011

By J. T. Burwell

The crystal orientation in silicon iron that has been given a particular treatment described by Goss,l has been studied by Goss, by Bozorth2 and by Sixtus,3 but their results do not agree and are almost entirely qualitative. The following pages give a description of the orientation of the crystals in the material as determined by means of X-rays and expressed graphically in a pole figure. The treatment consists of hot-rolling the material into strip and then giving it two cycles of cold reduction followed by recrystallization. This produces remarkably good properties in the rolling direction, the product having a maximum permeability in this direction of more than 25,000 and a permeability at 16,000 Gauss of more than 2200. It is now generally agreed that Goss's original conclusion1 that the crystals in the final product are randomly oriented was incorrect, since Bozorth2 and Sixtus,3 using different methods, have shown that there is a decided preference in orientation. Those writers, however, expressed their results only in terms of one or more ideal orientations with deviations therefrom. X-ray Data A strip of the material containing 3.1 per cent Si, prepared by Goss,† 1.2 by 0.0125 in., was etched rapidly in warm dilute hydrochloric acid until it was 0.005 in. thick, in order to eliminate the effect of the two surface layers. The specimen was then mounted in an integrating camera similar to one described in the literature.4 The purpose of this camera is to translate the specimen during exposure, so that a statistically large number of grains contribute to the pattern photographed. The camera also allows the plane of the specimen to make various angles with the X-ray beam. An area 5 by 1.2 in. was scanned by a beam of unfiltered radiation from a molybdenum target tube operating at 37 kv., and the measurements were made principally on the peak of the white radiation. X-ray photographs were taken at intervals of 15" in a plane

Jan 1, 1940

By J. T. Burwell

The crystal orientation in silicon iron that has been given a particular treatment described by Goss,l has been studied by Goss, by Bozorth2 and by Sixtus,3 but their results do not agree and are almost entirely qualitative. The following pages give a description of the orientation of the crystals in the material as determined by means of X-rays and expressed graphically in a pole figure. The treatment consists of hot-rolling the material into strip and then giving it two cycles of cold reduction followed by recrystallization. This produces remarkably good properties in the rolling direction, the product having a maximum permeability in this direction of more than 25,000 and a permeability at 16,000 Gauss of more than 2200. It is now generally agreed that Goss's original conclusion1 that the crystals in the final product are randomly oriented was incorrect, since Bozorth2 and Sixtus,3 using different methods, have shown that there is a decided preference in orientation. Those writers, however, expressed their results only in terms of one or more ideal orientations with deviations therefrom. X-ray Data A strip of the material containing 3.1 per cent Si, prepared by Goss,† 1.2 by 0.0125 in., was etched rapidly in warm dilute hydrochloric acid until it was 0.005 in. thick, in order to eliminate the effect of the two surface layers. The specimen was then mounted in an integrating camera similar to one described in the literature.4 The purpose of this camera is to translate the specimen during exposure, so that a statistically large number of grains contribute to the pattern photographed. The camera also allows the plane of the specimen to make various angles with the X-ray beam. An area 5 by 1.2 in. was scanned by a beam of unfiltered radiation from a molybdenum target tube operating at 37 kv., and the measurements were made principally on the peak of the white radiation. X-ray photographs were taken at intervals of 15" in a plane

Jan 1, 1940

By D. R. Arnold

Discussion of the above paper by D. R. ARNOLDt This paper is the result of an excellent piece of work performed as a service to hyUrometallurgy in general and to the South African uranium industry in particular, and the authors are to be congratulated, Authors' reply Dr Arnold is correct in saying that the present Senbrix resins, which are based on the experimental heavy resins first developed at the National Institute for Metallurgy (NIM), need not necessarily show the same poor performance with respect to cobalt poisoning as the NIM prototypes. Oceanology International The next 01 World Conference is to be held Brighton, England, from 2nd to 7th March, 1980. The programme will concern technical advances in the offshore oil and gas industries, and is expected to include 140 papers from 20 countries.

Jan 1, 1979

By Borsaru M

The production of high-grade calcined bauxite is very dependent on the moisture content of the final product. Existing procedures rely on the ignition of small samples to monitor the effectiveness of the calcination process. The results obtained by this gravimetric technique are several hours behind production and do not permit regular adjustment of the furnace to optimize the control of the chemically bound water content (LOI).To provide rapid and hence more relevant results, a neutron moderation technique has been developed for measuring the LOI of bulk samples of calcined bauxite while they are still hot. The method uses fast neutrons from an 241 Am-Be neutron source to irradiate the samples, and the backscattered thermal neutrons detected are a measure of bound moisture content.The rms deviation between neutron and conventional determinations of LOI, in 15 calcined bauxite samples, was 0.08 per cent LOI over the range 0.1 to 0.9 per cent LOI. When allowance is made for the rms error in the ignition method, the error in the neutron method is found to be 0.07 per cent LOI.

Jan 1, 1985

By J. Uys, P. J. Mokganya, J. Olwagen, R. C. W. Webber-Youngman

This article discusses the critical role of leadership in the technology adoption process within organizations, particularly in industries like mining, where innovation is essential for maintaining competitiveness and operational efficiency. It highlights the limitations of traditional technology adoption models, such as the Technology Acceptance Model (TAM), Diffusion of Innovations (DOI), and Unified Theory of Acceptance and Use of Technology (UTAUT), which focus on individual factors and overlook the strategic and organizational roles of leadership. The study proposes the Ambidextrous Leadership-Technology Adoption (ALTA) model, which integrates leadership styles such as transformational, transactional, adaptive, and ambidextrous leadership into the technology adoption process. The model emphasizes the balance between exploration (fostering innovation) and exploitation (ensuring operational efficiency). The findings suggest that transformational leadership fosters innovation by encouraging risk-taking and creativity, while transactional leadership ensures efficient technology integration. The article also identifies key barriers to technology adoption, such as organizational resistance to change, which can be mitigated through adaptive leadership that addresses employee concerns. The research emphasizes the importance of a supportive organizational culture and cross-functional collaboration, which are essential for successful technology adoption. The study concludes by offering practical recommendations for leaders to foster a culture of innovation, manage resistance, and balance short-term efficiency with long-term technological advancement.

Nov 27, 2024

In order to meet the increasing demand for coal for their Newcastle Steel Works, the Broken Hill Pty. Co. Ltd., on June 5, 1937, approved of a scheme to sink a tunnel to the Victoria Seam at their Burwood Colliery. This seam was virgin at this locality and lay nominally horizontal at a depth of 320ft. vertical from the surface.For the purpose of despatch of the coal produced it was decided that the tunnel be equipped with a rubber belt conveyor system.This was a comparatively new departure in Australia, and, indeed, was one of the first installations of its kind in the world, designed to raise coal from considerable depth by this means. Later the tunnel was extended to the Borehole Seam, which lay nominally horizontal at a vertical depth of 600ft. from the surface. The whole installation is the subject of this paper.In planning a project of this kind, consideration had to be given to the following:-1. Location of tunnel with regard to existing surface railway sidings and shafts.2. Ultimate tonnage required.3. Width and construction of belt.4. Speed of belt.5. Inclination of belts.6. Number of belts and design of equipment.7. Cross-sectional area of tunnel.8. Inclination of tunnel.9. Surface drainage.10. Type of equipment for drifting the tunnel.11. Method of ventilating the tunnel during sinking.After the general layout and design of the scheme had been prepared it was decided that tunnel drifting would begin immediately and that the belt installation, together with the feeder plant, would be detailed and manufactured by the time the drift...

Jan 1, 1947

By C. Braun, C. Kennedy, P. Katsabanis

A series of small scale tests, simulating multi-hole blasts have been performed to establish the effect of delays on blast fragmentation. The blasts were performed in high quality granodiorite blocks, which were cut from stone prepared by dimensional stone quarry operations. The pattern used was equilateral triangular, with a distance of 10.2cm between boreholes, which had a diameter of 11mm, were loaded with detonating cord and the coupling medium was water. The delays used were achieved using different lengths of detonating cord for the cases of delays between 0 and 100 microseconds between holes and a sequential blasting machine firing seismic detonators for larger delays up to 4ms. All fragments were collected and screened. The experiments showed that the coarsest fragmentation was achieved with simultaneous initiation of all charges. Fragmentation became finer with delay time between holes up to 1ms between holes. The results show that in moderate to competent rock, similar to the granodiorite of the experiments, fragmentation optimization requires delays of few milliseconds per meter of burden. In view of the findings, which agree with previous published work, the current trend of selecting fast firing times for fragmentation optimization is questioned.

Jan 1, 2006

By Wing L. Lew

LEAD, silver, and zinc, in quantities of economic importance are found in the Aguilar ore. The lead occurs as galena and the zinc as sphalerite and marmatite. The silver occurrence is more complex. Pyrargyrite and proustite have been identified only occasionally. Galena is silver-bearing and so are the various other sulphides, though to a lesser degree. The principal nonsulphide gangue minerals include calcite, quartz, wollastonite, rhodonite, and various calcium, aluminum, and iron silicates. A typical analysis of, the ore is: Pb, 11.2; Zn, 12.3; Fe, 4.4; Mn, 2.2; Cu, 0.15; S, 11.2; CaO. 7.6; "Insoluble," 50.1 percent; and Ag 263 g per ton. Crushing is done in three stages. The primary crusher at the mine is set to deliver about a 5-in. product. The crushed ore is then transported to the secondary crushing plant by a 3-km cableway where the general practice is to hold the product of the first Symons to about 1 in., and of the second Symons to about 1/2 in. When the ore is soft and rich the product of the first Symons is by-passed directly to the ball-mill bins. Dust control in the secondary crushing plant is effected by enclosing the dust-emanating sources and exhausting the enclosures with a Clarage No. 18 fan driven at 1300 rpm by a 20-hp motor. Use is also made of spray water at one or two critical places. Every effort is made to keep the air free from visible dust. Dust counts taken at the working places show dust concentrations of less than six million particles ner cu ft. The composition

Jan 1, 1947