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By S. P. Pereira

The mechanized mining cycle using loaders and shuttle cars had it speak in terms of usage in the mining industry during 1950 through 1960. In Brazil, this system is still used at underground coal mines in southern Santa Catarina coal basin. With the aim of investigating the benefits of a new mining scheme using the room and pillar method for these local mines, a computational simulator model was developed in order to investigate the mining cycle. This paper presents the methodology used to develop the simulator and the results that the simulation shows regarding impact of the proposed new scheme on mining productivity.

Jan 1, 2012

By Scott A. Walker, Roberto A. Lopez, Lori A. Simpson, David A. Shook

500 Folsom Street is part of the new Transbay neighborhood in San Francisco, which is being redeveloped after the 1989 Loma Prieta Earthquake damaged a freeway viaduct; removal of the viaduct created parcels of land available for development. The development consists of a 42-story residential tower with a six-level basement. The slender, core-only structure was designed using performance-based seismic design. Subsurface conditions include undocumented fill, Dune sand, marsh deposits, sand, and clay, all overlying sloping bedrock of the Franciscan Formation. The building is supported on a 10-foot-thick mat foundation approximately 62 to 72 feet below street grades; clay, sand, and bedrock are all present at mat subgrade. Under a portion of the mat, sand susceptible to liquefaction was present. The variable subgrade conditions and potential for ground failure, along with the depth of mat subgrade below street grade, created a challenge for the design and construction team to solve. The ground below mat subgrade needed to be improved to mitigate the liquefaction potential and provide more uniform support. The areal extent and depth of ground improvement necessary to support the mat with an acceptable amount of deformation was determined. Settlement was analyzed and subgrade moduli were provided for design of the mat, with multiple iterations performed to converge between the geotechnical and structural models. Based on the project schedule and logistics, it was beneficial to work from street grade to improve the ground. In order to target the depths below the mat and minimize wasted effort and materials within the depth of excavation, grids of jet grouting were determined to be the most economical ground improvement method; however, it was challenging to install the columns from 65 feet above the top of the target zone. During installation, QA/QC was performed to check that the jet-grouted columns were installed to the design depth and diameter and developed the design strength.

Jan 1, 2018

By S. D. Zhang

The first reinforced earth railway bridge abutment in China has been successfully constructed of September, 1985 under the supervision of the Reinforced Earth Researth Group of Shanghai Institute of Railway Technology. In order to verify the reliability of the designed structure and its behaviuors, the 1:10 reduced scale model tests in laboratory and field tests on the actual structure during construction were proceeded. Various loads of different positions were charged, the vertical and lateral earth pressure in the filling soil, the stresses developed in the reinforcements, and the deformations of the models or the actual structure were recorded in those tests. The behaviors recorded are presented and discussed in this paper.

Jan 1, 2010

The addition of a thallous salt to the cyanide leach of a calcined pyritic concentrate causes a marked increase in the rate of extraction of gold. This is due probably to the activation of passive gold by the thallous ions. Lead, bismuth, and mercury salts, which should produce a similar effect, fail to do so. It is postulated that this latter result, together with the reprecipitation of silver at low cyanide levels, is due to the presence of soluble sulphide.INTRODUCTIONThe work of Fink and Putnam (1950) showed that the rate of solution of gold in cyanide can be increased by the addition of small amounts of lead, bismuth, mercury, and thallium salts. Mills (1951), during a study of the electrochemistry of gold, with particular reference to cyanidation, was able to show that gold may become passive towards cyanide solution. The addition of lead or thallium salts prevented this passivity, although the action of lead was limited to the pH range 10 to 12. In a recent paper Cathro (1963) confirmed the findings of Mills, and presented results which showed that the addition of thallium to a cyanide leach of a calcine from Lake View and Star mine, Kalgoorlie, increased the rate of extraction of gold appreciably. In, this paper the use of thallium to prevent the gold becoming passive, and hence to decrease leaching time and cyanide consumption, is examined.EXPERIMENTALA series of leaching tests was carried out on a sample of Lake View and Star calcine, comprising calcined pyrite (about 70 per cent.) and siliceous gangue (about 30 per cent.) and containing 165 p.p.m. gold, 45 p.p.m. silver, 0·1...

Jan 1, 1964

Northern Iron Ltd (NIL) is an Australian listed company that recently brought the historic Sydvaranger open pit Magnetite Mine (the Project) in Northern Norway successfully back into production. NIL made the decision to operate the Project on an owner mining basis, due to limited large scale mining expertise amongst Norwegian mining contractors, a long mine life, a limited range in planned mining rate and to minimise costs. As a new mine operator in a country where labour practices are strictly regulated, there was the desire to reduce the risk associated employing and managing skilled personnel. This was achieved by coupling the purchase of the required mining equipment from the original equipment manufacturer's (OEM) regional dealers with OEM supported Maintenance and Repair Contracts (MARC). This paper examines the process that was followed to implement an owner mining operation in a short time frame; approximately 12 months from the initial requests for quotation to actual delivery of mining equipment to site, and some of the challenges faced. By following a formal and well-tested process, not only was the implementation achieved in the set time frame, but significant value was added through the cost savings achieved in the equipment purchase price and MARC rates that were negotiated through this process.

May 1, 2010

By M. H. Solomon

After the global financial crisis of 2008, African mining is entering anew phase of development. The rapid withdrawal of emerging market funding from the critical exploration and development industries provided a hiatus in funding, a gap which was quickly filled by Chinese and other Asian investors. While the continent is still economically dependent on its extractive industries, the prevalence of Dutch Disease has undermined Africa?s ability to benefit fully from its mining, oil, and gas industries. While the extractive industries are closely related to many of the more fragile and failed states in Africa, it is equally true that the strongest states in Africa have mining-based economies. This paper explores the possible linkages between mining, strong and weak political economies, and poverty in Africa. It draws the conclusion that neither Dutch Disease nor Resource Course is a given in resource-endowed countries, and that it can be avoided if the mining economies in these countries are actively integrated into their respective broader economies and used to foster economic diversification. The author asserts that given the capacity constraints of many African governments, it is contingent on mining companies to become integrally involved in catalysing diversification around their infrastructure and supply chains.

Jan 1, 2011

By H. Jang, Y. Kawamura

Unplanned dilution and ore loss directly influence not only the productivity of underground stopes, but also the profitability of the entire mining process. Stope dilution is a result of complex interactions between a number of factors, and cannot be predicted prior to mining. In this study, unplanned dilution and ore loss prediction models were established using multiple linear and nonlinear regression analysis (MLRA and MNRA), as well as an artificial neural network (ANN) method based on 1067 datasets with ten causative factors from three underground longhole stoping mines in Western Australia. Models were established for individual mines, as well as a general model that includes all of the mine data-sets. The correlation coefficient (R) was used to evaluate the methods, and the values for MLRA, MNRA, and ANN compared with the general model were 0.419, 0.438, and 0.719, respectively. Considering that the current unplanned dilution and ore loss prediction for the mines investigated yielded an R of 0.088, the ANN model results are noteworthy. The proposed ANN model can be used directly as a practical tool to predict unplanned dilution and ore loss in mines, which will not only enhance productivity, but will also be beneficial for stope planning and design.

Jan 1, 2015

Rock engineering has now been practised as a discipline for about50 years, and many sophisticated methods of analysis for use in rock engineering design have been developed. However, analysis is only a tool for use in engineering design, and rock masses are often so complex that realistic modelling of them, even with sophisticated methods of analysis, is impossible. At the other end of the scale, rock mass classification methods have been developed to quantify the rock mass. These ?numbers? are now widely used for assessment of stability of underground and surface excavations in rock, for the determination of rock support requirements, and for the estimation of rock mass strength and deformation properties. In considering these areas, the two concepts?design, and prediction of behaviour?will be dealt with. The discussion will be introduced by a consideration of the characteristics of the rock mass, which will highlight the variability in its properties and hence the uncertainty in the behavioural parameters. Examples of real projects will be used to illustrate the discussion.

Jan 1, 2003

By Harry: Lobb Verakis

Mining operations have made tremendous strides in improving the safety of blasting as shown by the significant and continual decrease in fatalities and serious injuries. Advances in blasting technology and blasting practices have played a significant role in reducing fatalities and injuries. However, even with the decline of fatalities and injuries blast area security continues to be by far the leading factor in blasting accidents. Even though there continues to be an increase in the use of industrial explosives and blasting agents in the U.S.A., the decline in fatalities and injuries from blasting accidents has persisted.

Jan 1, 2010

The re-use of waste water from coal preparation plant tailings is always desirable, but is generally problematic in terms of solid-liquid separation. Dewatering and disposal of coal slurry at a high percentage of moisture poses a major technological and environmental challenge to mining and mineral processing industries world-wide. Characterization and flocculation of these coal tailings reveals that the separation of fine coal tailings depends on factors such as size distribution, slurry viscosity, zeta potential, pulp density, circuit design, plant operating parameters, and the behaviour of solid particles in an aqueous medium. The present study was carried out on -600 mm coal tailings collected from a coking coal preparation plant of Jharia Coalfield, India, using anionic flocculent. Characterization studies revealed that the zeta potential was highest (-44 mV) at a pH of 9.0, the size range of the particles was 1.1?700 m, and the average ash content was 62.57%. Flocculation studies were performed at different solid concentrations, pH values, and polymer dosages. The results indicated an efficient settling rate of 178.15 mm/min at 8% solid (w/w) at a flocculent dosage of 32.50 g/t solid. The turbidity of the clear liquid obtained was 7.42 NTU.

Jan 1, 2014

By Robert C. Horton

The Getchell Mine is located on the east flank of the Osgood Mountain Range in the Potosi Mining District, Humboldt County, NV. Mining in the area first began in 1883 for copper, lead and silver in skarn-related deposits. Tungsten was discovered in the skarns in 1916 and was mined sporadically until 1957. The first major discovery was made in 1933 when two Winnemucca prospectors, Edward Knight and Emmett Chase, found gold at the present site of the Getchell gold mine. In 1934, after a small amount of preliminary prospecting, the claims were purchased by Noble H. Getchell of Midas, NV. The Getchell Mine Inc. was organized and exploration and development work began on a broad scale. Major funding was provided by George Wingfield and investors he assembled. Laxalt described Wingfield’s immediate history prior to his financing of Getchell as follows.

Jan 1, 1999

By L. W. Saperstein

Public Law (PL) 95-87 contains explicit demands for land use planning in its reclamation and designation sections. Both sections require recognition of local land use plans; however, they are not well integrated. Accommodation to these planning requirements affords an opportunity to create better links among local land use planners, the state's permitting authority and designation office, and mine designers. Mining companies should take a more positive interest in local land use plans and in resource inventories. States should consider handing down to local government the responsibility for accepting mine permit applications and designation of unsuitability petitions.

Jan 12, 1983

By Donald Strickland, Peter Kresin, Dave Hall

"Have your parents or grandparents ever tried to share with you their wisdom and you ignored it because it did not relate to you‘? I have been ignorant and inevitably grew older and wished I had listened. The result: learning the hard way. As British Astronomer Fred Hoyle once said. “It is the true nature of mankind to learn from mistakes not from example.“ Hopefully we will continue to learn from the examples shared by our fellow mineral processors in these conference proceedings. It is the intent of this paper to share wisdom from the Musselwhite Mine that you may apply to your own operation.This paper is divided into three sections:1. Feasibility3. Operation3 . DesignKey points of the Feasibility and Design stages are summarized. followed by an analysis of actual operating statistics. An attempt is made to relate these statistics back to the feasibility and design with emphasis on areas of success and those with potential for improvement."

Jan 1, 1999

The variation of carbon monoxide and hydrogen utilization with the amount of the reductant in the blast furnace bosh gas was investigated for the No. 4 blast furnace at The Broken Hill Proprietary Co. Ltd.iron and steel works. Newcastle. The degree of CO utilization decreased with increasing CO in the bosh gas; the H., utilization increased with the H., content of the gas. Empirical relationships for CO and H., utilization are proposed.H2, is 3-6 times as effective a reductant as CO at present levels of CO (34-39 per cent) and H2 (6-10 per cent) in blast furnace bosh gas. H2, gas injection into the blast furnace is proposed as a means of lowering the coke consumption, and the economics of H2 injection are evaluated.

Jan 1, 1975

By R. Zunich, E. Rybinski, M. Grondin, B. Flintoff

It is uncommon these days to read a business magazine or newspaper without finding a reference to Knowledge Management (KM), and its critical importance to corporate success. One definition of KM is: “getting the right knowledge to the right people at the right time and helping them to put information into action in such ways that strive to improve organizational performance.” In the minerals processing industry we could assert that we have been practicing this for years through effective operator training. In most cases we would probably be wrong. Training has certainly filled the need of addressing safety and basic operational issues, but we must collectively focus on education (learning), and the difference, as measured in outcomes, is not at all subtle. This paper briefly examines the history of training and education in the mining industry, and looks in more detail at the impact of one company’s approach to empower its workforce, while keeping the ultimate goal clearly in mind: “The great end of knowledge is not knowledge, but action.” (T.H. Huxley)

Jan 1, 2001

By Kenneth Wardell

Criteria have been fully developed for determining the optimum size of oil and gas well blocks. The criteria lead to the formation of well barrier pillars which are, of themselves, inherently stable and take account of variable mine roof and floor conditions. The criteria ensure, through considerations of ground movement, that strains transmitted to well casings, are within tolerable limits of casing specifications. The criteria cater for well barrier pillars in multi-seam mining situations and where previous old mining has taken place. The criteria maintain flexibility in being adaptable to local mine design situations. The criteria are applicable to proposed extraction thicknesses up to 15 feet at depths up to 2,400 feet. The criteria are related to producing wells and to abandoned wells. In the latter connection, various states of well abandonment are recognised.

Jan 1, 1980

This paper discusses the impacts that advances in metallurgy and process engineering have on minerals project execution. Ausenco's business is focused on integrating minerals processing technology and the delivery of cost effective processing plants that exceed client performance expectations. The metallurgical development is a small but critical part of this process. Metallurgical development and innovation outcomes need to be transformed into an engineered solution and that solution converted into an operating plant in a cost conscious and competitive environment. Including new or innovative processes in a project flow sheet increases a project's technical and commercial risk. However, it also gives the project, and/or the engineering company, a potential advantage over projects using mainline practices. Managing the balance between risk and opportunity has been a cornerstone of Ausenco's success in recent years. Some advances in "technology" that are discussed in the paper include: larger capacity equipment new flow sheet concepts simplification of process interfaces, and more effective project strategies The common theme is that having a new idea can be the easy bit, putting it into operation effectively involves numerous people, many interfaces and strong project management.

Sep 13, 2010

By J. E. Davidsen, M. Honstad

"A well-maintained tap-hole channel is important in order to achieve good and stable furnace operation over time. A worn or short tap-hole channel can lead to more violent flow, significantly increasing the fume emissions during tapping and leading to more metal being mixed with and lost to the slag. Over time, a worn tapping channel might cause side channels and damage to the lining around the tap-hole area. This can result in a burn-through which is a considerable safety risk and will cause significant production losses. At Eramet Norway Porsgrunn, tap-hole maintenance has been done regularly with electrode paste for over three decades with good results. This article summarizes some of the experiences obtained from this practice on a 33 MW SiMn furnace, as well as a change to a coal tar pitch-free binder. IntroductionA well-maintained tap-hole channel is important in order to achieve good and stable furnace operation over time. Metal and slag are regularly tapped from the furnace and may cause a lot of wear on the tapping channel, increasing the risk of lining damage and ultimately leading to a burn-through. On furnace 10 at Eramet Norway Porsgrunn, the tap-hole area is the part of the lining that has been by far the most prone to burn-through since the startup of the furnace.Experience shows that almost all lining problems have started with burn-through in the tap-hole area or in close proximity to the tap-hole. During tap-hole repairs, side channels with metal and slag have also been observed emanating from the main tapping channel. In addition, a shorter tapping channel will cause more violent flow. This can lead to more metal droplets being entrained in the slag, and increase the risk of the furnace not being closed properly at the end of the tap.As a burn-through is a considerable safety risk, and also causes significant production losses, systematic work has been performed over the years to maintain the tapping channel in order to prevent burn-through."

Jun 1, 2019

By W. H. Van Niekerk

The metal zinc has been around since only about 1400 AD. This may sound like a long time, but when compared to fellow base metals copper and lead, which were discovered in 5000 and 4000 BC respectively, it is evident that zinc is a fairly new kid on the block. This may also be the reason why many new facts and benefits of zinc are still being discovered. For instance, it has been discovered only in the last few decades that virtually no life on earth is possible without zinc. In this address it will be shown that zinc is not only very useful to mankind, but is in fact vitally important for all forms of life. It will be shown that zinc is natural, zinc is essential for life, zinc protects, zinc contributes to the well-being of society and that zinc is fully recyclable. It is therefore hoped, that by the end of this address, zinc will no longer be viewed only as the metal that is responsible for the nice colour of roofing sheets and steel buckets, but may indeed be man?s best friend.

Jan 1, 2005

By Steve Kral

For a state whose roots are in mining, most Colorado residents probably do not realize that the industry still contributes heavily to the state’s economy. In 2005, the industry contributed, directly and indirectly, about $8 billion to the state’s economy, according to the Colorado Mining Association (CMA). It employed nearly 10,000 people at mines and support businesses. And the mining industry in Colorado is one of the highest paying occupations in the state, averaging about $80,000 a year in wages and benefits. The state’s coal mining industry produced nearly 36 Mt (40 million st) of coal in 2005, valued at $800 million, the CMA said. That was seventh in the nation. And Colorado’s only major gold mine produced 10.2 t (329,000 oz) last year, valued at $124 million. That was third in the nation. And Phelps Dodge’s Henderson Mine produced about 12.7 kt (28 million lbs) of molybdenum, valued at $350 million. Colorado is the largest molybdenum producing state in the nation.

Jan 1, 2006