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By P. Srinivasan

Corrosion is a major operational problem in amine-treating plants causing significant expenditures each year, Corrosion may become more severe when the amine plants contain process contaminants ? namely heat-stable salts. The heat-stable salts enter the plants with feed-gas streams and makeup-solution, and/or are produced within the plants by reactions of alkanolamine and available carboxylic-acid anions, This work investigated interaction corrosion effects that may exist in amine-treating plants containing a mixture of heat-stable salts, The investigation was experimentally carried out in a 5 kmol/m3 monoethanolamine (MEA) solution containing 0,20 mol/mol carbon dioxide (CO2) loading at 80°C under atmospheric pressure using carbon steel 1018, Six heat-stable salts, including formate, oxalate, bicine, acetate, thiosulfate and chloride, were tested with a series of salt combinations, Potentiodynamic Polarization, Tafel Extrapolation, and Cyclic Polarization were used for revealing corrosion behavior, determining corrosion rate, and examining the pitting tendency, respectively, Results show that thiosulfate induces the most corrosive environment when present either individually or in the form of salt mixtures.

Jan 1, 2005

By Jim Peterson, Ricardo Freire, Mason Biernat

Variable nature of rock and face conditions, varying execution and changing nature of blasting are making ongoing optimization challenging. Intelligent planning and on-going analytics are required to mitigate variability and convert blasting into a predictable outcome by use of technology. Blasting operations generate a huge amount of data which can be used intelligently for optimization. In this paper, details are provided of a system which is used for blasting data collection in the field – Key details around blast parameters, explosives, initiating system details, video, photographs, vibration and fragmentation are collected in a cloud-based platform. Data can also be collected through a mobility device in the field (even without internet connectivity) and synchronized with cloud-based system. Also, data from various sources can be imported in excel formats in the software including from upstream and downstream processes from blasting. App also gives indication about exceeding of vibration, air blast overpressure, fragment size etc. Thus, making it possible to perform QA-QC before charging and deciding initiation timing and sequence at the blasting site. The data can be processed and analyzed to spot trends, help predict events, and formulate strategies at the design and execution stage. Data gathering of blast parameters, explosive used processing and analysis can be used to optimize operational efficiency, improve safety and environmental controls.

Jan 1, 2019

By S. J. Buckler

Many chemical and metallurgical processes use submerged gas injection to increase contact area between gas and liquid phases in order to promote faster overall reaction or refining rates. The total interfacial area produced by gas injection through lances, nozzles or tuyeres is both an important design parameter for new vessels and a measurement for estimating the maximum processing capacity of existing equipment. Estimating total interfacial area from submerged injection into industrial pyrometallurgical vessels from existing knowledge is a problem with two aspects. The first difficulty is the difference in behaviour of cold (aqueous) and hot (molten metal) systems, implying that existing models and correlations of gas-liquid behaviour developed in low temperature systems are not necessarily appropriate for estimation of high temperature behaviour. The second difficulty is the issue of scale-up of correlations from laboratory to industrial sized vessels. The work presented in this paper is part of an ongoing experimental investigation, at the GK Williams CRC for Extractive Metallurgy, to quantify the total gas-liquid interfacial area available in pyrometallurgical vessels using chemical measurement methods. The effects of three operating variables, injected gas flow rate, nozzle diameter and nozzle submergence, on total interfacial area are quantified in a IOOL aqueous system - the first stage of a three stage process in examining the implications for scale-up of high temperature, medium-scale results are discussed. The results of work at high, injected gas flow rates (up to 500/min) show that the submerged Froude number is not sufficient for use as the sole variable in a predictive model of total interfacial area. Further work is being undertaken to identify other dimensionless variables that will better represent the gas-liquid characteristics in submerged injection that influence the formation of total interfacial area. The second and third stages of the experimental investigation involve measuring the total interfacial area in a large-scale (1000L) aqueous sodium sulphite and small-medium scale molten metal baths.

Jan 1, 2002

By H. R. Quina

Phosphate is one of the most important minerals in our world today. It contains the life-giving element of phosphorus, which is essential to the growth of every living cell in plant, animal, and man. This vital mineral is found in twenty-three states of the United States; however, for more than 70 years, Florida has led the nation in phosphate-production and now produces 70% of the requirements of this country. Since the early 1880% when rich phosphate deposits were accidentally discovered in a river-bed in Central Florida, the industry has developed into a multi-million-dollar operation. Phosphate mining began in Florida in 1887 with very crude methods and equipment. The original process was necessarily slow and tedious, resulting in total production of 3000 tons in 1888. Progress was made in improved mining operations, and by 1894. Florida had grabbed the lead as the nation?s largest phosphate-producing area, and is still in the top position.

Jan 1, 1962

By E. Dadzie

This paper will review some methods used to manage geotechnical risk at Damang Pit Cutback. The pit depth is designed up to 250m with push back on the eastern and western walls of the existed and depleted Railway Cutback (RCB) pit. The geotechnical design was presented by SRK Perth, focussing on the optimisation of the bench face angle which finally evolved with ?steep slope strategy?; 24m at 800 and 24m at 750 on the eastern and western walls respectively. The east wall was designed strategically to optimise the proximity of the tailings dam to the final pit crest of the push back. The pit has experienced failure in the weathered profile transgressing through the transitional material into the fresh rock at different location of the east wall since development in July 2005. To ensure stability and to minimise ore loss, the east wall has been redesigned using 700 batter angles and reduced berm width of 4m compared to 800 and 8.5 berm width of 24m bench height. The paper will also discuss how slope failures to the east wall had been sustained, managed and monitored to enhance production. Emphasis is placed on slope management at Damang which includes the principles of wall control blast, visual inspection, slope depressurisation and the state-of-the art of slope monitoring using Autoslope automated prism monitoring. Future slope monitoring is considering the use of 3D Laser and Radar to provide early warning so that evacuation could be effected. The intension is to provide mine personnel the means to identify risk areas during mining activities.

Jan 1, 2008

By Antonio Segatori, Bjørn Holmedal, Kai Zhang, Trond Aukrust, Knut Marthinsen

"The visual appearance and mechanical properties of aluminium alloy extrusions are strongly dependent on the microstructure and texture of the extruded profiles, where the desired microstructure and texture may depend on the specific applications. In the present work, the evolution of deformation, as well as recrystallization textures during extrusion of AA6xxx aluminium alloys, have been experimentally and numerically investigated. Extrusion trials were performed in a laboratory extrusion set-up, which enabled immediate water-quenching of the profiles at the exit of the die, and thus the possibility to capture the deformation texture prior to post-extrusion recrystallization. The textures and their through-thickness variations were experimentally measured by the electron back-scatter diffraction technique (EBSD, and the deformation textures numerically modelled by coupling FEM flow simulations and crystal plasticity (CP) simulations. Different CP models as well as different choices of model parameters were employed and evaluated for texture predictions. With an appropriate choice of crystal plasticity model and model parameters, the deformation texture can mainly be predicted, although the accurate intensities are hard to reproduce. The corresponding recrystallization textures, either generated through spontaneous recrystallization of the extruded profiles or through post-extrusion annealing, are far more challenging to reproduce with available recrystallization models.INTRODUCTION Extrusion is a widely applied thermal-mechanical process to produce aluminium profiles. The properties of the profiles, for example mechanical, fatigue, fracture, corrosion as well surface appearance, are strongly dependent on the underlying microstructure and texture, and the requirements with respect to these aspects may vary with applications (Ralston et al., 2010; Dumoulin et al., 2012; Donati et al., 2013). Moreover, it is often a challenge to produce extrusions with a consistent and homogenous grain structure and texture along as well as through the cross section of the profiles. It is thus vital to understand and be able to predict (model) how different microstructures and textures are formed and how they evolve during and after extrusion, as basis for controlling the final appearance and properties of extruded profiles."

Jan 1, 2018

By George Holderer

THE relation between man-hours of labor and production may be correlated for any industry, and already it has been widely used in piece-work studies. It is not in general use as yet for recording labor efficiency of an enterprise or an industry. An exception to this is the Cement Institute, which tabulates the man-hours used in each operation and FIG. 1.-LABOR PRODUCTIVITY IN COPPER MINING. thus gets the total man-hours per barrel of cement. The writer knows of one steel company that keeps a complete record of man-hours for every operation from mining the ore to finishing the product. No doubt many others find the information useful, and such a study could be of value to the mineral industries.

Jan 1, 1935

By Paul W. Johnson

A computer program for calculating capital and operating costs from material and energy requirements and equipment costs for use in preparing cost estimates for metallurgical process evaluations has been written by the Bureau of Mines' College Park process evaluation group. The program permits rapid recalculation of processing costs when changes of data or equipment are desired, and produces tables of capital and operating costs suitable for publication. Equipment cost summary tables for each process section end supplemental information for input-data checking is included in the computer printout. The program is written in Fortran IV except for several subroutines which are written in machine assembly language for the IBM 7094.3 With a few modifications, the program can be used on other computers.

Jan 1, 1969

By R. Jacobs, R. E. L. Pobe

The Moab Khotsong Metallurgical Complex comprises a gold recovery circuit (Noligwa Gold Plant) and a uranium recovery circuit (South Uranium Plant). The metallurgical complex employs the reverse leach technology for the recovery of uranium; specifically, uranium extraction prior to gold using acid leaching processing. The inherent uranium species in the ore are uraninite, coffinite and brannerite. The slurry that has been subjected to the uranium leach is further subjected to solid-liquid separation to separate the uranium in a solution through counter-current decantation and the solids (solids carrying all the gold), which are repulped and returned to the gold plant for gold processing. The uranium leaching process is critical to the uranium playing a pivotal role as a value adding by-product to the gold operation. The benefit of adopting this reverse leach process, for improved gold recovery, is that it exposes gold particles occluded within the uranium matrices and avails them for cyanidation. However, the drive for operational efficiency in uranium extraction must be weighed against the incremental operating cost against the backdrop of depressed spot uranium market prices. Over the years, efforts were directed at maintaining the benefit of extracting uranium to enhance gold recovery and simultaneously, optimising the operating cost model for the uranium operation to remain relevant to the gold operation. The aim of this paper and the corresponding presentation is to give an account of the uranium processing optimisation journey embarked on over the years; namely, the operational tradeoffs made in the process of ensuring that uranium continues to add value to the gold operation. These challenges were faced while striking a fine balance between processing cost and operational efficiencies against the prevailing depressed uranium spot market prices. Mineralogical- and laboratory tests conducted form the support basis for the results and observations articulated in the paper. Keywords: By-products, gold extraction, reverse leach benefit, uranium extraction

Jan 1, 2020

By H. L. Monro

Contribution by B. K. Martust I congratulate the author on his interesting paper. In my view, the establishment of the level at which South African gold output is at some kind of optimum is an interesting though somewhat academic exercise. Contribution by D. M. Hawkins* The thesis of the paper is a very interesting one, but, before it is used as the basis of any firm proposals to restructure the mining industry, which changes may be irreversible, one should be very sure that the basis of the calculations is sound. Contribution by P. J. Niewenhuizen* The hypothesis advanced by Mr Monro that the demonetization of gold in August 1971 introduced a major new policy variable, namely the supply-pricejdemand-price relationships, into the decision making process touches on a matter that has never really been given serious thought by the industry. Contribution by B. G. Kingsman* As a co-worker on the development of an econometric model for supply and demand in the world gold market with Mr H. L. Monro, it would perhaps be useful for me to make some comments on the various points raised in the discussions on his paper.

Jan 1, 1984

By G B. Smith, D Hillier, T Gibbons, D B. Donato, M D. Adams, S Davies, R S. Schulz

Responsible management of cyanide solutions and tailings on gold processing plants worldwide is an important aspect to these operations and is regulated via guidelines provided by the International Cyanide Management Code, an industry initiative designed to minimise cyanide risk to operators and the environment. Here we demonstrate the unprecedented causal relationships surrounding the saline (>14 000 mg/L total dissolved solids - TDS) and hypersaline (>50 000 mg/L TDS) cyanide solutions in gold plant tailings in the Central Goldfields of Western Australia, resulting in zero wildlife mortalities on three sites over the study period of almost one year. Wildlife interaction and ingestion is significantly lower than that experienced at other gold mine sites, with more rapid degradation of weak-acid dissociable (WAD) cyanide within the tailings storage facility (TSF). A rigorous chemical sampling using a novel æminimal accessÆ robotic sampler device and wildlife observation exercise was carried out at two hypersaline mine sites: Barrick Kanowna Belle (BKB) and Gold Fields St Ives (GSI) and one saline site, Barrick Granny Smith (BGS). The data was compared with available reported chemical sampling and wildlife observation data from a previously operational fresh water site (<2000 mg/L TDS) that had experienced wildlife mortalities, Case Study D (CSD). The comprehensive body of work, along with cyanide degradation test work carried out in the laboratory, was analysed via hypothesis development and testing, causation analysis and dynamic chemical modelling. The non-mortality effect on these sites appears to hold over a further four years of routine wildlife and cyanide monitoring by site personnel. This study has helped these three mine sites achieve and maintain full Compliance Cyanide Code status over a significant period while removing the need for operating the detoxification plants they would otherwise have required.CITATION:Adams, M D, Donato, D B, Schulz, R S, Smith, G B, Gibbons, T, Davies, S and Hillier, D, 2013. Hypersaline-induced reduction in cyanide ecotoxicity at gold operations, thereby obviating detoxification plants, in Proceedings World Gold 2013, pp 489-502 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By John K. Hammes

This paper has been written as one of a group of papers dealing with the subject "Cost Elements in Mining". What are cost elements in mining? The mine operator thinks of direct mining costs in terms of labor, materials, supplies and power, and we might define cost more generally as the price paid to acquire or produce something. Economic theory also has its concepts of cost. From one point of view, that of the consumer, the cost of mineral commodities might be viewed as the total price industry pays for mine output. Similarly, the mining company engaged in the on-going business of finding, developing and operating new mines is concerned very much today with the distribution of all the revenue paid for mine output and not just with its direct or controllable cash costs. In other words, what will the labor force, the supplier of energy, explosives, and reagents, and the supplier of government services, management, capital and the ore reserves receive for their contribution to production.

Jan 1, 1974

By V. Lessels, W. A. Hamilton

White Pine Copper Co. is a wholly owned subsidiary of the Copper Range Co. The property of White Pine is about 5 miles south of Lake Superior in Carp Lake Township, Ontonagon County, Mich. The new town of White Pine, adjacent to the company plant, is 18 miles south and west of the town of Ontonagon, and about 55 miles north and east of Ironwood, Mich. A diamond drilling program begun in 1937 to develop the orebody was carried on until 1950. During this period a test shaft, known as the Schacht shaft, was sunk on the orebody and approximately 8000 ft of development drift were driven. In an effort to solve the ore beneficiation problems, considerable metallurgical test work was done on ore extracted through the mine development. This work was conducted in a small pilot plant located in the mill of the Copper Range Co. at Freda, Mich.

May 1, 1956

By Thomas J. Neil, O&apos

Most analysts find that progress has been evolutionary in any technologic field. To be sure, a few discrete breakthroughs can usually be identified, but viewed in its entirety, the curve of technologic progress over time tends to be relatively smooth with few discontinuities. Even in those cases where a major scientific discovery is achieved, the rate of technologic progress is limited by the often surprisingly slow rate of commercializing the concept into usable products. Whereas discovery and invention tend to be discrete events, technical innovation is often a painfully slow process. In spite of overall gradual change, technologic progress in most fields, when viewed in retrospect, tends to reveal certain relatively homogeneous periods where little change is evident, separated by episodes of accelerated progress. Thus, open-pit mining over the past century has changed from predominately train haulage to truck haulage and is now experiencing a major increase in belt haulage. Ore reserve estimation is another field that fits the same pattern, and the history of mine evaluation lends itself to a similar analysis. Evaluating mine investment opportunities is a fascinating aspect of mining. The unique set of risks inherent to every mining project is particularly intriguing. Geologic risks are most obvious, since faulty ore grade and tonnage estimates are among the leading causes of mine failures. Wide swine's in mineral commodity prices are usually cited as another major risk in mining. Because any ore deposit is a finite resource and the miner has limited discretion in selecting a mining sequence, mines are generally at the mercy of notoriously fickle commodity markets. There is a tendency for many mine investment analysts to feel that mineral market uncertainties are unprecedented in severity. Of course, prices in other markets rise and fall also-in some cases as precipitously as with minerals. However, two other mining characteristics tend to compound this marketing risk. First, the preproduction development period for a new mine is characteristically long. Under extremely favorable conditions, a significant mine may be developed in as little as two years, but the norm is four to six years or more. Second, mining is among the most capital intensive industries, consistently ranking near the top among all industrial sectors in assets per employee, and near the bottom in annual sales dollars per dollar of assets. Thus, mine investors typically have large sums invested for a long time before the outcome of the venture is determined by notoriously unpredictable markets. This is not a business for the faint of heart, and the importance of sound investment decision making is obvious. The high risk and technical complexity of mining operations have combined to require greater attention to financial evaluation by mining engineers than by most engineers in other specialties. Nearly all early mining engineering textbooks dealt with problems in mine valuation in a detailed manner; and, today, the sophistication of capital investment analysis is high in the mineral industries. Traditional Mine Valuation Methods Although some evaluation process has no doubt accompanied nearly every mine development throughout history, a formalized quantitative approach first emerged in the last half of the 19th century with the establishment of academic programs in mining engineering. The philosophy and approach to mine valuation that evolved at this time were, with periodic minor refinements, considered the standard for nearly a century. Only after 1960 did major changes begin to occur. The traditional approach to mine valuation reflected the investment community's historic attitudes toward risk. Mines were generally considered too risky for debt financing, and virtually every new mine was financed from internally generated funds or new equity subscriptions. The investment evaluation methods that evolved focused on mining's higher risk relative to other

Jan 11, 1982

By D. Royston

Gold ores containing antimony suffer from poor recoveries of gold in cyanidation due to the impact of antimony on the cyanidation process. Techniques such as lowering the pH for cyanidation can improve gold recovery, nevertheless a limit can be reached where high cyanide consumption makes traditional processing uneconomic. The paper outlines a process for the pre-treatment of gold-antimony concentrates to remove the antimony resulting in a low-antimony content gold-bearing residue suitable for efficient treatment for gold recovery through cyanidation. This hydrometallurgical process produces a by-product credit of commercial grade antimony trioxide as Senarmontite that can significantly offset the cost of the pre-treatment.

Jan 1, 2007

By S. Banisi, A. Ghasemi, A. Fazeli, M. Rezaei, M. Maleki-Moghaddam

The efficiency of high capacity SAG mills which consume large amounts of energy depends on the grinding and slurry discharge systems. A 9.7 m × 4.8 m SAG mill with radial pulp lifters is used at the Sarcheshmeh copper complex grinding circuit. The process audit indicated that the pulp discharge system was not efficient, judging by the amount of slurry flow back and carry over. These events limited the discharge rate and increased the wear rate of the lifters and grates. With the objective of finding a new design for pulp lifters, a 3D DEM software (KMPCDEM ©), along with the plant operational data and photographic evidence was used. The KMPCDEM © software was used to compare the efficiency of the radial and curved pulp lifter design based on the material flow. The slurry flow was analysed in terms of ease of discharge and lifter wear rate. It was found that changing the radial pulp lifters to curved pulp lifters could improve the discharge efficiency,and decrease wear rate of the pulp lifter in particular at the base of the pulp lifters. The simulation results showed that if curved lifters with a radius of 0.3×mill radius are used, the amount of slurry flow back and carry over will be negligible. It is predicted that by installing the curved pulp lifters, the capacity of the mill increases by 10% and the pulp lifter service life improves by at least 20%. Keywords: SAG mill, radial pulp lifter, DEM,curved pulp lifter, Sarcheshmeh

Jan 1, 2020

By W. G. Davenport

A flash furnace can be run many different ways. It can, for example, be operated with: (a) highly 02"enriched, ambient temperature blast and no fossil fuel (b) considerable fossil fuel and hot, slightly Or enriched blast. It can also produce different grades of matte. With all these possibilities, the flash furnace operator can benefit from any technique that will indicate the 'best' way to operate his furnace. One such technique is Excel's 'Solver'optimizationroutine#. This chapter shows how our matrices and Excers optimization.abllity can be used to optimize a flash furnace operation. The chapter sets three optimization goals: (a) minimum industrial oxygen + oil cost, $ per tonne of concentrate (b) maximum smelting rate, tonnes of concentrate per hour (c) maximum profit, $ per hour.

Jan 1, 2001

By William Priestley

IN THE manufacture of gun forgings and other steel parts that, in service, are subject to sudden high stresses and shocks, it is most desirable to use steel possessing the greatest toughness and ductility possible without sacrifice of strength. In order to obtain this condition, it is necessary to procure steel that shows the highest possible elongation and reduction of area without lowering the tensile strength and elastic limit. Proper heat treatment of the steel can control this condition within certain limits. When heat treatment has failed to produce the desired results, metallurgists have used steels containing molybdenum, zirconium, vanadium, chromium, tungsten, etc. The purpose of this paper is to describe a method by which these desired physical properties may be procured-by the elimination of certain impurities that inherently exist in steel made by the open-hearth process, and without the use of expensive alloys. DESIGN OF GUN FORGINGS In the manufacture of gun forgings, a certain elastic limit is fixed by the designer, and the walls of the gun are made of the proper thickness, allowing a suitable factor of safety for the high stresses and sudden shocks that occur during gun firing. The elastic strength of the gun is about 1.4 times the stress set up at any point along the bore of the gun during firing with the maximum powder charge.

Jan 12, 1921

By Eric Best

"In the past two to three years, all continuous mining machines at the Potash Corporation of Saskatchewan Mining Limited, Lanigan Division, have been changed over to a new cutting pattern using 1 -inch- and 1-3/l6-inch-diameter self-sharpening pencil bits. The bits are arranged in a cone-type pattern across the face on 2 1/2 -inch and 3-inch spacing. The result is that the ore is removed by chipping and flaking. Previously, rap-lock bits were used, with the pattern being several bits in single rows at wide spacings. The cutting action was grinding and breaking.Besides improved penetration rates and lower bit costs, there are many other advantages. The ore size is much smaller, resulting in less wear and tear on conveyors and other associated equipment. Feeder-breakers are no longer routinely set up at the head end of every extensible belt, as the banana-shaped chunks of ore that used to require breaking are no longer produced. Also, less dust is generated by the cutting heads and fewer stops are required for bit changes. Even the mill operation has been improved, as fewer fines are produced.Further improvements are still sought after, but, all in all, the new cutting pattern is considered to be a giant step forward from the old method."

Jan 1, 1981

By Martin A. Moyers

THE nation's effort to win the war speedily is reflected in current trends in coal utilization, as in all other fields of our lives. In all industries, wherever coal is used for the production of heat and power the emphasis is on getting the most useful result with the least expenditure of matt.ria1. In addition to carrying its own share of the load, increased as it is by the demands of war industry, coal has had to fill in for the other fuels, mainly petroleum products, whose distribution from their more distant sources has been crippled by lack of shipping. Thus, the outstanding note in the utilization of coal this year is not the development of new methods of burning or handling coal but the extraordinary job that the industry has done in producing enough coal to serve all needs.

Jan 1, 1943