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This paper examines some of the fundamental economics of mining - in particular, for optimisation studies, for production rate determination and for reserve estimates.It includes introductory discussion on the principles as to how economics drives mining investment decision-making, applicable to the optimising of pit shapes and production, or truck fleets, or any other part of the mine.The main part of this paper looks at the decision to start-up a mine and why the 'optimum' production rate to start-up a mine is not the point of lowest cost according to traditional discounted cash flow (DCF) analysis. The optimum production rate is usually substantially less than this rate. The paper recognises the difference between typical mining investments and investments in other industries that do not have the unique characteristics of mining and the problem of uncertainty resolution. It examines the marginal revenue effects, the marginal cost of capital and the value of a real option to expand pending uncertainty resolution as determinants of optimum initial production rates.The final part of this paper looks at applying these principles to renewable and non-renewable resources. It examines mine life and reserve estimates from an economic perspective.

Dec 6, 2010

Misiman society is matrilineal and despite relatively long contact with Europeans and mining, it retains its traditional consensus style of decision making. Many Misimans at least understand English, and this has encouraged comfortable communication between the people and the company (Misima Mines Pty Limited). Company care in monitoring the environment (mostly using Misiman staff), its policy of maintaining a largely Misiman workforce, and its emphasis on training and safety, have all created an environment compatible with Misiman society. In addition, the company has constructed and/or upgraded community facilities such as the airstrip, roads, the health centre, police station and schools, and has actively promoted local business endeavours. All these initiatives have been accomplished by constant dialogue with the largely Misiman workforce, and with the Misiman people, both before and during implementation. Constant, careful communication, using traditional Misiman consensus methods, appears to be the key to continued community acceptance of the project.

Jan 1, 1991

By P Mulvey

"Currently mine process studies and geochemical waste characterisation are considered as two interdependent studies, necessary for the development of the mine and inclusion in the environmental impact statement (EIS). Geochemical waste characterisation will utilise the simulated tailings produced by the mine process studies team to understand the behaviour of the tailings, but the two teams rarely integrate these to develop a coherent and agreed final design.Thorough mine waste geochemical assessments can develop processes to minimise environmental harm, resulting in substantial savings in the decommissioning, closure and rehabilitation phases, and may also be able to address changes in mineral processing methods that can result in substantial savings in process inputs, or even recovery of metal concentrates.Based on geochemical waste characterisation, the full cost of waste management can be calculated and incorporated into the costing of milling.  This allows for a more effective evaluation of the metallurgy.  A number of examples are presented in which substantial improvements have been made from the collaboration of both the metallurgical and geochemical teams during planning and the metallurgical team and environmental team during operations.*This paper is only available for individual download. It is not included in the conference proceedings*CITATION:Mulvey, P, 2013. Optimising metallurgy at the planning stage to minimise environmental impact - a feedback loop from geochemical waste characterisation, presented to MetPlant 2013 Conference (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013

By Donald E. Raab, Lee W. Saperstein

INTRODUCTION The Premise Not much time has to be spent in a tunneling project to realize the tremendous interdependence that exists among the various unit operations. The research that is to be described attempts to examine one set of these linked operations, namely, the effect of cutters on muck handling properties. All too often research focuses on too minute an aspect of a problem for the results to be of much immediate, practical use. The goal of this research is to avoid this specificity. Apologies are tendered if this goal is missed. It is known that the mode of flow of bulk solids under the influence of gravity -- emptying a bin or hopper -- is dependent on several basic parameters. The size of the particles and the distribution of sizes (consist) determine whether the solids will first flow out of a given aperture; the cohesion of the solids will determine if flow will continue after the bin is opened; and the angle of internal friction determines the size of the flow regime (1,2,3). It is well understood that the latter two parameters affect the behavior of bulk material on a conveyor belt. Cohesion of material to a belt is always an undesired problem. Heaping of material on a belt depends on the material's internal friction. It is also known that varying the particle size, and the packing density of the material can affect the material's angle of internal friction (4,5). The question was posed whether sufficient variation in a mechanical tunneling machine's (mole) cutting function could be arranged to affect materially the handling properties of the muck

Jan 1, 1974

The results of self potential geophysical surveys conducted over base metal prospects near Orange, Goulburn, and Wellington, N.S.W., indicate that this rapid and inexpensive exploration procedure merits wider application within eastern New South Wales, and in similar environments elsewhere.

Jan 1, 1973

By P. A. Mahanwar

Flyash were melt mixed with nylon 6 at a 30wt% concentration. TYZOR® TPT, a coupling agent, was used to facilitate the link between filler and matrix. The morphological characterization, using SEM, revealed sufficient matrix residue on the filler surfaces thus confirming the strong interfacial bonding between the filler and the matrix on treating. Tensile, impact and the flexural properties of the composites were also improved with the incorporation of coupling agent. As flyash particles tend to impart a grayish color to the plastic, TiO2 pigment was employed to make the formulations aesthetic. The pigment was added to the filled system in 0.1, 0.5, 1.0, 1.5, 2.0 wt/wt ratios. Scattering of incident light and spectral reflectance was higher for smaller particle size flyash. Moreover an increase in the scattering with increase in pigment concentration indicates better dispersion of the pigment, which again is due to the presence of coupling agent.

Jan 1, 2006

By Paul D. Tomlingson

During the next several months, SME’s E-Newsletter will feature 15 articles on maintenance management. The articles may be read online or downloaded and distributed within your organization. They will address maintenance management topics, offer guidelines to mining managers and provide techniques that the maintenance manager can use. The articles will stress equipment management, a strategy that the mining industry has accepted as a modern replacement for outdated maintenance practices. Equipment management is the mutually supportive interaction of all mine departments as they establish equipment needs, procure equipment, test, commission, operate, maintain, modify and eventually replace equipment. The successful application of equipment management principles can quickly and reliably produce cost reduction and performance improvement results while providing a dependable way of sustaining them. Equipment management embraces modern management techniques. These include reliability-centered maintenance, life-cycle costing, capital performance, the effective use of information and productive organizational models.

Jan 1, 2003

By Laura E. Beverage

The Changes 2008 Brought -MSHA recently posted a PowerPoint to its website which shows statistical performance information for fiscal years 2000 to 2008. -Interesting statistics: Fatality rate in Coal dropped by nearly 30% (.0348 to .0246 per 10,000 workers)

Jan 1, 2009

By B. Solar Menéndez, M. B. Díaz Aguado, I. Á. Fernández, C. González Nicieza

The analysis of subsidence due to the opening of an underground void (mining, water exploitation or civil works hole) is a problem usually hard to solve. First of all, it requires a predictive model, in order to define both the displacement magnitude and area affected by subsidence. Such model should be validated with measurements of the actual movements sustained on the surface, in order to adjust it properly and enable influence of future behaviour in a reliable way. Two different kinds of problems might arise. On one side, it is necessary to control and measure surface movements in a very exhaustive way during a long period of time, beginning before underground works take place and finishing years after they are over. Furthermore, three factors bring in errors, some times of magnitudes higher than the displacement magnitudes measured. These include: the fact that reliable and long-term information cannot always be achieved; the precision of measuring devices; and the design of the topographical network itself. In addition, the predictive models more widely used only apply to certain excavation geometries, mainly to horizontal holes. In light of this background, the Group of Rock Engineering, of the University of Oviedo Mining Department, has developed a working methodology and a specific software tool, Subsidence 3D, to estimate ground displacements and strains. The program will allow for predictive models to be defined and also allows the treatment of data related with topographical marks and its comparative analysis with calculated results. The software has been programmed using Visual C++. Graphical outputs however are generated using AutoCAD 2000. This paper mainly refers to a practical situation, an underground coalmine, remarking the main difficulties arisen during the study of the available information and proposing how to solve them. A predictive model in subsidence 3D was established and validated. The actual behaviour of the ground was that in the model.

Jan 1, 2003

The Takasima Coal Mines comprise four islands near the entrance to Nagasaki Harbour, and are owned and worked by the Mitsu Bishi Company.There are several unusual features in the occurrence and working of these coal seams, the steep angle of "dip," the numerous seams of good coal separated by hundreds of feet of sedimentary rocks, the extensive faulting of the strata, and the way in which the coal is won, when so little surface is available for works, and where there is the ever present danger of subsidence of the roof and consequent flooding of the workings by the ocean. The author trusts that short notes on these few points will be of interest to members.The Islands are named respectively Hasima (Extreme Island), Nakanosima (Middle Island), Takasima (High Island), and Yokosima, and are situated about one mile from the main land.

Jan 1, 1901

GOLD has played a part in the development of Australia. The total yield exceeds SIX hundred million pounds sterling, while the glamour of gold-mining and the unfailing demand for the product have enhanced its influence. The production is still considerable, but the yield is less than one-quarter of that twenty years previously, while the number of men employed has dropped from 70,000 to 11,000. Not only has there been a marked decline in production, but it is anticipated that thisdecline will continue, and continue more markedly. It is therefore desirable to ascertain the causes of the decline and inquire into means for diminishing or preventing it.The problem under discussion is far from being only local. Finlay states: The grand feature of the history of the business has been the progress of an economic cycle unfavourable to gold milling. The USA yield fell from $101,000,000 to $44,000,000.South Afriea has for some time produced one-half of the world's gold; yet in the Mining and Scientific Press of 11th February, IH22, General Smuts is quoted as saying that if the premium disappeared entirely 24 out of 34 mines would shut down. The solution, however, might be either general eg, a great advance in the metallurgy of gold; or local eg, a bonus; but before discussing any of the proposed solutions it will be advantageous to review the situation.STATISTICS OF THE PAST AND PRESENT PRODUCTION OF THE WORLD AND OF AUSTRALIAThe inquirer soon finds that there is a good deal of uncertainty, and that much care is needed in collating figures. In some cases a considerable part of the output is not officially reported, and returns...

Jan 1, 1924

By William B. Hughes

The rubber-sleeve core barrel was developed to improve core recovery from unconsolidated sands, where it is most difficult to obtain cores with conventional barrels. The use of a rubber-sleeve core retainer, together with other departures from clsual design, has required a considerable amount of testing to prove its op-erability. Tests run in shallow experimental holes and in drilling wells in the U. S. and Vemzuela have, to a large extent, proved the operation of the barrel. Internal mechanism troubles, such as sandbinding of the sleeve, have been largely overcome. Cores have been recovered from completely unconsolidated sands where conventional coring has almost been abandoned because of poor recovery. In addition to retaining the core until brought to the surface, the barrel gives a "packaged-ar-cut" core, which is coilverzient for handling and transportatiorz. In the initial work, drag blade cutters, roller cutters, and tungsten carbide insert cutters were usrd for cutting unconsolidated sands. Further bit head development is presently being conducted using diamond heads in unconsolidated sands where shaler, hard sands, and limestones are encountered in adjacent formations. Thir work should render the barrel capable of cratting and recovering most types of formations, possibly including broken and frac- tured fornlations. This development is being carried on in cooperation with a diamond bit manufacturer. INTRODUCTIO N For many years the oil industry has needed greater recovery of cores from unconsolidated formations. Conventional equipment has been used to core unconsolidated sands with little success. Specifically, a core barrel was needed which would recover unconsolidated sands in a condition that would give useful reservoir information. DEVELOPMENT OF 'THE RUBBER-SLEEVE CORE BARREL Basic Requirements of Unconsolidated Sand Corino The basic need was defined as a core barrel that would obtain a continuous unconsolidated core with sand grains in place as deposited in the formation. A preliminary survey of coring equipment and search of the literature pointed out the weaknesses of conventional core barrels. Laboratory tests using unconsolidated sand in a metal tube simulated actual sand movement into the core barrel during conventional coring. In conventional barrels the core sometimes crumbles and bridges, or fails under compressive column action, becomes oversize, and wedges against the walls of the inner barrel. The core barrel requirements established by the surveys and preliminary tests are as follows. 1. The core should be held to- gether as it is cut so it cannot crumble and bridge against the walls of the coring tool, care being taken not to permit damage from fluid circulation. 2. The core should be continuously supported as it is cut so it will not have to support itself in compression. 3. The core should be packaged in the barrel to retain an undisturbed condition during the trip out of the well. The packaging should be such that the core can be removed from the barrel and shipped to the core analysis laboratory without physical disturbance or alteration of fluid content by exposure to the atmosphere. Operation of the Rubber-Sleeve Core Barrel The rubber-sleeve core barrel (Fig. 1) meets the basic requirements for the recovery of unconsolidated sands.

By W. P. Erasmus

This paper will focus on the use of the ?wet-mix? steel fibre re-in forced shotcrete as a permanent lining in deep shafts, assessing gold bearing reef. It will cover all aspects relating to the choice of this material covering the geological conditions through to the final quality control. All procedures are in line with ISO 9001,as JCI projects who manage the project, are an approved company therof.

Jan 1, 2001

Agglomeration for Copper Heap Leaching Agglomeration of ore is a method which can be used to eliminate the migration of fine grained particles throughout a leach heap. Without agglomeration, fine ore particles are able to migration within the heap, clogging flow channels and producing large areas where access of the solution is poor. In order to gain the benefits of agglomeration and improve agglomerate strength even further in copper heap leaching, an economical, acid-resistant binder is needed. However, most binders have been used without any systematic reasoning. A set of novel testing methods were developed, including a soak test, percolation flooded columns, and larger long-term leach columns. The soak test compares the degree of breakdown when agglomerates are subjected to an acidic environment. While the percolation flooded columns and larger long-term leach columns evaluate the flow of leach solution throughout the ore bed. Systematic studies have been completed on a wide range of binders using these novel testing procedures. It was found that for a low grade chalcocite ore, which was rich in silica, from a southwest US mine, polyacrylamides reduced the fines migration the best in the novel soak test. The non-ionic binder, in particular, was found to reduce fines migration as much as 93 per cent. Several of the binders tested were shown to increase the hydraulic conductivities of the agglomerated ore up to 2.5 mm/sec, compared to a hydraulic conductivity of only 0.25 mm/sec when no binder was used. These binders also prevented 'slumping' of the ore, which indicates a decrease in breakdown of the agglomerates. The use of a binder also showed no interference with leaching reactions in long-term leaching experiments.

Sep 13, 2010

Mine ore, reduced to minus 71/2 in. by primary crushers, is stockpiled. Size reduction of the reclaimed material by secondary and tertiary crushers is achieved in a closed circuit crushing and screening plant. Screen products of minus 30 mm plus 6 mm lump, and minus 6 mm fines are stockpiled by conveyor and stacker systems prior to rail despatch 10 port facilities at Dampier. Crusher settings, determined from experience, are closely maintained to obtain the desired lump/fines ratio. Chemical and sizing analyses from automatically taken samples are used to maintain product specifications. The beneficiation plant upgrades the fines product when this is necessary. The recorded wear life of individual plant components is the basis of a planned maintenance programme.

Jan 1, 1970

This modern plant consists of a battery of 72 Otto Wilputte Compound Under-jet Ovens with extensive plant for the recovery by-products. The ovens produce 9000 tons of furnace coke per week together with some 17,000,000 cub. ft. of coke oven gas, which is used for heating purposes throughout the works and for heating the ovens.Coal is supplied from the, company's colliel'ies and is stored under a Coal Handling Bridge of 264 ft. span and 365 ft. overall, capable of handling 250 tons per hour. The coal storage space of 1600 ft. can. be extended to a maximum of 2800 ft.Preparation of the coal for coking involves fine grinding which is carried out as follows:-Coal is dumped from rail waggons on to a conveyer belt which delivers it to a 12 ft. x 22 ft. Bradford Breaker, with a capacity of 400 tons per hour. The coal, then approximately 4 in. in size, passes, to the mixing bins; and after careful blending is reduced in the,hammer mills to a fineness suitable for the ovens.The fire coal is elevated to the main storage bin over the battery for subsequent charging by electric larry car. The average cokingtime is 15 hrs. 36 mins. At the end of ,this period the doors, are removed and the coke pushed from the oven by a mm. The coke, is, then quenched with fresh, water and sent to the Blast Furnace in 50-ton Copper Waggons.The gas is exhausted from the ovens by Brown Boveri turbine, exhausters of 23,000. cub, ft, per min. capacity. Exhaust steam from these is used for various. purposes in the By-Product plant. After removing the last traces of tar by Electrostatic Precipitators', the gas is bubbled through sulphuric acid, the ammonia forming ammonium sulphate, which is subsequently washed, dried and bagged for sa,le as a fertilizer. The gas then goes to the Benzol Scrubber Towers, where benzol and other derivatives are recovered and later redistilled and purified. The cleaned gas is then piped to the main works for heating purposes, being used with tar to fire the steel furnaces, and also the soaking pits and reheating furnaces.BLAST FURNACES.The company is at present operating two Blast Furnaces of 800, and 1000 tons nominal daily capacity respectively. The latter was...

Jan 1, 1938

By Hernán Parra

El presente trabajo señala la fase de tratamiento metalúrgico de pirrotitas que contienen oro, donde en la concentración por flotación se encontró un esquema adecuado para tratar pirrotitas auríferas considerando las restricciones ambientales que no permitieron incorporar técnicas de cianuración directa, que es como suelen tratarse es-tos minerales en el mundo. Asimismo, se propuso el uso de concentradores centrífugos para recuperar el oro libre fino en una primera etapa gravimé-trica, y concentradores de mesa Gemeni para obtener concentrados de alta cali-dad disponibles para fundición.

Sep 9, 2007

By G. Boehler

The purpose of this program is to demonstrate the feasibility and practicality of noise control for secondary and tertiary crushers in surface non-coal mining plants and mills. It is a part of the broad Bureau of Mines program to reduce noise in mines to levels mandated in the Coal Mine Health and Safety Act. Utilizing the results of previous contractual research efforts in which noise levels of secondary crushers had been measured, two noise enclosures were designed and evaluated for the REXNORD Symons 7-ft diameter secondary and tertiary crushers installed at the Jackson County Iron Company, in Black River Falls, Wisconsin. The first enclosure had a circular shape following closely that of the crusher and was built up entirely of quick-release panels which can be handled by the crusher operator alone. The second enclosure was octogonal in shape and can be rapidly removed, partially or totally using an overhead crane. Both enclosures fully satisfy the noise reduction objectives and permit daily and long-term maintenance of the crushers. Cost analyses show the cost of the enclosure to be less than 10 per cent of the cost of the crusher, the cost of the octagonal enclosure being estimated at only 60 percent of that of the circular one, e. g. $15,000 against $25,000. It is concluded that the octagonal enclosure best meets the needs of the Jackson County Mining Company and it is recommended that an experimental enclosure be built at the earliest possible time, as proof-of-concept.

Jan 1, 1977

The Mahakipawa gold deposit is located 21 km northwest of Blenheim. It became the site of a small hardrock gold rush in 1889 following nearby alluvial gold discoveries in 1888. The study investigates the geology of the area of hard rock mining in the vicinity between Cullens and Waikakaho Creeks. The Marlborough Schist which hosts the gold depos, it consists of polydeformed greenschist facies quartzofeldspathic psammitic, pelitic and volcanigenic schist.

Jan 1, 1993

By P. den Hoed, R. I. Rambiyana

"Four sulphide minerals - pyrite (FeS2), pyrrhotite (Fe1-xS), pentlandite ([Ni,Fe]9S8), and chalcopyrite (CuFeS2) - contain the base metals and most of the iron in concentrates of platinum group metals (PGMs). In the pyrometallurgical processing of PGM concentrates these sulphides form a matte during smelting, and iron and sulphur are removed from the matte during the converting process. This paper discusses the roasting of Merensky concentrate in air before smelting, with the purpose of reducing the matte load to the converter.Roasting tests were conducted in a bench-scale rotary kiln at temperatures from 350°C to 700°C. The concentrate tested contained 17.4% sulphur and consisted of 23% pyrrhotite, 16% pentlandite, 11% chalcopyrite, and 2% pyrite. The particles were fine (d50 = 22 µm), and all the sulphide particles were liberated. Roasting in air at 550°C and 650°C for 20 minutes removed respectively 60% and 70% of the sulphur. The iron in the sulphides was oxidized to Fe3O4 (magnetite) at temperatures below 500°C and to Fe2O3 (haematite) at temperatures above 550°C. At 700°C the bed sintered and copper oxides formed. At temperatures below 450°C oxidation was incomplete: pyrrhotite remained and only 30% of the sulphur was removed. Smelting tests were conducted to assess matte fall and the deportment of copper and nickel to matte. It was evident that roasting resulted in lower matte falls (a drop of approximately 60%) compared with matte falls from unroasted concentrate. The iron and sulphur levels in the matte were reduced to below 3.5% and 22% respectively.This paper also briefly describes the mechanisms by which pyrrhotite, chalcopyrite, and pentlandite are oxidized during roasting. For chalcopyrite, the mechanism proceeds through an intermediate solid solution phase, which extends from Cu1.02Fe1.04S2 to Cu2.04Fe0.72S2 to a copper-rich solid solution of bornite (Cu4Fe1.4S4-Cu2S). The oxidation of pentlandite proceeds through a monosulphide solid solution (Ni0.39Fe0.53S-Ni0.74Fe0.15S) to a solid solution of heazlewoodite ([Ni,Fe]3}xS2). These mechanisms are explored in relation to chemical thermodynamics and microstructures."

Jan 1, 2015