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By Stanley M. Moos

The Pueblo Viejo gold/silver mine, located in the Dominican Republic, started production in early 1974 processing ores averaging 4 g/tonne gold and 20 g/tonne silver at a rate of 7,250 tonnes/day. The ore milled is a silicified siltstone with average work index of about 8 that occurs as an extensive oxide capping of a primary sulfide orebody. The sulfide ores are refractory to conventional treatment process and extensive research work is now in progress to develop a treatment process for them. The ore deposit has a long history having been mined by the indigenous Arawak Indians (for some time in the early sixteenth century) prior to the arrival of the Spanish and then by the Spaniards. In the early 1950?s, Italian engineers attempted to process the sulfide ores. Mining by the Indians and Spanish was abandoned because of low grade and little coarse gold in the oxide ores and by the Italians because of the refractory nature of the sulfide ore. In 1969, Rosario Resources geologists discovered that there existed sufficient reserves of oxide ore for a viable mining operation and accordingly, the plant was designed, built and brought into production.

Jan 1, 1979

By A. M. Christie

Acknowledgements The following account has been compiled mainly from records and maps of Eldorado Mining and Refining (1944), Limited, hereinafter called the Crown Company. This work was done under the supervision first of R. F. Murphy, Chief Geologist, and later of E. B. Gillanders, Eldorado Mine Manager and Manager of Eldorado Exploration Division. W. F. James and B. S. W. Buffam are consulting geologists. Since 1946, S. N. Kesten has supervised geological work for the Company in the Goldfields area. Where maps of Eldorado properties have been included in this paper, the name of the geologist who examined the property is acknowledged on the map. Outline of General Geology The geology of the area is described in the Goldfields and Martin Lake preliminary maps of the Geological Survey and accompanying Paper 49-17. In brief, the Tazin series of Precambrian age, consisting mainly of sediments with minor interbedded volcanics and basic intrusives, is intruded and replaced by granite, now generally gneissic. The late-Precambrian Athabaska series of conglomerate and arkose, with interbedded basalt and andesite flows, rests unconformably on the older rocks. All these rocks are cut by small diabase dykes. The geological terms used in this paper and in the accompanying figures are standard with the exception of the term 'mafic rocks'. These include all the basic or dark coloured rocks of the Tazin group, such as amphibolites, biotite schists, and chlorite-epidote rocks (greenstones), whether they be of extrusive, intrusive, or sedimentary origin.

Jan 1, 1949

Waitemata Tectonic Event(25 Ma ago) created a subduction system from the northeast of Northland, causing: (1) the emplacement of the Northland Allochthon (24-23 Ma) which provided argillaceous limestone and serpentine to Northland, and minor copper to both there and East Cape (located off Northland then); and (2) Northland volcanism (from 22 Ma), which lacked economic mineralisation. The Kiwitahi Tectonic Event (1714 Ma) caused: (1) a realignment of volcanism - from coastal western Northland, to west of the Hauraki Plains (Kiwitahi); (2) a start to the migration southwards from Northland of (a) the Alpine Fault System towards Marlborough today, (b) subduction towards Cook Strait, and (c) volcanism towards Taranaki-to-Bay of Plenty (initially through Coromandel, Kiwitahi, and offshore west coast); and (3) a start to rhyolitic volcanism & associated hydrothermal activity. The latter caused epithermal mineralisation, providing in Coromandel the best known North Island metalliferous deposits. Andesitic volcanism has been active in both of these two contrasting, subequal belts since 22 Ma. Rhyolitic volcanism and hydrothermal activity was wholly restricted to the eastern Marshall Belt, with an abrupt limit to economic mineralisation at the Volcanic Divide (within Hauraki Plains) and a major change there to basaltic volcanism of the western Searle Belt. The Kaimai Tectonic Event (5-1.5 Ma) caused: (1) a temporary reversal in volcanic migration in the Searle Belt, and a duplication of rhyolitic & hydrothermal activity at Waihi (Marshall Belt); (2) the rotational rifting of both the Central Volcanic Region (by 30¦) and the Hauraki Rift (10¦), causing major curvature of the North Island and New Zealand, and the transfer of the offshore subduction system from Coromandel to East Coast; and (3) an effective end to Coromandel mineralisation. Post-Kaimai Volcanism (1.5-0 Ma) included: (1) andesitic volcanism in the Searle Belt, yielding the western coastal titanomagnetite deposits; and (2) andesitic, and rhyolitic & hydrothermal activity in the Marshall Belt - the latter providing geothermal energy, sulphur, and pumice/perlite deposits. Post-Subduction (Intraplate) Volcanism (10-0 Ma) developed in a steadily expanding northwest region of relative tectonic quiescence, as subduction and its volcanism migrated southwards. Intraplate volcanism was predominantly basaltic, providing excellent aggregate; but less common rhyolitic & hydrothermal activity provided geothermal potential and mercury at Ngawha and at Puhipuhi, and halloysitic clays of extreme brightness elsewhere in Northland. This volcanism has reached as far SE as Mayor Island, providing an early New Zealand mineral resource - obsidian.

Jan 1, 1997

By G. H. Clevenger

(Continuing the discussion of the paper of James Johnston, presented at the New York meeting, February, 1914, and printed in Bulletin No. 85, January, 1914, pp. 107 to 133.) This paper cannot fail of being of great interest and value to all who are interested in the cyanide process, on account of the important developments which it records. Mr. Johnston is to be commended for the large amount of detail which he gives, and the company and its management for permitting the publication of data of this character, which while of great value to others could well be considered private property. It might be discussed from a number of standpoints: First, as an example of recent practice in mill and cyanide plant construction; second, the mill practice; third, the cyanide practice; and fourth, the new features in cyanide treatment involved. Perhaps a more vivid way of expressing it would be : First, the equipment or tools with which the various operations are carried on, are they the best and most efficient which could have been selected for their respective uses; and, second, is the best use in every case made of these tools? It may be well inquired is the highest possible recovery of silver made at the lowest cost per ounce recovered? For after all, the making of the greatest ultimate profit is inseparably associated with successful metallurgical practice; there must therefore be at all times a careful balance maintained between recovery and cost of obtaining it. I wish to call attention in a very general way to the equipment used and to an anticipation of questions which are bound to arise in this connection. However, the. bulk of my discussion will be confined to the presentation of certain additional data, together with a more or less general discussion showing the line of development which leads up to the present practice and .the applicability of certain features of it to similar problems elsewhere. There are a number of vital points of broad general interest involved in Nipissing low-grade practice upon which metallurgists will by no means be agreed to which I wish to call particular attention in the hope that it will lead to the presentation of data y others of practice in other districts which will' assist in reconciling this divergence of opinion.

Jan 7, 1914

By Lazar Kricak, Vladislav Kecojevic, Dragan Bogunovic

In spite of many advantages explosives have, their usage may cause environmental problem such as seismic vibration. One of the solutions to this particular problem may be application of an artificial screen as a barrier to the seismic wave path. This paper presents the results of experimental research on the artificial screen concept, its characteristics and role in attenuation of seismic effects generated by blasting. More than 1,500 laboratory measurements were conducted with different combinations of screen sizes, positions of the screen to blasting source, and intensities of blasting impulses. The results of the study show a significant reduction of generated vibrations by employment of artificial screens.

Jan 1, 2007

By M. Springett

Organization of teams for rapid and effective evaluation of international mining properties requires special considerations beyond those needed for domestic activities. Experience, technical ability, a sense of perspective, humor and self-discipline are vital characteristics to look for in the selection of individuals for forming an efficient and productive team.

Jan 1, 1994

By J. E. Marshall

"The concept of employing a project management team to coordinate all aspects of the construction of a new resource development has gained wide acceptance. This team can be formed from within the staff of large mining companies or contracted from major engineering firms and consultants. The mandate of the project managers usually terminates on successful startup of the operation. For frontier mineral developments in the Canadian Arctic or in the developing countries, startup and the initial year of operation represents the period in which the project is most vulnerable to technical, political and managerial problems. A complete change of the management team or the retention of the construction project managers and the resulting cost combined with the breakdown of organizational accountability within the operating staff .are unnecessary management problems.Independent project management services provide the commitment necessary to sustain the continuity of management through all project phases. Efficiency and the ability to make decisions quickly are characteristics of the many successful small mining companies. These qualities are necessary in the project management group, which will be responsible for up to 90% of the preproduction costs.Continuous project management in the construction and operational phases of a mineral development are common in the iron ore industry, but remain anomalous in the base metal, energy mineral and industrial mineral fields.The Nanisivik project on Baffin Island in the Canadian Arctic is used to illustrate the advantages of total project management through construction and operation.Total project management has further potential for foreign interests and financial and utility organizations desirous of participating in the Canadian mining industry, but with no direct involvement in the construction or operating management. Participation agreements in the operating phase of a project can be negotiated to have management fees related to both the production and the profits of the enterprise."

Jan 1, 1980

By Robert K. Linn

The New ldria Mining District is in the southern part of the Diablo mountains of the California Coast Range, 140 miles southeast of San Francisco. The district, noted primarily for quicksilver, also has become important recently as a producer of short-fiber chrysotile asbestos. Between 1853 and 1966, the New Idria district produced 568,092 flasks of quicksilver valued at about $55,600,000, 99 per cent of which was recovered from one deposit, the New Idria mine. In 1944, the district was ranked third in all-time production of North American quicksilver districts, and, since that time, the New Idria mine produced an additional 129,045 flasks, placing the district and the New Idria mine second in all-time production. The major structure of the region is the northwest-trending Coalinga anticline consisting of an asymmetric dome of sedimentary beds ranging in age from Jurassic to Quaternary and marked at its northwest end by an oval body of sheared serpentine 14 miles long by 4 miles wide. The serpentine core, rimmed by Franciscan sandstone of probable Jurassic age, was uplifted in stages between Jurassic and Quaternary time and was intruded along a ring of faults into beds of the Panoche Formation of upper Cretaceous age. The core of serpentine and Franciscan rocks is the locus of about 20 quicksilver mines that rim the faultbounded core and lie within the serpentine mass. The host rock of the most productive deposits is altered Panoche shale and sandstone that lies intermittently along the perimeter of the core. Deposits of the New Idria group of mines and those of a few other small mines lie along the northeast contact in the footwall of the New ldria thrust fault, and a few others occur on steep normal faults around the south and southwest. The chief ore mineral in all quicksilver mines is cinnabar, but minor amounts of metacinnabar and native mercury are found in some of the mines. Ore shoots were deposited in fracture zones and stockworks in altered Panoche shale and sandstone and in definite fissure veins in Franciscan sandstone. Rocks made highly amenable to fracturing by hydrothermal alteration were fractured extensively by late faults. The resulting fracture zones, located along the late faults and at changes in strike or dip of the hanging wall or footwall, are the principal controls of most ore shoots. The largest and richest ore shoots are those of the New Idria mine. The major ore bodies occur in fractured shale and sandstone beneath the New ldria thrust fault at its junction with major tear faults.

Jan 1, 1968

By William E. Greenawalt

IN these days of special legislation for the benefit of various industries one might well consider one branch of human endeavor intimately associated with engineering-that of patents and patent litigation. It is estimated that 85 per cent of all industries in the United States are based directly or indirectly on patents. Most inventors are engineers, and most patent litigation pertains to the engineering industries. It is fitting, therefore, that engineers should be vitally interested in discussing patent affairs, particularly as inventors are not a professional group, and invention is mostly a transitory phase incident to the development of specific industrial problems.

Jan 1, 1937

By C. E. More

Some observations on 'ancient' mining at Phalaborwa C. E. MORE. B.A. (Pretoria) (Visitor) A brief account is given of historical references to the Phalaborwa area, the first being to the mountain of copper and iron sought by Francois de Cuiper in 1725. These are followed by a description of several finds in the area, which are related to finds described in the literature and to Bantu tradition on the subject. Phalaborwa is one of the earliest known mining sites in the Republic of South Africa, Loolekop having been a mining centre, as shown by carbon-14 dating, since 770 A.D.

Jan 1, 1974

By Martin D. Larisch

The construction of diaphragm walls and most large-diameter bored piles (piers) is often carried out under drilling support fluids to temporarily stabilise the excavation prior to concrete placement. In most cases such fluids are either mineral-based slurries (bentonite) or polymer support fluids. The working mechanisms of these two fluid types are fundamentally different. Designers need to consider possible fluid-related impacts on the permanent design performance of the project-specific deep foundations as well as for the temporary excavation stage during construction. Robust design methods for bentonite slurry-supported excavations have been developed in the last few decades and the working principles and associated risks of such mineral-based slurries are understood reasonably well. However, such meth-ods have not been developed in detail for polymer-based drilling fluids. This document provides a brief overview of the main characteristics of bentonite- and polymer-based drilling fluids as a guide for construction practitioners and design engineers alike. The paper also high-lights some common construction risks related to casing installation and the selection of suitable fluid systems for different ground conditions. Typical defects caused by the incorrect application of drilling support fluids, and their pro-active mitigation, are discussed, too. In addition, the basic concepts of sta-bility calculations for bentonite fluid-supported deep excavations are briefly introduced and their ap-plicability for other fluid types such as polymer-based support fluids or water are reviewed.

Nov 1, 2022

By L. Xinghua

Limonite is a general term for a group of amorphous iron oxide and iron hydroxide materials. It is considered as one of the very refractory iron ore types due to its wide variation in chemical composition, iron content, moisture content and easily sliming in the course of comminution. Iron grade of test sample is 25.48%, the iron minerals are mainly limonite; and the gangue minerals consist of quartz and feldspar in majority, secondarily silicate minerals. In this test work, high intensity magnetic separation (HIMS)-cationic reverse flotation and magnetic roasting-low intensity magnetic separation (LIMS) tests were conducted on limonite ore. The test results show that the concentrate with iron grade of 50.97% and recovery of 68.50% can be obtained by HIMS-cationic reverse flotation technique; while using magnetic roasting-LIMS technique, the better concentrate indexes of iron grade of 60.36% and recovery of 89.71% are achieved, and the iron grade of tailing is only 4.42%. Therefore, the magnetic roasting-LIMS technique is a better suitable method for beneficiation of low-grade limonite ore. Keywords: Low-grade limonite; Mineralogy; HIMS; Cationic reverse flotation; Magnetic roasting; LIMS

Feb 27, 2013

By AIME AIME

COMMITTEES. CANAL ZONE.-Col. George W. Goethals, U. S. A., Chairman; Lt.-Col. H. F. Hodges, U. S. A. ; Lt.: Col. D. D. Gaillard, U. S. A. ; Lt.-Col. William L. Sibert, IT. S. A. ; H. H. Rousseau, U. S. N.; Col. W. C. Gorgas, U. S. A.; Maurice H. Thatcher ; Joseph Bucklin Bishop ; Lt.-Col. Charles F. Mason, U. S. A.; S. B. Williamson ; Major Eugene T. Wilson, U. S. A. ; Edward Schildhauer ; Henry Goldmark ; Edward C. Sherman ; W. G. Comber ; W. B. Corse ; J. A. Walker; Joseph A. Le Prince; J. A. Smith ; Lt. Frederick Mears, U. S. A. HAVANA.-V. T. Polledo, Chairman; Diego Lombillo Clark, Jose Primelles, J. R. Villalon, Jose Artola, J. Ducassi, Luis Morales, Enrique Montonlieu. ENTERTAINMENT ON SHIPBOARD.-William L. Saunders, Chairman; Mr. and Mrs. S. D. Warriner, Mr. and Mrs. Thomas Robins, Mr. and Mrs. George.D. Barron, Mr. and Mrs. R. B. Watson, W. E. Greene. GENERAL MANAGEMENT. .Joseph Struthers, Chairman; Albert E. Vaughan. There were ten sessions of the Institute held for the presentation and discussion of, technical or professional papers. Eight of these sessions were held on the steamer while en route, and two in the ball-room of the Hotel Tivoli, at Ancon, C. Z. Mr. David W- Brunton, President of the Council, presided at all the sessions, except the sixth, at which Mr. Charles Kirchhoff, past President, occupied the chair. The following list includes the papers presented in oral abstract by the authors: First Session., October 24. The Summit Hill Mine-Fire, by W. A. Lathrop, Philadelphia, Pa. Mine-Fire at the Calumet and Hecla Mine, No. 8 Shaft., by S. D. Warriner, Wilkes-Barre, Pa. Fire in the Big Lick Stope, Lykens Valley and Williamstown Colliery, by R. V. Norris, Wilkes-Barre, Pa. Mine-Fire in the Hecksherville Valley, Schuylkill Field, Pa., by W. J. Richards, Pottsville, Pa.. Fire in the Monarch Mine, near Rock Springs, Wyo., by S. A. Taylor, Pittsburg, Pa.

Dec 1, 1910

By Robin Belley

Outline Introduction Wabush Mines HistoricalBackground Mine and Concentrator at WabushMines High Intensity Magnetic Separators (HIMS) Development of the Manganese Removal Process Pilot Plant Testing Phase Manganese Removal Line 1 Coming Phase: Manganese Removal Line 2 Manganese Concentration Process Development Historical Background 1847: Creation of the Cleveland Iron Company1850: Opening of its first iron ore mine in the Upper Peninsula of Michigan 1965: Beginning of Wabush Mines at Scully Mines, Wabush, Labrador. 1980-1990: Questions raised about how to exploit Scully high Mn Ore (> 2%)Part of the available ore is not saleable due to too high a level of pyrolusite (MnO2) Adding this ore to the resources would be valuable (longer mine life and lower stripping ratio) 1990s: Testwork for Manganese removal Many different processes are studied over more than a decade High Intensity Magnetic Separators (HIMS) are identified as the best technology for Mn removal 2007: Pilot Mn removal line installed Testing carried out through 2007-2008 First Production Line is ordered (2008) 2009: Cleveland Cliffs (now Cliffs Natural Resources)acquire the remaining part of Wabush Mines 2010: Mn Removal Line 1 construction & commissioning Summer 2011: Mn Line 2 Construction

May 1, 2011

JOINT convention week has become a feature of the year with western mining men. The first was held at Denver in 1926, the second at Salt Lake City in 1927, and the third is about to take place at Los Angeles. Holding in the same city in one week the meetings of a number of related organizations has been .found to permit the development of a well-rounded program at the same time that it economizes time and money for the members, many of whom belong to several of the participating organizations. For the third time, the American Mining Congress, represented by its Western Division, of which Philip Wiseman is chairman, is taking the lead and assuming the main responsibility. The A.I.M.E. is furnishing the papers for two sessions and the California Development Association for one. The Southern California Section, Robert R. Boyd, chairman, is host for the Institute, but the Northern California, Nevada and Arizona sections have each contributed papers to the program, and will be represented at the meeting. It will be a real reunion of the mining men of the Southwest.

Sep 1, 1928

By A Hughes, J Agius, T Ferguson, A Parbhakar-Fox, D Lester, L M. Jackson

Management of historic tailings is a major challenge facing the mining industry and its regulators. However, through improved mineralogical and chemical characterisation of such materials the opportunity to develop better rehabilitation strategies arises. Microanalytical techniques including microscopy, mineral liberation analysis and laser ablation inductively coupled plasma mass spectrometry (ICPMS) allow for improved tailings characterisation – but the challenge posed by these techniques is how to use them effectively. Additionally, data sets collected by such techniques must be properly integrated, only then can they assist in the identification of the most appropriate rehabilitation strategies. A study conducted at the Old Tailings Dam (OTD) located at the Savage River Mine, Tasmania allowed for the integrated use of several microanalytical techniques to help evaluate the benefits of a shallow water cover as a potential rehabilitation strategy. Samples (n = 144) from 14 trenches and 11 boring cores (2 m maximum depth) were collected across the OTD. These were subjected to routine acid-base accounting, with a subset subjected to detailed mineralogy using a modified sulfide alteration index (SAI), X-ray diffractometry and mineral liberation analysis (MLA). In addition, representative samples (n = 6) from across the OTD were subjected to laser-ablation ICPMS to characterise the pyrite chemistry. Our results showed that tailings in the northern area submerged under a natural water cover were relatively unoxidised from approximately 1 m depth, with SAI values of 1 to 2. Tailings from the subaerial southern portion were extensively oxidised to approximately 35 cm depth (SAI = maximum 5.8), with fresher materials observed underneath (SAI = 5 to 5.8). Pyrite from across the OTD is enriched in Co, Cu and Ni. Through the integrated application of microanalytical tools, we determined that establishing a water cover of at least 1.5 m depth across the OTD is a suitable rehabilitation option for this historic site. However, consideration for the reprocessing of these tailings to extract Co should be further investigated.CITATION:Jackson, L M, Parbhakar-Fox, A, Hughes, A, Agius, J, Ferguson, T and Lester, D, 2015. Microanalytical evaluations of the savage river old tailings dam, north-?west Tasmania, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 111–124 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By L. J. Vincze

The program of study of pellet binder materials was begun by the ORF in 1963 to examine various Canadian materials as substitutes for bentonite which is imported in large tonnages (199,270 tons in 1969) from the U.S.A. for Canadian pellet plant operations. Most of the raw bentonite used in Canada originates in Wyoming, North Dakota and more recently Greece, resulting in relatively high transportation costs to pellet producers. Some Canadian bentonites available in Western Canada (Alberta) can be beneficiated for uses as pellet binders but could not compete in cost with U.S. sources due to the cost of beneficiation and the higher rail transport charges to Eastern Canada. It is difficult to find a substitute for bentonite, and many materials have been investigated by research groups but, so far, no economic substitute is in use. However, some success is apparent in studies of low cost materials such as clays, sea weed, peat moss and low grade coal, The work done by the ORF over several years has covered systematic test¬ing of Ontario clays, lignite, some types of tree bark, waste sulphite liquors of various kinds, and peat moss as binders for iron ore pellets. The major effort has been concentrated on peat moss and has included a study of the influence of different additives. Since analysis of peat moss for humic acid is difficult and time consuming, a certain amount of time was devoted to development of improved methods, the most useful of which was a spectrophotometric method based on extraction of peat by sodium pyrophosphate for determination of humic substances. In the present paper, only the most recent work concerning the use of peat moss with suitable additives is discussed in detail, since it is the most conclusive and best documented portion of the program.

Jan 1, 1971

By H Jones

Closure cost estimates may be generated at any stage of a mining operationÆs life; commencing with the initial prefeasibility studies and continuing through to the final decommissioning cost estimates. However, not all mine closure cost estimates are necessarily the same. Cost estimates will vary depending on the purpose for which they are prepared, the organisations requiring or undertaking the estimate and the stage of the mining operation. Different organisations can legitimately arrive at disparate cost estimates for closing the same mine because the organisations have different reasons for requiring the estimates. Another, equally valid, reason for potentially wide variations in cost estimates by different organisations on the same mine site is the different definitions of æclosure costsÆ used by different estimators. This paper considers the different approaches by different organisations including operating companies, government authorities and financial organisations and uses a hypothetical example based on practical experience to illustrate some of these differences in estimation methods.The paper suggest that a more consistent approach to closure cost estimating in the Australian mining industry would assist mining companies, governments, the accounting industry and the broader community to better understand this complex component of mine planning. One possible approach to closure cost estimating is briefly outlined.CITATION:Jones, H, 2012. Closure cost estimation - All things to all men?, in Proceedings International Mine Management 2012, pp 115-124 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By Gary B. Glass

In 1997, 92.3% or 235.7 Mt (259.8 million st) of coal produced in Wyoming came from the Wyodak coal zone in the eastern Powder River coalfield. The mined portions of the zone consist of one to three beds of coal with an aggregate thickness between 15 and 33.5 m (50 and 110 ft). The thickest expression is 61 m (200 ft). The delivered coal from this zone averages 0.33% sulfur, 5.12% ash and 19.98 MJ/kg (8,590 Btu/lb.). This coal zone occurs at or near the top of the Paleocene Fort Union Formation, which is overlain by the Eocene Wasatch Formation. There is also production from two coalbeds in the lower portion of the Wasatch at the southern end of the basin. Production of coalbed methane derived from the Wyodak coal zone is currently an estimated 289 Mm3/a (10.2 billion cu ft/year). This production is occurring west and downdip from the coal mines and is increasing each year.

Jan 1, 1998

By T Hughes

Upward pressure on all mining operations is coming from the triple bottom line. To some extent this is being offset by the rise in mineral prices, but this may or may not continue. The other serious issue facing all companies is the replacement of economic reserves as exploration levels over the past decade continued to decline in line with falling mineral prices. In order to underpin the sustainability of the mining industry it is necessary to continue to reduce cost, reduce the mine environmental footprint, whilst increasing community benefit. At the same time it is imperative that we increase the economic reserves. The highest risk is in adding new mineral discoveries as the strike rate for economic discovery decreases. Gekko Systems Pty Ltd recognises that the most simple and risk averse route to increasing economic reserves is to reduce cut-off grade in the mine, thereby bringing formerly uneconomic reserves into the economic category. We have been developing a new process flow sheet which embodies the triple bottom line and the issue of economic replacement of reserves. This paper describes this flow sheet and presents four examples where this concept is/can be applied to bring about triple bottom line benefits. Sustainability can only be assured if we are the ones in control of our environment, costs and reserves.

Jan 1, 2007