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By J. A. Finch, T. Weber

"Bubble size in flotation is strongly influenced by frother concentration in the pulp liquor. There is no accepted method of judging the dosage and thus how effectively frother is being distributed to control bubble size is not known. This will hamper certain plant test work where constant bubble size (e.g., when comparing reagents) is implicit. Bubble size is not easy to measure in plant and gas holdup is suggested as a surrogate in the development of a proposed “meter” to estimate frother concentration. The meter is calibrated to enable frother concentration to be estimated on samples drawn from any location in the flotation circuit. The meter and its calibration are described.As general background the action of frothers in reducing bubble size by retarding coalescence is discussed and the bubble generation systems for which the effect will be important are considered.INTRODUCTIONBubble size is an important variable in flotation. The flotation rate constant k has been related to mean bubble size Db by k % Db -n with n ranging up to 2 (Ahmed and Jameson, 1989) and even 3 (Yoon, 1993). Recent work has introduced k % Sb, the bubble surface area flux, given by Sb = 6 Jg / Db (where Jg is the superficial gas velocity or volumetric gas rate per unit cell cross-sectional area), i.e., n = 1 (Gorain et al., 1998). Regardless of the exact value of n, the significance of bubble size in flotation remains. In many plant trials it will be implicit that bubble size has not changed and attention will focus on other process variables. The measurement of bubble size, or a surrogate, would be useful addition to any test work.The size of the bubbles is influenced by several variables, gas rate, gas injection system (e.g., impeller design and rotation speed in a mechanical cell) and pulp composition (chemicals added, percent solids), but the most important is frother concentration (Harris, 1976). The frother functions by retarding coalescence (see appendix), which acts to preserve the small bubbles generated in the pulp (and permits a stable froth to form on top of the pulp). The measurement of bubble size is thus related to measuring frother concentration. The distribution of frother and whether sufficient (to control bubble size) is reaching the intended parts of the circuit then become important considerations. At present there is no simple way to judge frother concentration in a plant. In this communication we introduce a possible methodology, a “frother concentration meter”."

Jan 1, 2003

"Some of the tools developed for the processing of nickel laterite ore by resin-in-pulp (RIP) may be applicable to the remediation of metalliferous mine drainage (MMD). In both cases, recovery of metal value and production of a stable waste stream appropriate for long term storage is desired. MMD typically has the additional challenge of management of toxic low-value metals. Seen in this light, innovations in RIP reactor configuration, selective elution strategies and novel synthetic ion exchange resins become useful tools for taking on the MMD challenge in a way that maximizes both environmental and economic benefit. INTRODUCTIONAcid mine drainage (AMD) is a common problem in any country with significant past mining activity. When sulphide containing minerals, tailings or slag are exposed to water, oxygen and sulphur oxidizing bacteria, AMD will result. Abundant and reactive iron sulphide minerals leach first, providing acidity and the ferrous/ferric couple that can enhance the oxidation kinetics of other minerals. If this runoff contacts encounters acid consuming carbonates or silicates, the acidity may be neutralized, but certain heavy metals remain in solution and can continue to be an environmental hazard (Gray, 1997). For this reason, the remainder of this paper will refer to the broader term metalliferous mine drainage (MMD) rather than acid mine drainage. In either case, such drainage, containing high heavy metal concentrations and often significant acidity, is toxic to aquatic life and can lead to significant damage to ecosystems and to public watercourses. MMD is a problem most commonly associated with now defunct sulphide mineral mines, but similarly toxic streams can result from many types of waste, such as poorly stabilized leach tailings, slag heaps, and coal flotation tailings (Johnson and Hallberg, 2005; Lee et al., 2002; Sainz et al., 2002; Schüring et al., 1997). In any case, the management and remediation of MMD is an important ongoing problem for the resource industry, particularly for the many mines in Canada closed before the advent of more stringent environmental standards. MMD remediation represents a significant long term expense for the resource industry. Multi-disciplinary efforts to understand and mitigate this problem range from creation of artificial wetlands (Poulin and Lawrence, 1996; Sheoran and Sheoran, 2006) to sophisticated biochemical reactors and precipitation processes (Hatami, 2010). Certain remediation technologies such as ion exchange offer methods to make a saleable product by recovering valuable dissolved metals. This paper will show how these technologies can help defray the cost of remediation, and offer potential to turn a dangerous waste stream into a useful product."

Jan 1, 2012

By T S. Cochrane

This paper is based on observations made during a recent visit by the writer to three of the dust research laboratories .in West Germany, each .of which is mainly concerned with studymg the composition and character of the respirable dust produced in mines or at industrial sites. The three institutes are discussed as regards their orgamzat10n and duties, their methods of dust sampling and analysis, and recent trends in research and development. An extensive bibliography completes the paper. Introduction A RECENT trip to Europe to attend international conferences m Austria and m Belgium gave the writer the opportunity to visit a number of research laboratories and mines in Western Europe. The visits to the dust research laboratories in West Germany are the basis of this report. In Germany, cooperative associations formed prior to and since the turn of the 20th Century to promote the safety and welfare of their workers have recognized the effects of airborne dust on the general health of the labour force.

Jan 1, 1964

By C. Matthews, A. Vo

Australia is one of the world’s leading exporters of bulk commodities and the extensive use of sampling equipment is key to the successful management of each mining operation. At the process plant, without a full understanding of the feed, product and tails, it is impossible to fully optimise the performance of the plant, such that the metallurgical balance is often open to error. At the port, a statistically correct, bias free and compliant sampling system is crucial to ensuring exported minerals are reflective of their true value and to avoid penalties. Over the last decade, as a result of the iron ore boom, there has been high demand for reliable, representative and standard compliant solids sample systems in Australia. This paper reviews several solids sampling applications at Australian mine sites, the challenges and experience gained and how the implementation of reliable representative sampling systems has provided better understanding of plant process performance, improved plant control and overall benefits to the operations. INTRODUCTION Mining is the primary contributor to the Australian economy with Australia ranking in the top 4 in economic resources for 21 primary industrial minerals in 2016 (Britt, et al., 2017). Australia is one of the world leaders in the export of the majority of its commodities including gold, copper and iron ore (Britt, et al., 2017). Therefore, a suitable and standard compliant sampling system is essential for evaluating plant performance and content verification. At the mine and at the port, the larger iron ore miners in Australia have developed stockpile models to predict the grade of their ore down to individual blocks of the stockpile. This allows the miner to create the right blend of material for sale to their customers and ensures they are not underselling their product or at risk of penalties for impurities or low grade. As an example, the average difference between the benchmark 62% Fe and low grade 58% Fe fines at the time of this report averaged US $20/tonne according to the Metal Bulletin Iron Ore Index (Fastmarkets MB, 2019). At a shipload of 180kt this would be a variation of US $3.6M. Whilst this is an extreme example, it highlights the economic importance of producing the correct grade product and a recognised representative sample of said product.

Jan 1, 2019

This paper deals mainly with the modernization in the coal loading system at the loading piers of the Dominion Coal Company, Ltd., Sydney, Nova Scotia. The history of the operation is briefly outlined, and the construction of the Company's new pier is described in considerable de-tail. Particular attention is paid to the bins and conveyors, and to the loading tower. The paper concludes with a description of the S.S. Cape Breton Miner, built specifically for the coal trade, and the unloading facilities at Lakeview, Ontario. Coal Shipping at Sydney C OAL from the mines operated in Cape Breton by the Dominion Coal Company, Limited, has been shipped from the International Piers, situated on the east side of Sydney Harbour, for over sixty years. There were three piers, of which two were active-ly used in the shipping of coal until 1964. Nos. 2 and 3 were high piers about 600 feet long, of wooden construction throughout. They were founded on' rock-filled cribs and creosoted piles driven into the harbour bottom, and each had two decks which carried standard-gauge railway tracks.

Jan 1, 1965

By W. W. Rudolph, L. N. Trevani, P. R. Tremaine

UV-visible spectroscopy, Raman spectroscopy, and vibrating tube densimetry have been used in our laboratory to determine equilibrium constants of aqueous species at temperatures as high as 325 °C. The UV-visible and Raman spectra of solutions containing metal complexes and ionized acids or bases can be used to yield formation constants by applying curve fitting methods to resolve the contribution of each species. Colorimetric pH indicators identified by Johnston and coworkers at the University of Texas (Austin) provide an alternative means of determining ionization constants and the pH of complex mixtures. High precision density measurements over the same range yield standard partial molar volumes, which are key parameters for "equations of state" for aqueous species. Examples are given for the copper-ammonia system, simple carboxylic acids, and the iron-sulphate system.

Jan 1, 2004

By J. E. Dutrizac

"The end of an era in zinc metallurgy took place on July 31, 1976 when the horizontal retort furnaces of the National Zinc Company in Bartlesville, Oklahoma were permanently shut down (1) . For more than a century, horizontal retorting had been the most common method of producing zinc in the United States; it was a thriving industry in many parts of that country, especially in the natural gas belts of Oklahoma and Texas. With the Bartlesville closure, yet another metallurgical process has become an object of historical interest for North American metallurgists. Although shrouded in controversy, the origins of zinc metallurgy seem to date back at least 2000 years. Pyrometallurgical methods with carbon reductants are capable of producing zinc from oxidic zinc ores, but only above the boiling point of the metal. Although slow cooling results in re-oxidation of the zinc vapour by air or carbon monoxide, quenching yields liquid zinc; some form of rapid cooling, either accidental or intentional, was likely used by ancient metallurgists to liquify the metal. Zinc metal found in Athenian objects of the Roman era was likely of accidental origin. The Romans employed brass extensively for coins and ornaments(2) , and this was intentionally produced by the calamine process whereby oxidic zinc ores were added to molten copper under strongly reducing conditions. Zinc appears to have been known in China and India as early as 1000-1300 A.D., and was probably smelted commercially in those countries from the 14th century. Although the early metallurgical procedures were probably inefficient, they were able to produce zinc metal in significant amounts. The large heaps of zinc residues with clay retorts bear testimony to an early smelting industry of impressive magnitude. It is estimated that the heaps at Zawar, India alone represent the extraction of 100 000 tons of metallic zinc(2) In the 1730s the smelting of oxidic zinc ores was developed in England using a vertical retort method. In 1788 a British patent was granted for making zinc from zinc blends (ZnS) by roasting the ore in a coalfired reverberatory furnace, mixing the calcine with charcoal and smelting the mixture with suitable zinc condensation. The English process was very energy intensive, however, and early in the 19th century the Belgians developed a horizontal retort process for the reductiondistillation of zinc that was more fuel efficient. This technique was gradually developed into what came to be known as the Belgian process, the forerunner of the ""modern"" horizontal retort furnace."

Jan 1, 1999

By D. B. Smith

DURING the summer of 1953, test work commenced at the Sullivan Concentrator with a view to the modification of filtration practice by the inclusion of wet cyclone classification of the lead concentrates, with separate filtration of the underflow and overflow products. Formerly, practice was conventional and the equipment employed comprised one 50-foot diameter thickener ?with the underflow routed via a 20-foot stock tank to two 8-foot by 12-foot Oliver filters. Heating of the filter feeds to 40° C. and the use of mechanical slappers on the filter drums ?have both been standard features of Sullivan practice for years. Both of these have been retained. Currently (February, 1956), lead concentrates are being classified into sands and slimes by 12-inch cyclones with the underflow, at 75 per cent solids, being fed to No. 1 Oliver filter. The overflow is thickened to 75 per cent solids and filtered separately by a No. 2 Oliver filter . The tonnage split is approximately two of underflow to one of overflow. The overflow contains 75 to 80 per cent of the total minus I 500 mesh slimes in the feed.

Jan 1, 1956

By Robert Keyes, Charle Knowles, Glenn Kendall, Gary Fletcher

"The metal mining industry in Canada has been dramatically affected by the changes that have occurred in the world mineral market place. World economic restructuring in the post ""oil shock"" period of the mid-1970s, greatly increased competition from suppliers in the developing countries, and commodity price and currency pressures have all combined to severely test Canadian competitiveness. In the new mining world, the rate of growth of demand for metals has declined due to product downsizing, materials substitution, and a relatively slower growth of over-all world economic activity.The interplay of market and political factors is complex. Canadian metal mining companies must compete in world markets against low-cost producers in developing nations whose priorities often appear to be centred on maximizing foreign exchange earnings to foster development goals and debt repayment. Many of these countries have high levels of government intervention in their mining industries. The result is a greatly in-creased number of suppliers all vying for a share of a world demand growing at a relatively slower rate than in the past. To be able to compete under these circumstances, Canadian companies have had to undertake 'survival mode' measures and look to new ways of doing things. In order to identify the effects that the recent market and economic trends have had on the Canadian metal mining industry, a study was undertaken by Canada Employment and Immigration to assess these changes and their implications for the metal mining workforce.The Canadian Occupational Projection System (COPS)—Sector Study Group with the cooperation of the Mining Association of Canada, undertook a human resource survey to gather current employment and occupation information. This formed an important part of the Canadian Occupational Projection System Metal Mining Sector Study. This article addresses the with survey results, a C.E.I.C. worker mobility study, and trends and issues that are changing the mix of jobs and the way they are being done.Figure 1 shows metal mining employment for the period from 1974 to 1984. It provides a clear picture of the employment swings that the industry has experienced especially during the recession period of 1981 to 1983. From 1981 to 1983, employment dropped by 14 000, from 68 000 to 54 764, and then dropped to its lowest point in 1984 of 52 783. We feel that employment in the medium term will be flat with growth in gold mines being largely offset by continued workforce rationalizing in other sectors.Perhaps the key point is that equivalent levels of output have been achieved in the recent period (1981-1984) with a workforce that is 25% smaller than it was in 1974. This also raises the questions which the COPS/MAC survey and COPS mobility study sought to clarify, namely, what jobs have been cut and where have these people gone? Equally important are the questions of occupational skill level changes, and what types of jobs are declining and which ones are becoming increasingly important, as economic and technological changes have altered the mining work place."

Jan 1, 1987

By L. Larson

Rock samples were taken, away from zones of mineralization , from seven sections of five rhyolitic zones as define d by Spence (l967) in the Noranda area. The purpose of the investigation was to test whether there were intrinsic differences between the zones which would differentiate between non-productive zones and productive zones. For the elements sought (major elements, Cu , Pb , Zn and S) , no clear chemical difference between the zones was found. Thus, identification of a favour able zone from the over -all composition of the zone does not appear promising. Within sampled sections, there is no clear gradual compositional change up through the sections. A capping of highly siliceous massive rhyolite is present in five of the sections sampled. A layer of relatively basic material occurs near the base of individual units. The third (mine zone) and later zones contain abundant pyroclastic material, where as the non-productive zones do not.

Jan 1, 1977

By Xiang Yu

Hong Kong has a dense distribution of utility services laid under its road network. Utility undertakers frequently demand road openings to install new services and/or maintain existing ones. Road openings can cause troubles to the road network and negatively impact the public interest. Highways Department is responsible for managing road openings in Hong Kong under the Land (Miscellaneous Provisions) Ordinance. Highways Department has spent a lot of efforts to computerize excavation permit processing and utility management. The computerized system has gone through several generations and the current one is called the excavation permit management system (XPMS). On the one hand, the XPMS handles various excavation permit processing functions including permit application/approval/refusal/issuance/extension/termination, fees/costs, permit conditions, and permit period assessment; on the other hand, the XPMS accounts for some important utility management issues such as spatial check, coordination of multiple openings, traffic management, audit inspection, and defect liability. This paper discusses how the application, coordination, and other administrations of an excavation permit are eased by using the XPMS in Hong Kong. Background information such as the governing legal and regulatory framework, and Highways Department?s administrative structure is introduced. The system architecture and advantages of the XPMS are presented. The work procedures and various functions of the XPMS are studied in detail.

Aug 1, 2013

By Bird. M.

As the Cadia mill was the first 40ft diameter SAG mill, commissioned in 1998, its performance, liner and discharge design attracted considerable international attention. Twelve years on, the liner design and the control philosophy are being readdressed to further improve the mill?s performance. A comprehensive series of 3D liner scans, over life of the liner, have been used to calibrate liner mass loss and progressive changes in the liner profile. This data is being used to provide true charge mass and mill filling, plus progressive trajectory profiles over life of liner. This information, along with measures of mill performance over liner life, is being used to select the optimal operating conditions as the liner wears, and hopes to inform future liner design.

Jan 1, 2012

By C. Blawert

In spite of various corrosion studies on HPDC AZ91, there is no clear indication which microstructure gives the best corrosion performance. The skin with its fine microstructure is sometimes reported to have the best corrosion resistance, but there is no clear definition of the skin. If the skin is the outermost part of the casting and nothing is removed from it, then it is contaminated and the corrosion resistance is low. If the outermost skin is removed (about 25 µm) then a better corrosion resistance can be obtained. However this does not automatically mean that there is no other region in the bulk of the casting which could have a similar or even better corrosion resistance. Indeed, the corrosion measurements including potentiodynamic polarization and long term electrochemical impedance spectroscopy (EIS) revealed a lower corrosion resistance of the original as-cast skin about 100 pm thick. The thickness of this region is more or less independent from the thickness of the casting section. The surface region is free from any dendritic grain growth which influences the amount and distribution of the 13-phase and therefore the distribution of the most important alloying element Al. This could explain the different corrosion behavior. Further reason can be found in the enrichment of some impurities such as Fe in the near surface.

Jan 1, 2006

The Santa Rita mine is located in north eastern part of Bahia in Brazil and is owned and operated by Mirabela Mineração do Brasil Ltda. Typical SABC circuit was designed as the preferred option for the 4.0 mtpa (500tph) to produce a P80 of 125um for flotation. Although the SAG was originally designed to operate with conventional radial pulp lifters, later it was fitted with Outotec?s Turbo Pulp Lifters ? TPL (Latchireddi, 2005). The milling circuit commenced commissioning on the 24th of October 2009 and the milling circuit achieved the nameplate capacity within days. with small and relatively simple measures to rectify. Since commissioning, the SAG mill has been working in fully autogenous grinding (FAG) mode with no balls (in contrast to the estimated 10% ball charge) and has been consistently treated up to 650tph. This paper examines the comminution design process, the operating philosophies, start-up experiences, post commissioning optimization and future development works. An evaluation of mill performance relative to the design criteria for the project life to date is also included.

Jan 1, 2012

By W. Petruk

Mineralogical studies and concentration tests were conducted on samples from an oolitic iron deposit from the Peace River district in Alberta to determine what concentrate grades and metal recoveries could be obtained. The samples assayed 32 to 37 wt. % Fe, and consisted of goethite, nontronite, ferruginous opal, siderite , quartz, amorphous phosphate and illite . Flotation with fatty acids yielded the best over-all results. A flotation concentrate from a composite sample of the iron horizon assayed, by weight, 43.0% Fe, 12.3% SiO2 , 1.9% CaD, 0.9% MgO, 4.5% Al2O3 and 2.0% P2O5 and lost 17.2% on ignition, for an iron recovery of 48.8% and a silica rejection of 80%. When heated to drive off the water, the concentrate assayed 52 w t. % Fe and 14. 8% w t. % SiO2

Jan 1, 1977

By Anil K. Beersing

Effective drainage systems are required for reclamation of mine-disturbed areas to control surface water runoff and avoid excessive erosion. For the conventional structural design approach, armouring material necessary to satisfy the design criteria should not move during the design flood event since displacement would uncover the erodible underlying materials. This paper discusses an alternative geomorphic approach for designing drainage channels and watershed landscape. The approach is based on quantitative studies of geomorphic processes operating in a watershed. A design based on the geomorphic approach replicates the configuration, channel regime, sediment volume and hydrology of natural and mature drainage systems. Movement of some armouring material is acceptable in such an approach because the channels are allowed to mature by natural degradation and aggradation, with erosion rates comparable to the natural environment. The key advantages of a geomorphic approach over a purely structural approach include reduced sizes of armouring material, geomorphologically sustainable landscapes, ?walk-away? or maintenance-free design and reduced liability in the future. The geomorphic approach is illustrated using the example of a coal mining operation in northwest U.S.A. The paper discusses field data collection, design criteria, typical design details, and construction methods.

Apr 1, 2005

By C. J. Preston, R. E. Ström, G. R. Baiden

"On January 1st 1996 Inco Limited, Tamrock OY, Dyno Explosives Group and CANMET formed a consortium for the development of robotic mining equipment. This project is a five year research and development agreement that combines the talents of the above organizations to facilitate the creation of mining equipment and systems for robotic mining.The projects are based on the communication system developed by Inco Mines Research and currently sold and marketed by Automated Mining Systems Limited. Main projects include the development and implementation of a positioning and navigation module (including a software mapping system that will be inherent to each piece of equipment), robotic systems for development and mining, and software systems to support the use of this equipment. Included in the program is the establishment of a test mine, at Inco’s 175 ore- body at Copper Cliff. This facility will allow collaboration of companies and research organizations for the design and testing of techniques and equipment for Robotic mining.This paper discusses the creation of this new research alliance, the Mining Automation Program or MAP."

Jan 1, 1997

By L. R. Fyffe, D. R. Lentz, S. H. Mcclenaghan

"Abstract - The Eel River area in the southwestern Miramichi terrane of New Brunswick contains a complete calc-alkaline suite of volcanic rocks that are interlayered with intervals of sedimentary and polylithic fragmental rocks, and are overlain by a thick sedimentary sequence. This package, collectively referred to as the Meductic Group, was deposited in a submerged volcanic arc setting interpreted to be part of the Popelogan arc. Rifting of this arc led to the development of the Tetagouche-Exploits back-arc basin, and formation of volcanogenic massive sulfide deposits in bimodal volcanic rocks of the Bathurst Mining Camp in the northeastern Miramichi Terrane. Unlike the Bathurst Mining Camp, volcanic rocks in the southeastern Miramichi Highlands form a continuous calc-alkaline suite characterized by increasing Zr/TiO2 with increasing SiO2, in part resulting from progressive coupled assimilation and fractional crystallization of nested magma systems. Slumping of semi-consolidated volcanic and sedimentary rocks in topographically unstable areas resulted in numerous slumps and debris flows that are preserved throughout the Eel River area. In the early 1990s, the discovery of a large sulfide clast in a road cut along the Benton road sparked interest in the volcanogenic massive sulfide potential of the Eel River area. Subsequent drilling intersected smaller fragments, one clast of which graded 16.7% Zn, 5.6% Pb, 90 ppm Ag, and 220 ppb Au. The intersection of thin lenses of stratiform sulfides in another drillhole indicates favorable conditions for the preservation of massive sulfides. Their subsequent incorporation into synvolcanic debris flows resulted in the transport and deposition of sulfide clasts from hydrothermal vents to more distal locations. Similar to the Buchans deposits of Newfoundland, tracing these debris flows back to their source would be beneficial from an exploration perspective. Approximately 15 km to the southwest of the Eel River area, gold-bearing base metal sulfide clasts (11.1% Zn, 6.13% Pb, 0.19% Cu, 108 ppm Ag, and 1100 ppb Au) occur within intermediate-composition volcanic rocks at Monument Brook in eastern Maine. Sommaire - Le secteur d’Eel River dans le sud-ouest de la terrane de Miramichi au Nouveau Brunswick contient une séquence complète de roches volcaniques calco-alcalines interstratifiées avec des roches sédimentaires et fragmentaires polylithologiques, sous une épaisse couverture sédimentaire. Cet assemblage constitue le Groupe de Meductic, et a été déposé dans un environnement d’arc insulaire interprété comme une partie de l’arc de Popelogan. Le rifting de cet arc à mené au développement du bassin d’arrière-arc de Tetagouche-Exploits, et à la formation de gisements de sulfures massifs volcanogènes dans les roches volcaniques bimodales du Camp Minier de Bathurst dans le nord-est de la terrane de Miramichi. Contrairement au Camp Minier de Bathurst, les roches volcaniques des hautes terres du sud-est de Miramichi constituent une suite calco-alcaline continue caractérisée par un accroissement du rapport Zr/TiO2 à des valeurs croissantes de SiO2, résultant en partie de l’assimilation progressive et de la cristallisation fractionnée de systèmes magmatiques superposés. L’effondrement de roches volcaniques et sédimentaires semi-consolidées dans des secteurs topographiquement instables est à l’origine des nombreux slumps et coulées de débris qui sont préservés dans le secteur d’Eel River. Au début des années 1990, la découverte d’un large claste de sulfures le long de la route Benton provoqué un intérêt pour le potentiel en gisements de sulfures massifs volcanogènes dans les secteur d’Eel River. Des forages ont par la suite recoupé des fragments plus petits, dont un claste qui a retourné des teneurs de 16.7% Zn, 5.6% Pb, 90 ppm Ag et 220 ppb Au. Le recoupement de minces lentilles de sulfures stratiformes dans un autre forage indique des conditions propices à la préservation des sulfures massifs."

Jan 1, 2006

By Denis Yaychuk, Gary Billingsley

The economic eva luation of a mineral property or mining venture should include the quantification of ri k as part of the analy is. The re ults of such an analysis provide the decision-makers not only with the most likely financial outcome and the probability of achieving that or any other outcome. but al o with a ranki ng of the relative impact of all the ri sk factors. These type of resu lts offer more complete information for investment and technical deci ions than the traditional cash flow/ ensitivity analysis. In addi tion. by attempting to quantify ri sk. the personnel providing the va ri able input are forced to take a much clo e r look at the data involved, and are fo rced to work together. the reby increa ing substantially the awa reness of the impact their work and others· work has on th e outcome of the analysis.

Jan 1, 1986

By G. H. Blackwell, N. I. Norrish

"At most operating mines, geostatistical are reserve estimation methods have been implemented by head office or consulting groups . With recent advances in small computer technology it is now possible for a remotely-located mine department to independently implement a geostatistical package.This paper describes the evolution of geostatistical routines to calculate the mineral inventory for porphyry type copper/ molybdenum or similar are bodies. The problems encountered in down sizing the geostatistical routines to run using limited minesite computing facilities are discussed. The high quality of the results, in spite of some compromises to geostatistical theory, is emphasized.The first stage entailed the development of a mineral inventory based on diamond drill data. The difficulties in fitting variogram models to two metals, copper and molybdenum, and the shortcomings of the mineral inventory due to the mixing of lesser quality exploration data with data from more recent diamond drilling are discussed.To improve the ore reserve estimates for short-term planning, a mineral inventory was produced using both the diamond drill and production blast hole drilling data. This inventory, when compared to actual grades, was found to be quite satisfactory for short-term planning. The inventory also provided a reliable data base for long range pit design and financial planning. By regularly updating the mineral inventory, many of the uncertainties of mining a low-grade orebody were minimizedIntroductionThe comparatively low grades of many Canadian mineral deposit s, the escalation of mine operating costs, and the volatility of metal prices in recent years, has required improvements to both short- and long-term mine planning.One of the prerequisites to improved planning systems is the need for accurate grade prediction. This paper describes the on-site implementation of geostatistical techniques for grade estimation of a porphyry I vein type copper/molybdenum ore body ."

Jan 1, 1987