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Many organisations, including those in the resources industry have Board-level endorsed principles on sustainability. A key challenge, however, is how to systematically integrate these high-level principles into the design and operation of mineral processing plants. In an effort to meet this challenge the Sustainable Operations framework, called SUSOP®, was conceived and developed through the Corporative Research Centre for Sustainable Resource Processing (CSRP) in Australia. Somewhat analogous to HAZOP (Hazard and Operability Studies) which is well entrenched in the resources industry, the key aim of SUSOP® is to produce a holistic, systematic and rigorous methodology for identifying and assessing sustainability opportunities and risks. This paper argues the need for such a sustainability framework, presents the key elements of SUSOP®, highlights how case studies enhanced its development and articulates the reasons why such a framework will have growing importance into the future.

Jan 1, 2011

By J. P. Golightly

The structure and occurrence of nickeliferous laterite profiles are described and explained in terms of mineral solubility and drainage conditions. Complete profiles, from top to bottom, include: limonite zone; nontronite or silica zone; and saprolite zone. The middle zone is present only where drainage is sufficiently slow to allow saturation conditions to build up with resulting quartz or smectite precipitation. This precipitation may occur in any climate at a water table or in tropical climates with a long dry season. The degree of serpentinization of the laterite parent rock is important in determining the nature of the saprolite zone. Unserpentinized peridotite produces saprolite ores with hard residual rock cores, nontronitic or amorphous saprolitic rims, and fracture fillings of garnierite and quartz. Ser-pentinites yield relatively homogeneous serpentine saprolite, with minimal quartz or garnierite.

Jan 1, 1979

By John William Carlson

The Y2K or "Millenium" bug is a tiny critter, comprising no more than two digits in a date field. This bug, like its' more lethal cousins of biological and computer virus fame, has the potential to derail the economy of the U.S. and the rest of world. Whatever the reader's perception, rest assured that you will be affected by Y2K along with every person in the civilized world. How did we get to this position? It is really quite simple. The Y2K problem is a creation of computer programmers who, in an effort to conserve valuable memory in the early days of computer development, used two digits as shorthand- to define the year in date sensitive applications. Instead of typing in "1982," our experts employed "82." They believed-correctly­that the problem of limited memory would be solved by technology and assumed (nasty word) that software would be modified to take care of any problems associated with a date rollover in the year 2000. Their assumption resulted in the problem facing us today.

Jan 1, 1999

By Neil and Associates

Seismic tomography is one of several additions to the suite of geotechnical engineering tools for use in various underground rock and mineral geologic structures. Seismic tomography is a method for reconstructing a cross section of an object based on attributes of seismic energy that have been transmitted through the object. The in-seam seismic tomogram provides a dataset that can be graphically portrayed in a color-coded format that is then used to infer relative stress concentration (Fig. 1). During the past several years, the US Bureau of Mines (USBM) at its Denver, CO and Twin Cities Research Centers in Minnesota funded several innovative hardware and software developments. These were directed toward use of in-seam seismic tomography for underground geologic strata evaluations. These preliminary investigations have matured into well-defined and field-proven technical advances for improving ground-control decision making in the mining industry.

Jan 1, 1996

By Tim Neil, O&apos

Introduction Compania de Carbones de Chile (Cocar SA) has brought into production Chile's first large-scale, open-pit coal mine, located in the Magellan Province. The US $65 million project includes a 1.1-Mt/a (1.2-million stpy) subbituminous steam coal mine and a mechanized bulk loading marine terminal with water depth sufficient to receive 60 kt (66,000 st) Panamax vessels. The loading terminal will be one of the largest in Chile. The Pecket coal project is expected to save Chile about $40 million in energy production costs and a further $100 million in oil imports, or about 25% of the country's oil import costs. Pecket coal will generate electricity for Codelco and will also supply general electricity needs for northern Chile. The Pecket coalfield is located on the Brunswick Peninsula, about 30 km (19 miles) northeast of Punta Arenas, the provincial capital, as shown in Fig. 1. Pecket is part of a large, coal-bearing basin. It extends from Punta Arenas 250 km (155 miles) north to Puerto Natales and across the border into the Rio Turbio coalfield in Argentina. A fleet of large and small O&K hydraulic shovels and backhoes is used to dig and load overburden and coal into mining trucks while O&K graders maintain the haul roads in and around the pit. Coal occurrence in the Magellan area of Chile has long been

Jan 1, 1988

By G. M. Rao, P. N. Deo

Graphite is soft and easily floatable but it is quite difficult to obtain high purity concentrate at coarse sizes. Chemical treatment can produce high grade concentrate but it is an expensive process. Graphite containing plus 96% fixed carbon (FC) with coarse flakes commands high price in international market. Such graphite concentrate containing plus 96% FC was produced in Indian Bureau of Mines (IBM) by using newly developed reagent (mixture of different hydrocarbons and terpenes, IBM/D7) instead of commonly used frothers viz. pine oil, MIBC, kerosine etc. and regrinding in a special type of mill with special grinding media instead of grinding in a conventional ball/ rod mill followed by cleaning. Both the new reagent (frother) and special grinding media are inexpensive and readily available. The process is under patenting. This paper focuses application of this new grinding methodology for flake size protection, and the new reagent for selective flotation of high purity graphite.

Jan 1, 1995

By Charles G. Frush

The function of the mine surveyor is to (a) provide a network of points of accurately known position, covering the entire mine property, (b) obtain the required data for the preparation of useful maps and sections! (c) provide position and directional control for the guidance of the operations, (d) measure the progress of the work, (e) measure the movement of rock masses, and (f) make miscellaneous surveys as needed. Mining properties range from the very small to the extremely large, and from those which involve only surface operations to those involving extensive underground workings. Active mines undergo constant change, necessitating continual updating of the surveys. The differences in the character of the deposits, the scale of mining and the mining methods result in large differences in the surveyor's activities and techniques, but many of the problems involved are common to most mines. The surface work of the mine surveyor is very similar to that, of the plane surveyor in that control points are established by triangulation, trilateration and traversing. Detail is taken by direct measurement, by stadia and by aerial photography. The equipment used, the techniques and the methods of processing the resulting data are likewise very similar. However, the underground work is quite different : A. The lines of sight frequently must be carried through constricted openings, often involving short lines of sight and awkward setups. B. The lighting often is poor, requiring illumination of the backsights and foresights, and the crosshairs. C. The ambient conditions often are difficult, involving falling water, high tem- peratures, poor visibi 'kv and heavy traffic through the area being suneyed. D. The surrounding rock map be unstable, resulting in movement or loss of the surveying stations, as well as hazard to the surveyors. E. The points to be measured often are difficult or impossible to reach. F. Steep vertical sights often are necessary, requiring the use of special equipment. G. Many working levels commonly are involved, requiring the transfer of position and orientation to each with a high level of precision. This section therefore will concentrate on surveying problems peculiar to the mine surveyor, chiefly underground work. 22.1-THE MINE COORDINATE SYSTEM A system of coordinates is essential for all permanent mining operations It is very desirable that all mining operations in a ,given area b~ tied into the same system, as this minimizes problems of boundaries and connections Whenever possible this system should be tied into and made part of the state or regional grid system. It is desirable to orient the coordinate grid on a true-north line and to position the origin of the coordinates so that all of the work will be in the "northeast" quadrant, making the north and east coordinates always positive. This can be done by subtracting suitable constant values from the north and east coordinates of the regional system The residual values are of more convenient magnitude and can be used as the local mine coordinates. If the long axis of the mineralization is not generally north-south or east-west.

Jan 1, 1973

By C. J. Pritchard

I commend the authors on examining an interesting method of shaft lining and attempting to improve safety in a dangerous environment by remotely installing the shaft lining. It is important, though, to not trade off shaft lining safety for long-term mine safety by lining an intake shaft with combustible material. In many operations, the mine utilities are installed next to the lining of the intake shaft, supplying a possible ignition source if damaged or overloaded. Although the polyurethane studied in the paper is of relatively high density, no mention is made of the flame retardency of the samples. When exposed to heat, small amounts of polyure¬thane will melt and bum but are extinguished when the heat source is removed. If large surface areas of combustible polyurethane - a tunnel or mine shaft - are exposed to ignition heat sources that are not removed or extinguished early, an uncontrollable, fuel rich fire may result with high carbon monoxide levels, low oxygen concentrations, and greatly increased burning rates that can have devastating effects on the ventilation system and miners' safety.

Jan 1, 1990

By Scott G. Britton

This chapter is concerned with the construction of the dynamic component of belt haulage systems. The dynamic system includes the belt line and tailpiece extension and retraction movements in a production system where mine management is continually placing the belt in the most effective operating position. Correct installation of the belt and tailpiece during an extension is very important for many performance reasons. Two of the most important reasons are to eliminate spillage and safely operate the belt line. This chapter is divided into three major discussions. The first discussion looks at analyzing the parameters of effective belt line construction. This includes a review of the parameters and management tools needed for proper scheduling of a move-up. The second major discussion topic centers on efficient procedures for a belt line extension. Topics such as site preparation, tailpiece breakdown and setup, stringing the belt line and structure, plus operating and maintenance tasks needed after the belt line is installed and running, are covered. The third discussion presents a list of conveyor and conveyor component manufacturers who provide services and products to the coal mining industry. Again, any discussion on underground haulage systems must generalize much of the site specific design approaches to be practical. This text will mention, where applicable, some of the alternatives available to construction engineers in designing belt line systems.

Jan 1, 1983

By Arthur E. Lord, W. Martin McCabe, Robert M. Koerner

Following the driving of each new section of tunnel, a prompt decision is required regarding the type and extent of primary support to control convergence and prevent ground failure. Sometime thereafter, the effectiveness of the in-place support must be evaluated over the entire length of excavation. It is therefore extremely desirable to have available a lightweight, portable, easy to install and interpret, cost effective monitoring system to assist with these ground control functions. Such a system can be assembled based on the acoustic emission (or microseismic) technique. This monitoring technique uses a piezoelectric transducer to detect subaudible noises associated with deformation of and/or crack propagation in the soil or rock being monitored. After detection, the signals are then amplified, filtered and electronically counted to provide a quantified assessment of the stability of the structure. In the simplest sense, the absence of emission, or counts, signifies no deformation and thus stability. Conversely, the occurrance of counts signifies instability to varying degrees. The higher the count rate, the greater the instability and the need for immediate or additional support. Described in this paper is an overview of the acoustic emission (microseismic) method, details of its use in a laboratory study measuring convergence and stand-up time in soil, and the behavior of rock samples under similar stress conditions. Field use of the method is recommended for ground control monitoring in tunnels, and some suggestions regarding monitoring procedure are presented.

Jan 1, 1979

By M. H. Pelkki, R. J. Sweigard, P. W. Conrad, J. M. Ringe, D. H. Graves

Research has shown that excessive soil compaction is detrimental to the establishment of trees in reclaimed soils. Dry bulk density and penetration resistance are two soil parameters that can be used to indicate the level of compaction in reclaimed soils. It is believed that reclamation practices that minimize soil compaction will produce better results when forestland is the intended postmining use. The University of Kentucky has developed reforestation test cells on reclaimed soils at a surface mine in eastern Kentucky to test this hypothesis. Each test cell has been planted with various species of trees. Since 1997, data have been collected at these test cells for soil average dry bulk density, average penetration resistance, average depth to refusal and average survival rate of trees. These data have been correlated to determine the relationship between soil compaction and tree-survival rate. It is believed that these two soil-compaction parameters may ultimately be used to predict tree-survival rates on reclaimed surface mined lands.

Jan 1, 2003

By W. C. Hellyer

In an autogenous grinding circuit in which feed at approximately nine inches top size is reduced to a size suitable for subsequent processing, the build- up of a "critical size" fraction in the media causes problems. A "critical size" fraction has been defined as, "media too small to effect reduction by impact grinding of ore coarser than a quarter of an inch and too large to be broken by the largest size of media in the charge. 9, (1) The buildup of a "critical size" fraction reduces the capacity of the mill, increases the grinding power requirements per ton of finished product, and generally produces a finer grind than is desired. It is general practice to overcome this problem by the addition of large diameter steel balls to the grinding charge. This has certain disadvantages, such as; (i) an increase in mill liner wear; (ii) wear on the steel balls, and; (iii) some loss in flexibility in grinding circuit operations resulting from difficulties in removing the steel balls by means other than by grinding out.

Jan 1, 1970

By D. W. Boening

Xanthate salts have demonstrated effectiveness as a flotation reagent in the recovery of heavy metals from mining wastewater. However, due to their strong ionic potentials, they are generally toxic to aquatic life. Under ambient environmental conditions, the half¬life of a xanthate is approximately four days. As a soluble salt, xanthates will complex with the metallic ions contained in water and fish. Some researchers have proposed that this complexing may extend the halflife, as well as optimizing the transfer of a given metal from solution across the gill surface. Leakage of xanthate treated wastewater into the surrounding surface waters is the most common route of exposure for aquatic plants, invertebrates and fish. Because this is an emerging mineral-recovery technology, more information is needed regarding xanthate toxicity and environmental fate before environmental impacts can be assessed with any degree of certainty.

Jan 1, 1999

By D. Van Orden, Y. Kamiya, R. Lee, E. Ilgren

Crocidolite is a well-known causative agent for mesothelioma. However, studies have shown that the pathogenicity of the fiber from different mines varies considerably and it has been postulated the parameter that appears most likely to account for this variation is fiber width although this has never been formally confirmed. To date, crocidolite appears to be the only asbestos mineral for which an epidemiological study comparing the risk of mesothelioma in a population exposed to ‘thin’ fibers with another exposed to ‘thick’ fibers of the same species may be carried out. Finnish anthophyllite, South African amosite, and African Transvaal crocidolite can also be classified as thick fibers, and there is a paucity of mesotheliomas in populations exposed to them compared to those exposed to thin Cape crocidolite. No thin occurrences of these minerals are known. Our previous study looked at crocidolite from several sources. The present study considers the amphibole anthophyllite found in many places in the world. This mineral, regardless of source, does not show the same variation in fiber width found with crocidolite from different areas. All anthophyllite fibers that have been mined may be classified as thick and populations exposed show very low levels of mesothelioma. We suggest the most likely explanation is related to the fiber width distribution and a concomitant reduction in the ‘Stanton fiber size’ fraction.

Jan 1, 2012

By Francis S. Kendorski

INTRODUCTION Drift design problems in caving operations are a re¬sult of the geologic factors contributing to the overall success of the system, of the engineering factors dictated by economic and technical considerations, and of ore production practices. Combining these factors, a rational underground sup¬port system of rock reinforcement, light steel channel section or welded wire fabric, and shotcrete can be de¬signed based on rock fracturing, rock load, abutment loadings, ground movement, expected repair and desired flexibility. The design concept uses the effect achieved by restraining, reinforcing, and maintaining some of the intrinsic strength of the fractured rock mass composed of interlocked blocks of intact rock and rock fractures. Three different examples of drift support design in hypo¬thetical mines using the caving system are given. Caving is a system of underground mining where ore is extracted by means of gravity after the ore body is allowed to fail by removing support from underneath. The rock mass of the ore body fractures and flows ver¬tically downward to let gravity do as much work as pos¬sible. Caving differs from many other mining systems in that blasting is used only to initiate the rock mass failure by removing the rock supporting the ore but not to break the ore itself. The initial movement of the rock mass dur¬ing failure and the consequent crushing and grinding during the continued movement serve to reduce the ore to particles of a manageable size, with only limited sec¬ondary blasting necessary. The broken ore is extracted from the bottom of the failed rock mass through funnels of some sort pre-excavated in the rock. Ore extraction must continue or the swell of the broken rock will even¬tually fill the cavity and stop further rock mass failure and movement. The excellent general discussion on block caving in the SME Mining Engineering Handbook (Julin and Tobie, 1973) adequately covers the principles and application of this type of underground mining. Many rock mechanics aspects of block caving have been covered by others (McMahon and Kendrick, 1969; Swaisgood, et al., 1972; Mahtab and Dixon, 1975; King, 1946) and will not be reviewed further. Maintaining the stability of production drifts is one of the most troublesome problems plaguing the mine manager in a caving operation. Many factors contrib¬ute to drift support problems, and identifying the causes of instability and producing a reasonable support design are two steps toward achieving stability consistent with the mine plan. This chapter sets forth a technique for the design of support systems for production drifts in caving opera¬tions. The basic support system elements employed are rock reinforcement, welded wire fabric, and shotcrete. Recognized as contributing to the design are the factors of rock load, additional load from mining activity, rock fracture characteristics, repair expected, and flexibility. It must be emphasized that the drift must first be stabilized as for a tunnel, and the additional strengthen¬ing for mining-induced loads cannot contribute to the initial premining stabilization, or the reserve of strength is used up. MINE PLANNING The efficient mine planning engineer not only must satisfy the economic, human, and environmental aspects of his task but must also consider the mechanical con¬sequences of his plan. The problems created for the mine by placing parallel drifts too close, by crossing drifts on different levels with inadequate, if any, separa¬tion, and by installing connections and crossovers in the haulage plan without regard for the effective spans cre¬ated, are only a few of the problems a mine planning engineer can create for himself and the mine. The effect on immediately adjacent mine areas when an area is caved is important to drift design because the removal of vertical support from a rock mass causes the weight of that rock mass to be shifted elsewhere. The adjacent rock mass will carry this load and reach a new equilibrium with the applied stress. The advancing front of stress increase that results from caving (and many other mining systems) is generally called the abutment load and is the increase in stress over the gravity or tec¬tonic stress that already exists, as shown in Fig. 1. In general, the abutment load will be similar in nature to the stress change found around an opening in rock and will be taken as causing an increase in the vertical prin¬cipal stress, due to an approaching caving boundary, so that

Jan 1, 1982

By B. P. Boisen

INTRODUCTION The rapidity of onset, rate of increase, and magni¬tude of loads in an underground support system can be measured using load cells or pressure cells, whichever is appropriate to the type of support. These instruments should be installed at the various instrumented station locations immediately after excavation. If the loading of a member is of interest, the load should be measured, whereas if the deflection or strain of a member is of interest, the strain should be mea¬sured. It makes as little sense to use a load cell to allow computation of strain as it does to measure the strain and then back calculate the load. Tunnel steel set de¬signers today invariably rely on the early work of Karl Terzaghi, the basis for which is load, so load measure¬ment should be the main concern. The current trend of using strain gages on steel sup¬port systems stems from the inability by some to eval¬uate unusual loading conditions caused by uneven block¬ing. In fact, uneven blocking will obscure almost any attempt (whether with load cells or strain gages) to properly evaluate support performance. The load curve in Fig. I shows the development of a characteristic early peak load sometimes called the "rear abutment load" seen in many underground open¬ings. It is thought that the peak reflects the coupling of the rock and the support system, and that the magnitude will increase until some yielding, or minor failure, of the support system occurs. At that time, the slight deforma¬tion of the support system promotes the formation of minute shears in the opening walls, and these shears tend to distribute stress between the support system and the adjacent rock in proportion to the relative rigidity of the support elements and the rock. In normal rock, as a result of this stress redistribu¬tion, subsequent load magnitudes generally do not reach the magnitude of the early peak load. In physically unstable (squeezing) or chemically un¬stable (swelling) rock, however, the loads experienced after passage of the early peak load may in fact show a slow, continuous increase. One of the very important purposes of load instrumentation is to provide the means for recognizing such long-term adverse trends, thus enabling the proper remedial steps to be taken. Another purpose of load instrumentation is to pro¬vide a comparison between the magnitudes of the early peak load and the subsequent stable load. The ratio of these two loads is analogous to a safety factor, and may be used to evaluate the efficiency and economy of the support system design. Aside from considerations of economy, it may be well to design support systems which do not have excessively high ratios of early peak load to subsequent stable load. Should these ratios be exces¬sively high, the support system may be so rigid that the yield or failure associated with stress redistribution may occur with explosive violence. Load cells for use in mines, tunnels, and on con¬struction projects come in many forms. Almost all, however, employ the same procedures for installation, readout, etc. Therefore the following comments are almost universal in application. LOAD CELL INSTALLATION Load cells should be installed with bases parallel to the surfaces against which they bear. Care must be taken to orient the cells so that their signal cables are protected from accidental damage as a result of con¬struction, maintenance, or cleanup activities. Most electronic load cells are compensated for tem¬perature variations likely to be encountered during nor¬mal operations. However, if a large difference is an¬ticipated between the calibration temperature [21°C (70°F)] and the average operating temperature, the cells should be conditioned to the operating temperature for at least 8 hr prior to installation. This is to insure that the initial reading, made under no-load conditions prior to installation, provides a stable value to which subse¬quent measurements can be referred. Hydraulic load cells tend to be temperature sensitive and should be used with that in mind. Also, hydraulic load cells tend to be soft compared to electronic types and will sometimes allow movement to take place in a system intended to be semirigid. Furthermore, hydrau¬lic load cells tend to be difficult to read remotely. Care must be taken to use bearing plates on both sides of load cells which are sufficiently rigid and of high enough bearing capacity to prevent bending and crush¬ing under load. This is very important with tieback load cells (basically a ring of steel) which can easily dig into bearing plates. MAINTENANCE AND TROUBLESHOOTING Except for a direct hit by a miner's axe or flyrock from a blast, most hydraulic load cells are nearly in¬destructible and require little, if any, maintenance. Hy¬draulic oil on the bearing plates is a good indication of a leak and the need for corrective action. Field maintenance of electronic load cells involves protecting the instrument and signal cable from mechani¬cal damage and from unnecessary exposure to dirt and moisture, and recognizing and correcting damage and the effects of normal wear and tear.

Jan 1, 1982

By J. P. Wilson, T. Cook, H. Kling

The Tessenderlo-Kerley Leachprocess has been shown to be effective in the removal of residual copper from molybdenite concentrates. Concentrates of varying mineralogy, including those containing relatively large amounts of chalcopyrite, have been successfully leached on laboratory and pilot plant scales. The lixiviant system is ammonia andammonium bisulfite with air / oxygen addition. An abrasive is added which greatly enhances the kinetics, and it is subsequently screened out and reused. The dissolved copper is easily recovered using existing technology. Extraction profiles, reagent consumptions, and mineralogical data are presented.

Jan 1, 1999

By C. O. Brawner

Geotechnical theory is reasonably well developed to evaluate the stability of rock slopes for surface mining projects. It is recognized widely that structural geology, groundwater pressures and seepage, and blasting are key factors that influence the stability of such slopes. However, our capabilities to model the structural geology, to determine rock strength along discontinuities and to model groundwater pressures and profiles are still very approximate. Plus, practical experience of the rock mechanics engineer is one of the most important inputs to the design of open pit mine slopes. To emphasize the use of practical experience, a number of case examples are reviewed here to illustrate key factors that must be evaluated. These case examples comprise a continuation of other examples presented in the Jackling lecture to the SME in 1986 by the author (Brawner, 1986). Example no. 1 In situations where the orientation of geologic discontinuities will not influence rock slope stability, extremely steep slopes can be developed, providing blasting and groundwater are controlled adequately. An excellent example of this condition is the Republic Pit of Cleveland Cliffs in Michigan. The rock slope in Fig. 1 isover400fthigh with a face angle of approximately 80". The rock is hard and massive, and blasting was carefully controlled. The original design of this slope was at45", a standard design angle at that time. The competency of the rock and the lack of critical geologic structure subsequently was recognized, and the much steeper slope angle was developed successfully. The rock proved to be so competent and the slope sufficiently stable that an underground crusher station was developed with entrance and exit tunnels excavated at the toe of the steep wall.

Jan 1, 1991

By Michel Dagbert

The determination of the precision of reserve estimates (tonnage, grade, quantity of metal) for an entire deposit or a large block in a deposit has received some attention in the early developments of geostatistics. A general formula to derive the estimation variance of any linear combination of a large number of sample values can be found in any geostatistical textbook like David (1977) or Journel and Huijbregts (1978). A particular case of this general formula is of course the kriging of the entire deposit. However, besides the technical difficulty of dealing with many samples the application of this formula necessitates the knowledge of the covariance between any two samples in the deposit. This is quite unrealistic in the usual case of limited stationarity where the assumption of a covariance or a variogram just function of the distance vector between two samples is only valid for samples within the same area of restricted size.

Jan 1, 1982

By Pat DeWilliam

The Yakobi nickel-copper deposit is located essentially at tidewater in the east-central part of Yakobi Island, about 16 1 airline km (100 airline miles) west of Juneau, and can be reached by float plane and boat from Juneau and Sitka. The fishing village of Pelican, population 400, is situated 14.5 km (9 miles) to the east. An unimproved road, approximately 4 km (2.5 miles) long, connects a dock site at Lisianski Strait with the main part of the deposit known as the Basin Area (Fig. I). Other mineral occurrences are known as the Takanis, Flapjack, and Beach Areas. Another smaller nickel-copper deposit is located about 32 km (20 miles) to the south on Western Chichagof Island and is known as the Mirror Harbor nickel-copper deposit. The original discovery of the Yakobi deposit was made by S.H.P. Vevelstad about 1920 and a 47.5-m (156-ft) long adit was driven on the southwest side of the deposit in the Basin Area. The deposit was examined by J.R. Van Fleet of Union Carbide in 1930 and by J.G. Fairchild in September 1931. Stanley and Yates of the International Nickel Co. of Canada (Inco) visited the property in August or September 1937. In 1942, the controlling interest in the deposit, covered by 124 unpatented claims, was said to be held by Vevelstad and associates

Jan 1, 1991