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By Robert L. Akright

The Sumich (Victorine) gold mine is located in the Toiyabe Mountain Range on the east side of Victorine Canyon, a north-trending branch off Kingston Canyon in the northwest quarter of Section 27 and southwest quarter of Section 22, T16N, R43E, in the southern end of Lander County, Nevada (Fig. 1). HISTORY Discovered in 1862, the Victorine reached a peak of development between 1872 and 1887. The "Victorine" and "Morning Star" lode mining claims, located on the outcrop of a prominent auriferous quartz vein, were patented in 1869 and 1891, respectively. 1, respectively. Gold ore was mined underground in adits driven, on the level, directly into the side of the mountain. Ore brought to the surface was trammed about 457 m (1500 ft) south on a track constructed along the contour to ore bins. From this transfer point, the ore was moved by aerial tram to the bottom of the canyon then hauled by horse-drawn wagon to the mill located about 3.2 km (2 miles) east down Kingston Canyon. Exact details of the milling process used on the Victorine are lacking, but old reports mention water-driven stamp mills, amalgamation, chlorination, and cyanidation. Gold and silver mill products are reported to have been sent to England for final refining. High-grade gold values of 103 g/t (3 oz per ton) remaining in mine walls and on outcrops, attest to the lack of success in treating the Victorine ore in the early mills. The Victorine mine may have been worked sporadically after 1887 with little success. In 1934, control of the property was acquired by William P. Moloney, an attorney from Marion, OH, who also control- 1 led an interest in the successful Goldacres mine in Lander County, NV. This property was studied, sampled, and metallurgical tests were done in 1934, but no development resulted from this work.

Jan 1, 1990

By F. J. Susko

The U.S. Bureau of Mines is using Fourier-transform infrared (FT-IR) analysis to investigate the bonding mechanism which occurs during the dewatering of clay slurries. High molecular weight polymers are used as flocculating agents in these processes. This investigation presents the results of an FT-IR study of calcium-exchanged montmorillonite treated with polyacrylamide (PAM) and polyethylene oxide (PEO). Both thin film and attenuated total reflectance (ATR) spectroscopic techniques were employed to study this clay-polymer system~ Results suggest PAM is adsorbed to the clay via the nitrogen atom of the polymer. A water bridge is involved in the bonding between the clay and PE~. Evidence also suggests that PEO may be adsorbed directly onto the surface of the clay.

Jan 1, 1990

By Corbett G, Iwai N

The Japanese gold mining industry has a long and productive history and is presently undergoing a period of revitalisation encouraged by the Hishikari discovery. Deposits exhibiting the characteristics of epithermal mineralisation are very widely distributed throughout the island chain and an encouraging number of these are large, seven containing gold in excess of one million ounces. All the important deposits are quartz vein type and contain extremely high grade, or "bonanza". Zones.

Jan 1, 1990

By L. Lui, A. Cauchon, A. R. Laplante

"The gravity circuit at Les Mines Camchib Inc. consists of two pinched sluices to bleed a feed to one of two 76 cm (30"") Knelson concentrator. The Knelson concentrate is upgraded to smeltable grade with a smaller Knelson (18/30 cm) and a riffleless table. Their tails are column cyanided and washed prior to recycle to the grinding circuit. This paper details size-by-size circuit performance. The Knelsons recover around 90% of free gold (as determined by Mozley Laboratory Separator), even below 37 µm. The sluices are ineffective, with upgrading ratios around 2, but approaching unity in the fine sizes. Much of the effectiveness of the circuit lies in the high gold circulating loads in the grinding circuit, which partly atone for the poor sluice performance, and the ability of the Knelsons to recover free gold. Secondary upgrading recovers slightly above 99% of the primary concentrate gold, 90% of it in a 65% Au concentrate and the balance in a heavily loaded (10 to 20 oz/st) pregnant solution. INTRODUCTIONBackgroundThe operating performance of the mill of Les Mines Camchib Inc. has been described earlier (Laplante et al., 1989). The presence of significant chalcopyrite (1 % and up) makes flotation necessary prior to cyanidation, to limit cyanide consumption and minimize environmental impact. In 1982, the presence of very high gold circulating loads in the grinding circuit lead to the commissioning of a gravity circuit, schematically shown in Figure 1. Gravity recovery of gold has been found beneficial because it increases metallurgical recovery by 1-3% (Laplante et al, 1987), as only part of the flotation tail is cyanided, and economic recovery, because of the lower net smelter return of gold in the flotation concentrate (as compared with the gravity concentrate). The latter increase is estimated, with a net smelter return of 95%, at 1.5% when gold recovery by gravity is equal to 30%. In early 1988, a sampling program was initiated to characterize the behaviour of gold in the grinding/gravity circuit. This paper reports on the results of this study."

Jan 1, 1990

By G. J. Simandl, H. -L. Jacob, S. Paradis, G. Valiquette

"Nos travaux de terrain dans le Grenville, effectués dans le cadre d'un projet d'inventaire des gîtes de wollastonite, ont démontré qu'il existe un secteur exceptionnellement favorable à l’exploration pour la wollastonite. Ce secteur s'étend de la municipalité de Grenville jusqu'au pare du Mont-Tremblant (nord de St-Jovite). D'autres secteurs favorables a 'exploration pour la wollastonite ont été délimités dans les regions du Lac-Saint-Jean, de Shawinigan et de la Gatineau. Neuf categories litho-structurales de gites de wollastonite furent identifiées. L'importance d'un système ou vert pour la formation des gîtes de hautes teneurs fut établie. Un guide de prospection pour la wollastonite propre à la province tectonique de Grenville fut développé. Plusieurs des indices sont prometteurs et mériteraient des travaux de raise en valeur afin de determiner s'ils représentent une source de wollastonite exploitable à profit. Lac-Saint-Jean, Shawinigan and Gatineau areas. Deposits may be classified into nine categories depending on their relationship to intrusive rocks, discordant or concordant contacts with the host rocks, morphology, and major structural controls. Deposits consist mainly of wollastonite, calcite and clinopyroxene. They may contain one or several of the following minerals: feldspar, scapolite, quartz, titanite sulphides, zoisite, clinozoisite, garnet, idocrase and prehnite. Wollastonite content may reach over 70%. Some deposits are associated with graphite veins. Better understanding of the geology, combined with the proposed classification provides new exploration guide for wollastonite. Several deposits have grades of economic interest. Further work is needed to determine if any of these deposits can be exploited for profit."

Jan 1, 1990

By M. Jennings

In 1987, Echo Bay discovered a major silver/gold ore body at their McCoy property in Nevada, and quickly made a decision to build a 5000 tpd mill which was expanded during the design to 7500 tpd. Since the ore reserves consisted of cyanide leachable oxide as well as sulfide, the plant flow sheet involved an oxide leach, a gravity circuit, and lead sulfide and a pyrite sulfide recovery by flotation. The paper describes the process development, equipment selection, plant design and the startup of the oxide treatment.

Jan 1, 1990

By Kubik K

This paper reviews the historical data on relative height changes of landmasses with respect to sea level for Pacific Rim countries.It discusses existing theories of the Greenhouse effect, and the interaction with the vertical movements of the continental plates which leads to different effects for different places. Possible future scenarios are described and directions for future research and measurement programs are given.Relative sea levels are governed not only the increase of water from deglaciation but also by a range of other factors such as variable water storage in lakes and the atmosphere, thermal expansion of the ocean, ocean currents, and the shape of the ocean and the continents. Sea floor spreading, for example, is ultimately more significant than deglaciation in sea level control but is generally much slower.

Jan 1, 1990

By Kobe HW, Balance PF, Black PM, Sporli KB, Smith IEM, Locke CA

The Hauraki Goldfield consists of a large number of volcanic-associated epithermal gold deposits within the Coromandel Volcanic Zone (CVZ), North Island , New Zealand; it is the most accessible and most studied of the Southwest Pacific gold regions. The deposits occur generally as steeply dipping quartz veins and breccia sheets in faults and fractures.From a tectonic perspective, the CVZ is generally considered a Neogene convergent volcanic arc constructed under an extensional tectonic regime; the common tectonic setting for epithermal mineralisation. The gold deposits are mostly hosted in subaerial andesitic arc-type volcanic rocks. Temporally, however, mineralisation is associated with rhyolitic rocks of a bimodal volcanic suite that may represent a back-arc environment. Rifting and calderas may be important components of the latter regime, but this is not yet clear; the general structural framework controlling the location of CVZ gold deposits remains poorly understood. Geophysics, particularly aeromagnetics, has a role in mapping regional fault patterns in the CVZ

Jan 1, 1990

By W. S. Fyfe

The future environment of our planet, with the concept of sustainable development, has moved to centre stage of all future plans for development. This global view is new. It presents great opportunities and challenges for the Earth Sciences. We have the tools to describe our environment on all scales - planetary to molecular levels. We must respond to this great demand by world society.

Jan 1, 1990

By Welby G. Courtney

This publication reviews recent U.S. Bureau of Mines studies of frictional ignition of a methane-air environment by coal mining bits cutting into sandstone and the effectiveness of remedial techniques to reduce the likelihood of frictional ignition. Frictional ignition with a mining bit always involves a worn bit having a wear flat on the tip of the bit. The worn bit forms hot spots on the surface of the sandstone because of frictional abrasion. The hot spots then can ignite the methane-air environment. A small wear flat forms a small hot spot, which does not give ignition, while a large wear flat forms a large hot spot, which gives ignition. The likelihood of frictional ignition can be somewhat reduced by using a mushroom-shaped tungsten-carbide bit tip on the mining bit and by increasing the bit clearance angle; it can be significantly reduced by using a water spray nozzle in back of each bit, which is carefully oriented to direct the water spray onto the sandstone surface directly behind the bit and thereby cool the hot spots formed by the worn bit. A bit replacement schedule must be used to avoid the formation of a dangerously worn bit.

Jan 1, 1990

By Qisu W

The ground vibration produced by the bench blasts of a single hole and a row of two or three holes is recorded in an iron mine. Using the seismic signal generated by a single-hole shot as the source function, we have developed a computer program of a simulating ground vibration by bench blast. The reasonable delay time of blast in the iron mine has been discussed tentatively with the Fourmap invented by Anderson, D.A. The seismograms measured from the single-row blasts of two or three holes have shown the method of simulating vibration is feasible on the whole. For large scale production blasts, a combination of the vibration simulation and the high-speed photograph is used to choose the delay Time.

Jan 1, 1990

By J. D. McKay

Flotation columns have been readily accepted for use in most sulfide flotation plants; however, recently columns are being used in many other areas. Recent improvements in design methodologies have overcome many operating problems and led to improvements in metallurgy. In addition, physical improvements in column design have simplified their operation while leading to better control. The Turbo-Air External Bubble Generator has provided a method for bubble size control and variation in air holdup and carrying capacity. These have enabled commercial operations to improve grades and recoveries by optimizing performance.

Jan 1, 1990

By Stewart Gillies A D, Just G. D

An internationally recognised and uniform method for classification, categorisation and designation of mineral and energy resources is not yet available. With the increasing need for reliable and comparable coal resource data it is necessary to standardise the traditional classification procedures by quantifying the three basic evaluation criteria of economic feasibility, geologic assurance and recovery. For well documented deposits, geostatistical methods can considerably improve classification quality. A review is undertaken of major classification with particular emphasis on those that incorporate limits on estimation error.A geostatistically based algorithm for classifying coal resources within the current Queensland and New South Wales codes has been developed.Application of the classification algorithm for resources from a number of seams exhibiting different structural characteristics is assessed. The method is found to give classification results that closely reflect the error associated with an estimate of resource quantities based on current sampling densities.lbis requires a careful geostatistical analysis with an emphasis on geological awareness. Resource category restrictions although albitrarily assigned should remain constant for all deposits being compared. This requires some engineering judgement with additional interpretation also required for isolated and peripheral block.

Jan 1, 1990

By Hani S. Mitri

The behaviour of grouted cable bolts used for rock reinforcement as a means of ground control in hard rock mining is investigated. The study utilizes an analytical model which is based on the variational principle to calculate the shear bond stress distribution along the embedded length of cable bolt. In this paper, a comprehensive parametric study which covers both geometric and mechanical design parameters involved is presented. Special emphasis is placed on studying the characteristics of the grout model represented by Winkler springs. This involved varying the maximum shear strength of the grout, its residual strength and the slip occurring between the cable and the borehole wall.

Jan 1, 1990

By Reilly SY, Green TH, O&apos

Alkali feldspar meggacrysts are commonly found (with aluminous clinopyroxene, kaersutitic amphibole, titanomagnetite, ilmenite and apatite, and more rarely with zircon and corundum) in alkalic basalts and their derivatives as discrete crystals and fragments. They are commonly euhedral or subhedral and may be up to 15 cm in size. Their occurrence has been reported from many localities around the world, e.g., Africa, Antarctica, eastern Australia, eastern China, East Fife (Scotland), Eifel (Germany), Massif Central (France), Mongolia, New Zealand, New Mexico (USA) and Siberia (USSR). These megacrysts are relatively homogeneous and belong to the Na-rich anorthoclase group, although Kutolin and Frolova (1970) called them sanidine due to their monoclinic nature. The majority of megacrysts have a molar orthoclase content (Or%) between 20 and 30 (Fig.1). These anorthoclase megacrysts possess a high degree of disorder, with the structural state belonging to the high albite-high sanidine series (Hoffer and Hoffer, 1973; Chapman, 1976).Published interpretations of the origin of anorthoclase megacrysts fall into the following two categories: either (1) Anorthoclase together with the associated pyroxene and amphibole crystallized from basaltic magmas as phenocrysts (cumulate phases) at high pressure and the present host basaltic rocks are the parent magmas for the anorthoclase megacrysts (Binns,l969; Binns et al. 1970; Kutolin and Frolova, 1970; Hoffer and Hoffer, 1973; Laughlin et al. 1974); or (2) Anorthoclase probably crystallized from a more evolved liquid at relatively lower pressure and was then picked up and carried to the surface by a later

Jan 1, 1990

By Calvin Konya, Theodore R. Myers, Robert Lundquist

The design of a single, large mass blast using ring drilling may take two to three months. This time requirement inhibits the evaluation of multiple designs. It also reduces the flexibility to redesign a blast when a parameter affecting the blast changes. Manual preparation exposes the design of a ring blast to a greater probability of human error. The use of Computer Aided Design (CAD) can help to overcome the shortcomings of manual design preparation. High speed electronic calculation, as well as programming, allow for many designs to be considered before blasting. Parametric programming allows single or multiple parameter changes to be introduced into an existing design, such as changes in drilling equipment, variations in ore density or changes in explosive. Exposure to human error is reduced by programming that performs calculations and produces graphical displays for review by the designing engineer. The goal of achieving desirable fragmentation for the minimum cost, when using ring blasting, is obtainable using blasting design techniques and CAD. Multiple designs can quickly be generated and costed, producing cost curves that indicate an optimum design with respect to cost.

Jan 1, 1990

By L. Lichty, R Bhappu, R. Rowan, G. Ramadorai

Treatment of refractory gold ores containing arsenic have always presented a major problem in their processing to recover the contained precious metal values. The major difficulties are concerned with lower recoveries, production of hazardous fumes, effluents and residues. Because of'these arsenic related problems, many otherwise economically attractive precious metal deposits and dumps all over the world are not exploited. In recent years, treatment processee for refractory gold ores and concentrates have been explored and a few commercial operations employing roasting or pressure leaching have resulted. Roasting has limitations due to environmental constraints related to off gases. Pressure leaching involving high temperatures (180% to 200%) and pressures (400 psi) is accompanied by high capital and operating costs. An alternate route to roasting for treating pyrite and arsenopyrite ores and concentrates ia the "lime-oxygen hydromet" process carried out at a moderate temperature (100%) and pressure (100 psi). A simplified process for treating such arsenic containing ores and concentrates utilizing low temperature and pressure oxidation is presented. This low cost treatment with compressed air and lime renders arsenic as an inert component in the residue, meeting all the requirements of the EPA Toxicity Test. The precious metal values are then extracted from the autoclaved residue by standard cyanidation. This paper discusses this new development.

Jan 1, 1990

By M. J. Collins

Direct pressure leaching of zinc sulphide concentrates was started? commercially in October 1980. Continuing research and development studies at Sherritt and feasibility studies for a number of clients have defined various pressure leach configurations for integrattons with existing roast- 1 each operations and for grass roots plants. Existing and potential applications of zinc pressure leaching are discussed.

Jan 1, 1990

By T. Mutoh

Tellurium in raw slime has recently been recovered as copper telluride in Onahama Smelter & Refinery. The slime is decopperized with sulfuric acid solution in conventional leaching tanks. The pregnant leach solution containing 45 g/l of copper and 1 g/l of tellurium is introduced to a copper telluride recovering reactor. The tail solution from the reactor containing less than 20 mg/l of tellurium is recycled directly to circulation tanks of copper electrolysis. The impurities of the product copper telluride is kept below 1% without any purification.

Jan 1, 1990

The Elura Orebody consists of a number of parallel, vertically oriented pipe-like structures of pyrite-sphalerite-galena mineralization located at the core of a structural dome. Concentric zoning of the mineralization into an outer Siliceous, intermediate Pyritic and inner Pyrrhotitic Zone has been previously recognized and is used in routine geologic modelling of the lead, zinc and silver grades.Statistical analysis of the metal grade distribution in the orebody has confirmed the importance of the mineralogical zones in the understanding of grade trends. The gradational nature of intra-zone boundaries, especially those related to the subjective definition of the Siliceous Zone, are apparent in the statistics.

Jan 1, 1990