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The selection of a particular machine for production drilling is the most critical drill evaluation the pit engineer is called upon to make. It is a true engineering design problem requiring value judgments. Generally, the procedure follows these steps: (1) Determine and specify the conditions under which the machine will be used, including such service factors as labor, site, weather, etc. (2) State the objectives for the rock-breakage phases of the production cycle of operations--considering excavation and haulage restrictions, crushing capacity, production quota, and pit geometry-in terms of tonnage, fragmentation, throw, etc. (3) On the basis of blasting requirements, design the drill-hole pattern (hole size and depth, in- clination, burden, spacing, etc.) (4) Determine the drillability factors and select the drilling methods which appear feasible for the kind of rock anticipated. (5) Specify the operating variables for each system under study, considering drill, rod, bit and circulation fluid factors. (6) Estimate and compare performance parameters, including costs. Major cost items are bits, drill depreciation, labor, maintenance, power and fluids. (7) Select the drilling system that best satisfies all requirements with the lowest over-all cost.

Jan 10, 1967

By Brad E. Melanson

Because mine haul trucks consume considerable quantities of fuel, they are ideal candidates for the adoption of cleaner and cheaper fuels like natural gas. Impressive fuel cost savings will be realized in regions where liquefied natural gas (LNG) has cost advantage to diesel fuel, while also providing significant reductions of air contaminants and greenhouse gases. High Pressure Direct Injection (HPDI) of natural gas utilizes the diesel cycle combustion process and therefore retains the diesel engine?s high performance and efficiency characteristics. HPDI has been demonstrated in on-road Class 8 trucks since 2001 accumulating almost 10 million kilometres to date. The supply of LNG fuel will be an essential parallel aspect in the introduction of HPDI to mining. LNG can be transported to site as diesel is today, or may be produced on or near mine operations that have access to methane sources or pipelines.

May 1, 2006

The Sao Chico gold project is located on the Tocantinzinho trend which is the most mineralised zone in the Tapajos Mineral Field of Brazil (see Figure 1). The Tapajos goldfi eld was the site of the biggest gold rush in Brazilian history in the late 1970s and 1980s when approximately 500 000 garimpeiros (artisanal miners) rushed to the area to exploit extensive areas of newly discovered alluvial gold. Approximately 20 - 30 million ounces of gold were produced from these operations before the easily won alluvial gold deposits were largely depleted. The Tapajos region has had little exploration by modern exploration methods compared to any other equivalent gold fields in the world. The gold occurs in sulfide veins developed in shear zones within Proterozoic granites. Gold grades vary from approximately 15 g/t in the hard rock veins, to up to several ounces per tonne in the supergene weathered upper portions of the veins. Goldbearing vein zones in the weathered profile are free digging. In addition, tailings dumps from previous mining operations contain gold grades of approximately 1 g/t. Metallurgical test work conducted to date indicates that gold recoveries of at least 70 per cent can be achieved via gravity concentration. Gold Anomaly, via its 100 per cent owned Brazilian subsidiary, Gold Aura Do Brasil Mineracao Ltda (GOAB), plans to mine the tailings and weathered vein material by open cut methods to generate a quick cash fl ow and to provide a better understanding of the mineralisation as part of a feasibility study for mining the underlying sulfide zone mineralisation (see Figure 2). Mining will utilise locally hired excavators and trucks and ramp up to a rate of 100 tonnes per day. To treat the gold-bearing material, GOAB has purchased an integrated 'state of the art' gravity concentration processing plant from Gekko Systems of Australia. The processing plant includes a scrubber for clay and oversize removal, coarse gold gravity separation via an inline pressure jig and an inline spinner; and fine gold gravity separation via a Falcon Concentrator. The plant is expected to be operational by late 2010. This is an ABSTRACT ONLY. No paper was prepared for this presentation. 

Aug 1, 2010

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

By Sidney Fischler

Large striation-free single crystals of bismuth have been grown from the melt by rapid freezing. Zone-refined bismuth, together with doping impurities if desired, is placed in a shallow flat-bottomed graphite boat and melted in air with a propane hand torch. The torch is then withdrawn in a manner which causes the melt to freeze direction-ally. Crystallization, which resuires only a few minutes, usually results in the formation of a single crystal even when a seed crystal is not used. Crys -tals of any desired orientation may be grown by using oriented seeds. Undoped crystals grown by this method have residual resistivity ratios greater than 200. THE growth of large single crystals of bismuth by either the Czochralski or horizontal zoning technique is not entirely satisfactory. Specifically, difficulties are encountered in producing single crystals of the required dimensions in all desired orientations, and striations caused by low-angle polysynthetic twins are frequently present in the crystals. In addition, both methods are time-consuming and require special apparatus of some complexity. A simpler method has now been developed for growing large striation-free bismuth single crystals of desired orientation in a short time. Fig. 1 shows a typical setup consisting of a rectangular graphite boat which contains zone-refined bismuth, a 1/8-in.-thick flat quartz plate which covers the entire inner bottom of the boat, and three additional quartz plates about 1/4 in. thick which are used to separate the bismuth from the graphite everywhere except at a small area at the left of the boat. The graphite boat is 1 in. high, and its sides and bottom are about 1/8 in. thick. The quartz plates should be smooth and clean. The graphite boat is heated from the right with a propane torch, as shown in Fig. 1, until the bismuth is completely melted. The melt has the shape of a triangle with a narrow neck at the apex farthest from the torch. The melt is frozen direc-tionally by gradually moving the torch toward the right, away from the boat. The bismuth in contact with the graphite, at the left end of the neck, freezes first. The freezing interface then moves down the neck into the main bulk of material, where it develops a convex shape ideal for the continuation of single-crystal growth. The interface continues to move through the melt until the entire bulk is solid. The entire procedure may be completed, in air, in a matter of minutes. The technique described almost always yields a single crystal whose basal plane is nearly perpendi,cular to the bottom of the graphite boat. In earlier experiments, in which the bottom of the melt was in direct contact with the graphite boat, single crystals were grown with basal planes parallel, perpendicular, or at some intermediate angle to the bottom of the boat. At times the orientation of the bulk of the material differed from the orientation of the material in the narrow neck. In these cases, a nucleation site initiated the growth of a differently oriented crystal, and the thermal conditions favored the new orientation over the initial one. The thermal conditions depend on a number of factors, including the heating technique, the placement, shape, and thickness of the quartz plates, the thickness of the walls and bottom of the graphite boat, and the quantity of bulk bismuth employed. All of these factors, plus the initial orientation and the presence and effectiveness of nucleation sites, will determine the orientation of the final large single-crystal slab. When a crystal of specific orientation is desired, an oriented section of a rapid-freeze crystal is shaped by spark cutting and grinding for use as a seed. To grow a doped crystal, the desired impurity is placed in the graphite boat together with the bismuth chunks and seed. Crystals doped with mercury, cadmium, lead, and selenium have been grown. The rate of freezing is so great that the distribution coefficient of any impurity approximates unity. On a gross scale, therefore, impurities should be more homogeneously distributed in rapid-freeze crystals than in Czochralski or zoned crystals. Because of the possibility of constitutional supercooling, however, it is quite possible that impurities are not homogeneously distributed on a microscopic scale in the rapid-freeze crystals. Generally the single crystal slabs which have been prepared are initially 5 to 7 mm thick. Thicker crystals may be obtained by using one of these slabs as a seed. The slab is placed in a graphite boat resting on a large aluminum block, either air- or

Jan 1, 1964

By V. Steve Reed, Ed L. Reed

The in situ leach mining process generates a waste stream that is high in sulfates, total dissolved solids, and radium 226. During the mining phase, the volume of the waste stream is relatively low and consists primarily of the bleed stream. During the restoration phase, larger volumes of waste water are generated. These waste streams require environrnentally sound disposal. The low net evaporation rate in the Coastal Bend area precludes pond evaporation as a feasible disposal alternative. Reverse osmosis is a practical method of reducing the volume of the waste water handled, but the concentrated waste stream from the reverse osmosis unit must be disposed properly. Deep well injection into highly saline reservoirs is considered a sound method of disposing of the liquid waste generated by in situ mining in the Gulf Coast uranium district. Thirteen injection wells have been permitted to serve the disposal needs of the leach mining industry in Texas. Of these 13, 11 have actually been drilled. Seven applications are pending. The injection zones for the permitted wells range from depths of 3050 to 6200 feet. Pressure limitations imposed on these wells range from 500 psi to 1350 psi. The following criteria are used to determine the desirability of a disposal well site: 1. A minimal number of nearby, improperly plugged borings which penetrate the disposal zone; 2. Minimal crustal disturbance; 3. Sufficient salinity of the water contained in the disposal zone; 4. Protection of oil and gas producing zones; and 5. Sand of sufficient permeability and areal extent to handle the desired volume without fracturing the reservoir. 1. Improperly plugged borings: During the early part of the century, oil wells, gas wells and test holes were drilled using cable tool equipment, often with a minimum amount of surface casing. Production casing, when it was set, was often partly removed when the holes were abandoned. Thus, wells drilled prior to 1940 frequently have less than 100 feet of surface casing and either no production casing or the upper part of the production casing removed. Additionally, these holes are often plugged only with mud. The close proximity of these holes to an injection well location are a concern in that they can provide an avenue for injection-depth fluids to migrate up the bore hole and jeopardize shallower fresh water reservoirs. Usually, where there are more than 6 or 8 poorly plugged borings in a 2 1/2 mile radius of the well site, it is preferable to examine deeper zones for disposal well potential. The deeper zones are especially attractive where the borings are not in a cluster, which renders monitoring more difficult. Often, even the deeper disposal zones are penetrated by a few improperly plugged borings. When this condition arises, the potential for leakage through the borings can be addressed in the following ways. a. Demonstration that the static head in the boring is higher than the anticipated increase in bottom hole pressure generated at the boring by the disposal well. A 100 psi differential between these two pressures is recommended. The calculated increased pressure at a boring caused by injection should be refined using annual bottom hole pressure measurements in the disposal well. Figure 1 illustrates an injection pressure map which can be overlain on the oil well map to determine the anticipated increase in pressure expected at each oil, gas or abandoned hole. b. Shallow ground water monitoring. A shallow monitor well is drilled next to the boring and both pressure and quality measurements are made periodically in the shallow well. c. Disposal zone monitoring. Recently there has been a tendency for regulators to require disposal depth monitor wells instead of shallow well monitoring. We consider disposal depth monitoring to be a less effective method of monitoring because it provides only indirect evidence of potential problems. Assumptions have to be made for the unplugged borings, such as mud weight, that are not addressed by the disposal zone monitoring program. There is little improvement with this system to that discussed in "a" above. A shallow zone monitoring program, however, yields direct evidence of a developing problem with an unplugged boring. Leakage by the boring will be detected quickly by an abnormal increase in pressure in the shallow well. Quality monitoring will detect upward migration of poor quality fluids. The pressure data provide an early warning of impending leakage; the quality monitoring will detect actual fluid migration.

Jan 1, 1980

By Robert M. Owen

The rare earth elements (REE1s; atomic number 57 -71) exhibit a coherent chemistry, are widespread in nature, and tend to occur in characteristic concentrations in different geochemical phases. Because of their predictable chemistry, the REE's-are highly useful as indicators or tracers of geochemical processes, and are often used as such in investigations of the genesis of terrestrial ore deposits. However, analogous applications of the REE's to the study of marine mineral deposits have been constrained by our limited understanding of the marine geochemical cycle of these elements. For example, a continuing area of uncertainty in this regard involves the so-called "REE Mass Balance Problem." This problem refers to the fact that detailed geochemical mass balance calculations typically predict a significant imbalance for the REE's; i.e., the calculations predict that REE removal rates from seawater are 11-18 times greater than their input rates. Yet all other chemical considerations indicate that the REE budget should be roughly in balance. Recent studies at The University of Michigan suggest the solution to this problem lies in understanding the the role of seafloor hydrothermal activity in the marine budget of the REE's. Geochemical analyses of hydrothermal sediments from two Pacific sites (East pacific Rise at 19°s and the Southern Juan de Fuca Ridge at 45°N) clearly show that the REE component of hydrothermal sediments is primarily acquired via scavenging from seawater. Iron oxyhydroxides, which form as precipitates when hydrothermal solutions are debouched onto the seafloor, are the active scavenging agent. Although the REE content of hydrothermal sediments generally increases with increasing distance from the rise crest, this increase is especially pronounced for sediments deposited below the lysocline,

Jan 1, 1989

By G Byrne, A Bowden

There is often a difference in opinion about the allocation of risk in the establishment of mine closure bonds or financial assurances. From the State’s perspective, protection is needed to ensure that the broader community is not left with the liability of properly closing a mine in the event of a default by the mine operator. Such a default might occur where an operator decides to abandon a site, perform incomplete rehabilitation, becomes insolvent or claims limited liability. On the other hand, mine operators who can demonstrate a strong financial position plus a record of social and environmental commitment and performance, argue that there should be some recognition of this in setting a bond that is less than the full cost of early closure. They argue that a mine rehabilitation bond based on the full cost of early closure is overly conservative and ignores the actual risk of the operator being in default. This paper examines an approach that incorporates the risk of default into the establishment of mine closure and rehabilitation bonds. CITATION:Bowden, A and Byrne, G, 2018. Mine closure bonds (financial assurances) – the ‘how much?’ conundrum, in Proceedings Life-of-Mine 2018, pp 32–34 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By B. K. Sternberg

Since 1986, we have developed a series of electromagnetic (EM) sounding systems at the Laboratory for Advanced Subsurface Imaging (LASI). These may be categorized by their frequency ranges: low frequency (LF, 30 Hz to 30 kHz), medium frequency (MF, 1 kHz to 1 MHz), and high frequency (HF, 30 kHz to 30 MHz). We have applied these EM systems to a variety of targets, including: mapping of plumes of contaminated groundwater, tracing leachate for an in-situ leaching operation, locating buried hazardous waste, identifying subsidence-prone zones and detecting buried voids. These systems are also applicable to exploration for ore bodies. Currently, our sounding system uses a vertical magnetic field vector. Previous systems of this type required a slow and relatively inaccurate manual rotation of the sensing coils. The systems also used occasional calibrations of the measuring system. We have developed a 3-dimensional mathematical rotation procedure for the data, as well as a simultaneous, high-accuracy, calibration method. These new developments have greatly increased the speed of the measurements, as well as improving the accuracy of the ellipticity data. We use stepped-frequency measurements along with narrow-band filtering to allow accurate measurements, even in high-noise areas. We typically obtain ellipticity measurements at eleven frequencies and along densely sampled profile lines. We use neural networks to help interpret the measured ellipticity patterns. Neural networks can be trained to relate the measured ellipticity patterns to earth resistivities or to discrete targets buried in the earth. The neural network training may use theoretical EM responses calculated from computer codes for relatively simple structures. The theoretical EM response for many complex targets that are of interest cannot currently be reliably calculated, even with the largest supercomputers available. We have therefore chosen to do some of the training using theoretical EM responses generated in a full-scale modeling tank located at our Avra Valley Geophysical Test Site. We have also developed data-visualization software to help interpret the large data sets produced by this system.

Jan 1, 1997

By WM. P. BLAKE

THE salt-beds at Salton, on the line of the Southern Pacific railway, in San Diego county, California, have been successfully worked for many years by the corporation known as the East Liverpool Salt Co., and the salt has been largely used upon the Pacific coast generally and in the interior. But the industry has lately been destroyed by the overflow from the Colorado river. The salt is dissolved, and the waves of the Salton sea now roll 50 ft. above the site of this once thriving and growing business. The salt-bed was evidently the residual accumulation from the waters of an ancient lake, which I have named Cahuilla, from the name by which a large part of the valley-the home of the Cahuilla tribe of Indians-is known. The deposit covered a comparatively small area in the lowest part of the valley, 280 ft. or more below the sea-level. This depressed area is now generally known as the Colorado desert, but has a soil of wonderful fertility wherever water can be had on its surface. The deserted beaches, and the water-lines, only a few feet above tide-level, upon the rocks of the bordering mountains, as well as a great abundance of shells in the soil, all bear decisive testimony to the former occupation of the valley by water. The depression is topographically the northern end of the Gulf of California, from which it is now separated by the delta of the Colorado river, extending practically from the mouth of the Gila river across the valley to the coast mountains on the west side. We may conclude that the imprisoned salt water was gradually displaced and freshened by the inflow and outflow of the river, so that the lake was changed to fresh or brackish water, with enough salt in it to give a bed at the bottom upon

Jan 1, 1908

1. Domestic Production and Use: Twelve companies operated 31 primary aluminum reduction plants, three firms accounting for 66% of production. Washington, Oregon, and Montana accounted for 32% of the total production; Gulf Coast States, 25%; Northern States, 29%; and other Southern States, 14%. Output of primary metal in 1973 was valued at $2.2 billion. About 80% of the secondary recovery was from new aluminum base scrap and 20% was from old scrap. Aluminum consumption by 25,000 firms was centered in the East Central United States. Of aluminum consuming industries in 1972, building accounted for 28%; transportation 19%; electrical, 13%; packaging, 16%; and consumer durab1es, 10%.

Jan 1, 1974

By Wallace W. Key

Mineral raw materials produced in California, other States, and foreign countries were purchased for consumption in quantities valued at over $60 million at 800 of the 1,200 chemical plants operating in California in 1960, according to questionnaires completed by company officials. These and other data received from mineral consumers, producers, dealers, and Government agencies formed the basis for this the first of a series of reports designed to present the intricate features and relationships controlling mineral raw material supply and demand in California industries. The results of this study indicated certain changes in use patterns of minerals in chemica 1 manufacturing; a shift in requirements from metals to nonmeta ls, from inorganics to organics, from natura 1 to synthet ic materia ls , and from distant to local sources of supply.

Jan 1, 1965

By Joseph H. White

In its investigations looking to the improvement of health condi- tions and the increase of efficiency in the mining industry, the Bureau of Mines, in cooperation with the Bureau of Public Health, is studying sanitary conditions in and about mines with the intent of pointing out how those conditions that are a menace to the health of the miner may be most efficiently removed or remedied. An out- line of sanitary betterment work at mining villages in the Birming- ham district of Alabama has already been published by the bureau," and in this bulletin are presented suggestions on the planning of mining towns and the construction of miners' houses. The bulletin does not pretend to be a treatise on the so-called "housing problem," and mentions sociologic issues only incidentally. It is assumed that the influence of proper shelter on health is understood and that not a lack of appreciation so much as a lack of knowledge of the best remedies is responsible for many of the undesirable conditions that exist at mining towns. The purpose of this bulletin is to supply facts on the building of well-lighted, well- ventilated, warm, attractive, and economical houses for miners, these houses being assumed to be units of an industrial village or town the building and management of which are under the control of a corporation, so that special conditions hold which do not apply to houses built and owned by individual miners. From this it is not to be inferred that the company-controlled town is the best system or the only one in vogue. The discussion of this side of the subject in all its phases is too involved to be included in this paper. One element in favor of the company-controlled town is its possible immediate responsiveness. Hence this assumption. Also the assumption is made that a-new isolated town is being built, and hence the selection of the site, the arrangement of the streets, and the situation of the houses are discussed before the house itself is treated, for one of the most important factors in obtaining an economical sanitary house is a well-selected town site. Many of the suggestions, however, may be applied in improving conditions in existing towns, in building new houses in old towns, or in repairing old houses. Emphasis must be laid on the fact that as a rule a mining village has a shorter life than a manufacturing town. Economy is emphasized frequently because the discussion is predi- cated upon the assumption that the miner himself is to pay for all that he gets. House rent will doubtless be expected to bring in a reasonable return on all money invested in streets, sidewalks, water supply, sewer system, and houses; in other words, the town is to be run on a business and not on a paternal or charitable basis. "Fair and reasonable" precludes, of course, the idea of excessive returns. Some companies do not consider it good policy to realize as high a rate of interest as an independent realty company would be war- ranted in realizing. Under some circumstances part of the town improvements might be charged as "expense of the industry," that is, to the consumer. The isolation of a mining town introduces a unique responsibility. As the miners are practically obliged to rent the company houses, the officials of the company ought to scrutinize all expenditures in- volved so that house rent may be reduced to a minimum. In a way the town builders are placed in the position of trustees. They deter- mine, within certain limits, what proportion of a man's wages shall be spent on house rent. This consideration should restrain fanciful and unnecessarily expensive building; the other extreme should like- wise be avoided. True economy should be distinguished from cheap- ness. Ugly, insanitary, uncomfortable shacks should not be built even if, because of their cheapness, there is a demand for them from tenants. The obligation of the industry to society as a whole as well us to the tenant ought to forbid this. A cheerful, strong, healthy, virile race will not rise out of the filth and squalor of cheap hovels. An insanitary environment often does its damage slowly and silently; vitiated air does not, like mine gas, announce its deadly work by an explosion. As Talbot⚫ says: Health depends in part on freedom from infection. The probability of obtain- ing that freedom will be greatly increased by maintaining the body at a high state of vigor, or "vitality," as it is popularly called. This implies the promo- tion of all agencies which have to do with the physical well-being as well as with the control of sources of infection. Many men realize that in building houses for their workmen they are invested with a peculiar responsibility that must be wielded wisely, and in large developments they call into consultation the land- scape architect, the sanitary engineer, and the building architect, as well as the mining engineer.

Jan 1, 1914

By Ralph P. Hackl

Ore at the Congress gold property, located near Goldbridge, British Columbia, is extremely refractory with most of the gold disseminated in fine-grained arsenopyrite. Metallurgical testwork conducted by Giant Bay Biotech Inc. indicated that biooxidation pretreatment was capable of increasing cyanide gold recovery from the ore to greater than 90%. To determine if the bioleach process could be successfully scaled up, a 225m' (7950-cu ft) commercial size bioleach reactor was built and tested at the mine site in 1989. At that time, the tank was the largest bioleach reactor ever operated. The objectives of the program were: • to ascertain if the biooxidation rates obtained in lab and pilot-scale reactors could be duplicated in a commercial scale tank; • to identify agitation conditions under which the process will function optimally; and • to demonstrate the bioleach process on a scale sufficient to satisfy the owners and potential investors.

Jan 1, 1990

By GA Harrison

The introduction of Extra Low Profile (XLP) mechanised equipment within Anglo Platinum is aligned with the overall New Mining Technologies strategy to focus on continuing modernization of our mining operations to achieve injury free sustainable production and cost effective mining technologies. The method allows for the introduction of a suite of XLP and Low Profile (LP) equipment in a narrow reef (1,2m) mining environment. For the first time it is now possible to achieve total trackless mechanisation at these stoping widths and XLP Breast mining has the potential to add more value when benchmarked with conventional mining and other mechanised methods. Various types of XLP equipment were tested at different sites within Anglo Platinum and this paper describes the XLP equipment evolution to-date. It concludes with recommendations on our future strategy regarding implementation and roll out of the XLP technology within Anglo Platinum.

Jan 1, 2008

By K. Meyer, M. E. Goddfellow

"At Teck-Corona Operating Corporation's David Bell Mine, a water quality management strategy is employed to produce both a chemically and biologically clean effluent prior to discharge to the environment.The strategy includes operating methods to minimize contaminants leaving the concentrator and an effluent treatment plant for cyanide, antimony, and heavy metal removal of concentrator, mine and site waste streams.Concentrator practices, the effluent treatment plant, process chemistry and the present day performance of the water quality management strategy are reviewed.INTRODUCTIONThe David Bell Mine is located in the Hernia gold camp 35 km east of Marathon, Ontario. The concentrator has a design throughput of 1,000 tonnes per day. ROM ore (-6"") is ground in a semi-autogenous mill followed by a ball mill, thickener, leaching, and carbon-in-pulp gold recovery unit operations. The concentrator flow sheet is shown in Figure 1."

Jan 1, 1991

"Industry Guide 7 contains the Securities and Exchange Commission’s basic mining disclosure policy. It provides guidance for Registrants on various matters including the definition and disclosure of proven and probable reserves and the definitions of exploration, development and production stages. The definitions and disclosure instructions contained in this Guide apply to all public mining entities and their public disclosures. As NI 43-101 is law in Canada, the SEC allows mineral resources and mineral reserves prepared under CIM Definition Standards for issuers that are reporting in Canada but are also registered with the SEC. The SEC places conditions on the disclosure of these estimates. US shareholders are cautioned that the requirements under NI 43-101 and the CIM Definition Standards differ significantly from those of Industry Guide 7.Note: this Guide contains the Commission's basic mining disclosure policy. The definitions and disclosure instructions contained in this Guide apply to all public mining entities and their public disclosures pursuant to the rules of Regulation S-K. Questions regarding the application of these definitions and rules to specific situations should be asked of the Commission's mining engineers or geologists at either the Office of Engineering, Division of Corporation Finance, 202-272-3252, or the Branch of Geology, Central Regional Office, 303-844-1000.(a) Definitions. The following definitions apply to registrants engaged or to be engaged in significant mining operations:(1) Reserve. That part of a mineral deposit which could be economically and legally extracted or produced at the time of the reserve determination.Note: Reserves are customarily stated in terms of DoreD when dealing with metalliferous minerals; when other materials such as coal, oil shale, tar, sands, limestone, etc. are involved, an appropriate term such as Drecoverable coalD may be substituted.(2) Proven (Measured) Reserves. Reserves for which (a) quantity is computed from dimensions revealed in outcrops, trenches, workings or drill holes, grade and/or quality are computed from the results of detailed sampling and (b) the sites for inspection, sampling and measurement are spaced so closely and the geologic character is so well defined that size, shape, depth and mineral content of reserves are well- established.(3) Probable (Indicated) Reserves. Reserves for which quantity and grade and/or quality are computed from information similar to that used for proven (measured) reserves, but the sites for inspection, sampling, and measurement are farther apart or are otherwise less adequately spaced. The degree of assurance, although lower than that for proven (measured) reserves, is high enough to assume continuity between points of observation.(4)(i) Exploration StageDincludes all issuers engaged in the search for mineral deposit (reserves) which are not in either the development or production stage."

Jan 1, 2003

By D. L. Albright, G. A. Colligan

An investigation has been conducted to determine the nature of the crystallographic substructure of nickel and a 1.0 wt pct Ag-Ni alloy which had been undercooled 105°C prior to solidification. A rotating back-reflection X-ray technique and modified Weissmann diffractometer were used to orient single-crystal sections from these poly-crystalline ingots and to determine the substruc-tural features of these single crystals, The sub-grain size in the pure nickel ingot is 0.5 mm diam while the silver-doped nickel subgrain size is only 0.1 mm diam. The misorientation between adjacent subgrains is approximately 1 deg of arc in both ingots, and the spread of orientation of sub-grains about the mean orientation of the crystal is 5 deg of arc in both ingots. The addition of silver results in a stable impurity substructure which is preserved during isothermal solidification and subsequent cooling to room temperature. In the absence of silver the initial impurity substructure is destroyed by dislocation interactions which produce a secondary substructure which grows to a size five times larger than the initial substructure. THE process of undercooling a metal entails cooling of the molten sample below the equilibrium freezing point without the occurrence of solidification, i.e., by exercising proper constraint over the experimental variables contributing to nucleation in the melt. The current work of walker1 and Colligan Metal reports undercooling large continuous samples of nickel by imposing appropriate restrictions upon the parameters of solidification. The silver-nickel equilibrium diagram3 reveals the presence of a monotectic reaction at 1435°C. At this temperature the maximum solid solubility of silver in nickel is approximately 3 wt pct, but this solubility decreases with decreasing temperature and the solute is rejected as a silver-rich liquid phase at temperatures below 1435°C. Thus, the 1.0 wt pct solute should be held in solution during undercooling and solidification and subsequently precipitate as a silver-rich liquid phase at grain and subgrain boundaries following solidification during cooling below 1435. This assumes no solute segregation sufficient to cause the monotectic reaction. One would expect this second phase to inhibit grain and subgrain growth by retarding dislocation motion after solidification is complete. The effectiveness of silver addition in growth retardation of high-angle grain boundaries has been demonstrated by Colligan and suprenantS4 The principal [l00] dendrite growth directions in a 2 wt pct Ag-Ni alloy undercooled 53 all radiated from the nucleation site. A similar pure nickel ingot undercooled 59°C exhibited a random orientation of [l00] dendrite directions with respect to the nucleation site. Since undoped nickel ingots do not retain any evidence of the casting or solidification texture and silver-doped ingots do retain this texture, it is reasonable to assume that considerable grain growth has taken place in the pure nickel. These particular experiments were performed in order to reveal the differences, if any, in the features of the crystallographic substructure of undoped undercooled nickel and silver-doped undercooled nickel. 1) EXPERIMENTAL PROCEDURE Data are reported on selected specimens from two massive (approximately 260 g) undercooled ingots of nickel. One ingot consisted of electrolytic nickel and the other of this same material with 1.0 wt pct addition of high-purity silver. Powder patterns were taken of both the as-received and as-solidified materials; in all cases the reflections recorded were attributable to the individual elements nickel and/or silver. Fig. 1 is a. schematic diagram of the apparatus employed for the undercooling experiments. The equipment consists in part of a fused silica crucible for containing the charge. A fused silica tube encloses the system, which is covered by a brass cap to permit partial sealing of the inert atmosphere. This cap contains a hole through which a Pt-Pt 13 pct Rh thermocouple is inserted for temperature measurement. The charge is inductively heated under a purified argon atmosphere.

Jan 1, 1963

By V. Králová

The TESCAN Integrated Mineral Analyzer (TIMA), an automated mineralogy system, enables fast and quantitative mineral analyses of rocks, ores, concentrates, tailings, leach residues or smelter products. It combines BSE and EDX analysis for identification and measurement of mineral concentrations, particle size distribution, and liberation/locking parameters. In addition, it can provide bright particle searches for PGM, gold-silver ores, and/or REE. With the newly developed Automated Loading System (AutoLoader), the TIMA has become the world?s first automated mineral analyzer which permits robust, continuous and unattended sample loading. With the AutoLoader (robotics) system, the TIMA has emerged as a powerful plant support instrument. It increases the sample throughput, minimizes manual labor and enables 24/7 operations. As such, it can be used in daily, continuous mineralogy for mine geology/ore control, concentrators, leach operations, and smelter support. It will also increase the capabilities of technical service centers for mining companies, commercial laboratories, large drilling programs or pilot test campaigns. In combination with a highly automated sample preparation lab (sizing, potting and polishing), TIMA technology can establish high-throughput and fast-turnaround automated mineralogy lab modules for mine-site production support.

Feb 23, 2014

By George B. Griswold

The two most stringent parameters for in place fracturing of rock are the lack of any initial void space in the rock which to expand into and the ability to gain access only through drill holes. These two restrictions have proven so severe that as of today the only proven techniques for efficient fracturing are the contained nuclear detonation and hydrofracing. Both of these methods have highly developed technologies for their application. Hydrofracing has been a standard oil field practice for two decades, and the experience gained from a couple hundred underground nuclear detonations has resulted in a thorough understanding of the phenomenology of cavity and chimney formation. What is still lacking is a practical method to create a suit- able degree of fracturing for those ore bodies which do not meet the application criteria for either the nuclear explosion or hydrofracing. Nuclear applications must be restricted to thick ore deposits so as to take advantage of chimney collapse height--preferable in excess of 200 feet thick. Other requirements such as ground shock, containment, and radioactive contamination further reduce the number of sites that prudently can be selected.

Jan 1, 1969