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By I. K. Kapageridis

Environmental management and planning requires the integration of large volumes of disparate information from many sources and the analysis of this information with efficient tools for assessment and evaluation. Effective methods of communication that allow interactive participation in the planning, assessment and decision-making processes are also very important. The VULCAN software package from Maptek (Pty) Ltd comprises a large number of 3D graphical tools within an interactive 3D interface called ENVISAGE. These tools are designed and developed to help engineers and scientists to identify and solve environmental problems. The combination of VULCAN 3D Software and the I-SiTE 3D Laser Imaging system leads to powerful solutions for environmental management. This paper presents the capabilities of this integrated system and its applications for environmental management.

Jan 1, 2002

By Y. C. Kim

Three rock fracture parameters define three points along empirical cumulative size (of rock fragments) distribution curves at Inspiration copper mine. These parameters are: rock quality designation (RQD), longest piece of intact rock and % of +1 inch. The RQD and the longest piece are actually measured on drill hole cores whereas % of +1 inch is visually estimated on the same cores. These size distribution curves are then utilized in a variety of engineering applications such as; slope instability analysis, blast design, copper recovery prediction from heap leaching, etc. The three rock fracture parameters for two dominant rock types (porphyry and schist) in the pit had to be estimated separately due to different rock fracture characteristics.' Both ordinary kriging (OK) with measured hard data only and soft kriging (SFTK) with hard and soft data were used to estimate each parameter. The cross validation of 100 measured sample values served as the-basis for evaluating the potential benefits of SFTK over OK. Use of subjective information during SFTK required obtaining (prior) probability distributions for all three rock fracture parameters. These distributions were obtained from the typical rock fracture parameters observed in drill hole cores falling inside the geologically interpreted structural domains with varying degrees. of fracture intensity and also through direct mapping along the exposed bench faces. Two different types of soft information were developed for this study; namely, Type "A" and Type "K". The former is based on sample distribution of fracture parameters whereas the latter is based on two step estimation designed to narrow the range of variation observed in data Type "A". The results of the cross validation were analyzed using a linear regression of actual values versus estimated values. The results confirm an improvement on the estimates made by SFTK with hard and. both types of soft data over those produced by OK with hard data only.

Jan 1, 1989

By M. J. Friedel

The scale-dependent hydraulic properties in a fractured porphyry copper oxide deposit are investigated for relevance to In Situ Leach Mining (ISLM) design. In most well field designs, mine operators assume that hydraulic properties represent a continuous spatial function, or continuum. The problem, however, is that the representative elemental volume, the volume over which hydraulic properties are described as a continuum, is a domain (if it exists) that occurs between end members representing varying degrees of heterogeneity. At the Cyprus Casa Grande mine, transmissivity fluctuations are spatially correlated. This suggests that, at the scale of ISLM, the hydraulic process is heterogeneous, and a typical continuum representation is inappropriate for design. Alternatively, a conditional stochastic approach using the Simulated Annealing (SA) technique is deemed useful for the imaging of heterogeneous hydraulic properties. Specifically, SA preserves transmissivity extremes and spatial complexity, both necessary for accurate conditioning of a flow simulator. Also, the stochastic continuum approach provides an avenue whereby uncertainty (or risk) may be addressed. Currently, the SA weaknesses are that it is computationally time consuming and that uncertainty may increase when simulating under conditions of statistical isotropy. Recognizing that ISLM exerts a dynamic influence on hydraulic properties with time, the mine design should be re-evaluated at intervals throughout the evolution of the leaching process.

Jan 1, 1994

By John W. Wilson

Every operation connected with the working of a deep-level mine has, to a greater or lesser extent, a direct bearing on the costs of production, and hence, profitability of the mine. If adequate mine planning is not done in the early stages in the life of a mine, considerable expenditure can result from the cost of maintaining mine service tunnels, production delays in stopes caused by poor strata control, distortion of fittings in hoisting shafts, rockbursts and so on. In fact, the optimum profitability of a deep-level, hard-rock mine can only be achieved if the layout of the shaft systems, ore passes, tunnels, stoping areas and other underground excavations are designed to withstand or accommodate the rock stress conditions that will be created by mining operations. In South Africa where the deepest mines in the world are located, access to the underground workings of most deep-level gold mines is via vertical shaft systems and a network of tunnels connecting the shaft systems to the stoping areas. In current practice, there are two basic methods of extracting the gold-bearing reef,* namely, the scattered stoping method and the longwall stoping method. The choice of the stoping method is governed largely by the anticipated gold distribution and payability of the reef in the area, the geological conditions, the degree and complexity of faulting and dyke intrusions, the depth at which the gold-bearing reef is to be mined and the inclination and width of the reef. The longwall system was first introduced at the East 717 Rand Proprietary Mines Limited in 1942 in an effort to combat the rockburst hazard which appeared to increase with increase in depth. This mining method became standard practice on that mine for stoping operations 700 ft. below the surface. Since that date, several deep mines on the Central Rand, East Rand and West Wits gold mining areas have adopted this method.

Jan 1, 1977

By R. L. McNearny, K. A. Barker

Four numerical models written with the "PFC2D " program were compared against four similar physical models. The numerical models were constrained numerically to closely follow the caving behavior of the physical models. Results from the numerical analyses closely simulated both the granular and blocky behaviors of the physical models, including bridging and interlocking of the simulated orebody during draw. The drawdown patterns and the rate of draw developed during numerical modeling also closely simulated the physical models. The same assumptions and governing parameters used in analyzing the first four models were applied to an additional model. The fifth model employed a completely different, uneven, draw sequence than the other four models, allowing the material to flow in a more granular manner with a demonstrated instability of the undercut sections between each drawpoint opening. Drawdown patterns and behavior of the numerical material of the first four models progressed at uneven and inconsistent rates, similar to those seen in the physical models. By inspection, the overall shape and flow lines of both the numerical and physical models were close in the area removed and in the flow characteristics. The fifth model proved to be the most unstable of all the models tested, with poor correlation to the physical models. The uneven draw sequence, coupled with an additional frictionless wall condition and an added drawpoint, caused the material to flow in a very granular manner. Information generated by this study can be used as a first approach in determining the proper draw rate, drawpoint spacing and undercut thickness for a block-caving operation. Numerical models are often difficult to predict and interpret. However, this study should increase the confidence level for use of the PFC2D program in the future.

Jan 1, 2000

By H Sohn, R. R. Fernández

Microscopic gold inclusions in sulfide minerals cannot typically be extracted by conventional cyanidation. The gold ore must be pretreated to oxidize sulfide minerals associated with gold and to remove other minerals and chemical compounds that interfere in the cyanidation leaching process. The recovery of gold from refractory sulfidic-carbonaceous ores after roasting pretreatment was studied. With the addition of an oxygen-containing gas (e.g., air or oxygen-enriched air), sulfides of iron, zinc. copper and other metals are tramformed into solid oxides or sulfates and gaseous sulfur dioxide at elevated temperatures (e.g., 400° to 800°C). When the sulfides are oxidized, individual particles lose internal volume and become porous, allowing leaching solutions access to the gold. The structural characteristics of the calcine have a strong influence on the eventual recovery of gold by cyanidation. These characteristics are strongly dependent on the roasting conditions and roasting method. The optimum combination of particle size, roasting temperature, reaction time and oxygen concentration in the off-gas was determined for a typical refractory sulfidic-carbonaceous ore from the Carlin Trend in Nevada. The tests were run using a 150-mm laboratory rotating tube furnace and 160- and 200-mm.fluid-bed pilot roasters. Laboratory results indicated that the maximum gold extraction was 92%, with the head and the leach residue containing 5.7 and 0.4 g/t (0.166 and 0.013 oz/st) Au, respectively. The maximum extraction was achieved under the following roasting conditions: a top particle size of 150 yin, a residence time of 2 hrs, a roasting temperature of 475°C and with 40% oxygen (by volume) in the off-gas. Similar results were obtained from circulating fluid bed (CFB) pilot-plant testing. The maximum gold extraction was 90%, with the head and leach residue containing of 5.1 and 0.5 g/t (0. 149 and 0.015 oz/st) Au, respective) v. These results were achieved with the same particle size and oxygen concentration as in the laboratory testing but with the roasting temperature of 500 ° to 525°C and a residence time of 30 min.

Jan 1, 2000

By David Pentz, Paul Hodges

GENERAL INTRODUCTION The object of this paper is to discuss those aspects of open pit mine design which are affected by geotechnical factors. The temptation exists for some practitioners of geotechnical engineering to believe that this relatively new engineering discipline is the ‘be all and end all of mining.’ In the opinion of the authors, this is fallacious but, as our ability to put numbers to the behaviour of rocks and soils improves, it is clear that geotechnical engineering will become an integral and important part of designing and operationg mines success- fully. Open pit mines in the context of this paper also includes open cast mines, where the 'ore" is extracted and the waste material is immediately replaced or ' backfilled in the mined portion of the pit. Open pit mines operating today move from very small tonnages a day to in excess of 400,000 tons per day. Several mines are operating and are being designed to capital expenditure for such projects in some cases exceeds five hundred million dollars and in a few cases will exceed one billion dollars. The size of this investment means that financing will have to be provided from banks or joint partnerships. This financial environment means that planning will be carefully scrutinized by experienced representatives of financial institutions or other mining companies. All too often a project has been put in jeopardy because the personal desire of one or two men to make a project proceed has caused incomplete planning or perhaps in some instances deliberately leading observers 'down the garden path.’ In our opinion the day is rapidly arriving when the quality, logic, practicability and completeness of the planning will make the difference between securing financing or not and, in the cases of existing open pit mines, of the difference between survival and closure.

Jan 1, 1977

By Danny W. Hagood

High methane liberation and mining depth were two major factors which prompted the development of a high- capacity face ventilation system at Jim Walter Re- sources, Inc., No. 4 Mine. No. 4 Mine, one of four deep shaft mines presently under development, is located approximately 50 miles southwest of Birmingham, near Brookwood, Alabama (Figure 1). The coal seams under development are located in the Warrior Coal Field and include both the Blue Creek and Mary Lee Seams, Depth of cover averages 2000 ft. (610 m) with an average total mining height of 8 ft. C2.4 m). [ ] It is generally accepted that the methane content of a particular coal increases as the overburden depth is increased [l] ; experience to date has shown that the gas condition of the No. 4 Mine is no exception to the rule. To further compound the problem, the over- burden depth, coupled with the relatively soft nature of the Blue Creek coal, has resulted in an initial layout based upon 150 x 150 ft (45.7 x 45.7 m) centers. Considering the above-mentioned mining conditions, the means and the effectiveness of the face ventilation system becomes paramount where productivity is concerned.

Jan 1, 1980

By Robert L. Runkel, D. Kirk Nordstrom, James W. Ball

Low-flow reactive-transport processes in Wightman Fork downstream of the Summitville Mine, south-central Colorado were simulated using the OTIS and OTEQ solute-transport models. The simulation was calibrated using data from a synoptic study conducted during October, 1998. Discharge over the 8-km reach from just below the mine site to the Alamosa River confluence ranged from 0.077 to 0.17 m3/s; travel time was 10.7 hours; pH ranged from 4.6 to 5.7. Simulations revealed that mass balance for SO4 was maintained, and that pH, Fe, and Al were non-conservative. Simulations allowing hydrous ferric and aluminum oxide or hydroxysulfate precipitation matched observed water quality conditions more closely than simulations without precipitation.

Jan 1, 2000

By Charles H. Jacoby

In 1960 the management of International Salt Company made the decision that all waste material from the Watkins Glen plant would be stored in underground salt cavities. The cavities which they contemplated using had been depleted of salt to a point where continued operation would have impaired their structural stability. Originally, the waste to be disposed of included vacuum pan bleeds, cinders, contaminated salt and sewage. It was proposed that this material, in a slurry form, was to be injected into the salt cavity through one of the abandoned wells. Brine, displaced from the cavity, was to be recovered from an adjacent well and subsequently injected into the Cherry Valley limestone, This Cherry Valley limestone which underlies a large portion of north central New York contains a connate water with high concentrations of ammonia, hydrogen sulphide and the chlorides of calcium, magnesium and sodium. A number of questions were immediately raised on various aspects of the technical feasibility of the project. Of major concern was the buildup of insolubles adjacent to the bore of the injection well. Another pertinent question was the carryover in the displaced liquor of finely-divided, mechanically-suspended particles. Criticism was leveled at the inclusion of sewage. Engineering studies were started by the company's Mineral & Mines Development Department and on April 3, 1961 a preliminary feasibility report was issued.

Jan 1, 1973

By D. G. Klaren

Self-cleaning fluidized bed heat exchangers are conquering the world for reason that they are able to solve any severe fouling problem in indirect heat transfer due to the circulation of cleaning particles through the tubes of vertical shell and tube exchangers. In most cases, these particles consist of chopped metal wire. Moreover, self-cleaning fluidized bed heat exchangers perform with excellent heat transfer at very low liquid velocities, which enables completely new designs of conventional shell and tube configurations. This article explains the principle and application of this self-cleaning heat exchange technology and also pays attention to an actual case of a revamp of the severely fouling exchangers of a conventional multi-effect evaporator into a self-cleaning configuration. Possibilities for the revamp of conventional exchangers suffering from massive and very hard scale deposits are found in a variety of metallurgical processes, such as: The refining of nickel, the production of alumina from bauxite and many others.

Jan 1, 2003

By J. Fuller, L. Marsden

Windborne dust from alkaline salt flats and mining-related tailings ponds is especially prone to threaten applicable ambient air quality standards. Sodium carbonate crystals, typically present, weather to an exceedingly fine, non-cohesive dust, causing air quality problems for miles downwind. Recently developed specialized polymers react with alkaline dust to form sturdy, wind-resistant crusts with good longevity. An on-going demonstration project at a major trona facility has developed techniques for cost-effective application of these polymers over large areas of soft tailings or sediments in a wide variety of situations. Recently treated areas on the order of 80 acres show effective suppression of dust.

Jan 1, 2004

By E. J. Beckman, R. M. Enick, C. Shi

A novel liquid-liquid separation for the recovery of free or liberated gold from mixtures of fine particles was evaluated. Two inexpensive and environmentally benign fluids were selected for the study, water and carbon dioxide. The separation, which is conducted at 295 K and at the vapor pressure of carbon dioxide (6.0 MPa), is based on differences in wettability between the precious metals and other minerals. Contact-angle results indicated that, in the presence of water and liquid CO2, gold is slightly hydrophobic. The addition of CO2-soluble fluoroalkyl thiols or f uoroetherthiols increased the hydrophobicity of gold exposed to water and CO2 to a greater extent than alkylthiols. Minerals, including quartz, pyrite and magnetite, were hydrophilic. During the separation, an aqueous slurry of fine mineral and gold particles was mixed with liquid carbon dioxide. Pure gold particles (-325 mesh) were found to agglomerate at the H2O-CO2 interface. The minerals tended to remain in the aqueous phase. Despite these promising preliminary results, very poor gold recoveries were obtained when applying the procedure to an Australian gravity concentrate. This was attributed to the native gold particles in the concentrate being either too large, agglomerated in slimes or coated with minerals. Although this particular application was unsuccessful, this water-CO2 biphase technique may be applicable for other separations that require the removal of very fine, hydrophobic particles from an aqueous slurry.

Jan 1, 2000

By John W. Rozelle, David S. Bolin

INTRODUCTION During the normal course of a mining project, a feasibility study will be prepared that addresses all the aspects of the project including geology and mineral inventories, mining and geo- technical, metallurgical processing, infrastructure, environmental considerations and economic analyses. These studies are prepared for various reasons. Occasionally, a feasibility study will be prepared solely for use within a company as justification for development expenditures, however, these documents are frequently submitted outside the company either to raise funds from financial institutions or from public financing on one of the various securities exchanges. Mineral industry consultants are often called upon to participate in the preparation of feasibility studies or to conduct an independent audit and review of an internally prepared study. As the recoverable mineral resources form the foundation upon which the balance of a feasibility study is based, including the economic analysis of the project, the resource aspect of the study is examined very carefully by financial and securities organizations. The balance of this discussion is directed toward the various geological and resource estimation aspects of feasibility studies that experience has shown to be of particular importance. Much of this discussion will be directed toward open pit gold operations, although the principles are applicable to any type of deposit. 2.0 GEOLOGIC RESPONSIBILITIES IN FEASIBILITY STUDIES The principal geological effort in the preparation of a feasibility study is generally dedicated to the following areas: - Preparation of Geologic Reserve/Resource Estimates - Condemnation of Sites for Facilities, Access Roads, Leach Pads, Waste Dumps and Tailings Disposal - Collection of Geotechnical Data - Provision of Mineralogical and Petrological Data Pertinent to Metallurgical Processing - Selection of Appropriate Bulk Sampling Sites for Collection of Metallurgical Samples Each of these items will be addressed in detail in the following sections. 3.0 RESERVE/RESOURCE ESTIMATION An ore reserve estimate consists of the determination of a volume, or tonnage, and a grade for the deposit. There are numerous cases in the mining industry of projects that have experienced severe difficulties when operational ore grade, tonnage or metallurgical amenability have proven to be deficient compared to predicted estimates. An error in estimation of tonnage generally leads to more long term problems affecting mine life and production schedules. However, a significant error in the estimation of grade, particularly if mined grade is lower than anticipated, can have an immediate, and often disastrous, effect upon a project. The geologic preparation leading to an ore reserve estimate generally follows a logical sequence familiar to

Jan 1, 1987

By Erkan Bozkurtoglu

The most important difference between weathering and alteration, which are the definition of the change in rocks that occur with the help of physical and chemical effects, is a new product is formed as a result of alteration. Although atmospherical conditions are the most important factor during rock change, geothermal fields play a large role in the developing of alteration phenomenon. Because every geothermal system shows different characteristics including the chemistry of geothermal fluids and their potential applications, alteration on the field is important for the studies to find geothermal energy sources and to obtain the thermal fluids. The development of weathering and alteration which is the mark of interaction , between the physical and chemical properties of geothermal fluids and gases with the reservoir and wall rock, gives out important data about the hydrogeology, hydrology, reservoir conditions and characteristics of reservoir rocks of the geothermal field. Therefore defining the development of weathering and alteration phenomenon in a geothermal field and modeling the change in rocks, is very important for the benefication of the geothermal field economically. In this study 70 km2 that reside between Kösedere plains, Uzunburun, Çamtepe, Centirler villages in Çanakkale - Ayvacik - Tuzla geothermal field were studied and subsurface travel of saline thermal fluids and their interaction with the rocks and development of weathering and alteration phenomenon in the field were investigated. For this purpose geological mapping of the field were done and observations and measurements as well as rock sampling were carried in locations more than 220. As the result of petrographical investigations of rock samples development of weathering and alteration phenomenon were defined and 16 rock samples out of 220 that represent the field in general were chosen to be chemically analized and after that geochemical comments on the Tuzla geothermal field were made. Also hydrothermal alteration zones that are located in Tuzla Tepe, on which weathering and alteration phenomenon is observed as widespread and thermal water discharge locations in the near perimeter of Tuzla Tepe were mapped and from these data rock change in Tuzla geothermal field were modeled.

Jan 1, 2005

By Ernst Langer

INTRODUCTION Morro do Niquel is located near the small town of Pratdáolis in the southwest part of the State of Minas Gerais, Brazil, about 300 km in a straight line north of São Paulo and 300 krn west of Belo Horizonte. The deposit is known since 1935. Systematic exploration started, however, only in 1957 and production with one furnace in 1962. Since 1969, after the installation of a second furnace, the mine produces about 2 500 tons of nickel, contained in ferronickel, per year. This production is now consumed totally by the Brazilian steel industry. The "Morro do Niquel" is a serpentinite stock of 900 by 400 m which rises 200 m high above the surrounding metamorphic rocks of Algokian age (see Figure 1). On top of the hill there is a leached barren zone of about 200 by 400 m, generally 20-30 m deep, which consists practically only of a boxwork of quartz colored brown by limonite. Surrounding this zone on the sides of the hill is weathered, decomposed serpentinite which contains about 213 of the economic nickel mineralization. Roughly 113 of the ore reserves lie below the leached overburden representing ore of a different type. The geological map and cross-section, Figure 2, give a clear picture of the occurrence.

Jan 1, 1979

Marble has been recognized as a valuable natural resource ever since ancient times. Due to its peculiar aesthetic and technical characteristics as well as the lithotype uniqueness, it has widely been appreciated over the past centuries. In present times its production and demand are enjoying an increasing trend, with comparatively high market prices. All this considered, marble can be included among these natural resources whose exploitation provided, and still provides, an important contribution to the growth of the economic system. Nevertheless, there is at least one more important reason that makes marble a valued resource. For ages, marble represented one of the most important raw materials for sculpture sand architectural masterpieces, which constitute part of the cultural heritage of mankind. With this in mind, the value of marble is strictly related to its extraordinary capability to preserve cultural heritage and therefore to convey civilization from past to future generations. In other words, the role of marble should be recognized as being of the utmost importance in order to attain an overall objective of ?cultural sustainability?, that is, the assurance of the inter-generational flow of the cultural heritage capital. To achieve this sustainability goal, the priorities should be to protect and preserve the world?s artistic and architectural historical heritage, which require restoration works. In this field, a very il task is entrusted to the extractive industry: this industry, in cooperation with historians, art experts and public authorities, is in charge of detecting and supplying historical stones for restoration purposes, taking into consideration that, in order to restore a monument in a correct way, the same lithotypes the monument was made from are needed. These marbles are often no longer in production, so that it becomes necessary to find the location of the original quarries, as only there is it possible to extract even the small quantities of stones that are needed. In this case, the stone, located in its geological context, could have such valued characteristics as to be considered an important public asset and consequently a resource to be preserved and protected even beyond the market conditions. This important task should be carried out by the public administration through a targeted intervention of territorial planning and monitoring, which could include the support for the specific extractive activity.

Jan 1, 2003

By Samuel M. Cassidy

The exact date of man's first use of coal is lost in antiquity. The discovery that certain black rock would burn was undoubtedly accidental and probably occurred independently and many times in the world over thousands of years. It is quite likely that these independent discoveries were made when primitive man chanced to build camp fires on exposed ledges of a black rock, then was amazed when it caught fire. The Chinese recorded the use of coal 1100 years before the Christian Era and from the Bible we learn that King Solomon was familiar with coal in what is now Syria. In Wales, there .is evidence that the Bronze Age people used coal for funeral pyres, and it is known that the Romans used this fuel. There are other ancient references. So the knowledge that coal would burn, and even some uses of that knowledge, go back thousands of years. However, practical and consistent use of coal seems to date to England in the Middle Ages.

Jan 1, 1981

By Patzen Wu

The Hai-Shan No. 1 Coal Mine, located in northern Taiwan, is one of the typical coal mines on the island which, limited by natural condition, are mostly small in scale. With the advancing longwall method, the mine is now winning a seam, 80 cm thick, at a 32° dip, with a working depth of 824 m below surface. The annual output is about 50,000 mt of clean coal. At the working gallery, the virgin rock temperature may go up to 46°C, difficult to be brought dam to n acceptable level: because .of the tropical climate with high intake temperature and high humidity. Besides, at this depth, the intake air that goes down the long inclined shaft generates considerable heat due to autocompression. The mine is ventilated by a set of axial-flow fan with 38 m3/S of intake air at 2.2 KPA WG. With this volume of air, the temperature at the working-face is usually above 30°C WB. Appreciable lowering of the temperature is not expected even with an increased volume of ventilated air. For this reason, decision has. been made to try the installation of a pilot underground refrigeration unit near. the lowest gate road to cool the intake. air. from 32°C WB to 28°C WB which seems acceptable to on-the-spot workers exerting heavy physical labor. The experimental unit is designed for carrying away a total heat load of 90 Kw. The capacity of the unit is 200 Kw. The unit consists of a compressor, an evaporator, a condensor and a motor. The heat rejection is done in a cooling tower. Chilled water is circulated from the evaporator to the cooler by insulated pipes. The cooler consists of 90 Kw-coils with two fans and forces air by flexible ducting onto the working face. This paper examines mainly the effect of this additional reduction of working temperature, on working efficiency of the workers. Another aspect of this experiment is to evaluate the overall economy of underground refrigeration in small-sized coal mines under tropical condition. The success of such an experiment may lead to wider application of refrigeration to render many of the deeper mines economically workable.

Jan 1, 1980

By D. Piper, J. Noble, M. Richardson, J. Wojcik, L. W. Cope

L. Cope Welcome. I am pleased to see so many people interested enough to stay until this last session of the last afternoon of the convention. Of the people on the panel here, everyone has done everything in placer mining, but we have tried to sectionalize it with each one of us taking a particular portion. Any one of us could probably answer any question. I am very pleased to see some well experienced people in the audience. To start the discussion, Joe, can you give us a brief comparison of pit and drill sampling? J. Wojcik They both have their place. If you expect your deposit is something that is going to have widespread fairly uniform grades, then the pits may be the way to go. If you are going to have something you have to trace for several miles down the river valley, you can't do it with pits and do a proper sampling job. C. McLain Joe, the end result of all of this is to go ahead and mine it if it is a deposit. Do you try to relate your drilling results to something in mining itself against the recovery, because the drilling in different types of ground will give you different kinds of recoveries, and mining in the end is what you are going to do? Do you try to relate this to your mining method?

Jan 1, 1992