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By Ralf Winterberg, Axel G. Nitschke

"Macro synthetic fiber reinforced concrete or shotcrete is seen by many design engineers as offering a viable alternative to steel reinforcement in tunnel linings. The technology is now commonplace for primary and permanent ground support in both mining and civil tunnel applications. It has for instance become the standard form of reinforcement in the Australian mining industry, and has been used for a majority of permanent tunnel linings in recent tunnel construction in Norway. Similarly, macro synthetic fibers are becoming a standard solution for the initial lining in the USA.The use of macro synthetic fiber offers innovative solutions, yielding robust and sustainable tunnel lining designs. Citing recent research and actual projects, this paper presents state-of-the-art design considerations for fiber reinforced tunnel linings relating to structural and long-term performance. Topics include seismic resistance, crack width control, corrosion and durability, as well as sustainment of performance with age.INTRODUCTIONMacro synthetic fiber reinforced concrete (MSFRC) and shotcrete (MSFRS) has reached maturity as an engineered material and is widely used in all forms of tunnel linings, for temporary as well as permanent ground support in both, mining and civil tunnel applications. In the Australian underground mining industry, it became the standard form of reinforcement, where 2014 literally marked the end of steel fiber use in shotcrete [1], and has been used for over 80 percent of permanent tunnel linings in recent tunnel construction in Norway. Similarly, macro synthetic fibers are becoming a standard solution for tunnel initial linings in the USA. Recent examples in civil tunneling are the Devil’s Slide Tunnel and Caldecott Fourth Bore Tunnel in California or the Anacostia River Tunnel Intershaft Connector Tunnel in Washington D.C. In addition, an increasing number of tunnels are adopting shotcrete permanent linings using macro synthetic fibers. Examples include the A3 Hindhead tunnel near Guildford in the UK and the North Strathfield Rail Underpass in Sydney, Australia [2, 3]."

Jan 1, 2016

By Joanna LaForte

"In response to “Arctic Mineral Wealth —Equitable Participation with Aboriginal Landowners – A slow or fast process?”, this author’s impression is one that, to her, seems obvious — this is definitely going to be a slow process. To question this issue seems ridiculous, unless the mining industry is considering following the same patters of the past, thereby adding to the suppression and injustices to which the aboriginals are so accustomed. To make genuine progress, where trust and good communication has been achieved with time as a factor in proceeding, the author feels, without a doubt, that the triangle of industry, government and aboriginals will seriously have to be restructured or eliminated. Anytime you mix government with progress, along with other problems, you are looking at bureaucracy, and that takes time. Issues such as the settlement of land claims have not been resolved, and in all likelihood could take forty years to finalize. Aboriginals have been suppressed for centuries by governments and industries with ethnocentric ideologies, and now that they are in a position to reclaim their lands, attain their own economies and government, and truly secure a wealthy, self-sufficient legacy for their descendants, how can anyone imagine they’ll move quickly? This author also strongly disagrees to some sections of Mr. Wakefeld’s article and will expand on her objections.We question whether aboriginals under-stand the process of mine development. If we encounter an electrical problem in our home, o we not call an electrician without having to learn the trade ourselves? This comparison seems simplistic, but does convey a point. As cited, “there are now over 100 000 aboriginals who have completed post-secondary education.” Are the numbers revealed in Mr. Wakefeld’s paper there to scare us? Is he suggesting that without the industry’s haste, the aboriginal’s new found intelligence could pose a problem to the mineral explorer. While it is true that not all are highly educated, the aboriginals have specialists in market fluctuations, feasibility studies and the needed skills. They have specialists, such as their representative organization of COPE 1984, (the Committee for Original People’s Entitlement), who under-stand their cultures, language and desires. Their education should expedite the negotiations and end the power struggles equitably. Aboriginal people are not stupid. Once they have reason to be proud, regain their communities and know the direction that they’re headed, their self-determination will return."

Jan 1, 1996

By Gisell Sumaria, Mike Martos

La analítica avanzada permite analizar los datos (en tiempo real, históricos, no estructurados, estructurados, cualitativos, cuantitativos, etc.) para identificar patrones, optimizar indicadores, mejorar procesos, generar conocimientos para informar y, en algunos casos, resolver conflictos con una mínima intervención humana, es decir, automatizar decisiones. El proceso analítico ha demostrado ser un excelente aliado para la toma de decisiones, o inclusive, desde el origen hasta la decisión, control y seguimiento de resultados del proceso.

Sep 29, 2023

By Tianzu Yang, Weifeng Liu, Lin Chen, BOYI XIE, DUCHAO ZHANG, HUI XIAO

In this study, the oxygen-rich bath smelting process of copper dross was simulated using Factsage software. It was found that the two-step simulation results agreed better with the industrial data, especially in the speiss. Bismuth (Bi), lead (Pb), antimony (Sb), arsenic (As) and copper (Cu) contents in the speiss by two-step simulation differed from the industrial data by 0.6, 0.8, 2.6, 7.2 and 8.6 weight percent, respectively. The two-step simulation results indicate that the speiss partitioning of Sb, As and Cu increased from 60.1, 32.3 and 27.5 percent to 81.6, 67.8 and 47.2 percent, respectively, with the smelting temperature increasing from 1,050 to 1,250 °C, while the metal partitioning of Sb and Cu increased from 0 and 2.7 percent to 15.2 and 13.3 percent, respectively, with the separation temperature increasing from 400 to 700 °C.

By Gene Asai

Properties obtained for columbium carbide-carbon castings ranging in car-bon content from 12 to 17 weight-percent were compared with those of hot-pressed composites of similar composition. The properties were oxidation resistance in static air between 500° and 700° C, linear thermal expansion between 20° and 2,400° C, electrical resistivity between 20° and 1,500° C; microhardness between 20° and 1,500° C, and modulus of rupture between 1,300° and 1,800° C. CbC-C castings differed markedly from hot-pressed material with respect to microstructure, electrical resistivity, and modulus of rupture, but behaved quite similarly with respect to oxidation resistance, thermal expansion, and hot hardness. In oxidation resistance, thermal expansion, and hot hardness both materials were independent of carbon content. Both castings and hot-pressed composites oxidize rapidly in air above 600° C, have thermal expansion coefficients very similar to columbium metal, and the logarithm of the hardness decreases linearly with increasing temperature. The microstructures of hot-pressed composites contained varying amounts of graphite in a CbC matrix but did not contain significant amounts of a eutectic structure present in all castings, nor did they contain graphite needles which were present in the hypereutectic castings. The higher electrical resistivity of hypereutectic castings over hypereutectic hot pressings was attributed to the presence of highly oriented graphite needles in the castings. The modulus of rupture of castings was 1-1/2 to 2 times that of hot-pressed composites. Both materials displayed bend ductility above 1,800° C.

Jan 1, 1971

"1 INTRODUCTIONThe use of nondestructive testing (NDT) methods to evaluate the integrity of Augered Cast-in-Place (ACIP) and Drilled Displacement (DD) piles has been a subject of significant debate among engineers, contractors and NDT practitioners. This guideline document will illustrate the importance of reviewing all available information in conjunction with the NDT records. ACIP and DD piles have unique properties that must be considered when using a specific NDT method. Any evaluation of the integrity of an ACIP or DD pile must also include a thorough review of the detailed pile installation records and the site specific soil conditions. Long or theoretical descriptions of the methods have not been included in this publication. More detailed information about these NDT methods including their theoretical and historical backgrounds can be found in DFI’s Manual for Non Destructive Testing and Evaluation of Drilled Shafts (2004). Additional information can also be found in the more comprehensive textbook Nondestructive Testing of Deep Foundations by Hertlein and Davis (2006).1.1 PurposeThe intent of this guideline is to provide practical guidance for the proper interpretation of NDT results on ACIP and DD piles. Short descriptions of the main integrity methods available are provided along with several examples of how to use all of the information available to make sound engineering judgments about the results. This publication is a state-of-the-practice guideline to promote accurate engineering evaluations.For engineers inexperienced with NDT, these guidelines provide sufficient background information on NDT methods to help understand the limitations of the testing, assess the results presented to them, and formulate appropriate questions. This is particularly important for engineers charged with the responsibility to determine from those results what, if any, consequences there may be on the performance of the structure under construction."

Jan 1, 2016

By R. Lai

This paper describes the application of a cyclonic flotation column (CFC) for coal cleaning. A CFC makes use of centrifugal force to create a density gradient in a column to augment the froth flotation process. In a CFC, a series of angular helical inserts is attached to the wall of a conventional column and coal slurry is mixed with a series of impellers attached to a central shaft. The hydrophobic froth concentrates near the center shaft and moves upward, while the relatively heavy hydrophilic particles concentrate near the wall and are guided downward by the helical inserts. Results of pyritic sulfur removal from an Upper Freeport coal during CFC flotation are discussed in this paper.

Jan 1, 2000

By K L. Avarmaa, M A. Rhamdhani, A D. P Putera, H T. B M Petrus, G A. Brooks

Multistage slag treatment was carried out to investigate boron removal from metallurgical grade silicon. Boron is known to be one of the most difficult elements to remove from silicon. Depending on boron initial concentration, boron can be removed from silicon into certain level; most previous studies have attained final 50–100 ppmw (parts per million weight) boron in the silicon using slag treatment. The term ‘multistage’ refers to a process where the resulting silicon from the initial slag treatment is further refined multiple times using a new slag. In this study, an initial slag composition of 45CaO-45SiO2-10Al2O3 (wt per cent) was utilised. Using this technique, boron level in the silicon was expected to be gradually lowered because the new slag will always have more capacity to reach the equilibrium distribution coefficient (LB = (ppmwB)slag/(ppmwB)Si). The current study was carried out through combined thermodynamic calculations (using FactSage™ ver 8.2, by Thermfact Ltd, thermochemical package) and high-temperature experimentation. The thermodynamic calculations were carried out for reactions at 1500, 1550, and 1600°C for three different scenarios: 1. Single stage refining with varied slag to Si ratio. 2. Multistage refining with slag to Si ratio of 1:1. 3. Multistage refining with slag to Si ratio of 2:1. The multistage experimental work was carried out at 1550°C under inert gas atmosphere each time for 2 hrs, with slag to Si ratio of 2:1. The simulation results indicate that the boron distribution coefficient stay essentially constant with varying slag to Si ratio and temperature, around 1.8 to 2, and the experimental results measured LB in the same range, between 1.5 and 2.5. By harnessing this feature, the simulation showed that boron can be removed by approximately 78 per cent in each stage. The experimental result confirmed that the boron concentration in the silicon was reduced by a total of 97.8 per cent from its initial value using four stages of slag treatment, from initial 270 ppmw down to 6 ppmw.

Aug 21, 2024

By V. T. McLemore

New Mexico Bureau of Geology and Mineral Resources (NMBGMR) has been collecting data on uranium mining districts, mines and mills since it was created in 1927 and has converted years of historical data into a relational database that can be imported in ArcMap. The database includes information on mining districts, mines, mills and geochemistry, as well as photographs and bibliographic resources. The available data includes location, production, reserves, geologic, geochemical, resource potential and other data. The National Uranium Resource Evaluation (NURE) stream-sediment data provides geochemical analyses for >27,000 samples collected in New Mexico during the 1970s. The NURE hydrogeochemical data provides analyses of water samples. ArcMap includes the location of individual ore bodies as polygons and incorporates the mines and NURE data as individual site locations. The purposes of these databases are to provide computerized data that will aid in identifying and evaluating resource potential, resource development and management, production and possible environmental concerns, such as physical hazards (i.e., hazardous mine openings), indoor radon, regional exposure to radiation from the mines, background geochemical data and point sources of possible pollution in areas of known mineral deposits.

Jan 1, 2010

By Janine Feitosa de Deus

Compósitos ambientalmente corretos, fabricados a partir de fibras naturais lignocelulósicas (FNL), estão entre os mais investigados e aplicados atualmente. Dentre as FNL, destacam-se as fibras de Rami (Boehmeria nivea), que surgem como alternativa em sistemas de blindagens multicamadas, para uso em coletes de proteção balística, por serem leves, de baixo custo, resistentes e ambientalmente corretos. No presente trabalho, investigou-se o comportamento mecânico de compósitos de matriz epóxi reforçados com tecido de rami, através de testes de flexão. Compósitos contendo separadamente 0, 10, 20 e 30% em volume de tecido de rami e resina epóxi, foram fabricados em um molde metálico, sob condições de vácuo. Os corpos de prova fraturados foram analisados em MEV e os resultados foram avaliados visando algumas propriedades de flexão com a incorporação do tecido de rami, visando sua posterior aplicação em blindagem balística.

Oct 30, 2017

By Sonia Güiza González

"El texto describe la aplicación de tres marcas de analizadores portátiles en diversas compañías peruanas, las cuales dan a conocer los alcances analíticos de esta herramienta en creciente auge a nivel mundial. Dicho analizador portátil de fluorescenciade rayos X (AP-FRX) genera resultados químicos de los núcleos de perforación, sin esperar el tiempo que tarda en entregar los resultados un laboratorio químico convencional, así como mapas geoquímicos a la par del desarrollo del trabajo de campo, evalúa prospectos y proyectos de impacto ambiental. "

Jun 1, 2013

By Evans E. C.

At first sight, the extinction of a mine fire by the action of some such gas as carbon dioxide would appear to be quite a simple and practicable operation. From a consideration of the theoretical aspects only of the question, it becomes evident that the matter is not so simple as it appears to be at first sight. The fire at the Senghenydd Colliery occurred as the result of the disastrous explosion of October 14th, 1913. This explosion was confined to the west side of the colliery; and as a result the timbers in the main intake on this side were set on fire; but these were soon buried beneath falls, and the tire continued under them. Attempts were made to extinguish it with water, with the aid of chemical extinguishers, and by digging it out; hut these had to he abandoned, and ultimately the fire-zone was sealed off by “ bashings” (stoppings). By December, progress in the decrease of combustion was so slow that it was decided to try the effect of inert gas. The installation, control and operation of the carbon dioxide plant and associated water-gauge are described in detail and conclusions drawn for the extinguishing of mine fires by CO2

Dec 1, 1916

By D. R. Torgoson, Th. G. Sahama

"This paper contains some new thermodynamic data for silicates in the series Mg2SiO4-Fe2siO4 and MgSiO3-FeSiO3 and gives the results of a thermodynamic attack on the problems of stability end parageneses.. Although some data are lacking satisfactory agreement with mineralogical and petrological observations is indicated.The use of thermodynamic methods in mineralogy and petrology has been rather limited, because accurate thermal data, especially for the more complicated and more important rock-forming minerals, have been too scanty to permit any systematic application to problems in those fields. It is, nevertheless, a fascinating task to investigate to what extent the mode of occurrence and the stability relations of the minerals and mineral parageneses, as revealed by petrological and mineralogical observations, agree with predictions of thermodynamics. At the present stage of development calorimetric data are needed for most of the abundant silicate minerals.Measurement of the heats of solution in hydrofluoric acid of minerals in the series Mg2SiO4-Fe2SiO4 and MgSiO3-FeSiO3 affords a ready means of obtaining their heats of formation from the oxides. Combination of such data with entropy and heat-capacity values gives a means of obtaining free energies of formation from the oxides, which, in turn, are connected di¬rectly with stability and paragenoses.The two silicates of magnesium, Mg2SiO4 and MgSi03, occur as rock-forming constituents as forsterite and clinoenstatite or enstatite. The orthosilicate (forsterite) forms a series of isomorphic mixtures with ferrous-orthosilicate (fayalite). The continuity of this series, suggested by petrological observations, has boon proved experimentally by Bowon and Shairer.4/ The present work shows that those minerals constitute a series of perfect solid solutions - that is, a series of solid solutions for which heats of formation from the individual pure silicates, Mg2Si04 and Fe2SiO4, aro negligibly small.The metasilicates of magnesium and iron also form an isomorphic series. However, this series differs from the forstorito-fayalite series in the fact that the most iron-rich mixtures, between about En10Fs90 and pure Fs, appear to be unstable with respect to the paragenesis iron-rich olivine plus quartz. The supposed instability of pure FeSiO3 as a crystalline compound, at least at high and at moderate temperatures, is remarkable, as no crystal struc¬tural reason for such instability is apparent. The present work indicates, also, that these minerals form a perfect series of solid solutions and throws additional light on the instability question.In the following, the samples used in this investigation will be described. For each of the natural olivines and orthopyroxenes, with the exception of sample L, a chemical analysis was made of the purified and actually used fraction. All the analytical work was carried cut by Oleg v. Knorring, and the specific gravity determinations, by moans of a pycnomctcr, by Oiva Joensuu, both of the University of Helsinki, Finland. The determinations of the optical properties were made by Mrs. Toini Mikkola, of the Geological Survey of Finland."

Feb 1, 1949

By I. I. Beloglazov, G. A. Iusupov, A. Ju. Feoktistov

"The aim of this paper is to study the numerical modeling of the crushing process in a jaw crusher with complex motion jaws using Discrete Element Method (DEM). The main goals are to ensure the conformity of numerical simulation results to the experimental data, optimize the operating modes and the crusher design and develop automated verification and calibration methodology. It is offered to use automated selection of mathematical model parameters using large- or laboratory-scale experiments instead of deriving parameters from conventional intensive material tests (e.g. drop-weight test). Experimental data were obtained from a large-scale crusher designed and manufactured by the company “Mekhanobr-Tekhnika”. Both jaws have their drive shafts located asymmetrically; one jaw is driven in the upper part, the second at the base. The crushing process involves fragmentation of single smoothed rectangular granite particles of the same weight. During the experiment, the required parameters such as particle size distribution were obtained for further computer simulations. Based on the obtained experimental data, the Rocky DEM model was built. Simulation breakage parameters were calibrated using automated parameter selection methodology based on multiple set of parameter-controlled simulations. A good correlation of the experimental data and numerical simulation data was obtained. The methodology in combination with well-known capabilities of simulation modeling will help reduce the research time in the development of new mineral processing equipment.INTRODUCTION Preparation of rock mass for enrichment includes the power-consuming processes of crushing and grinding. Initial rock mass crushing is performed by means of drilling and blasting operations. To reduce the average size of a rock piece, primary crushers, mostly jaw crushers, are further applied. The advantages of the jaw crusher are simple design, easy maintenance and repair. One of the drawbacks is large oscillating masses and, thus, high power consumption during operation (55 - 200 kW). Jaw crushing simulation will help optimize the crushing process and improve further rock transportation and processing performance."

Jan 1, 2018

By A. J. Kauffman

This inventory of the industrial mineral resources of the Pacific Northwest indicates that each of the States comprising this great region annually produces nonmetallic materials valued at mans million dollars. Commodities or their products that have a large, localized market predominate. These include Portland cement, sand and gravel, stone, clay, and lime. The region's output of magnesite, vermiculite, pumice, and diatomaceous earth is outstanding. The magnesite deposits of Stevens County, Wash., are the largest and most important in this country. Mast of the domestic vermiculite production is obtained from deposits in Lincoln County, Mont. Oregon and Idaho rank third and fourth, respectively, as domestic pumice producers. Production data for diatomaceous earth show Oregon second and Washington fourth among the producing States.

Jan 1, 1952

By Lon A. Williams

This report, authorized under Contract Number H0220065, Amendment Number Six, documents the results of an investigation of lighting system modifications and designs for working place illumination in high and low coal entries of underground coal mines. The portable and machine mounted system designs, both modified and prototype, represent a continuation of work performed under Contract Number H0111403, Amendment Number One. See the Final Technical Report dated May 26, 1972 for detailed information concerning this prior Contract. All modified and prototype systems met the performance requirements of Bureau of Mines Specification 2G, as proved by test. In addition, the systems met the requirement for illumination, as specified in the Contract and in the proposed standards which were generated in response to Public Law 91-173.

Jan 1, 1976

By Jorge Luís Coleti

A siderurgia mundial vive um momento de excesso de oferta, com isso as empresas necessitam reduzir custos por meio da melhora de processos e/ou através da substituição por matérias primas alternativas às convencionalmente utilizadas. Este trabalho trata justamente deste tópico e busca substituir a fluorita por outra fonte de fluxante, neste caso, o óxido de boro. Neste trabalho o óxido de boro foi adicionado a escórias sintéticas num banho de aço à 1600°C. Foram realizados testes com proporções de 3%, 5% e 7% de óxido de boro na composição das escórias. A fusão foi realizada em atmosfera inerte de argônio em um forno de resistência de dissiliceto de molibdênio. Amostras de aço foram removidas periodicamente a cada 5 minutos até os 25 minutos de experimento. Estas amostras foram analisadas em um espectrômetro de infravermelho. Os resultados indicam a viabilidade técnica para a aplicação do óxido de boro como substituinte da fluorita.

Aug 17, 2017

By C Rizos

Many of the ‘new paradigms in mining’ and notions of ‘sustainable mining’ have at their core the requirement for reliable, continuous centimetre-level positioning accuracy to enable increased automation of mining operations. The deployment of precision systems for navigating, controlling and monitoring machinery such as drills, dozers, draglines and shovels with real time position information increase their operational efficiency, and reduce the need for humans to be exposed to hazardous conditions. The Global Positioning System (GPS) is the best known, and only currently fully operational, Global Navigation Satellite System (GNSS) providing positioning capability anywhere in the globe, on a continuous 24/7 basis, with accuracies ranging from the dekametre-level to the sub-centimetre-level depending on hardware and operational configuration. Despite this versatility, GNSS cannot satisfy the high accuracy positioning requirements for many applications in mine surveying, and mine machine guidance and control. The reason is that increasingly open cut mines are getting deeper, resulting in a reduction of the ‘sky-view’ necessary for GNSS systems to operate satisfactorily. Yet, to date there have been no viable alternatives to GNSS that can be deployed in mine environments that can meet the challenging requirements in open cut mines.Locata Corporation, a Canberra-based company, has invented a terrestrial high accuracy positioning system known as ‘Locata’ that can augment GNSS with extra terrestrial signals to permit cm-level positioning accuracy even when there are insufficient GNSS satellite signals for reliable positioning and navigation. Locata relies on a network of synchronised ground-based transceivers that transmit positioning signals that can be tracked by suitably equipped user receivers. Hence Locata can be considered a new type of ‘local constellation’, able to provide high accuracy positioning coverage where GNSS fails. This paper introduces some of the technical aspects of this Australian technology and describes tests conducted by Leica Geosystems over the last few years at Newmont Boddington Gold in Western Australia. A recent news announcement by Leica Geosystems (12 January 2011) has confirmed that their new mine management system will have combined GNSS + Locata positioning capability – the first commercial product that integrates GNSS and Locata capabilities into a single high accuracy and high availability navigation device for open cut mine machine automation applications.

Nov 22, 2011

By R. H. Matjie, J. R. Bunt, A. C. Collins, J. C. van Dyk, C. A. Strydom

South African discard coal fines and K₂CO₃ blends were heated in a laboratory-scale rotary kiln to produce ashes for H₂SO₄ leaching tests. The optimized H₂SO₄ leaching conditions of 6.12 mol.dm³ (M) H₂SO₄, solid to liquid ratios 1:5 and 1:10, and 80°C for 8 hours were used. K₂CO₃ was added to increase the dissolution efficiency of K. The objective was to determine if the Al present in metakaolinite (Al₂O₃.2SiO₂), the Al, K, and Ti in the alumino-silicate glasses, and the Ti in rutile (TiO₂) in the ashes could be selectively dissolved in H₂SO₄. XRF results show that the ashes formed at 700°C dissolved more efficiently (87% Al, 89% K and 23% Ti) compared to the ashes formed at 1050°C. This can be attributed to the presence of Al₂O₃.2SiO₂, K₂CO₃ melt, K₂CO₃ remnants, KAl(SO₄)₂, and K-aluminosilicate glass in these ashes. XRD results indicate that the ashes prepared at 1050°C contained anorthite (CaAl₂Si₂O₈), microcline (KAlSi₃O₈), pseudomullite (Al₂O₃.SiO₂), and silicon spinel (2Al₂O₃.3SiO₂), which are either insoluble or only sparingly soluble in H₂SO₄. These minerals resulted in the lower dissolution efficiencies of Al and K. Based on the high dissolution efficiencies of Al and K for the ashes produced at 700°C, coal fines blended with K₂CO₃ could possibly be utilized as feedstocks for the production of aluminium(III), potassium(I), and titanium(IV) and a sulphate-containing leach liquor. Furthermore, the environmental issues and costs associated with the handling and disposal of large volumes of coal fines will also be resolved.

Aug 2, 2022

By Forest J. Sur

"INTRODUCTION This report describes an exploratory project conducted by the Bureaus of Mines on a fluorite deposit, near Glenwood, N. Mex. Results of wagon drilling, crosscutting, and test pitting are given, together with results of metallurgical tests made upon samples of the ore. Mining and treatment methods are suggested.C. H. Johnson, Bureau of Mines engineer, examined the deposit in August 1942. H. E. Rothrock, of the Federal Geological Survey, completed a preliminary geologic study and mapped the deposit during the fall of 1942. As a result of these brief investigations, it was concluded that the deposit contained substantial inferred ore reserves, and exploratory work was recommended. G. A. ApelI, also of the Bureau of Mines, made a topographic and underground survey and report on the mine in March and April 1944. A wagon drill, air compressor, and other equipment and supplies were delivered to the property on May 19 to 23, 1944. Drilling began under the direction of the author on May 25, 1944, and was completed in October 1944. The results of drilling and. sampling form the basis of this report."

Apr 1, 1947