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Cokriging uses a sparsely sampled, but accurate and precise primary dataset, together with a more abundant secondary data-set, for example grades in a polymetallic orebody, containing both error and bias, to provide improved results compared to estimation with the primary data alone, as well as filtering the error and mitigating the effects of conditional bias. The method described here may also be applied in polymetallic orebodies and in other cases where the primary and secondary data could be collocated, and one of the data-sets need not be biased, unreliable, etc. An artificially created reference data-set of 512 lognormally distributed precious metal grades sampled at 25×25 m intervals constitutes the primary data-set. A secondary data-set on a 10×10 m grid comprising 3200 samples drawn from the reference data-set includes 30 per cent error and 1.5 multiplicative bias on each measurement. The primary and secondary non-collocated data-sets are statistically described and compared to the reference data-set. Variograms based on the primary data-set are modelled and used in the kriging of 10×10 m blocks using the 25×25 m and 50×50 m data grids for comparison against the results of the cokriged estimation. A linear model of coregionalization (LMC) is established using the primary and secondary data-sets and cokriging using both data-sets is shown to be a significant improvement over kriging with the primary data-set alone. The effects of the error and bias are filtered and removed during the cokriging estimation procedure. Thus cokriging using the more abundant secondary data, even though it contains error and bias, significantly improves the estimation of recoverable reserves.

Jan 1, 2014

By B. F. Giyani, A. Salama

Tanzania is a country with a variety of mineral deposits, including metallic minerals, gemstones, mineral fuels, industrial minerals, and critical minerals. This study provides an overview of mining legal framework, mineral occurrence and production, challenges in the mining sector, and government initiatives. The aim is to demonstrate the development of the mining sector in Tanzania and explore the potential for further mining investment in the country. The mineral production data showed generally increasing trends over the years, for example, gold production increased from 42 tonnes in 2018/2019 to around 50 tonnes in 2023/2024. Despite the growth, the mining sector encounters several challenges, including a lack of detailed geological information on mineral deposits, inadequate infrastructures in some remote mining sites, the existence of informal artisanal miners, and mineral smuggling. The Tanzanian government has introduced several initiatives to address these challenges, including carrying out the highresolution airborne geophysical survey to increase geological information in some areas, the formalisation of artisanal and small-scale mining, establishing mineral markets to combat mineral smuggling, and encouraging mineral value addition within the country.

Oct 24, 2025

By D. R. Flinn

A newly developed chemical conditioning technique, which greatly simplifies the preparation of plating baths for the electrodeposition of titanium diboride (TiB2) coatings, is described in this report. The new plating technique was used to prepare samples of titanium diboride (TiB2) coatings on three types of substrate materials. These samples were then evaluated in both low- and high-speed wear-test programs to determine the wear resistance, microhardness, and adhesion of the coatings. In general, it was found that the wear resistance of the coatings is independent of substrate. Scanning electron micrographs have shown that the coating wear surfaces are very smooth, suggesting slow and continuous removal of the coating during the wear test (that is, adhesive wear). Adhesion between the coating and all substrates was excellent. Microhardness results show that the TiB2 coating is harder than alumina, with a hardness value exceeding 5,000 kg/mm2 measured in one test. The results of the wear tests show that TiB2 coatings have relatively poor wear resistance compared with alumina in low-speed unlubricated sliding environments, but exhibit wear properties comparable with alumina in high-speed unlubricated sliding environments.

Jan 1, 1981

By R. Hendrickson

In the 1940's a top blown water-cooled oxygen lance was developed to inject oxygen into liquid iron. This process, the LD or BOF process technique, today is used in 65% of the world's steel production, and represents the largest oxygen market for temperature enhancement in steel and non-ferrous smelting applications. There are three major approaches to the use of oxygen in metallurgical processes: (1) general enrichment of the air supplied to burners or tuyeres, (2) under-flame enrichment or injection, and (3) the use of an auxiliary oxy-fuel burner as a heat source. With each of these techniques there are technical and economic trade-offs.

Jan 1, 1990

As we look back through the Proceedings of our Institute, we find few papers dealing directly with education and recruitment. Apart from papers prepared in the earlier decades of this century, there was little written discussion on the subject until the 1950s, and mostly this was by the professionals, the professors and lecturers who staff the various mining schools of Australia and New Zealand.I use the term "mining school" in its fullest and widest meaning, to cover all aspects from ore to metal, and not in the narrow meaning that the word might imply. At the same time, in restricting the parameters of this address to "ore to metal" I recognize that I am excluding the very important fields of physical metallurgy and materials science; this I do because there is a limit to the quantum of any paper, and in fact these subjects are more closely allied to the use rather than the production of metals.However, the lack of education papers does not mean that education has been regarded lightly by The Institute. Sir Maurice Mawby in his presidential address in 1968, reminded us of the original objectives of The Institute, one 'of which was, "To promote the arts and sciences connected with the economical production of the useful minerals and metals ...". Our present Royal Charter is more specific when it says that one of the objects of The Institute is, ". . . to encourage the study of engineering with special reference to mining and metallurgy ...". If we recognize that in itself membership of our Institute is one means of continuing our education, it is true that education has been a concern of The Institute since it was first founded.Occasionally in recent years, an intrepid president has ventured to tell the academics what the industry needs, and he generally does this in a "no-question" situation! However it is encouraging that those entrusted with mineral education have always accepted this; they keep coming back for more and ask us to tell them what we want, and they will provide it.In 1948 a considerable dialogue on education was initiated when a standing committee was established by the Council of The Institute. In the period 1949 to 1951, three papers were prepared under the chair...

Jan 1, 1974

By Collin L. Stewart

The high cost and limited flexibility of modern longwall systems has resulted in the need for mine engineers and geologists to predict possible adverse mining areas ahead of mining and to then design and implement suitable ground control solutions in a timely and cost effective manner. Therefore, over the last 30 years, geo-technical evaluations for coal mine planning and development have advanced from a minor afterthought to an important part of today?s successful, high capacity, longwall mining operations. The latest iteration in this progression of improved analysis for predicting future mining conditions is a computer-based Stability Mapping System developed by West Virginia University. This system is designed to allow the mining engineer and geologist to effectively combine the mine geologic characteristics, stress influences, and structural features into an integrated stability map for use in mine planning and support design. This paper details the application of the stability mapping system to Bowie Resources, LLC, Bowie No. 3, multiple-seam longwall coal mine. At this mine, the prediction of adverse mining conditions using the stability mapping system allowed management to accurately adjust their support densities and operational procedures, and to successfully mine through difficult conditions safely and successfully.

Jan 1, 2006

By Daniel T. Brian, O&apos

Exploration targets and results in the mining industry are commonly summarized in terms of tonnage and grade. Business appraisals require, as additional information, the expected profit or loss implied by the physical summay. The early incorporation of knowledge gained through financial analysis computations can provide a means for economically resolving many common exploration and development problems. Examples of such applications from the activities of exploration planning, reconnaissance, land acquisition, and development planning are presented. While prospecting for mineral deposits, geologists are frequently asked what they hope to find or have found. The response is usually descriptive, such as "50 million tons of 1% copper," and the economic implications are deferred until a capital investment decision is required. At that time, a financial analysis integrating the four analysis components is completed. These components are: 1) Tonnage and Average grade above cutoff grade 2) Capital and operating costs 3) Product value 4) Appropriate profit or loss accounting Close examination of these components reveals that there is no intrinsic reason for avoiding financial analyses at earlier stages in exploration, as long as the uncertainty of the estimate is realized. Tonnage and average grades are commonly estimated at early stages in exploration. For this component, the appropriate cutoff is the major uncertainty. Capital and operating costs are difficult to estimate before detailed quantitative information is available, but estimates useful for the types of applications pertinent to earlier exploration stages are possible. Product value estimates may or may not be difficult, depending on the pricing structure of the particular commodity. A simplified accounting procedure usually may be adopted without introducing any significant loss of validity. This paper describe some of the financial analysis applications which are pertinent during mineral exploration and deposit development. These applications lend additional insight during exploration planning, land acquisition, physical exploration, and development. The examples are oriented toward a hypothetical management investment policy which is based on a single criterion, a minimum 15% discounted cash flow rate of return. In reality, managements use multiple criteria. This simplification is convenient for purposes of presentation and does not invalidate the examples. Computers are useful, but not a requirement, for the applications described. The use of computers provides the results on a more timely basis at costs lower than equivalent manual computations. UNDERLYING PRINCIPLES AND ANALYSIS METHODS Data estimates are subject to uncertainty. The analyst may choose to assess this uncertainty by using one of two principles. Each principle has some advantages. The principle most commonly employed is "assumed certainty." Each financial analysis is based on one set of selected data, which may represent the average estimates, minimum expected conditions, etc. The critical data is identified by making successive calculations, varying the values used. Such studies, called sensitivity analyses, isolate the economic effect of various uncertainties, and guide the allocation of future efforts toward improving the overall accuracy of the analysis. A second principle, "assumed risk," examines the interactive effect of the current uncertainties by qualitatively assigning probability distributions to each data element. These probability distributions indicate the currently appraised chance that a given numerical value will prove to be true. The corresponding procedure, risk analysis, consists of processing many individual financial analyses, each analysis being based on randomly selected numerical values from the probabilistic distributions. The result is a numerical presentation of the uncertainty, but care must be exercised in the interpretation of results. The advantage of this procedure is the direct measurement of economic uncertainty caused by the interaction of uncertain estimates. Kennecott Copper Corp. has developed computer systems for accomplishing sensitivity and risk analyses.

Jan 1, 1970

By Liang Shen

The Cooper River Bridge, the longest cable-stayed bridge in North America, replaces two existing bridges along U.S. Highway 17 and connects the City of Charleston and the town of Mount Pleasant, South Carolina. Two diamond shaped towers support the 1,546 ft long main span over Cooper River and allows for a 1000 ft wide navigation channel. The Charleston high-level approach is 4351 ft long and provides a 250 ft wide navigation channel for Town Creek, while the Mount Pleasant high-level approach is 2,090 ft long. Due to the high seismicity in the region, potential vessel impact, and hurricanes, large lateral loads are expected. From various types of foundations, 10-foot diameter drilled shafts were selected for their high capacity against vertical and lateral loadings. The shafts are founded on a stiff to very stiff lightly cemented calcareous sandy clay or sandy silt layer, called Cooper Marl, which underlies the coastal sediments of the interbedded clays and sands. A group of 11 shafts supports each main tower, while a rock island protects it from vessel collision. A group of 4 to 8 shafts foundations support the other piers of the main span unit. A pair of shafts supports the High Level Approach piers. The shaft tip elevations vary from 120 ft to 230 ft below water line. An elaborate geotechnical investigation was conducted on the site, including a load test program on full-scale shafts under axial and lateral loads. The results of the tests were used to calibrate the lateral and axial soil resistance. The objective of this paper is to present the different aspects of the bridge foundation design.

Jan 1, 2013

By Etienne Audibert

No satisfactory theory has yet been advanced to explain what takes place when an explosive is fired in a mixture of firedamp and air. The only means of measuring the' danger is to fire the explosive into the gas mixture and note the effect, but the conditions of firing must be chosen carefully. This report is presented in the hope that it will assist in determining what method to use. The experiments have been designed to show the effect of the principal factors involved in the conditions of firing, and the results give information that seems to have some value.

Jan 1, 1940

By Etienne Audibert

No satisfactory theory has yet been advanced to explain what takes place when an explosive is fired in a mixture of firedamp and air. The only means of measuring the danger is to fire the explosive into the gas mixture and note the effect, but the conditions of firing must be chosen carefully. This report is presented in the hope that it will assist in determining what method to use. The experiments have been designed to show the effect of the principal factors involved in the conditions of firing, and the results give information that seems to have some value.

Jan 1, 1940

By George A. Burrell, Frank M. Seibert

The Bureau of Mines, as part of its designated duty of investigating the causes of mine accidents, is conducting at its experiment station in Pittsburgh, Pa., a study of mine gases. Some of the work already done in connection with this study is outlined below. A large number of mine-gas samples have been collected under normal conditions in returns and in splits, and at other points in the ventilating current, also at the face, in the goave or gob, in unventilated places, and wherever the air was still. Samples have also been obtained under abnormal conditions, as after explosions and while mine fires were in progress, or from sealed areas behind stoppings and darns where the air had been stagnant for some time. Chemical changes in the composition of mine atmospheres during mine fires have been studied," and conditions peculiar to certain mines have been investigated. The question of the effect of a change in atmospheric pressure on the escape of gas (methane) in coal mines has been studied. Explosives have been fired in both coal and metal mines, and samples of resulting gases have been collected to ascertain the degree to which these gases vitiate the air. A series of samples in mines where gasoline locomotives were being used have been examined in order to ascertain the degree to which the exhaust gases from such locomotives foul the mine air. Experiments have also been performed in regard to the relative effect of carbon monoxide b upon men and small animals. A preliminary report relating to the inflammable gases in mine air has been published. Full reports of the results of the investigations outlined above will be published as soon as all the necessary data have been gathered. The first part of this report deals with the methods used by the bureau in the collection and examination of the various mine gases; the latter part discusses the bureau's methods of sampling and examining natural gas.

Jan 1, 1913

By Murat Alkan

In this study, a self-propagating high-temperature synthesis (SHS) and following acid leaching techniques were carried out to produce boron carbide (B4C) powder. First, B2O3 was obtained through calcinations of H3BO3 at 1073 K for 2 hours. Then, the glassy B2O3 obtained was crushed and sieved. In the SHS experiments, different amounts of B2O3, Mg and C black were used. The SHS product was obtained in the form of black, spongy solid. In the leaching step, the SHS product was leached in a HCl solution to eliminate the MgO and Mg3B2O6. The effect of acid concentration on the selective leaching was studied at different concentration range, solid/liquid (S/L) ratio, and temperature. The products obtained were characterized by using X-ray diffraction, chemical analysis and SEM techniques.

Jan 1, 2009

By S. P. Pearton

"Pumpable emulsion explosives have been available to surface and underground massive mining operations for decades, and their unique properties offer significant advantages in terms of improved safety, reliability, and performance. However, the benefits of pumpable emulsions have been unavailable to narrow-reef mining operations due to the lack of technology necessary for their successful implementation in this challenging environment. Despite efforts to promote and enhance the safety and performance of bulk emulsions for narrow-reef stoping, little research has been undertaken to advance the pump technologies required for their implementation. This has resulted in a gap in knowledge and technology, and as a consequence the successful implementation of a pumpable emulsion system has consistently eluded the narrow-reef environment.The purpose of the following investigation was to evaluate the viability of pumpable emulsion explosives for use in South African narrow-reef mining operations. By approaching the problem from multiple perspectives, this research aimed firstly to propose a theoretical framework and suite of equipment suitable for the implementation of pumpable emulsions within the narrow-reef environment. Through the development of this suite of pumpable emulsion technology, tests could be undertaken on the proposed narrow-reef emulsion formulation and pumpable emulsion technology to obtain the necessary understanding of the performance of the system under controlled operating conditions prior to its implementation in the broader mining industry."

Jan 1, 2015

New developments in the non-invasive and real-time measurement of the velocity profile of slurry flow in horizontal pipes will be described. This information can be used to determine the approach and onset of solid deposition on the bottom of the pipe. Having this information in real time can enable operation at lower velocities or higher solids concentration or both while avoiding solids deposition or plugging and their associated operational costs. In addition, advances have been made in the measurement and trending of pipewear on slurry lines. In contrast to manual methods, CiDRA?s system uses a permanently or semi-permanently installed ring of conformable ultrasonic transducers clamped onto the outside of the pipe. These transducers are used to measure the thickness of the pipe under their respective locations. This results in better repeatability, accuracy, and failure prediction, along with reduced labor costs. The benefit is significantly improved pipe wear monitoring in pipelines with abrasive solids. This provides an improvement in the ability to insure safe operation and avoidance of costly operational and environmental damage due to leaks caused by pipe wear.

Jan 1, 2009

By J. R. Nettle

The purpose of these studies by the Federal Bureau of Mines was to determine the feasibility of refining low-grade hafnium by an inert-gas-shielded molten-salt electrorefining technique to produce a hafnium metal meeting reactor specifications. The techniques were adapted from those used success-fully for titanium electrorefining. Three electrolytes containing hafnium chlorides were developed from which deposits having a Brinell hardness of 170 or below were recovered. A KC1 + NaC1 + HfC14 electrolyte produced deposits in the hardness range of 140 to 165 Brinell. Deposits with a hardness range of from 132 to 152 Brinell were pro-duced from an electrolyte composed of KC1 + LiC1 + HfC14. A third electrolyte composed of NaC1 + K3HfC17 produced deposits with a hardness as low as 139 Brinell. In a fourth electrolyte, composed of NaC1 + K2HfF6, a measure of refining was accomplished, but under the test conditions no metal meeting specifications was recovered; none was softer than 174 Brinell. A number of metallic impurities were reduced in quantity by the electro-refining process, notably iron, which normally was reduced from 250 p.p.m. to less than 50 p.p.m. Magnesium generally was reduced from 680 p.p.m. to less than 80 p.p.m. Manganese content was also reduced by the electrorefining process. Sponge containing 90 p.p.m. Mn yielded deposits containing a maximum of 50 p.p.m.; some deposits contained only 10 p.p.m.

Jan 1, 1961

By M. A. Meyer

Underground mining accidents in the USA in recent times have prompted the Mine Safety and Health Administration (MSHA) to review emergency and tracking systems for underground mines. Several communication and tracking systems are available on the market and various systems have been installed in mines around the world. In addition, MSHA?s standard on Diesel Particulate Matter (DPM) requires mines to comply with the final PEL of 160µg/m3 by May 20, 2008. Barrick Goldstrike Mines Inc., Underground Division, has been in operation since 1995 and an extensive control and monitoring network, and a leaky feeder voice network is in place. Enhancements to the communication and control system are currently being implemented to include a PED emergency notification system, wireless LAN with tracking of personnel and equipment in the mine, and a ventilation control system that will use the tracking information and ventilation data to automate much of the mine ventilation system. Expected benefits from such a system would be enhanced communication with miners, emergency notification, location of miners and equipment, energy savings, improved ventilation control, and improved atmospheric conditions in the mine including reduction of diesel particulate matter (DPM).

Jan 1, 2009

By Réjean Lévesque

SIDBEC-NORMINES a été incorporée en 1976. Depuis la fin de 1977, ses activités comprennent outre la concentration au lac Jeannine, près de Gagnon, du minerai de fer extrait du gisement du lac Fire, I'exploitation d'un atelier d 'enrichissement secondaire et une usine de bouletage à Port Cartier. L 'objectif principal de SIDBEC-NORMINES est de produire six millions de tonnes de boulettes d'oxyde de fer par année, dont trois millions auront une faible teneur en silice afin de répondre aux exigences de la réduction directe. Les installations de SIDBEC-NORMINES sont adjacentes aux installations portuaires de la Compagnie Minière Québec Cartier, à l'est de la ville de Port-Cartier. L 'ensemble est conçu pour produire les deux types de boulettes avec deux circuits d'agglomération installes en parallèle. La production de concentré enrichi (68% Fe et plus) est obtenue dans une usine d'enrichissement utilisant le precédé de séparation magnétique hum ide ahaute intensite (separateurs Jones). À l'usine de bouletage proprement dite, on effectue Ie broyage du concentré et sa mise en boulettes sur disques; l'in duration des deux types de boulettes est obtenue sur deux chaînes d'agglomération Dravo dont chacune a une capacité annuelle nominale de trois millions de tonnes.

Jan 1, 1979

Study on Flotation of the Low-Grade Magnesite Ore

Sep 13, 2010

By J. M. Davidson, F. Fraas, J. E. Conley

"A number of Reports of Investigations pertaining to the extraction of potash from cal¬cined polyhalite have been made by various members of the Nonmetallic Minerals Experiment Station of the United States Bureau of Mines. These reports describe results obtained in the study of samples of polyhalite (2CaS04.K2S04.MgS04.2H20) from deposits of possible com¬mercial importance in Texas and New Mexico.3Storch and Clarke6 in their initial paper presenting data on the properties of Texas polyhalite demonstrated the desirability of calcination and subsequent hot extraction with water as a satisfactory pronedure for treatment of this potash-bearing salt. Their preliminary data have been supplemented by an additional report7 dealing more particularly with the leaching of raw and calcined polyhalite with water and with saturated sodium chloride solu¬tions. Further data8 have been reported as a result of experiments made in a small labora¬tory rotary-tube furnace under various calcination and extraction conditions. Hot water was used as the leaching solution in all of these tests.In addition to the data on calcination and extraction, two processes as proposed by Storch and Clarke have been published by Wroth,9 and more recently a number of very promising processes have been proposed by Storoh and Fragen.10"

Apr 1, 1932

By D. Bienstock

As part of the development of the hot-carbonate scrubbing process by the Bureau of Mines, the corrosion rates of steel in boiling solutions of potassium carbonate saturated with carbon dioxide and hydrogen sulfide were determined, and the effectiveness of various inhibitors was evaluated by Bureau researchers. The highly corrosive solution of carbonate saturated with carbon dioxide can be inhibited with a 0.2-percent concentration of either potassium chromate or sodium metavanadate. Solutions of carbonate saturated with carbon dioxide and hydrogen sulfide are mildly corrosive, 0.01 inch per year. Complete absence of corrosion is obtained with 0.2 percent sodium metavanadate or 0.15 percent vanadium pentoxide. Oxidizing inhibitors such as potassium chromate are destroyed in the alkaline sulfide mixture, N-alkyl trimethylene diamines, at a concentration of 0.1 percent, lower the corrosion rate to about 0.005. Sodium metasilicate, at a concentration of 0.6 percent, completely inhibits the corrosion but may deposit free silica in the system. Commercial cladding materials such as the epoxy coatings also prevent corrosion.

Jan 1, 1962