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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 Weijian Yu, Jianbiao Bai, Jinlin Xin, Shiqiang Xu, Shuai Yan, Zizheng Zhang, Hai Wu

The retained roadway subjected to dynamic loading from thick and hard roof (THF) fracturing caused severe deformations in the thick coal seam (TCS). Understanding the dynamic loading mechanism of gob-side entry retaining (GER) in TCS with THF is the first step in determining the stability of the retained roadway. Characteristics of dynamic loading mechanism of gob-side entry retaining (GER) in TCS with THF are investigated through numerical simulation and field test of 150208 haulage gate in Sucun coal mine. To improve the reliability of numerical simulation, the double-yield model is used to simulate gob and the strain-softening model is used to simulate filling body; the dynamic module in FLAC3D is used to simulate the dynamic loading due to the THF fracture, and the global model are validated. Characteristics of surrounding rock convergence, plastic zone distribution, and vertical stress in the filling body after the THF fracture are reveled with respect to width to height ratio (W/H) of the filling body and the dynamic loading strength of the THF. The rational width to height ration of the filling body constructed with high-water materials is 0.57. Field monitoring results show that the GER with THF in Sucun coal mine could adapt the dynamic loading due to the THF fracture and meet the requirement. This study is helpful to better study the stability of GER according to the breaking dynamic load of THF and provides reference and guidance for the analysis of breaking dynamic load of THF under similar geological conditions.

Feb 23, 2023

By Frederic Benard

THE Ontario Refining Company, Limited, wholly-owned subsidiary of The International Nickel Company of Canada, refines the entire blister copper output of the latter's Copper Cliff smelter. Prior to 1936, the blister was cast in 460-lb. cakes at the smelter, loaded on open cars, and transported by rail to the refinery, a distance of approximately 1 1/4 miles. Here the cakes were transferred to the plant narrow-gauge system, charged to furnaces, and re-melted. This procedure necessitated the operation of holding furnaces and casting machines at the smelter -extensive re-handling-and melting down of a cold charge at the refinery. Transfer of the copper in molten form direct from converters to anode furnaces promised a considerable reduction in costs, and this possibility was investigated. As a result, a portable holding furnace, or hot-metal car, was designed and constructed. It was placed in operation in July, 1936, to be followed a year later by three additional units of slightly modified design. Figure 1 shows the original car, and Figure 2 the lacer type. With four cars in service, operations were placed on an all 'hot-metal' basis.

Jan 1, 1938

By J. B. Hadaway

The operation at Phu Kham commenced design and construction in early 2006 and was commissioned in May 2008. This paper will examine and discuss the project from the inception of flow sheet development and equipment selection, equipment design and manufacture, construction, commissioning and ramp up to full production. The paper will touch on the strategies employed to achieve a short schedule and the efficient use of capital, but with the main emphasis on the grinding circuit. Various challenges during the early years of operation will be discussed including the effect of ore characteristics, including competency, on the performance of the grinding circuit. Actions to overcome these challenges and to enhance performance will also be discussed. Finally, current and future plans to improve the performance of the grinding circuit and the overall plant will be summarised.

Jan 1, 2012

By T. Kessler

As part of a respirable mine-dust research program at the U.S. Bureau of Mines, spark-source mass spectrometry has been used for the semiquantitative determination of trace elements (200 ppm weight or less) in raw coals. In addition, several minor and major elements have been determined using this technique. Sixty-four elements ranging in concentration from 0.01 to 41,000 ppm weight were determined in one anthracite, two mvb, four lvb, and six hvab raw coal samples. The samples represented 10 coal seams located in Pennsylvania, West Virginia, Virginia, Utah, and Colorado.

Jan 1, 1973

By Q Zhou, G Barrett, Y Choi, J Jiang

As part of a general review of processing double refractory ores through Barrick GoldÆs autoclaves /carbon-in-leach (CIL) facility at Goldstrike, a study was made to evaluate the use of surfactants for reducing the loss of gold during cyanide leaching of preg-robbing gold ores. Consistent improvement of gold recovery was observed with surfactants at various testing conditions. This paper will discuss the results obtained from laboratory and pilot-scale testing, as well as, review potential mechanisms for the observed improvement in gold recovery.CITATION:Zhou, Q, Barrett, G, Jiang, J and Choi, Y, 2013. Surfactants for gold recovery improvement with preg-robbing gold ores, in Proceedings World Gold 2013 , pp 367-372 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By Harry R. Nicholls

A simple economical method has been developed for determining the in situ longitudinal and shear velocities in rock from which its elastic constants can be calculated. By detonating small charges of high explosives in shallow drill holes near a free surface, both longitudinal and shear waves were generated simultaneously. Accelerometers and velocity gages mounted to the rock surface were used to record the arrival time for both waves over travel path lengths from 50 to 450 feet, Measurements were made in two rock types. From the arrival time measurements, the longitudinal and shear wave velocities were calculated. From these velocities and the density of the rock, the elastic constants were calculated. The dynamic elastic constants of drill core samples of the two rock types were determined in the laboratory by the resonant-frequency method, The lab- oratory and in situ elastic constants are compared and significant differences noted. In general, there is less spread in the in situ data than in the laboratory data, and Poisson's ratio does not fall outside the theoretical limits for the in situ data as is often the case for laboratory-determined elastic constants.

Jan 1, 1961

By Ulrich Maidl, Marc Comulada, Janosch Stascheit

"INTRODUCTION Cohesive soils are notorious for causing clogging of the cutter head and the excavation chamber of tunnel boring machines (TBMs). While clogging leads to a drastic reduction in excavation performance, it further induces higher wear of tools and other parts of the cutter head and may even prevent a controlled support of the tunnel face and, thus, lead to face collapse and excess settlements or sinkholes. Employing well-balanced soil conditioning techniques, the clogging tendency can be significantly reduced. The monitoring and control of soil conditioning as well as the timely detection of potential clogging tendencies require a close monitoring of all relevant machine parameters and measurements. To this end, a reliable and powerful Process Controlling software that gathers all machine and process-related information is a prerequisite for successful mitigation of clogging-induced problems. The remainder of this contribution is organized as follows: First, a brief introduction to the Process Controlling system PROCON is given. Afterwards, the mechanisms and mitigation techniques of clogging are discussed. Finally, an example is given how Process Controlling has been employed to soil conditioning in a tunneling project with highly clogging soils.PROCESS CONTROLLING Being both the active part and a huge measuring device, the shield machine represents the core component in mechanized tunneling. This machine comprises a manifold of complex components and devices that require constant supervision and control and, thus, is equipped with a manifold of different sensors that provide a continuous monitoring of the state and condition of the machine (Maidl & Stascheit, 2014). If these data are put into the whole context of the tunneling process, they can provide insight to the assessment and optimization of the performance and to the prediction of potential risks and hazards such as, for example, the tendency of clogging of the cutter head."

Jan 1, 2016

By Louis M. Schlesinger

KMG Minerals, Inc., a mica-feldspar-quartz producer in Kings Mountain, N.C., uses about 50% of its plant's -200 mesh slimes to manufacture brick. However, the company is unable to market the remaining 50% of this fine mineral mixture. The NCSU Minerals Research Laboratory operated a pilot plant to process these slimes to produce an additional product. The process, consisting of blunging and hydraulic sizing, was designed to separate a kaolin-enriched -270 mesh product from the bulk of the coarser +270 mesh "grit" minerals. Size analysis showed that this product was 80% finer than 20 microns and 50% finer than 6 microns (in equivalent spherical diameter). An evaluation indicated that it is a hydrous aluminum silicate that might be suitable in the filler and extender markets for traffic paint, some types of plastics, joint cements, and dusting compounds. Because of its high viscosity, it will be difficult to use more than a small percentage in cast ceramic bodies. However, it might be possible to use up to 10% in extruded ceramic bodies (i.e., electrical porcelain). The 15.2 cm (6 in,) diameter Linatex Hydrosizer was tested using a range of teeter water flowrates, so that the net rise velocity was varied from 0.10 cm/s to 0.40 cm/s. The solid feed rate to the sizer was maintained at approximately 1.1 t/hr/m2 (0.12 ton/hr/ft2). Tests were run using both "shallow" (i.e., 6 in.) and "deep" (i.e., 15 in. teetered beds. The best overall result was obtained when the sizer was operated with the "deep" teeter bed and a net rise velocity of 0.10 cm/s. About 97% of the +270 mesh material was rejected and approximately 79% of the -270 mesh material was recovered in a 14% solids slurry.

Jan 1, 1994

By Bertrand L. Johnson

Langbeinite, a comparatively rare mineral that has been reported from only five countries in the entire world, has recently attained considerable economic importance in the United States and Poland. Since September 1940, several hundred thousand tons have been produced in one of the Carlsbad (N. Mex.), potash mines for chemical and fertilizer use. As it is a newcomer in this field, and as it is the source of fertilizers possessing special advantages, notably for soils deficient in magnesium or requiring sulfate fertilizers, a discussion of its properties, occurrences, uses, mining, and treatment is appropriate at this

Jan 1, 1944

By F. X. Tartaron

This report describes work done by the Bureau of Mines to simplify the design and operation of the vortex cone, a new device for prerefining blast furnace iron. Three new apparatus arrangements were tested. Results with one of these arrangements average 74.2 pct silicon removal and 61 pet oxygen efficiency (disregarding removal of carbon and manganese).

Jan 1, 1965

By I. L. Feld

This Bureau of Mines report describes the development of a simple method of producing low-phosphorus hematite concentrates from certain submarginal southeastern iron ores. The investigation was undertaken to obtain additional information on the Clinton iron ore outcrops at the southwestern extremity of the Birmingham district of Alabama and to assist in the development of operating techniques that would make it profitable to use the marginal ores of this area for blast-furnace feed. Batch and continuous pilot-plant tests demonstrated that a relatively simple wet scrubbing treatment) followed by a desliming operation to reject argillaceous (clayey) gangue, consistently yielded a marketable granular hematite product. Iron losses were relatively high but could be tolerated in view of the low treatment cost.

Jan 1, 1960

By R E. McIvor, K M. Bartholomew

Classification system efficiency (CSE) is a simple, powerful metric that provides a comprehensive measure of classification system performance. CSE directly quantifies the amount of coarse solids in the mill, and as a result, also directly quantifies the percentage of mill power being used effectively. In this manner, it is an effective, practical grinding energy efficiency metric.Three independent variables drive CSE: circulating load ratio, sharpness of classification, and classifier bypass. Due to practical downstream constrains on per cent solids, improvements realised by increasing circulating load reach diminishing returns as sharpness of classification and bypass deteriorate in the most commonly used classification device, the hydrocyclone. This combination of effects leads to the use of CSE, and its relationship to operational economics, as an objective circuit optimisation criterion.Its simplicity in measurement makes CSE a useful tool for the plant metallurgist, and it is not subject to a great amount of experimental error. CSE provides the plant operator a fast, simple, and effective means to evaluate the performance of the plant classification system. Improvements in CSE relate directly to circuit throughput and energy efficiency. This paper, through description and plant case studies demonstrates the power and utility of this emerging grinding system optimisation metric.CITATION:Bartholomew, K M and McIvor, R E, 2013. Classification system efficiency - a comprehensive closed-circuit grinding optimisation metric, in Proceedings World Gold 2013 , pp 389-394 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By I. C. Howard, E. J. Palmiere

"Heat transfer and friction in hot flat rolling have traditionally been characterised by an average heat transfer coefficient (h) and an average friction coefficient (p.). However, the presence of oxide scales and asperities at the interface question the use of such averages. The apparent irregularity and lack of pattern of interactions at the interface has prompted this present investigation to move away from averaged h and 11 values, and to study their local evolution based on probabilistic rules. The approach is based on the probability of finding the workpiece surface in a specific configuration at a particular instance of time in the roll gap. These rules are based on observations of surface phenomena such as scale behaviour during hot rolling. The model is implemented using user-subroutines integrated with the commercially available finite element program ABAQUS™. The results show the strong dependence of h and u on the local scale interactions. In particular, the effect of scale thickness, material behaviour and processing conditions on the evolution of hand 11 are discussed. Finally, the development of a Cellular Automata based Finite Element (CAFE) model is proposed to model the combined interfacial phenomenon of friction and heat transfer at the tool-work piece interface.IntroductionIntricate interactions between process variables in hot rolling of steels make it a challenge to the modelling community. For a given material and geometry combination, reducing interfacial power losses can increase the efficiency of the rolling process. The roll-strip interface, therefore, forms the critical zone and is currently the domain of intense investigation, especially to characterize interfacial frictionl • 2 and heat transfer3 • 4 . These interfacial phenomena are inter-related and cannot be studied in isolation. However, very few mathematical models4 • 5 combine an analysis of friction and heat transfer and deformation of the strip-roll interface taking into account the role of asperities and oxide scales."

Jan 1, 2001

By K. Kim

An analysis was conducted to determine the effects of blasting on slope stability and downstream comminution processes. To investigate these effects, the extent of blast-induced rock damage and the magnitude of induced stress were examined. This analysis showed that damage may extend up to 500 meters (1MPa, tensile strength) in the rock mass, a distance that is sufficient to impact the pit-scale slope over the long term. In addition, the damage zone was calculated using the reasonable assumption that compressive waves are the primary agent in microfracturing during blast fragmentation. The calculated damage zone ? up to 5.6 meters (30MPa, 30% of the compressive strength) ? indicates that microfracturing can occur throughout the entire rock mass in the blasting area. Finally, an economic analysis was conducted by comparing two reasonably assumed blasts in a copper mine. The change in energy required for crushing and grinding was demonstrated using Bond?s law after increasing the blast energy from 180kcal/t to 350kcal/t. A total cost saving of 13.3% ($9.4M) was achieved with the increase. An optimal blast design should consider both slope stability (safety) and downstream comminution energy (production).

Feb 23, 2014

By James W. Derrick

General widespread interest in fine coal cleaning circuits did not occur in the United States until the mid 1960's. Up until this period the relatively low price for which bituminous coal was sold did not justify for many operators the capital and maintenance costs associated with the beneficiation and drying of fine coal. However, with current growing interest in this area, the introduction of new types of process equipment along with modifications to existing components is occuring to maximize the recovery of coal fines. In 1973 Derrick Manufacturing Corporation introduced high frequency screening machinery into the coal industry. The first design consisted of a 4 ft. wide 18 ft. long single deck screen frame with three 100 mesh woven wire screen surfaces divided by repulping troughs for the addition of wash water. In addition, a special slotted rubber dewatering deck was installed on the discharge end of the unit to assure adequate dewatering of the screen oversize. This panel had nominal 25 mesh X 3.0" slotted openings. The machine was also equipped with a special high speed-low amplitude (3600 RPM .032" % AMP.) integral vibrator.

Jan 1, 1983

By Hong Yong Sohn, Miguel Olivas-Martinez

"Different approaches are used for calculating the ‘energy requirement’ of a process. The determination of energy requirement becomes confusing for a process in which a fuel is also a reactant. The key issue is which heat of chemical reaction should be included in the ‘energy requirement’ value. We will use the example of ironmaking processes to illustrate the problem. The different approaches essentially boil down to the question: does one include the combustion heat of the reductant used in the reduction reaction or just the heat of the reduction reaction? Depending on the viewpoint, either approach can be accepted; it is a matter of convention. There is a need, however, to select a standard approach because the absolute value of ‘energy requirement’ of a process depends on the choice. The energy requirement of a novel flash ironmaking process will be compared with that of an average blast furnace operation.IntroductionDifferent approaches are used for performing energy balance calculations and perhaps more significantly in presenting the ‘energy requirement’ of a process. The question becomes more involved for a process in which one or more reactants are also used to generate the process heat by combustion. Often the key issue is which heat of chemical reaction to include in presenting the ‘energy requirement’ of the process.It is worthwhile to note at the outset that the difference in energy requirements between different processes for converting similar raw materials to the same desired product is largely unaffected by the choice of chemical reactions to be included. However, the absolute value presented as the ‘energy requirement’ of a process can be different by a large amount depending on the approach. We use the example of ironmaking processes to illustrate the problem. In these processes, as currently practiced or under development, carbon and/or hydrocarbons (including hydrogen) are used as the fuel as well as the reactant for reducing the iron oxide mineral.The different approaches in this case essentially boil down to the following question: does one include the combustion heat of the reductant used in the reduction reaction or treat the reductant portion as just a reactant? Depending on the viewpoint, either approach can be considered acceptable. It is a matter of convention. There is a need, however, to select a standard approach because the absolute value of ‘energy requirement’ of an ironmaking process (e.g., the currently dominant blast furnace process) depends on such a choice. It is particularly important to clearly state the specific approach used when the energy requirement of ironmaking is compared with those of other industrial processes such as petrochemicals production."

Jan 1, 2014

By Alexis Baca

La presente investigación busca optimizar la producción y la ventilación en la industria minera, utilizando el método de ratios de energía y producción. Para ello, hace la estimación del consumo de energía en ventilación, obteniendo los ratios de producción en la unidad Huarón y aplicando estos para determinar la eficiencia del consumo en cada zona, logrando un comparativo de costos para conseguir una distribución eficiente de la ventilación. Asimismo, recomienda formas de optimizar el consumo de energía por ventilación mediante el uso de los ratios de energía y producción.

By Jun Li, Lin Chen, Tian-zu Yang, Wei-feng Liu, Wan-da Bin

"The Chinese bismuth production accounts for more than 80% all over the world in 2011. The main raw materials of bismuth smelting are bismuth concentrate and by-products of Cu or Pb smelting process. Many traditional methods of bismuth smelting in china was reviewed in this paper, such as reverberating furnace smelting, blast furnace smelting, fire-refining, ferric chloride leaching-hydrolysis, slurry electrolysis, and so on. But all the traditional pyrometallurgy or hydrometallurgy process have such shortages of low recovery, poor environment, and high cost. Therefore new technologies are introduced into the smelting process of bismuth concentrate, such as low-temperature alkaline smelting and side-blown bath smelting with oxygen-enrichment. These technologies have got great progress on energy saving, emission reduction, and friendly environment. Finally the development direction of new technology on bismuth smelting was prospected.IntroductionAs a green metal, bismuth has a wider applications, just extending from the traditional medicine, metallurgical-chemical engineering, low-melting alloys, solders, catalyst, and electronics to cosmetics, flame retardant, storage battery, semiconductor, supper conductor and nuclear energy etc[1,2,3,4,5,6,7]. This will increase the production of bismuth and promote the development and progress of bismuth smelting technology. At present, The major bismuth-product countries are China, Mexico, Peru, KZ, Bolivia and Canada etc, and China are dominating. A survey from the USGS[8] showed that Chinese bismuth production were 12,500 tonnes and got 80% of the world's in 2011. Thus the technology of Chinese bismuth smelting have a great representativeness."

Jan 1, 2013

By James T. Ludwiczak

Drilling and blasting in a Karst (sinkholes and mud seams) environment has long been a problem for blasters, miners, quarry operators, contractors, and developers. While one cannot change the geological conditions, one can take some measures during the bidding process and the initial preparation of the blasting program to help reduce some of the problems. During the geotechnical investigation and developing the test/core drilling grid, the owner/developer needs to take some additional measures that will provide important data to the blaster to help reduce the problems associated with blasting this type of geology. The owner/developer must also understand that, due to the geologic conditions, the results of the blasting will not be ideal and there may be additional blast-related costs. If provided the proper geologic data, the blaster can develop drilling patterns and blast designs that will help reduce some of the more problematic areas.

Jan 1, 2005