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By Alfred L. Anderson

Thorite and rare earth deposits in the Lemhi Pass area of southeastern Lemhi County, Idaho, are contained along complex shear and fracture zones and in reopened gold-quartz veins and copper lodes in quartzitic and phyllitic rocks of the Pre-cambrian belt series. Some of the shear and fracture zones are several tons of feet across and comprise broad zones of irregularly mineralized rock. These lodes contain a notable concentration of thorium and rare earth elements along with considerable amounts of barium, .potassium, calcium, iron, aluminum, phosphorus, sulfur, and silicon. The principal minerals are thorite, locally allanite, monazite, xenotime (?), apatite, specular hematite, barite, potash feldspar, occasionally calcite and quartz. Exept for some of 'the specular hematite, barite, reddish feldspar, calcite and quartz, the minerals are not distinguishable without the microscope. The thorite and locally allanite were deposited first, then the monazite and other phosphates, which were in turn followed successively by barite, potash, feldspar, calcite, and quartz. In exceptional cases, deposition of thorite and specular hematite was repeated after the feldspar. Some of the deposits contain several percent thoria, but the average os generally under one percent. The rare earth content is comparable with that of the thoria. The deposits appear to be of hydrothermal origin and are probably related genetically to late Cretaceous or early Tertiary igneous activity, manifested locally by a few dioritie and lamprophyric dikes.

Jan 1, 1959

By Dale R. Andrus

Why is there such an increased thrust toward positive multiple use land management and where will it lead? History and purpose of the mining law of 1872. John Marshall discovered gold at Sutter?s mill near Coloma, California, on January 19, 1848, and utter chaos resulted. The great migration of people to the undeveloped western lands had begun. Prior to this discovery, copper, lead, and iron had been the minerals for which the laws were made. With this discovery of gold on the public domain, it became apparent that congressional legislation was necessary. This became even more apparent as each of the numerous mining districts which were springing up in California, and elsewhere in the west adopted local miners' customs to regulate their activities. Although these early miners acted under mining district rules and in some cases state regulations, they were, in reality, appropriating minerals without sanction of federal law.

Jan 1, 1970

By Kanhaiya Mishra, Phanil. K. Mandal, S. K. Behera, P. S. Paul, Prashant Singh, C. N. Ghosh

The techno-economic and social benefits of cemented paste backfill (CPB) resulted in its wide acceptance by the mining industry. The Ordinary Portland Cement (OPC) remains the key binder but to diminish its economical constraints, suitability of alternate binders has been examined worldwide. The present study aimed to investigate the effect of partial replacement of OPC with fly ash on the CPB’s strength and to determine the most optimal mix to achieve the required strength (1 MPa at 28 days of curing) at the most cost-effective way using the Bayesian network (BN). The CPB mixes were prepared at 72 wt.% solid concentration with mill tailings (87–91%), OPC (6–13%), and fly ash (0–4%), and instantly after mixing, fresh (slump, bleeding, density) CPB properties were measured. The strength was tested at 7, 14, 28, and 56 days of curing and initially analysed through traditional model. The traditional models follow the aleatory principle and are considered not appropriate for geotechnical engineering. Hence, the BN model was developed and tested. The reliability of two classifiers in learning model structure was compared which gives Naïve Bayes as the highest reliable tool. The CPB’s strength is most sensitive to the OPC content. The most consistent mix(s) is mill tailings: 87–88%, OPC: 9–11%, fly ash: 1–4%. Adding fly ash at 89–91wt% mill tailings possesses high failure probability of the CPB. The collinearity test indicates that the fines percentage and chemical composition of CPB’s ingredients are highly correlated with its slump, bleeding, and strength development.

Jul 14, 2022

By A. J. Basu

Rock mass properties testing for determining strength parameters is an integral part of geomechanics. These tests are performed either in a laboratory environment or in a field (in-situ). The authors share their experience in using numerical modelling in simulating the laboratory test procedures. This approach helps studying the rock breakage and failure mechanism more efficiently and provides a high degree of visualization. Moreover, imperfections and discontinuities can be easily incorporated in these models. This capability of providing arbitrary fractures and discontinuities facilitates in building a large knowledgebase of rock strength and failure mechanisms. This knowledgebase may then be used to generate heuristics for determining rock strengths for rock mass with fractures and discontinuities.

Jan 1, 1997

By Henry E. Reed

This presentation is about a small company, Industrial Mineral Products, that was formed in 1972 with one product and one customer and by a series of value-added changes avoided disaster and increased sales many times over. The principal of the company stopped by my office in Seattle looking for industrial mineral opportunities in the Northwest. We got together and went through all the minerals in Ladoo's "Industrial Minerals" from Abrasives to Zircon to see if we could find something available on the vast holdings of the Burlington Northern. At that time one of our lessees was operating a silica sand mine near Ravensdale, Washington and indicated that he might be interested in selling out. This sounded interesting to my client and within two weeks the transaction was completed.

Jan 1, 1990

By G. P. Larson

We define a specialized mineral market as follows: Specialized Markets are markets where a low volume of a given mineral is used to convey a large benefit to a specific product. Sales of these value added minerals to small markets generally require a different marketing approach compared to bulk or commodity markets for traditional minerals. Specialized and commodity markets are differentiated by several characteristics as listed in Table 1.

Jan 1, 1990

By K. Kim, T. M. Yegulalp

A new explanation of the scale dependency of rock strength is presented based on the theory of extremes. A brief review of past work on specimen size and strength relationship is followed by an introduction to the fundamentals of the underlying theory of extremes and its relationship to the scale effect. It is shown that the weakest link theory is directly related to extremal statistics and that parameters of strength distributions of rock can be derived as a function of the specimen size. Three sets of Brazilian test data are used to demonstrate the use of this approach.

Jan 1, 1994

By J. K. Shurie

Calcined high quality bauxite is a staple raw material of the abrasive industry world-wide. The author discusses the factors which affect the economic value of calcined abrasive grade bauxite, and proposes an approach to the problem of estimating the relative value of available materials.

Jan 1, 1990

By Thomas Novak, Sampurna Arya, Joseph Sottile

Dust generation and its dispersion in a longwall mine pose significant health and safety issues. The concern is prominent at both the working face, where coal excavation exposes workers to high dust concentrations, and also in the return, where float dust accumulates. To address this issue, researchers at theUniversity of Kentucky designed and fabricated a flooded-bed dust scrubber integrated into a full-scale physical model of a longwall shearer. This mock-up was installed in the longwall test gallery at the Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH). A full-factorial experiment was designed to measure the effectiveness of the scrubber on dust capture. Test results indicated dust reduction of up to 57% in the return airways. This paper presents the development of a computational fluid dynamics (CFD) model and its validation by comparing the simulation results against the experimental results. The CFD simulations show good agreement with experimental results with differences between + 6.9 and − 9.7%. The validated CFD model was used further to predict the scrubber performance under additional operating conditions, resulting in a dust reduction of up to 66.5%. With this level of success, the scrubber concept can be a game changer for the mining industry, and it can be utilized to improve health and safety in longwall mines.

May 26, 2020

By ZHONGLING ZHAO, WANTING SONG, GUOZHONG LIU, LEIXIN SHI, ZUI WANG, YUANYUAN LIU, KE GAO, DONGHONG JIANG, WANG LUO, PEICHAO LU, Jianwei Cheng, WANCHENG ZHENG, Gang Zhao, YUNGANG WANG, JIANBING ZHAO

Coal spontaneous combustion is one of the disasters occurring in underground coal mines. As a typical case, the spontaneous combustion of broken coal left in the longwall gobs often happen which could greatly interrupt the normal mining production. Such concealed thermal event is featured as rapid development and difficulty in locating “hot” spots. If such spontaneous combustion fails to be timely prevented and controlled, a large amount of toxic gases (mainly CO) and smoke could flow and diffuse in the underground working sections, which could present safety hazards for coal miners. In this paper, based on an coal spontaneous combustion event happened in a Chinese gassy mine, the fire ratios derived from the gas composition data obtained through the tube bundle mine atmospheric monitoring system are used in determining the fire status. A comprehensive and collaborative fire extinguishing effort including inert gas injection, underground pressure balance, and sealing enhancement are made to control the fire progress. Simultaneously, the effects of such works to control the spontaneous combustion event have also been quantified using the fire ratios to justify again. Finally, the danger of coal spontaneous combustion in gob is eliminated, and the longwall panel is successfully re-opened for normal production.

May 6, 2021

By John Dodd

Corrosion studies in laboratory ball mills and grinding environment simulations produce corrosion rates and total metal removal rates much lower than those recorded in operating production ball mills. The corrosion component of ball metal loss in commercial mills represents less than 10% of the total loss expressed as micrometers/hour of exposure in recent USBM tests. Such small absolute losses are consistent with ball metal loss measured in production ball mill marked ball wear tests to determine effects of corrosion and abrasion resisting properties of alloys in operating mills which indicate that metal hardness and microstructure determine relative metal loss rates of a given situation. The combination of ore characteristics and grinding process dynamics determine metal loss severity. Alloying for corrosion resistance and modification of the milling corrosion environment yield relatively small metal loss reductions. Alloying and heat treatment to produce high hardness and microstructures of high carbon martensite and for cast irons, M7C3 carbides produces the lowest metal losses in typical wet grinding applications.

Jan 1, 1984

By R. R. Klimpel

The process of flotation is an extremely important solids separation technique employed in a wide variety of industrial process applications. Froth flotation is practiced in the coal industry to recover fines produced during the mining and cleaning of coal. A recent review article by Aplan (1) covers the processing variables encountered in the flotation of coal and the variety of chemicals and operating conditions which affect recovery. Numerous engineering and scientific studies have been performed with the goal of providing semifundamental laws of flotation behavior for improved screening of flotation chemicals, better equipment scale-up factors, etc. Often the results of such work are expressed in the form of mathematical models (e.g. 2, 3, 4, 5, 6) which are potentially useful for evaluating (simulating) on paper such alternatives as possibles process operating or configuration changes, the effects of ore and reagent changes, etc. It appears to be commonly accepted that a complete scientific/engineering characterization of flotation is immensely complicated and not sufficiently developed at the present to accurately predict (or understand) many important industrial facets of flotation. Thus, one is often reduced to detailed experimental characterization in both the laboratory and plant in order to fully evaluate flotation changes or alternatives. It is the purpose of this paper to describe a method of batch laboratory data characterization that is useful in evaluating flotation chemical reagents including froth flotation of coal. The approach consists of running a series of time-recovery curves in a batch float cell followed by the computer curve fitting of this data to a series of mathematical models based on semi-physical reasoning. The unknowns or parameters of these models are then optimally chosen so as to best fit the experimental data. It has been found in both coal and mineral systems that changes in reagent type, concentration, system pH, grind, etc. cause very consistent and logical changes to

Jan 1, 1979

By John Keefner, Charles Kocsis, Kyle A. Scalise

Geotechnical modeling of mines is crucial for understanding the many factors that can pose potential hazards or limit production opportunities. The process of back analyses for modeling is often used, but in many instances, the back analyses can be cumbersome and time inefficient.While thesemodels and back analyses may be accurate, these types of back analyses may not be ideal to be used at mines and by engineers because the process is so time-consuming. This paper introduces event-based back analyses that utilize prior events to create more accurate models while eliminating large modeling time because the models are back analyzed from previous events. The completed analyses supply a more detailed insight into the potential hazards at Round Mountain, an open pit operation, as well as provide a better understanding of how improper risk analysis results in missed opportunities. The more we understand about mining activities and processes through modeling, the safer and more productive mines will be.

May 24, 2021

By Saurabh Kundu, Shakuntala Tudu, Indrajit Paul, Chandra Sekhar, Manikanta Nallamilli, Shaik Mahaboob Basha, Neha Gupta, Srinivas Dwarapudi, Dhiraj Madhukar Kadhe

Iron ore pelletizing using compressive and shear action on wet mixture feed has been studied. The physical properties, namely, moisture content, drop strength, green compressive strength (GCS), dry compressive strength (DCS), porosity, and cold crushing strength (CCS), have been studied. Pelletizing tests were carried out on four different types of ore, namely, hematite ore, magnetite ore, goethite ore, and sinter return fines. The inference of shear forces on silica distribution index in dry pellet has been studied using optical and scanning electron microscopy. Significant improvement in physical strength was observed due to compressive and shear forces on the pellet mixture feed. However, decrease in moisture content and ball porosity has been observed. Silica distribution index improved by 1.72 times for hematite ore, 1.47 times for magnetite ore, and 1.68 times for goethite ore. It has been found that bubble cavity has been reduced which is good indicator in terms of physical properties.

Jan 29, 2022

By Richard J. Robbins

Mechanical raise and tunnel boring are new techniques to most of the mining industry. Coal, salt and potash have been bored economically, but until recently boring machines were not designed specifically for rock boring in underground mining. The construction industry has led the field of rock boring since 1854 when the first tunnel boring machines built by James S. Robbins and Associates went to work at Oahe Dam, South Dakota. Since that time the company has built boring machines for tunneling through ground conditions varying from cohesionless soil to hard rock, and in diameters ranging from 7 feet to 36 feet 8 inches. It is natural that the construction industry got the jump on mining with the use of mechanical rock boring equipment. Mines have looked for the long range answer to problems of underground excavation and they have chosen proved and established techniques they expect to employ for the next ten or twenty years. The mine development was laid out to accommodate these techniques.

Jan 1, 1964

By Edward J. McNamara

Sulphur as an element has been used for centuries. The technique of storing, handling and transporting it in its various forms has changed through the years. Freeport Sulphur Company, a division of Freeport Minerals Company, has produced sulphur since 1912. The first storing and transporting of this product as a liquid began in 1947. Significant environmental problems occurred in the handling of solid sulphur in the late fifties and early sixties. Since the sulphur WAS produced in the liquid form and the major customers used it in the liquid form, it became obvious that a liquid transportation system was the solution. The liquid sulphur delivery eliminated the dusty and hazardous handling problems and the contamination of the sulphur by dirt, acid, moisture and other materials. The remelting by the customer to use the sulphur is thusly eliminated with a savings in energy. In addition, this change in the mode of handling permitted a broad development of new sulphur mines in the marshy coastal area of Louisiana and offshore in the Gulf of Mexico.

Jan 1, 1978

By Glenn E. Craig

The practical and effective pulp distributor here presented is believed to be of a completely new and innovative design. It was developed at the San Nicolas Plant of the Marcona Mining Company in Peru, where it has been thoroughly plant tested using iron ore slurries of a particularly abrasive nature. It has proven to be superior to the apparatus originally installed, or to any observed in operation elsewhere. In plant practice the capacity and efficiency of many process units such as screens, magnetic separators, and jigs are strongly affected by the loading pattern, and for better results the flow of pulp must be proportioned across the receiving lip in equal quantities per unit width. The distributors originally installed on the drum magnetic separators in San Nicolas proved to be unsatisfactory, and several trial modifications failed to show any improvement. As is usually the case, feed rates were being steadily increased, and appreciable losses to tailings resulted. A check of the distributors on the market discloses no reasonable substitute, so efforts were directed toward devising an entirely new type. Required was a positive type of action which would guarantee that the pulp flow be spread equally along the length of the drum. Discussion As indicated, the motivation for development was simple necessity. The plant in San Nicolas crushes, grinds, and concentrates magnetic iron ores of a particularly abrasive nature, and depends largely on magnetic separation to obtain a marketable product. Feed to the numerous drum magnetic cobbers and finishers varies from rod mill discharge at a nominal minus ten mesh to a ball mill fine grind of seventy percent minus three hundred and twenty-five mesh. Operational factors affecting the magnetic separators were well controlled,

Jan 1, 1971

By F. M. Benavides

This paper presents recent developments in federal environmental regulations, which in the view of the author, affect mining and the mineral processing industries. This is a summary of activities by the administration, congress and regulatory agencies during 1990. The information presented is a recap from material published. The emphasis is given to Air Quality regulations, although other environmental concerns are reviewed.

Jan 1, 1991

By Geo. A. Wells

Abstract The consumption of barytes in certain paints polyurethane foams, seamless, flooring, glass, brake linings, plastisol caskets for food containers and in fluids used for gastrointestinal X-ray examinations rely on tie unique properties of barium sulfate, There are no readily available mineral substitutes. Barytes are also the essential raw material for the manufacture of industrially important barium chemicals. High quality barite ore has become scarce throughout the world. Processing ore into quality end products is both capital and energy intensive. These factors have tended to limit availability and increase prices which have encouraged the use of alternates and restricted market growth.

Jan 1, 1980

By J. Kretschmann, K. van de Loo, J. Brune

In 2018, the German Federal government decided to phase-out the energy production using coal-fired power plants and to terminate lignite mining completely by 2038 at the latest. This decision will impact approximately 60,000 jobs. It will have an enormous impact on the socioeconomic development especially in all German lignite mining regions. To avoid economic and political friction, it is of utmost importance to achieve a sustainable transition towards a post-mining era and to offer residents in the mining districts perspectives for a good future that include adequate job opportunities. In this context, the German government is providing massive structural aids early on. As previous closure experiences from the German hard coal mining industry have shown, it takes at least a generation to overcome the effects of a strategic closing decision of this magnitude. Therefore, the planned closure process appears to be a long time at first glance. In fact, however, it is not.

Mar 2, 2022