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By G. Boehler

The purpose of this program is to demonstrate the feasibility and practicality of noise control for secondary and tertiary crushers in surface non-coal mining plants and mills. It is a part of the broad Bureau of Mines program to reduce noise in mines to levels mandated in the Coal Mine Health and Safety Act. Utilizing the results of previous contractual research efforts in which noise levels of secondary crushers had been measured, two noise enclosures were designed and evaluated for the REXNORD Symons 7-ft diameter secondary and tertiary crushers installed at the Jackson County Iron Company, in Black River Falls, Wisconsin. The first enclosure had a circular shape following closely that of the crusher and was built up entirely of quick-release panels which can be handled by the crusher operator alone. The second enclosure was octogonal in shape and can be rapidly removed, partially or totally using an overhead crane. Both enclosures fully satisfy the noise reduction objectives and permit daily and long-term maintenance of the crushers. Cost analyses show the cost of the enclosure to be less than 10 per cent of the cost of the crusher, the cost of the octagonal enclosure being estimated at only 60 percent of that of the circular one, e. g. $15,000 against $25,000. It is concluded that the octagonal enclosure best meets the needs of the Jackson County Mining Company and it is recommended that an experimental enclosure be built at the earliest possible time, as proof-of-concept.

Jan 1, 1977

By Zhongwei Wang, Dong Wang, Feng Ju

The coal seam in the southern coal field of the Ordos Basin serves as the main aquifer, while the region is known for its high-intensity coal mining activities. The coupling effect of mine water and the strong disturbance caused by high-intensity mining have brought serious challenges to the stability of coal pillars. To address this, a formula for determining the reasonable width of coal pillars under the aforementioned coupling effect and establish a criterion for coal pillar instability in this paper. A case study was on the 11,215 working face at the Xiaojihan coal mine in the area to investigate coal pillar stability. Results indicate that the strength and stability of the coal pillar are affected by the water content, with a small water content increasing its strength and large water content weakening it. In high-intensity exploration of watery coal seams, the best stability of the coal pillar is achieved at optimal water content and mining rates. For the Xiaojihan coal mine, the optimum water content and mining rate are 3.31% and 20 m/d, respectively, ensuring the efficient mining of watery coal seams. Furthermore, this study's findings can provide valuable references for the mining design of coal mines with similar geological conditions in the region.

Feb 13, 2024

By T N. Little

The aim of any rock breaking activity is to achieve success by developing designs that are blasting objective-specific and geology-specific, and then implementing such designs. This paper targets mining geologists with the aim of extending their knowledge of the rock fragmentation processes and providing insights to the significant relationships between geology and blasting. There are two main relationships, and if mining geologists appreciate both these relationships, then they can play a key role in optimising production. The business risk continuum is introduced to support this understanding. The first relationship is between geology and potential blasting hazards, and the operational complexity required to manage those risks. The risks associated with eight different ground types are discussed in terms of ground conditions, hazards and controls. These types are: reactive ground, hot ground, geothermal ground, fibrous ground, cavernous ground, combustible ground, pyritic ground and conductive ground.The second relationship is between the bench geology and blasting results. The blasting results discussed include: muckpile characteristics, remaining rock faces and blasting emissions. In this regard, some detailed insights and graphical examples are given for the influence of geology on blasting emissions, in particular, vibration, airblast and flyrock.A detailed description of the geological materials themselves can convey much useful information for blasting operators provided they are able to utilise this knowledge. Geologists are ideally suited to provide this description more effectively if they are familiar with the blasting process and the rock mass properties that influence blasting hazards and blasting results. It is also important to have clear statements of blasting objectives and associated operational targets, and this will maximise the likelihood of achieving the desired outcomes. The main aim of the paper is to highlight that geology is currently not fully utilised in the blasting process. In this regard, geologists are often not entirely aware of the blasting process and how they can contribute. The two significant relationships discussed above are integral parts of this process, and thus they are discussed as separate issues in the main body of this investigation.

Aug 22, 2011

By M. E. Buzon, M. E. Gunter

Talc has been the focus of recent civil litigation based on claims that asbestos minerals exist in talc deposits and therefore have caused asbestos-related diseases in those who have regularly used talc products. Such litigation, and ensuing confusion over the petrology and asbestos content of these deposits, challenges the talc mining industry in Montana and elsewhere in the world. The talc deposits in southwest Montana were formed by hydrothermal alteration of dolomitic marbles and are still actively mined. In general, talc formed by hydrothermal alteration of preexisting carbonate rocks is known to be nearly monomineralic and lacking in amphiboles. This paper includes data from analyses of representative ore samples from this mining region in southwest Montana. The results conclude that the presence of asbestos minerals — both amphiboles and chrysotile — is unlikely and that the ores are nearly monomineralic, as expected. Samples were characterized using a suite of analytical methods, namely, powder X-ray diffraction, X-ray fluorescence spectroscopy and electron microprobe analyses, which allowed us to determine the minerals present and the formation process. Our data and interpretations suggest that previous identification of asbestos minerals in these deposits is not accurate.

Jan 1, 2018

By M. E. Buzon, M. E. Gunter

Talc has been the focus of recent civil litigation based on claims that asbestos minerals exist in talc deposits and therefore have caused asbestos-related diseases in those who have regularly used talc products. Such litigation, and ensuing confusion over the petrology and asbestos content of these deposits, challenges the talc mining industry in Montana and elsewhere in the world. The talc deposits in southwest Montana were formed by hydrothermal alteration of dolomitic marbles and are still actively mined. In general, talc formed by hydrothermal alteration of preexisting carbonate rocks is known to be nearly monomineralic and lacking in amphiboles. This paper includes data from analyses of representative ore samples from this mining region in southwest Montana. The results conclude that the presence of asbestos minerals — both amphiboles and chrysotile — is unlikely and that the ores are nearly monomineralic, as expected. Samples were characterized using a suite of analytical methods, namely, powder X-ray diffraction, X-ray fluorescence spectroscopy and electron microprobe analyses, which allowed us to determine the minerals present and the formation process. Our data and interpretations suggest that previous identification of asbestos minerals in these deposits is not accurate.

Jan 1, 2017

By Euler De Souza, Kyle Penner

"Booster fans play an important role in assisting main fans by boosting the air pressure of the ventilation air passing through it. The correct placement of underground booster fans in a mine is a critical decision since it not only influences the mine’s operational capacity in terms of costs and efficiency, but also affects safety and environmental conditions. There are many booster fan installations around mines that are inappropriate, in some cases resulting in system failure (fan stall) or in a major negative impact on mine production. Inadequate booster fan placement has resulted, in some cases, in extensive air leakage which has compromised the economics of the operation and, in other cases, in recirculation of contaminants which has seriously compromised safety. This paper provides guidelines for proper design and siting of booster fans underground, to not only achieve an economic ventilation system but to create safe work conditions and efficient atmospheric conditions. Procedures for the planning, installation, operation and maintenance of booster fans are also presented. A case study illustrating the design and siting of a major booster fan installation in a potash mine, supported by computational fluid dynamics analysis, is presented.INTRODUCTIONIn large underground operations with complex ventilation networks offering high resistances, the never ending increased required quantities of air can almost only be supplied through use of high pressure main fan systems. These fans may, in effect, induce significant leakage losses in the system, having a negative impact on safety performance. In such cases, booster fans can be designed to decrease the main fan pressures and reduce the leakage flows, improve system efficiency and reduce costs. In well designed systems, booster fans can thus be used to redistribute the airflow and assist the main surface fans.When the pressure supplied by the main fans is insufficient to meet the ventilation circuit pressure requirements, booster fans are placed in strategic locations where pressure boosting is essential. Booster fans are typically sited in sections of the circuit offering high ventilation resistance and requiring this form of ventilating air motivation. Booster fans are thus required when the mine expands, and so the resistance of the ventilation network, and the primary fans no longer can supply the required pressure and flow."

Jan 1, 2019

By Fearnsides W. G.

The second part of the paper, presented at the Midland Institute of Mining, Civil and Mechanical Engineers' general meeting held in Doncaster on 27th May 1916, addresses the post-Carboniferous and pre-Permian movements which brought about the partition of the area and gave to the North Midland district its individuality as a separate coalfield. As earth-movements of several ages subsequent to the Carboniferous have played a part in the formation of this particular coalfield, the aim is to elucidate the effects which belong to the post-Carboniferous and pre-Permian Period and to disentangle them from those of later date. This is done by comparing the geometry of the folded surface of one of the more important horizons in the Coal-Measures with that of the surface of unconformity which divides the Permian from the Carboniferous rocks in South Yorkshire, Derbyshire, and Nottinghamshire

Dec 1, 1916

By Robert Boehnke, Bernd Mueller

This contribution presents an innovative, statistically supported method to predict blast vibrations in rock mass. For modelling the processes during and after detonation, a theory is employed which is based on linear momentum (so-called momentum theory), strongly supported by new measurement methods. During the course of the investigations, the following parameters have been found to dominantly influence vibrations: ! charge WB, includes geometrical factors such as borehole length and diameter (kg) ! detonation velocity cd of the explosives used (m/s) ! distance r between the points of emission and immission (m) and the statistically determined negative exponent n ! factor RM or RS of the rock mass which is related to the specific blast momentum and the drilling and blasting technique used and is statistically determined together with the exponent m (mm/kg or mms/kgm)

Jan 1, 2004

By Michael L. Wayman

Archaeological and ethnographic work during the last century has shown clearly that metals have played a small but important role in prehistoric Arctic cultures. For at least the past several millenia both iron and copper have been used in the North, primarily for blades, projectile points, knives, awls, engraving tools, fishhooks, scrapers and axes. In addition they were used for joining purposes as staples and rivets. It is of great interest to enquire into the origins of these metals. In this connection one begins with the observation that to date there has been no clear evidence for the smelting or melting of metals in the Arctic prior to the arrival of Europeans. This can be explained partly by the absence of traditional pyrotechnologies such as the high-temperature firing of ceramics and the heat treatment of bone and wood. Another factor which surely inhibited the development of smelting/ melting operations is the relative absence of wood in the region. The production of charcoal for smelting requires large quantities of wood, to the extent that the desertification of a number of areas in the Old World is believed by some to have been at least partly caused by charcoal production. In the North this was obviously not possible. Thus the Arctic peoples were restricted to using native (naturally occurring) metals and metals obtained by various direct and indirect forms of contact with areas of the world where smelting was practiced. Both of these sources were important in the case of iron; we know that meteoritic iron, telluric (native) iron and smelted wrought iron were all used in the Arctic. These three types of iron will be considered in tum.

Jan 1, 1999

By CARLE R. HAYWARDC

BEFORE discussing this subject it is necessary to define somewhat the meaning of the tern metallurgical.. When I was a student at M. I. T. ore-dressing was not thought of as metallurgy in any sense of the word, but it was considered as more closely allied to mining, enabling the miner to market an otherwise unmarketable product, or at least to market it to better advantage. Progress in ore-dressing has gradually allied it more closely with smelting, for at present the raw material received by the smelter is predominantly concentrates and smelting practice has been profoundly affected by the products of the concentrating mill. It is not surprising therefore that in many schools ore-dressing is frankly considered as metallurgy and although there may be some dissenting opinions it will be considered as such in this discussion. Twenty-five years ago at M. I. T. metallography was taught in a few optional lectures. This subject has developed rapidly and been expanded into the new and increasingly important field of physical metallurgy. To many metallurgists the -term metallurgy means only physical metallurgy. They know little or nothing about smelting and leaching and even less about ore-dressing. Having then broadened the scope of the term metal¬lurgy to cover ore-dressing, smelting, leaching and phys-

Jan 1, 1930

By Lawrence L. Brown

As part of the Federal effort to help maintain an adequate supply of fertilizer materials, the Bureau of Mines conducted research to characterize complex low-grade Michigan phosphate materials and to devise methods for recovering fertilizer-grade phosphate concentrates. The rock is from middle Precambrian sedimentary formations in the Marquette Range located in the central part of the Upper Peninsula of Michigan. Occurrence of phosphate-bearing sediments in Precambrian rocks is rare. This deposit, containing 12 to 15 pct P2O5 is believed to be the richest Precambrian phosphate deposit in the United States. Petrographic examination showed that the conglomeritic rock contains crystalline apatite both in "black pebbles" and in quartz matrix. Attrition scrubbing and sizing tests showed that there is no tendency for phosphate to concentrate in any of the sized fractions. In beneficiation tests, which included grinding to minus 325 mesh followed by phosphate mineral flotation using a fatty acid-fuel oil collector, a phosphate concentrate was obtained that had a grade of 30 pet P2O5 and a P2O5 recovery of 72 pct. This concentrate should be suitable for fertilizer manufacture.

Jan 1, 1982

By Lachezar Tsotsorkov

Being a mining company, Assarel-Medet has a significant impact upon the environmental components. In order to meet the legal requirements and the requirements stipulated by the effective permits as well as to reduce the environmental imprint throughout the years, the policy of the company to implement a number of projects to improve the environmental components quality and the environmental state in the company?s region. The projects associated with atmospheric air quality management and reduction of the impact exercised by Assarel-Medet JSC by implementing various measures to eliminate the potential sources of the impact, preventive and rehabilitation initiatives as well as organizational and administrative activities are among the most important ones. A stable improvement of atmospheric air quality in the region and minimization of the company impact upon the ground air state in the region was observed in the period from 2005 to 2012 due to the applied measures. This project is a contribution to the environmental protection, in particular to atmospheric air protection, by applying integral monitoring and modeling methods to identify the negative impact by the mining companies and plan measures to reduce and restrict it as well as to improve the quality of the environment and living area of people working and living in the impact range as an element of sustainable development.

Aug 1, 2013

By Walter Miller

PETROLEUM refining, like other industries in the United States in 1940, focused much attention on its duties and opportunities in the field of national defense. In counter-distinction to the situation during the World War; the industry is well constituted as LO existing equipment, processes, and capacity together with planned additions to handle any demands that may be made upon it by the defense program needs. Evident throughout was the growing sense of ability to manipulate oil molecules for the production of materials not hitherto considered as being available commercially from petroleum The development and application of catalytically-induced reactions on a broad front is one of the distinguishing characteristics of refining progress during the year.

Jan 1, 1941

Located 350 km west of Sydney and 20 km outside Orange, NSW, lies the Ridgeway Gold Mine û NewcrestÆs flagship Underground Gold Mine. Key to success at Ridgeway has been the fast tracked development of the 3.8 km, 1 in 5.3 conveyor decline which houses the 850 t/hr conveying system feeding the dedicated Ridgeway Concentrator, built adjacent to the existing Cadia Hill Concentrator. Eroc was contracted to develop the steep conveyor decline, drawing on its personnel and experience from past metalliferous, tunnelling and coal mining projects to complete the ambitious schedule within 12 months. This paper deals with the complexities and experiences in safely delivering what is understood to be one of AustraliaÆs steepest declines of any substantial length in a metalliferous mine.

Jan 1, 2002

By Chiranjibi Santi, Amit Kumar Gorai, VIVEK KUMAR HIMANSHU

Air overpressure (AOp) and peak particle velocity (PPV) are the most undesirable effects of blasting in mines. It is an urgent need to design a predictor model for AOp and PPV for universal applications to minimize environmental effects and damages that occur due to blasting. The present study attempts to design an artificial neural network (ANN) model for the prediction of AOp and PPV in different conditions. In this study, the blast design parameters (number of holes, depth of the blast hole, stemming length, spacing, burden, distance of vibration monitoring location from the blast site, charge weight per delay) of two active mines (coal and iron ore) are considered in four different conditions for training and testing of the model for the prediction of AOp and PPV. The model was trained and tested in four different combinations of data (trained using data of one mine and tested using data of another mine, trained and tested using data of coal mine, trained and tested using data of an iron ore mine, trained and tested using combined data of both the mines) for examining the applicability in different conditions. The results indicate that R2 values are ranged from 0.886 to 0.908 and 0.8728 to 0.8959, respectively, in the prediction of PPV and AOp. A comparative study of the performances of the developed model with the other empirical model is also demonstrated. For this, the site constants of different empirical models were estimated individually for both the mines. The study results indicated that the ANN model performs much better than all the empirical models. It can be inferred from the results that blast vibration cannot be accurately predicted only from charge per delay and distance from the blast hole. The ANN model was considered many other factors and thus can predict the vibration level more accurately.

Jul 30, 2021

By A. H. C. A. Zimmerman

WE have just heard what must be regarded as a thoughtful, constructive and somewhat painful analysis of the financial function of our industry. While thinking about this, it is interesting to reflect on the conditions which have stunted the growth of the financial side of our affairs. Mining must be regarded as a wealthy business. •while immeasurable grub takes and development budgets have been lost, there can be little argument that a productive ore-body nearly always produces the type of wealth that breeds some extravagance. I recognize that this statement can be attacked from many sides, but an historical comparison with a commercial enterprise involving similar investment will demonstrate what I mean. However, these old times are be-ginning to disappear for a variety of reasons. High amongst these are: ( l) Increased costs of exploration. (2) Remoteness of many new finds. (3) Fixed or declining metal prices (particularly when expressed in constant dollars). ( 4) Constant demands for higher wages.

Jan 1, 1962

The paper point out the way whereby the Canadian gobernment regulates and motivates mineral development. In this sense, its important the role of Gobernment policy in the development of the industry to its a stage. The progress of industry is due to a favorauble political climate which created an atmosphere of trust that has atracted foreing investment. Therefore, Canada's position owes much to sound legislation that recognizes the high element of risk in exploration and development and also the exhaustibility of mineral deposits.

Nov 20, 1969

By Toby Mayo, Tassos Grammatikopoulos, Massoud Aghamirian, MARK FEDIKOW

The Zoro pegmatite project in east-central Manitoba occurs 20 km east of the historic mining town of Snow Lake. A composite sample (Master Comp) was prepared fromthree pegmatite zones within Zoro Dyke “D1” including the North, Central, and South Zones for mineralogical analysis and heavy liquid separation (HLS). The mineralogical examination was conducted on a subsample crushed to ca. P80 of 600 μm to determine the overall mineral assemblage, liberation of spodumene, and assess the potential recovery of spodumene by flotation. XRD and QEMSCAN results show that the sample consists of spodumene (10.5%), quartz (29.3%), plagioclase (29.0%), K-feldspars (21.3%), micas (5.1%), tourmaline (2.9%), and Fe-Mn-phosphates (0.1%). Spodumene is well liberated (88%), but also forms complex particles (7%), and middlings with quartz (4%). Liberation of spodumene increases from 81 in the + 600 μm to 95%in the − 106 μm size fraction. Liberation of quartz, feldspars, and micas account for 89%, 94%, and 83%, respectively. Electron probe micro-analyses and LA-ICP-MS showed that the average Li concentration is 3.7% in spodumene, 2196 ppm in micas, 1001 ppm in tourmaline, and 115 ppm in K-feldspars. Thus, spodumene accounts for 96%, micas 2%, Fe-Mn phosphates 1%, and both K-feldspars and tourmaline for < 1% of the total Li in the sample. The mineralogical data indicate the potential to recover spodumene by flotation with minimal Li losses due to other than spodumene carriers. Heavy liquid separation was conducted on the Master Comp which was crushed to − 6.4 mm, while the − 600 μmfractionwas removed fromthis test. The coarse fraction − 6.4mm/+ 600 μmwas subjected to HLS tests with eight heavy liquid-specific gravity cut-points (2.65 to 3.10 g/cm3). HLS indicates that it is possible to produce a high-grade lithium concentrate (close to 6% Li2O) after the rejection of iron silicates with magnetic separation.

Sep 16, 2020

By Yutaro Fukase

Various types of service robots have recently been developed for guarding facilities, caring for the elderly, carrying objects, and cleaning buildings. As barrier-free facilities improve and their use expands, these robots have more space within which to move inside buildings. Yet robots that move autonomously rely on position-detection systems. Though improving rapidly, these systems are far from perfect in determining positions in certain situations, especially when robots navigate large areas or cross various locations. Our group is working to solve this problem by developing a position-detection system using random-dot patterns on a floor. First, we construct a floor with a random-dot pattern and register the positions of all of the dots into a database. As the robot moves across the floor, a camera on the robot captures an image of the floor beneath it and crops the dot pattern in the image. The cropped dot pattern is matched to the dot patterns in the database to determine the position of the robot and the direction in which the robot is facing or moving. In this paper we propose a self-localization system and matching algorithms derived from a space technology and present the results of several experiments.

Aug 1, 2013

By P. W. Bridgman

Flow and fracture are admittedly complicated phenomena of which we are yet only partially masters. There is not even nni-.persal agreement as to the details of the language best adapted merely to describe the phenomena, to say nothing of any theory. Certain points of view, however, are widely held, and there are certain general expectations as to what sort of procedures will prove permissible. A complete description of any situation involving fracture would demand a complete history of all the variables in the control of the experimenter. The experimenter endeavors so to choose his independent variables that they are adequate to determine completely the situation in the sense that when an experiment is repeated on the same initial material and with the independent variables running through the same sequence, all the other measurable properties of the system will also run through the same course. It is, I think, the universal conviction that when we are dealing with phenomena of flow and fracture, the most important of the necessary variables are the external forces acting on the various parts of the body; when the force history repeats, with certain obvious restrictions such as that temperature must be constant and non-mechanical forces, such as magnetic field, must be small enough to be ineffective, then the history of all measurable properties will repeat; in particular the alteration of geometrical shape due to flow will run through the same course, and when fracture comes, the character of the fracture will be reproduced. Complete mastery of merely the descriptive aspects of flow and fracture would demand the ability to predict the entire course of flow and complete characterization of the final fracture for every possible combination of forces, varying in time in all possible ways, when applied to bodies of all possible shapes. This full situation is obviously of prohibitive complexity. The first stage in reduction to manageable simplicity is to resolve the total situation into the sum of contributions made by small elements. Our thesis is that if each of the elements is adequately characterized, the behavior of the whole system is fixed. The element is usually taken of a simple geometrical shape, suggested by the mathematics best adapted to the particular situation. The forces acting across the faces of the elements are ultimately determined by the forces acting across the free faces of the whole system. The detailed process of finding the precise forces on the faces of all the elements in terms of the external forces involves the use of a special mathematical invention, the stress, a constructional quantity consisting of six components. The stress at any point in the body is determined by both the external force system and by the physical properties of the body at all points; quite different stresses prevail at the interior of bodies of the same shape under the same external forces in the elastic and plastic ranges. The forces on the faces of any element are, however, uniquely determined by the stress system at the element. Our fundamental thesis

Jan 1, 1945