Search Documents

By H. R. Beard

The Federal Bureau of Mines investigated the absorption of radium and thorium from waste uranium leach liquor by clays and other materials. This work was conducted in support of the Bureau's goal of minimizing the environ¬mental conflicts, impacts, and occupational hazards Associated with mining and mineral processing operations. Tailings and soil samples from Wyoming and Utah were contacted with tailings liquors to determine the degree of absorp¬tion. Absorption ranged from 0 to 99 percent for radium and from 0 to 31 per¬cent for thorium. Some samples, which readily absorbed radium, were contacted with various salt solutions that could be present in tailings solutions to determine their effectiveness as desorbents. The desorption of radium ranged from 0.06 to 100 percent. An alpha-spectrometric method was used to determine the radium and thorium, concentrations in the solutions and the solids.

Jan 1, 1979

By A. Wahab Khair, John G. Oldsen, John C. Stankus, Song Guo

During the last several years, implementation of trusses, in lieu of wood cribs, has been successful for supplemental tailgate support in the Pittsburgh seam. This paper reviews, the truss support system provided by the new high strength 0.6" tensioned cable truss, which is now also being used in cribless tailgates. Cable loading and roof deformation were monitored to evaluate roof and floor performance. The test results indicate that the cable truss system successfully controlled the roof and floor during the first and second panel extraction. This paper will describe the advantages of cable trusses and their load transfer mechanism as well as mine evaluation.

Feb 24, 1997

By T. Tafi

The Ute-Ulay project area is located approximately five miles west of Lake City, in Hinsdale County, Colorado. The Ute-Ulay Mine site is approximately one mile east of the project area. The elevation of the site is 9,200 feet and is adjacent to Henson Creek (Figure 1) [ ] The Ute-Ulay Mining complex is an inactive gold, silver, and zinc mining/milling operation, that operated from the 1880?s until the 1970?s, and sporadically into the late 1990?s. The mining complex comprises several levels of underground mines, a flotation mill, and an abandoned town site. Due to the narrow, steep sided canyon, milled tailings were pumped upstream one mile in a sluice box to a wider section of the canyon, and deposited into five tailings impoundments and one berm located between the impoundments. An estimated 9,000 cubic yards (yd3) of fine grained tailings were located in the impoundments adjacent to the creek. The Ute-Ulay project area consisted of the mill tailings impoundments located upstream from the historic mine.

Jan 1, 2011

By M I. Pownceby, N A. S Webster, R Pattel, N Ware

The decrease in quality of Australian iron ore, coupled with the demand for more efficient energy use, necessitates closer monitoring and optimisation of process conditions for iron ore sinter production. Sinter properties are correlated with the mineralogical content and traditionally, quality control has relied on methods such as Fe2+ determination, point counting via optical microscopy and automated electron beam techniques such as QEMSCAN; these can have a typical turnaround time of several days between sampling and reporting of results. As well, there is additional uncertainty around quantifying some of the complex mineralogical phases in sinter such as silico-ferrite of calcium and aluminium (SFCA) and SFCA-I, which are key phases influencing sinter quality. There is a clear need for the implementation of alternative analytical methodologies that offer a turnaround in hours or even minutes to provide information to accurately maintain production conditions.X-ray diffraction (XRD) is a technique widely used for the quantitative mineralogical phase analysis (QPA) of ores and processed materials in the iron ore industry. Partial least squares regression (PLSR) analysis methods have recently been suggested as an indicator of sinter Fe2+ content from powder XRD data without the need for rigorous and often time-consuming mineralogical analysis by the operator. In this study we provide results from the implementation of PLSR to predict the strength of iron ore sinter. Results are sourced from a well-constrained data set comprising strength properties (as quantified by a tumble index (TI)) from a series of compact laboratory test samples. Using this data set it was determined that PLSR has potential to be used as a method for calculation of sinter TI from powder XRD data and, therefore, process control.CITATION:Webster, N A S, Pownceby, M I, Ware, N and Pattel, R, 2017. Predicting iron ore sinter strength through X-ray diffraction analysis, in Proceedings Iron Ore 2017, pp 331–334 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Albert W. Deurbrouck

The performance characteristics of five hydrocyclone coal washers were evaluated to determine the sharpness and efficiency of separation that might be anticipated in commercial operation. The hydrocyclone overflows contained generally good clean coal products that would require little re-treating to remove misplaced high-gravity material. The underflows, however, contained from 63.6 to 36.7 percent of misplaced low-gravity material, which would require secondary cleaning to provide acceptable clean coal yields.

Jan 1, 1974

By Steve Chorley

Open-type, or main beam, tunnel boring machines (TBMs) can achieve impressive rates of production. This type of TBM typically outperforms other types of TBMs currently in use around the world. In good ground conditions, main beam machines have achieved production rates of more than 1 km/month (0.6 miles/month). However, installing effective ground support in poorer rock conditions on main beam machines can be a major cause of concern. The design of main beam machines is such that installation of ground support equipment, particularly at the front of the machine in what is commonly known as the L1 support zone, has traditionally been limited to rock drills and basic working platforms. Personnel working in the L1 zone have, until recently, been protected by roof supports and extended fingers, often with restricted access to working areas.

Jan 1, 2011

By Lyman G. J

Dense medium drum separator efficiency was analysed at two Western Australian iron ore concentrators. Efficiency data had hitherto been difficult to accumulate due to the high cost of analysing representative, and therefore large, coarse ore samples. To overcome this problem, recoverable density tracers, which are in effect artificial mineral and gangue, were manufactured in three different sizes (15 mm, 30 mm and 60 mm). Their use enabled partition curves to be studied within one hour of conducting a test: separation densities were generally lower than the feed medium density for all three sizes of density tracer. For a given set of operating conditions, the smaller tracers had lower separation densities and larger ecart probab/es than the large tracers. These phenomena are explained with the aid of a conceptual model of a drum separator, which assumes that the feed ore plunges to the bottom of the drum upon introduction. Particle rising velocities are, therefore, process determining.Medium rheology was altered by adjusting the proportion of solids in the pulp. This was accomplished by changing both the pulp density and ferrosilicon/magnetite ratio. Higher solids volume fractions invariably caused a decrease in separation densities and an increase in ecart probables, most markedly for the smaller tracers. A similar response was observed when feed tonnages were raised.An explanation for these phenomena is sought in the discussion which also suggests means of improving drum separator efficiency.

Jan 1, 1987

By Albert L. St. Peter

The "Old Reliable" four million pound blast in March of 1972 marked the opening, as far as is known, of serious efforts to commercialize the In Situ concept. That was a coyote shot, and it was followed by three blasts at McAlester Fuel's "Zonia" operation which were surface hole shots. As the only individual who had a principal part in all four shots, it seems to be appropriate to present experiences in the developments and evolutions of the in Situ method of ore extraction. Some of the problems will be described, along with proposals for management of such projects in the future.

Jan 1, 1976

By J. Guha, D. Racicot, S. Peloquin, F. Lange-Brard, S. Bureau, A. Tremblay

The Devlin copper deposit consists of a flat-lying vein and a network of steeply dipping mineralized veinlets hosted by leucotonalite of the Chibougamau Pluton. Most of the vein is enclosed in a hydrothermal breccia zone which has been superimposed on a primary igneous breccia formed during the emplacement of the leucotonalite unit. This igneous breccia contains cognate fragments as well as fragments of the Dore Lake Complex, host rock to the pluton, set in a leucotonalite matrix. The hydrothermal breccia is formed of fragments of leucotonalite and the earlier breccia set in a matrix of finely comminuted rock variously altered in a roughly zonal arrangement. The major ore-bearing structure is the tabular flat-lying vein, varying in thickness from 10 centimetres to 1 metre, with a slight dip to the northeast. Well developed fracture planes, in four major orientations, contain both sulphides and gangue minerals. These appear to be displaced by the flat-lying vein. Late movements affecting the deposit include minor vertical displacements and an east-west shear truncating the southern edge of the vein. Widespread selective alteration of the leucotonalite, followed by multiple alteration veining stages characterize the deposit. Fluid inclusions associated with the mineralization indicate low temperatures, variable salinities with a variety of daughter minerals, and a vapour dominated phase. The fluid shows evidences of boiling at shallow depths. The sequence of events envisaged for the Devlin deposit is a primary brecciation during emplacement of the leucotonalite unit with widespread selective alteration possibly during the cooling stages followed by hydrothermal brecciation and late stage fract uring producing the vertical fractures and the flat-lying vein. From the alteration characteristics and the fluid data it is inferred that the Devlin deposit is the near-surface expression of a porphyry system.

Jan 1, 1984

By Steni Stefani, Sanjay Dave

"This paper describes an innovative method, used for the first time in India, for the construction of a 1.0metre-thick positive plastic concrete cut-off wall (CoW) at the upstream toe of the dam at the Kishanganga Hydro-Electric Project in Jammu & Kashmir- India. The extremely difficult bouldery geology with an overburden laden with very hard Panjal Volcanics (quartz, feldspar, muscovite and chlorite minerals) boulders of up to 0.8m to 1.8 metres in size with UCS of up to 265 MPa and the requirement of socketing the CoW into the underlying hard bedrock (UCS 265 MPa) for 1.50m made the choice for the excavation methodology critically difficult. After having evaluated several other existing methods – including hydromill trenchers – the Civil Contractor Hindustan Construction Company, in agreement with its Foundations Engineering Consultant (Ricerca e Sviluppo – Cantieri e Gestioni) opted for a two-stage construction method: firstly, preliminary full-depth drilling and “surgical” blasting with full-length inclinometer checking of borehole verticality to ensure the exact location of rock fracturing and fragmentation coincided with the required position and that it was vertical, notwithstanding efficient trenching into the bedrock of a nominal 1m by 1.5m section; and, secondly, excavation by using heavy duty mechanical rope grabs made locally and developed by the Consultant in collaboration with the Contractor. The details of the methodology and the salient construction data is presented and commented for the 33-metre deep CoW installed at a working platform elevation of 2364.50 m above sea level in a very remote area.BACKGROUNDThe Kishanganga Hydro Electric Project (KGHEP) is a ROR (run-of-the-river) project is located on the Kishanganga River some 140kms North-West of Srinagar, capital of Jammu & Kashmir State of India, for generating 330MW of power in a 90% dependable annual year. The key components of the project are: Concrete Face Rockfill Dam (CFRD), Chute Spillway, Plastic Concrete Cut-off Wall (CoW), Head Race Tunnel (HRT), Surge Shaft (SS), Inclined Pressure Shaft (PS), underground Power House and Transformer Hall, Tail Race Tunnel (TRT).The Power House Site is accessible throughout the year from Srinagar while the remote Dam Site, with its tortuous road climbing the Rajdan Pass at 3556m (11,667 ft) above sea level and several 20-tonne capacity Bailey bridges removed prior to snowfall, remains inaccessible for around 4 months between mid-November to mid-May due to winter and heavy snowfall - the only access is by helicopter, weather permitting. Temperature at the Dam Site drops down to minus 27degrees Celsius during winter, therefore, careful planning from the beginning was most essential for the successful delivery of the Project.This paper deals with the Cut-Off Wall construction which was performed, for the first time in India, adopting a “Drilling and Surgical Blasting” method. However, this technology is not new and diaphragm wall excavation with the aid of drilling and blasting has already been done in some of the projects globally; namely:"

Jan 1, 2017

By Jeremy P. Doolan, Leigh B. Neindorf, Geoff W. Capes

The development and use of rock mass classification tools have been a key component for improving stope design over the past 4 years at the Xstrata Zinc George Fisher Mine in northern Queensland, Australia. In 2003, stope extraction data from 3 years of open-stope mining provided an excellent situation to review the assumptions in the feasibility study. Extracted stope profile information, drillhole geotechnical data, underground observations, and oral and written communication were used to develop a thorough stope reconciliation performance database. With-out collecting the back analysis data and presenting the data in a usable format, engineers are left to debate opinion instead of engineered judgment. This can lead to biased and uninformed design parameter choices with the potential to repeat poor design. This paper demonstrates some effective, practical examples of empirical data collection where rock mass classifications tools were developed and used to create improved confidence in predicting stope stability and failure profiles. The work contributed to design changes that resulted in a reduction in stope hangingwall dilution and an increase in head grade while continuing to ramp up production from 2003–2005.

Jan 5, 2007

By Manuel Gomez, V. F. Parry, John B. Goodman

"INTRODUCTION The need for an accurate and precise analytical method for determining moisture in coals of high water content has been recognized by the coal industry as well as the fuel technologist. Interest in this particular phase of coal technology extends back to the early work of German investigators on the brown coals of Central Europe. Studies by these workers led to the establishment of a direct immiscible liquid-distillation method 4/ as the accepted moisture determining technique in European laboratories. Direct moisture determining methods, those methods that utilize various techniques to drive off the water from a given sample of coal and either collect the water in a calibrated receiver or selectively trap the water driven off in a suitable absorber, have found little favor in the United States. They have been treated merely as research tools.5/ The problem of moisture determination in low-rank coals of the United States has not been given much consideration because such coals contribute only about 2 percent of the total United States production. With renewed activity in low-temperature carbonization and with the growth of interest in coal and coal-tar hydrogenation, the American coals of lover rank containing 20 to 40 percent bed moisture will be subjected to extensive investigation. If the low-rank coals of the United States are to be accurately appraised, the need for qualitative and quantitative analytical proceeded becomes more pronounced. These coals, especially the lignites of Texas and North Dakota, are highly susceptible to oxidation, a process that proceeds to a greater or less extort when low-rank, high-moisture coals are treated by oven-drying methods. The extent of this atmospheric oxidation has been described and evaluated by numerous workers. 7/In many respects, the problem of moisture determination in low-rank coals, those found in the United States and the high-moisture coals of Central Europe, is similar. Conversely, the problem of moisture determination assumes a different aspect when the coals of the eastern and the middle-west sections of the United States are considered. Present methods, the loss in weight gravimetic-type procedures, serve adequately to test these low-moisture coals. The determination of moisture in coals containing 20 to 40 percent water should be approached from a direct method rather than from an indirect gravimetic-type procedure because of the oxidative tendencies of these coals and the demonstratrated inability of a loss-in-weight technique to remove all the water in a given sample of coal."

May 1, 1953

By A Litwinowicz, M Laxman, A Fourie, A L. Li

This paper presents a design approach and analytical methods that were used for assessing the potential of static liquefaction and developing the mitigation measures for a tailings dams. The rigour of the design and analysis approach represented leading practise in the industry to address static liquefaction, which contributed to a robust design with high confidence and certainty. The salient features of our approach to static liquefaction included geotechnical investigation and tailings characterisation, static liquefaction screening assessment, static liquefaction triggering analysis, limit equilibrium analyses and numerical modelling of static liquefaction using the NorSand model, which was amongst the first tailings dam projects involving numerical modelling of static liquefaction using these methods.

Jul 1, 2021

By Xinquan Zhou, Rudolf E. Greuer

MFIRE, written in Fortran 77, is a computer program for ventilation state simulation in the steady state or transient state condition. It can be applied for the calculation of normal ventilation system planning or the analysis of the dynamic state variation in a ventilation system under thermal or mechanical disturbance. The state simulator MFIRE is a useful tool for mine fire fighting. In the case of a mine fire, mine ventilation engineers want to get some help to obtain more information, such as what is happening in the underground mine and how to control the mine fire, for correct decision making. By use of program MF'IRE, forecasts can be made on the variation of airflow, temperature, and contaminant distribution in a ventilation system during a mine fire. The paths which the contaminant takes at each time interval can be traced. The program MFIRE can be of assistance in the preplanning of escape routes. It can also be helpful during a mine fire emergency and mine recovery operation. Besides of offering the information of state simulation during a mine fire, MFIRE can be applied for state control by pretesting the suitability of the selected state control measures. It is to simulate the effects of the state control measures on the airflow distribution of a dynamic ventilation system. The testing result can be used for fire fighting in a similar real case of a mine fire. By employing empirical methods or a qualitative analysis like Budryk approach, ventilation engineers can choose different combinations of locations and sizes of control devices as samples of state control for an underground mine fire. Program MFIRE can simulate the different combination samples, that consist of a certain mine fue, the corresponding different control measures, and obtain the control effects. After the different control results are compared, the state control measure, which creates the best effect among the different state control measures, will be chosen for that fire case. When a mine fire, which is similar to one of the pretested cases, breaks out, the corresponding choice of the state control measure is applied to the ventilation system. It means that the simulator MFIRE has the function of indirect state control [10]. To achieve the above two functions, state simulation and state control, the mine ventilation system condition, sometimes, should be changed in a wide range to meet the requirement of the fire fighting. These wide system condition changes, such as adding operating fans, stopping or reversing fans, changing fan characteristics, adding regulators and making airflow shortcuts are represented in the time table of the input data set When the data files are changed in a wide range, however, an iteration divergence and some other computing errors in the distribution of airflow, temperature, and contaminant may occur. More serious logical programming and flexible selection on the algorithms are wanted to meet the request of the different data sets, to achieve correct state distribution simulation and improve the iteration convergence. To enhance the reliability and common suitability of program MFIRE, it is necessary to make investigation, analysis, and modification for the formal versions of MFIRE. The version 1.29, permitting dry .calculation, and versions 2.01/v2.0, permitting dry and humidity calculation, are widely applied

By Tjaar A. Louw, Albert P. Van Niekerk, Johannes J. Louw, Attie J. Goosen

Unlike molecular high explosives, commercial explosives based on ammonium nitrate do not detonate ideally according to the theoretical model for steady state, one-dimensional detonation. One of the reasons for this deviation from ideal detonation is the slower chemical reaction, due to less intimate contact between the oxidiser and fuel components. It is well known that the inclusion of gas pockets, such as microballoons, in the formulation of ammonium nitrate based emulsions and watergels enhances the performance of these explosives. Various different interpretations of the “hot spot” theory have been proposed to explain this phenomenon.

Jan 1, 1997

All previous attempts to cut rock in boring by means of revolving steel cutters have failed, chiefly in consequence of the mis-shapen teeth grinding the rock and themselves simultaneously, until, after a very few revolutions, the points of the cutters were so worn that it was impossible to force them into the strata. The diamond drilling plant being cumbrous, complicated, and costly, and seeing that fully 70 per cent of the boring generally needed is in what is known as the" milder strata," it will be readily understood that much of the work done will not pay a dividend on the outlay, so great is the cost of removal, the wear and tear of the machinery, and the loss of diamonds. The Calyx Drill, however, invented by Mr. F. Harley Davis, has been constructed so as to overcome these difficulties, and will penetrate quickly and .at a low cost this 70 per cent. of the milder strata. The Drill has taken ten years' hard work and thought to bring it to its present state of perfection, and it will now drill with steel cutters the 70 per cent of the work performed by the diamond drills at a greater speed and at about one third the cost of the latter.The utility of the diamond drill for certain work is undeniable, but it cannot by any means be described as a machine of general popular usefulness that is to say, it is quite beyond the reach of the great masses of mankind.

The fundamental features of the Cable Belt Conveyor are described. It consists of independent wire ropes which take the transmission load, and a special reinforced rubber belt which acts 'only as carrier of material. The first cable belt installation in Scotland is described briefly.A general description of this type of conveyor is followed by details of the rubber belt construction and the method of joining sections of belt. The drive unit, the tensioning arrangements and the power requirements are outlined.Applications of the cable belt conveyor are 'dealt with and its advantages summarized.INTRODUCTIONThe cable belt conveyor, as its name implies is a conveyor composed of steel wire ropes and a rubber belt, in which the ropes serve as transmission members, and the belt merely as a carrier of materials.Over the years it has been the ambition of engineers connected with the belt conveyor industry to develop a conveyor that would use the high tensile strength of wire ropes to transmit the stresses involved in the driving of large capacity belt conveyors. Different lines of approach have been adopted in the United States of America and in Britain. In the United States the method adopted was to introduce a large number of flexible steel cables into the rubber belt itself, in the form of a closely packed layer arranged across the full width of the belt. These small cables are packed in a nylon filled duck envelope which is incorporated in the rubber belt. This is commonly known as the steel corded conveyor belt. In Britain, a Scottish firm developed a rubber belt conveyor in which full advantage was taken of the high tensile features of wire rope, without embodying or moulding the wire rope into the rubber belt, so that the two wire ropes and the rubber...

Jan 1, 1957

Concentrations of bright green material in the "Golden Mile" of Kalgoorlie, which carry particularly high gold values, are known locally as "green leader".This assemblage consists largely of quartz, sericitic muscovite, carbonates, and pyrite. Some of the sericitic muscovite contains vanadium, giving the rock its green colour. Vanadium oxides, including nolanite, are also present. Tellurides identified in this study are calaverite, altaite, petzite, melonite, and coloradoite. Native gold was found in most of the samples; some of the gold, at least, has been formed from the decomposition of gold tellurides.It is suggested that mineralizing solutions carrying gold and tellurium leached vanadium from the host rocks and subsequently deposited gold tellurides and vanadium-bearing minerals in the "green leader".

Jan 1, 1977

By L. T. Isaacs, W. H. Traves

A numerical model for analysing the drainage of fill in mine stopes has been described. The model can be used to analyse the process of fill drainage in existing and proposed mine stopes. The validity and potential value of the model have been established by experience with a simpler, 2-dimensional numerical model and by testing the new model against the earlier model. The new model is more useful than the 2-dimensional model because it allows for heterogeneity of fill material within the stope - a factor that has been demonstrated to affect drainage characteristics significantly. The 3-dimensional model is also capable of predicting pore pressures and drainage rates at specific locations in the stope without the need to resort to 2-dimensional generalisations. Such information, integrated with relevant field data as they become available, will provide valuable mine planning information for the scheduling of filling operations and design of fill mixes

May 1, 1991

By J. H. D. Hargrove, A. F. Snowball

Atmospheric pollution control has become increasingly important in re-cent years with laws and public opinion having required the reduction of contaminants from industrial gas effluents. Treatment methods have advanced to make possible, with proper plant design and operation, a satisfactory removal of these contaminants. Gases from Cominco's metallurgical operations at Trail, approximating 900,000 c.f.m., are treated by baghouses, electrostatic precipitators, cyclones, or wet scrubbers. The tabulated data include gas and dust conditions, plant performance, and some details of plant equipment. Discussion emphasizes the special features, scope of application, and basic design principles of the treatment methods, all based on Cominco experience. Recovery of over 99 per cent of the fume and dust is achieved by the major installations from which effluent gases go to atmosphere. Cooling of gases for baghouse recovery and conditioning for electrostatic precipitation are mentioned. Co3ts are tabulated for some of the installations on the basis of a unit of 1,000 cubic feet of gas. Suggestions are made on the procedure for assessing a smoke treatment problem and for selection of suitable equipment.

Jan 1, 1959