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By Fan Yang, Zhiping Wen, Tiancheng Nie, Jinhe Pan, Ruibo Jia, Changchun Zhou

Rare earth elements have important strategic significance and economic value, and the rare earth elements in coal resources have considerable development potential. This study took coal refuse in the Jungar area of Inner Mongolia, China, as the research object, and investigated the occurrence modes of rare earth elements. A special sequential chemical extraction experiment was designed, and the results showed that the rare earth elements in coal refuse mainly occur in silicate and aluminosilicate form, accounting for approximately 65% of the total rare earth elements. According to the results of SEM-EDS, micro morphology of the sample belonged to the lamellar structure of clay minerals, and Al, Si, Fe, S, Y, and La were all present in the sample. Through SPSS software analysis, rare earth elements have an obvious linear positive correlation with Al, Si, and Fe elements, and a negative correlation with S elements. The rare-earth element occurrence mode in coal refuse can provide a definite theoretical basis for the later extraction and enrichment work.

Feb 18, 2022

By J. F. Childs

Montana consists of an Archean crystalline basement overlain by Proterozoic through Cenozoic sedimentary rocks. Igneous rocks range in age from Archean to Pleistocene; the most voluminous magmatism and volcanism occurred during the Late Cretaceous and early Tertiary. The state can be divided into three tectonic provinces whose deformational styles are a function of different bedrock responses to Late Cretaceous-early Eocene compressional tectonism. Several long-lived structural zones have been periodically reactivated since the Precambrian, and were the sites of recurrent magmatism. Regional gold distributions are strongly influenced by the tectonic provinces and structural zones. Lode gold systems in Montana occur in diverse geologic settings resulting from a complex interaction between structure, magmatism, and sedimentary depositional processes. Reserves or resources are known for 19 significant lode gold systems, and additional unannounced discoveries have been made recently. Mineralization ranges in age from Archean to Tertiary. The influence of long-lived structures is apparent at both the regional and deposit scale, and in some cases multiple mineralizing events have been superimposed upon one another. Most Montana gold systems have a direct spatial and genetic association with Late Cretaceous through Oligocene igneous rocks. However, the importance of sedimentary rocks and associated depositional processes should not be underestimated.

Jan 1, 1993

By Frank Haehnig, Kurt Kogler

"With a height of 200 m, a crown width of 626 m and a concrete volume of 1.6 million m³, the Kölnbrein Dam in the upper Malta valley in Carinthia / Austria is the largest concrete dam in Austria. Boasting a storage capacity of 200 million m³ with a received water load of 54 MN, this is one of the strongest arch dams in the world.During its construction from 1974 to 1977, the dam was equipped with a comprehensive monitoring system capable of comparing developing deformations and stresses with the design values.With a planned reservoir level of 1,900 m a.s.l. the dam saw the reservoir level of 1,860 m a.s.l. breached in the year 1978. This led to extremely high seepage losses of up to 200 ltr/sec and a rise in the foundation water pressure up to 100% of the dam’s height. These observations were caused by the development of horizontal cracks in the area of the middle dam blocks, between the lowest inspection walkway and the waterside.As a consequence, power plant operations had to significantly be reduced and a number of additional measures were carried out – though these did not lead to the desired sealings.The developer subsequently decided that the dam should undergo a general rehabilitation from 1998 to 1994 in accordance with a concept developed by Professor Lombardi. This concept involved erecting a 50 m high support structure with a concrete volume of 500,000 m³ on the airside of the dam, along with the addition of neoprene bearings to transfer 1.2 million tons of the horizontal load. These measures were able to reduce the deformations in the dam enough so that mostly load-bearing injections into the cracks in the dam’s concrete could successfully be carried out by way of targeted grouting measures using injection resin (RODUR) specifically developed for this purpose.In the years 1998 - 1994, a total of 130,000 m of grouting, monitoring and control drillings were executed, and around 200,000 kg of synthetic resin was injected into the cracks in the dam’s concrete.These measures have ensured the dam‘s uninterrupted operation since 1994. A number of small re- injections were again carried out on the contact surface in the years 2011 and 2012."

Jan 1, 2016

By G. W. Birge, D. E. Wolfson, J. H. Lynch

This report by the Federal Bureau of Mines describes the carbonizing properties of coals from the principal beds in Boone County , W. Va . Results are given for samples of coals from No. 5 Block , Stockton - Lewiston , Coalburg , Winifrede , Chilton , Hernshaw , Cedar Grove , Alma , and No. 2 Gas beds . Boone County coals rank as high -volatile A bituminous . Eighteen of the 21 samples tested contained from 3.3 to 7.9 percent ash and 16 of the samples contained from 0.6 to 0.9 percent sulfur . Two samples from the Alma and No. 2 Gas beds , the lowest stratigraphically of the seams tested in Boone County , contained from 1.4 to 2.7 percent sulfur . Most Boone County coals yield

Jul 1, 1960

By Alan R. Buehler

The Bureau of Mines conducted a mineral investigation of the 10,500-hectare Cache Peak study area in 1992; the area had been proposed as wilderness. Bureau personnel examined and sampled prospect workings; 14 rock and 20 placer samples were taken during the investigation. The study area is centered about 40 km south-southeast of Burley. Idaho, in the Sawtooth National Forest. There were seven mining claims located inside the study area, and one additional historical mining claim location. Gold, silver, copper, lead, zinc: Possible resource, poor exposure precludes estimate. Marble: Several million tonnes may be suitable for a variety of uses; markets too distant to favor mining. Sand and Gravel: Several million m3, but markets and transportation costs do not favor mining. Quartzite: Several million tonnes may be suitable for metallurgical purposes; however, markets are too limited to mine. Slabs have been quarried at three localities adjacent to the study area, for decorative stone. Production: In 1979, two tonnes of ore were produced and a plan of operations was submitted calling for approximately 5 km of access road for the Last Chance mine. Decorative stone production was not recorded.

Jan 1, 1993

By P Christen, D R. Ashley, G R. Power

The Ernest Henry Mine is currently a copper-gold open pit operation situated in north-west Queensland, Australia. It is owned and operated by Xstrata Copper with a current throughput of 11 million tonnes per annum; however, open pit operations are scheduled to cease in late 2011. The deposit dips at approximately 45¦ and extends for at least another 400 vertical metres below the final 530 m deep pit design. Resource drilling from 2002 until mid 2008 has enabled an Indicated Mineral Resource to be established to 1000 m below surface. Scoping and prefeasibility studies (PFS) have been completed toward determining if this resource is suitable for underground mining and a feasibility study is currently progressing with a sublevel caving (SLC) concept. This paper briefly describes the process by which the SLC method was selected, conclusions regarding the non-selected methods, and then discusses the optimisation process used to derive the mining plan. The key optimisation parameters include the production drive spacing, level spacing, draw strategy, cut-off grade and production rate. Key risks will then be assessed and economic sensitivities studied. Final sensitivities will use Monte Carlo simulations to improve the transparency of the projectÆs risk profile. The feasibility study (FS) began in March 2008 and this paper describes the main optimisation steps at the time of writing and outlines the plan for study completion through to March 2009.

Jan 1, 2009

By T. A. Lang

The objective was to develop a Program Plan of analytical studies and tests for determining ( 1) the optimum installation tension of a coal mine roof bolt, (2) the most valid bolt support theory or theories, and ( 3) the most valid roof failure theory or theories. On this basis a comprehensive literature search was made and significant material dealing with coal mine roof behavior, roof bolting and roof support was collected, reviewed, classified and analyzed. Emphasis was given to the influence of rock reinforcement on the control of deformation, stress field modification and mine roof stability. An assessment was made of the effect of various parameters including bolt tension, bolt pattern and time of installation, on the effectiveness of rock reinforcement systems, and equations developed for bolt tension as a function of these parameters, and rock properties. From these studies, a major program plan of tests and studies was developed for verifying and validating the most tenable theories of roof behavior and roof support and for determining optimum bolt installation tension.

Jan 1, 1979

By E. S. Tankins

The main purpose of this work was to study the effect of gold on the activity coefficient of oxygen in the liquid Fe-Au alloy and to determine how copper and silver change the activity coefficient of oxygen. A preliminary investigation has been made of equilibrium in the reaction of hydrogen with oxygen in some of the liquid gold alloys. The experimental method, which has been described in detail elsewhere,' consisted of bubbling accurately known H-A-water vapor mixtures through the Fe-Au alloys contained in alumina crucibles within a vertical closed furnace. When equilibrium was reached, the samples were quenched by rapidly lowering the crucible under an atmosphere of argon to a water cooled brass fixture at the bottom of the furnace tube. The melts were found to freeze from the top in less than 4 sec. The heats were carefully prepared for oxygen analysis. The oxygen content was determined by vacuum fusion analysis.' Only high purity electrolytic materials were used in this investigation. The activity and free energy of oxygen in the liquid iron alloys were studied by means of the reaction; The data for the 80 Fe-Au alloys, obtained as a function of temperature, are summarized in Table I and presented in Fig. 1, where log is plotted against . The results can be expressed by: The data were obtained using water vapor-hydrogen ratios between 0.04 and 0.30, and a 25 pct H2-75 pct A mixture. An oxygen content between 0.030 and 0.060

Jan 1, 1970

By G. G. Bowser

PERUSAL of a list of present-day commercial explosives perhaps does not convey a full realization that there has been a great deal of improvement since the original dynamite was discovered nor that, in recent years, great developments have taken place in specialized explosives. This is true particularly of high-explosives for use in metalliferous mining or what is more commonly termed 'hard-rock' mining. Not many decades ago, only two or three types of explosive were avail-'able for commercial use. One was black blasting powder. Another was ordinary nitro-glycerin dynamite in various strengths. Black blasting powder remains with but very little change. Despite its ancient lineage, it is still with us as perhaps the sole explosive in use today which is almost identical in appearance, physical properties, and working ability or execution co the original. Which dynamite the story is different. Its evolution may be likened to that of the dog, nitro-glycerin as first discovered being the counterpart of the wild dog and, like it, dangerous and hard to control. The original dynamite as made by Nobel might then be considered as representing the first domesticaced species. This original dynamite, however, has been 'crossed with other bloods' until one sees now many distinct 'breeds' in the list. Present-day explosives still have the 'bark' and the 'bite', but with control and research have come many improvements; and types have been created which are specially adapted for particular kinds of work. We still have the direct descendant of Nobel's dynamite in the form of an improved nitro-glycerin dynamite. This C-I-L explosive, Polar Dynamite, is no longer the best type to use in the hunt for gold, silver, iron, and other metals. There have been developed other explosives more suitable for chat work. In Canada, such explosives are accomplishing this work effectively, not only where climatic conditions are moderate but through the rigours of our northern winters, with their sub-zero temperatures.

Jan 1, 1938

By C. Graham

Thin Spray-On Liners (TSLs) have been researched and in development for over two decades and yet their fully functional and widely justifiable application in mining has yet to be achieved. While the explanation for this is partly technical, it is also clear that proving and communicating the operational and economic case for why a mine should change from mesh or shotcrete liners to a TSL is not a trivial matter. Evidence must be presented and communicated effectively, that is both obvious and compelling for a mine operator. The paper describes recent work carried out and directed towards this end, with funding from CAMIRO?s Deep Mining Research Consortium and additional support from 3M Canada and ABB Canada. The essential progress that has been, or is in the process of being made, will be described in providing the necessary proof of acceptable or superior TSL performance in the following areas: polymer formulation, health and safety, geotechnical specification, robotic liner application, business case economics and yielding ground support effectiveness. Future plans are also presented to demonstrate the performance of a new 3M composite TSL/yielding bolt support system in underground trials where the substrate rock is intended to fail through a number of mining-induced mechanisms.

Aug 1, 2013

The following delegates were appointed to the National Conservation Congress on May 2, 3, and 4, 1916, in Washington, D. C. HENRY S.. DRINKER, a GEORGE OTIS SMITH, A. F. Lucas, - W. L. SAUNDERS, VAN H. MANNING. President Ricketts was appointed delegate to the dedication ceremonies of the new buildings of the Massachusetts Institute of Technology in June. W. L. Saunders was appointed delegate to the ceremonies in celebration of the 150th Anniversary of the founding of Rutgers College to be held in October. George C. Stone was appointed delegate to the meeting on Standard Screen Scale of the U. S. Bureau of Standards. George D. Barron and Thomas T. Read were appointed delegates to the Second National Exposition of Chemical Industries to be held in New York in September. It was resolved, that the Institute shall pay the transportation of the Secretaries of the Local Sections to and from the Arizona Meeting. It was resolved that certain general topics' should be selected for discussion at the next meeting of the Institute and a session devoted to each.

Jan 6, 1916

By Carl R. Peterson

This report describes the development and testing of a prototype tunneling machine. Principal efforts were aimed at testing of the fragmentation subsystem of a continuous drill and blast hard rock excavation machine suitable for use in underground mining and tunneling applications. The concept utilizes a unique self -shielding spiral blasting pattern that permits efficient performance with relatively small single shots, while at the same time directing major blast fragments at right angles to the tunnel axis. A major accomplishement was the development of a remote controlled, loading and initiation system in which explosive slurry and a detonator are Simultaneously placed (pumped) into the blasthole via a loading hose. The special electric long-delay detonator is inductively ignited upon emplacement, and the machine remains at the face during the blast.

Jan 1, 1976

By M Uceda, E Guerra, Y Choi, J L. Shepherd

In this paper we describe the leaching characteristics of pure gold in thiosulfate solutions that contain a known chelator; meso-2,3-dimercaptosuccinic acid (DMSA). The interfacial and chemical characterisation of the system was accomplished using both electrochemical methods and inductively coupled plasma mass spectrometry (ICP-MS) analysis after pure gold samples were exposed to solutions composed of 65 mM Na2S2O3, 1 mM NaOH and a range of DMSA concentrations. In the absence of DMSA, cyclic voltammetry revealed the onset of thiosulfate mediated gold dissolution, the degree of which was reduced at more positive potentials due to the formation of oxidised thiosulfate products on the gold surface. The addition of small amounts of DMSA (<10 ¦M) to the electrolyte resulted in minor changes to the voltammograms indicating a subtle interaction of the additive with the gold surface that may improve leaching. However, at higher concentrations of DMSA (up to 100 ¦M), electrochemical evidence suggests the formation of new oxidation products in solution as well as the formation of more compact monolayers of DMSA on the surface, which contribute to partial repassivation of the surface. The influence of DMSA on thiosulfate leaching of pure gold electrodes at the open circuit potential for a period of 90 minutes was tested and the corresponding gold leaching performance evaluated with ICP-MS analysis. Our data shows that small amounts of DMSA (1 ¦M) doubled the amount of total gold in solution when compared to the same study in the absence of the additive. However, higher concentrations (5 ¦M DMSA) reduced the overall amount of dissolved gold. These results may point to a mechanism where small amounts of DMSA improve leaching by adsorbing onto the surface in a highly defective monolayer that partially blocks or disrupts the formation of passivation products caused by thiosulfate oxidation, but excess DMSA can limit the leaching process itself by forming too coherent a monolayer on the gold surface.CITATION:Uceda, M, Choi, Y, Shepherd, J L and Guerra, E, 2013. Investigating the influence of meso-2,3-dimercaptosuccinic acid on thiosulfate leaching of bulk gold electrodes, in Proceedings World Gold 2013 , pp 207-214 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By L. Valentik

Many attempts have been made during the last forty years to evaluate the performance of gravity separation equipment, that is, the effectiveness with which light and heavy particles are separated. The most comprehensive treatment of the subject was made at the 1st International Conference on Coal Preparation held in Paris (1950) by Cerchar. The methods suggested by the Conference were accepted and very widely used in the last 25 years. This paper discusses an improved method of evaluation in the light of the now accepted standard presentation. The float and sink analysis of the product is presented on a Gaussian distribution curve, resulting in an easier visualization of the inherent difficulties of separation. The ogives of the distribution curve are then plotted, giving a quantitative measure of the deviation from perfect separation as an error distance instead of an error area. Illustrations of the new method are given both for gravel and for coal preparation, but the concept is valid and applicable to other types of minerals which are separated by gravity methods.

Jan 1, 1968

By John S. Crout

TWENTY-FIVE years ago the training of an engineer was of interest solely to the educator and to the student entering the field. At that time the engineer's position in society was relatively simple. His training emphasized design and operation and he expected to enter industry to handle the engineering problems of raw materials production, mechanical and product design, and the operation of power plants, factories, transportation and communication systems, and similar phases of industrial activity. He was not concerned with or particularly interested in the problems of management, administration, sales, publicity, industrial relations, or of legislation. To a large degree he was content to leave these matters to self-made businessmen, or men trained in law, finance, or commerce. That period in the evolution of the engineer is now history. It is generally conceded that the modern world is dependent upon engineering technology for its day-to-day survival. The continued operation of facilities on which mankind relies is dependent upon the functioning of mines, utilities, chemical plants, and other factories, all of which require the knowledge and the skills of trained engineers. Thus from a purely mechanical point of view, the engineer has become indispensable to

Jan 1, 1947

By G Forbes, D J. Bradshaw, G S. Heinrich, D

Traditionally, operators on mineral flotation plants have relied on visual inspection of the froth surface when making adjustments to process set-points. Machine vision systems are being developed to relate froth surface descriptors, which can be consistently measured in real time, to flotation performance. By investigating the impact of various selected operating variables on both froth surface characteristics and metallurgical performance it is possible to develop a management strategy for the control and optimisation of the process. This paper presents the results of testwork conducted at Kennecott copper mine which investigates the relationship between the froth colour and the concentrate grade and discusses the factors which affect the froth colour. This work shows that the main factors that influence the froth colour in this system are molybdenum, copper and iron concentrate grade, pulp and concentrate per cent solids and pulp iron grade.It goes on to develop models to predict the concentrate grade based on colour information and velocity and stability information. It also shows that the most accurate prediction is made with combined colour and stability information.

Jan 1, 2005

By K. K. Kohli

Since the adoption of the Surface Mining Reclamation and Control Act of 1977, which mandates that surface subsidence be an intergral part of the underground coal mine design, there has been a sudden rise of demand on guidelines for minimizing surface subsidence and its associated structural damages. Unfortunately there is no sufficient amount of systematic subsidence data to fill such a gap, although considerable research has been devoted to the subsidence-induced damages of surface structures in the past. However, it was said that many surface subsidence surveys have been performed and monitored by coal companies during the past twenty years, and that it will be a great source of information for subsidence engineering design if they can be collected and assembled together. An effort was therefore initiated in the Department of Mining Engineering, West Virginia University, under contract with the U. S. Bureau of Mines in December 1978 to contact each individual coal company in the Northern Appalachian Coal Field for any surface subsidence survey data. After 10 months' survey, the data collected include 17 longwall panels and 2 room and pillar sections. The data in-each panel and section cover the complete set of subsidence survey raw data, underground mine layout maps, surface topo maps, geological loggings showing the stratigraphic sequences and thickness of the overburden, and if available, locations and types of surface structures. On-site visits were followed to study the surface terraines and structures. Interviews were conducted with the owners of the surface structures in most cases about, if any, the history and characteristics of damages.

Jan 1, 1980

By Warren E. Wilson

THE transportation of solids in pipe lines is a matter of deep concern in many fields of engineering. Much experimental and theoretical work has been done in an effort to devise means of designing pipe lines that will satisfactorily transport given solid loads, but there remain many unanswered questions in this field. The present discussion will be confined to a rather narrow portion of this field and will endeavor to point out certain factors that may well be considered when comparing the relative economy of various installations. The data have been presented previously but a new interpretation was prompted by a suggestion in a paper by Professor O'Brien,1 of the University of California, that the friction work per pound of dry material should be considered in determining the relative efficiency of various installations. This method of considering relative economy in various pipe lines leads to some rather unexpected conclusions, especially with reference to the economy of large pipe sizes. A previous suggestion by the writer3 concerning the economy of a rather peculiar type of installation is strengthened. It is not believed that the considerations set forth herein apply directly in the case of dredge lines, where economy is largely a matter of a high rate of pumping in order to reduce the unit overhead charge. However, it is believed that some value may be gained from these considerations in cases involving the disposal of a fixed amount of solids per unit time with a minimum expenditure of energy and at a low cost for replacement of worn pipes. Such situations are not uncommon in the disposal of mill tailings and the disposal of solids deposited from irrigation waters. It was found that data leading to general conclusions for various pipe sizes were not available but certain definite trends are indicated and methods of analyzing available data are presented in the hope that they may be of assistance in preparing engineering estimates on designs of pipe lines of the type described above. ENERGY. REQUIREMENTS Carrying out the idea contained in Professor O'Brien's paper concerning the method of computing energy required to transport solids, the following analysis leads to some rather interesting conclusions. Let us represent: [Solids load in terms of mass per unit time by W Ratio of mass of suspended solids to total mass of mixture flowing by p Volume rate of flow of mixture by Q Length of pipe by L Slope of energy grade line by s Mass per unit volume of solids by m, Mass per unit volume of liquid by ml Mass per unit volume of mixture by m,,, We then have as an expression for the solids load: W = pQm¬] The work done per unit mass, P, on the mixture to move it along the pipe the

Jan 1, 1945

By M Hopkins, A Mutale, A E. Vidal da Silva

The Cliffs Nickel Mine extracts a narrow near vertical nickel vein using a mining method of underhand bench stoping with paste backfill. In 2014, at a depth of 400 m below surface, the Northern block of the mine began to experience squeezing within ore development. At first the deformation was localised, within 30 m of the stoping front, but later became pervasive extending across the Northern block and resulting in a hiatus in mine production. The global mechanism is a progressive pillar failure, where the inter-level pillars in advance of the production front could no longer withstand the induced load and progressively yielded. The local mechanism of failure was observed as crushing of the massive sulphide ore and ‘punching’ of the pillars into the ultramafic hangingwall exhibited as floor and sidewall dilation and unravelling of the mafic footwall. The cause of the global mechanism was attributed to a combination of factors, including: high overall extraction ratio, small vertical pillar heights between ore development, high stress in relation to the low rock mass strength, shallow stope front angle, and insufficient ground support capacity. Following the progressive failure, the remnant rock mass conditions across the northern block were severely degraded, with numerous falls of ground that led to a reassessment of the mine plan. Recovery of the Northern block started in 2016 as a staged process. Development of the safe recovery work methodology involved a number of considerations, such as: production sequencing, development access design, ground support, and development of specific procedural controls. The Northern block was then broken into smaller mining precincts based on tactical factors such as location, ease of access, scale of rock mass damage and nickel content. A specific ground support standard and work methodology are employed, while cycle sheets are used to ensure quality and completeness of work. Large intersections showing signs of deformation have either been bypassed or treated using Rocprops to maintain stability during stope production. This approach has been successful in safely regaining access and restarting production in areas that had previously been removed from the mining reserve.

Mar 15, 2021

By Paul C. Lingo

Two recent antitrust cases, coming from widely separated areas, different industries and involving wholly different facts were decided by the Supreme Court on June 7, 1965. The decisions in there two cases may well prove to be the most important and far-reaching decisions in the field of labor law that have been handed down in the last 24 years. These cases, although quite dissimilar factually, had one common element. In both, the gravamen of the antitrust violation was bottomed on the terms of labor agreements negotiated by a multiemployer group. These cases are usually referred to as Pennington1 and Jewel Teat. Since a number of references will be made to the antitrust laws, it may be well to state briefly the applicable portions. Section 1 of the Sherman Antitrust Act makes "every contract, combination in the form of trust or otherwise, or conspiracy, in restraint of trade or commerce among the several states, or with foreign nations, is declared to be illegal...". Section 2 imposes criminal sanctions against "Every person who shall monopolize, or attempt to monopolize, or combine or conspire with any other person or persons, to monopolize any part of the trade or commerce among the several states...". Under Section 4 of the Clayton Act a person who sustains damages as a result of a violation of the anti¬trust laws is entitled to recover treble damages plus costs.

Jan 1, 1966