Search Documents

By Feng Gao

A general unsteady- state model, based on a cracked substrate, has been developed to account for reaction and diffusion within porous substrate during oxidation of Carbon Fiber Reinforced Carbon matrix (CIC) composites. The effects of several parameters, such as diffusion and reaction rate ratio, oxygen concentration, and composite density, on oxidation process are explored. Also, theoretical results for a set of parameter values of the CIC composites are compared with experimental data. It shows that the model predicted values agreed well with the experimental data in weight loss. Based on this model, quantitative predictions of oxidation of a composite with cracked substrate can be made.

Jan 1, 1993

By G. H. Faye

The prospect of obtaining high-grade concentrates from Canadian pyrochlore ores is rather unlikely, and experimental beneficiation pro-cesses ?appear to have yielded products in the range of 3 to 20 per cent N'b205? A possible solution of the problem is to find an economical chemical method for recovering high-purity Nb2?05 from such concentrates. A technically feasible but economically unproved process is outlined in this paper, in which the concentrate is decomposed by an acid attack and the oxides of niobium and tantalum are isolated and then separated by liquid-liquid extraction. The solution of the ore is adjusted to 7 M HF-5 M HNO3 and the niobium and tantalum are extracted from this solution with methyl isobutyl ketone. The mixed oxides of niobium and tantalum are recovered from the oxdanic phase and dissolved in 0.5 M HF-1.0 M HNO3. Tantalum is extracted preferentially from this solution with methyl isobutyl ketone, leaving niobium in the aqueous phase. By the use of this process it is possible to produce niobium pentoxide and tantalum pentoxi.de in 99.5 per cent purity with a recovery of approximately 95 'per cent, under lab-oratory conditions.

Jan 1, 1957

By William L. Young

I think I should let you in on one of Canada's best-kept secrets, if you will promise not to tell it all over the place. Believe it or not, good, honest, enterprising capitalism is still alive and flourishing north of our common border, and I am living proof that capitalism is still working for the little guy. My personal story of mining development in Canada isn't all that rare -- you've probably heard something like it from other areas and other days several times -- but my case brings it up-to-date. I would like to Tell you briefly the history of Northumberland Mines Limited, a contemporary case of individual enterprise getting a mining operation underway. And if I can do it you probably can too.

Jan 1, 1981

By T. E. Howard

The western phosphate field, comprising parts of Idaho, Montana, Wyoming, and Utah, contains one of the world's largest known reserves of phosphate rock. Although phosphate-rock deposits of good-grade have been known since before the turn of the century and production has been recorded since 1906, real development of this important field did not begin until immediately after World War II. Since then fertilizer-manufacturing facilities using western phosphate rock have been expanded, and three electric-furnace plants for producing elemental phosphorus have been installed, resulting in a rise in mine production from 323,955 long tons2/ in 1945 to 1,653,916 long tons3/ in 1953. Interest in the field is increasing, and it is reasonable to expect that the western phosphate industry will continue to expand. Before 1945 all western production was from underground mines. In that year the first strip mine in the field was started near Montpelier, Idaho,~ and in sub-sequent years a number of other open-pit mines were opened in southeast Idaho and western Wyoming. At present the major part of the production comes from surface mines. Underground mining has continued, and new underground mines have been opened in the field, but recent exploration by operating companies has been aimed primarily at developing additional deposits suitable for low-cost surface mining. Preliminary reserve estimates by the Federal Geological Survey5/ indicate that only a very small part of the total resource may be recovered by surface methods and that the industry eventually must depend largely on underground mining. Because one function of the Bureau of Mines is promoting the conservation and development of the Nation's mineral resources, it is appropriate that research be conducted to develop low-cost maximum-recovery underground mining methods applicable to western phosphate-rock deposits.

Jan 1, 1956

We did install one 100% brick bottom in our #33 furnace which is basically the same design as Inland's furnace. We had previously embarked on a program of replacing all bottoms in our 300 ton furnaces every 2nd campaign which would be about every 2000 - 2300 heats. This had been necessitated by the effect of our rather high oxygen blowing rates and our desire to maintain a minimum bottom interval level. This meant that we were able to compare bottom performance of various types of materials on a realistic bas is. Since furnace availability is critical to our operation, we are organized to employ every piece of equipment and all the necessary man power to complete a rebuild in the shortest possible time. A 300 ton furnace requires 7.5 days to rebuild. If a new bottom is to be installed an additional 2.5 days is added - 24 hours for tear out and 36 hours for bricklaying - making a total of 10 days.

Jan 1, 1972

By H Tran

Local communities are undertaking an increased role in mine project decision making processes, associated with growing pressure and expectations from regulators, financiers and the general public. This is particularly evident in international projects within developing economies. Environmental and social issues are often complex. Solutions demand difficult choices and trade-offs between sustainable development dimensions: economic growth, social equity and environmental integrity. Proactive stakeholder engagement can play a critical role in assisting decision-makers in determining the operational reality of sustainable development by jointly exploring project trade-offs between proponents and affected stakeholders. Good stakeholder engagement has other potential benefits, ranging from reduced financial risk due to regulator delays, legal disputes or negative publicity to increasing market share through good public image. Approaches to consultation and disclosure have changed from short-term regulatory based focuses, to longer-term, strategic tools for relationship building, proactive risk management and new business identification. Approaches to consultation form a significant opportunity to contribute to overall social sustainability. This paper discusses, based on authorsÆ experience, the broader concept of stakeholder engagement and its contribution to social sustainability of the mining industry. The focus is on key considerations for an effective stakeholder engagement. Three case studies outline how broad based, proactive stakeholder engagement can contribute to improved operation and overall sustainability. The case studies include: a greenfields project in Ghana; a long-term mine in Australia; and an open-pit mine in Vietnam.

Jan 1, 2009

By R. M. Hardgrove

PULVERIZED coal was first used for firing cement kilns about 45 years ago, with such success that it has continued in general use. Based on cost, pulverized coal is usually the most economical fuel. In some localities natural gas or oil is cheaper, but 85.5 per cent of all cement kilns at present are fired with pulverized coal. The pulverized-coal flame is well suited to kiln conditions. Its soft, luminous nature gives it a high radiating property and the length of the flame can be readily varied to suit conditions in a kiln of any length. Ash and slag cause most of the difficulties incident to the burning of coal. In a cement kiln, however, the ash, being similar in composition to the raw mix and being deposited uniformly in the mix and clinker, occasions no difficulty as long as it remains constant in quality and quantity. Until 6 years ago almost all cement kilns using pulverized coal employed the bin system. The coal was dried and pulverized in a separate plant and delivered into a bin at the kiln. Thus the bin system requires driers, storage-type pulverizers, conveying systems, individual kiln bins, pulverized-coal feeders and primary air fans. The direct-fired system requires only a pulverizer and a blower. Fig. I shows typical plants. The first installations of direct-fired pulverizers were of the impact type but fineness of pulverization was both inadequate and variable. About 1927 a few direct-fired installations employing tube-type pulverizers were made, which were much more satisfactory. As more efficient pulverizers were developed from 1934 on, equipment for direct firing was installed at a large number of plants, until now 196 of about 900 kilns in use in the United States are direct-fired. Most of these replaced antiquated bin systems. PROCESS OF BURNING CEMENT CLINKERS The process of burning cement clinkers is fundamentally one of heat transfer. In boilers and other heat-exchange apparatus the area of the surface receiving heat from the gases is the best unit for comparing output. This seems to be equally true for kilns. The inside kiln surface is the heat-receiving surface and its area is used as the unit of kiln size in the following comparisons. Heat input is based on British thermal units in the fuel. E. G. Bailey,1 in his work on boiler-furnace heat absorption, has used the unit "B.t.u. available." This is the practical calorific power of the fuel, plus the heat in the air used for combustion. In other words, it is the heat available for useful work in the furnace or kiln. The unit of kiln output is barrels per hour. The composition of the raw mix, the percentage of water in the slurry of wet plants and hardness of burning all affect the output. These conditions, however, are hard to evaluate and probably have less effect on the output than irregularities of raw feed and clinker discharge and inexpert control of combustion. WET VS. DRY PLANTS The study presented here covers 88 plants, of which 41 are wet and 47 dry. Of

Jan 1, 1941

By H. Eccles

BNFL, an internationally acclaimed company noted for its nuclear fuel cycle services and waste management technologies, collaborated with Viridian BioProcessing Ltd, a small company acknowledged for developing environmental biological processes, and an internationally recognised professor of biological sciences, to develop an unique bioremediation process for treating toxic, heavy metal contaminated land. This paper describes the process, with particular reference to the problem and scope of land contamination with toxic, heavy metals and the current available technologies. The process technologies are based on using indigenous, soil micro-organisms which can be stimulated to produce acid or sulphide ions to mobilise or precipitate the heavy metals respectively. Laboratory studies have indicated metal removal efficiencies of greater than 90 % can be achieved, whilst recovery efficiencies from the metal loaded leachate are even higher at approximately 95%.

Jan 1, 1996

By J. M. Van Langen

In 1965 Hoogovens was looking for additional capacity for burden preparation in the order of 2,5 to 3 million metric tons per annum of some kind of optimal blast furnace ore feed. In principle four solutions offered them-selves for further investigation: 1. purchase of screened ore and/or run of mine ores with the provision of a corresponding ore screening capacity on the blast furnace site; 2. manufacture of sinter; 3. purchase of pellets; 4. manufacture of pellets. After studying the technological, technical, economical and commercial factors Hoogovens decided for the last mentioned possibility. Before taking this decision not only a great number of different mixtures of iron ore were tested, but during a long period in one of the big blast furnaces a number of tests were also executed with purchased pellets from South and North America. It was found, that using 50% acid pellets with 40% basic sinter a coke rate saving of 25 kg per ton hot metal (50 lbs/net THM) and a production gain of 15% could be obtained as compared with a full sinter practice. With some pellets it became clear, that due to properties, commonly referred to as swelling, we got very poor furnace performances; so in studying the production of pellets, pellet quality should be regarded as the most important aspect of the problem.

Jan 1, 1972

By H. I. NORTON, H. O. Hofman

ZINC smelters in the central western. States have established a very high standard of purity for blende-concentrates, viz., zinc 60, iron less than 3, and lead less than 1 per cent. The very low percentage of iron is made possible by the blende containing less than 0.5 percent of isomorphous iron sulphide and by the sparing occurrence of pyritic material in the large blende-deposits of southwestern Missouri and southeastern Kansas. The blende in these districts occurs in sub-Carboniferous limestone, and is associated with chert, residual clay, calcite, pyrite or rnarcasite and bitumen. The different minerals are coarse and therefore readily separated by mechanical washing from the blende, with the exception of pyrite and marcasite, as blende has a specific gravity of from 3.9 to 4.1, marcasite, from 4.85 to 4.90, and pyrite, from 4.95 to 5.10. The common procedure of dressing the ores is to crush in a breaker, size in a trommel with 0.5-in. holes, pass the over-size through roughing-rolls and then jig the ore, now reduced to 0.5 in. maximum size, in roughing multiple-sieve jigs. The products of these are waste-tailings, sine-discharge coarse concentrates, side-discharge coarse middlings and bottom-discharge fine middlings. The coarse concentrates are sent to the market. The coarse middlings are crushed in middlings-rolls and brought back into the system by feeding into the main trommel. The fine middlings are cleaned upon finishing-jigs. Any pyrite or marcasite present follows the blende and increases the percent-

Mar 1, 1905

By E. D. Gardner

"It has only been in recent years that the proper ventilation of metal mires has received serious consideration. Increasing temperature and humidity with greater depth in some of the larger mines of the West prevented the efficient operation of the mines and made the installation of mechanical ventilation systems necessary. Doors that interfere with tramming are generally needed to control properly the mechanically induced air currents and are one of the inherent disadvantages of the system. In fact the necessity for the use of doors in the main haulageways has discouraged the installation of mechanical ventilation in some metal mines.A number of mining companies in Arizona are using ventilation doors which can be opened and shut mechanically by the motorman without leaving his seat or stopping his train, end thus interfere very little with the transportation of the ore. The Copper Queen Branch of the Phelps-Dodge Corporation at Bisbee introduced these ventilation doors and adapted them from those in use in the company's coal mine at Dawson, New Mexico. Other mining companies have installed the same type of door and it is now being used in a number of districts in Arizona.The doors at the Calumet and Arizona mine in the Bisbee district are representative of those in use. The doors at this mine are substantially built of 2-inch lumber, are air tight, are well placed and have two openings or passageways. The main door, which is used for the motor trains, is 5 feet wide by 6 feet high and is opened by compressed air and closed by a counterweight. At the side of the motor door is the man door, which is 16 inches wide by 5 feet high and is opened and closed by hand."

Aug 1, 1921

By R. M. Hardgrove

PULVERIZED coal was first used for firing cement kilns about 45 years ago, with such success that it has continued in general use. Based on cost, pulverized coal is usually the most economical fuel. In some localities natural gas or oil is cheaper, but 85.5 per cent of all cement kilns at present are fired with pulverized coal. The pulverized-coal flame is well suited to kiln conditions. Its soft, luminous nature gives it a high radiating property and the length of the flame can be readily varied to suit conditions in a kiln of any length. Ash and slag cause most of the difficulties incident to the burning of coal. In a cement kiln, however, the ash, being similar in composition to the raw mix and being deposited uniformly in the mix and clinker, occasions no difficulty as long as it remains constant in quality and quantity. Until 6 years ago almost all cement kilns using pulverized coal employed the bin system. The coal was dried and pulverized in a separate plant and delivered into a bin at the kiln. Thus the bin system requires driers, storage-type pulverizers, conveying systems, individual kiln bins, pulverized-coal feeders and primary air fans. The direct-fired system requires only a pulverizer and a blower. Fig. I shows typical plants. The first installations of direct-fired pulverizers were of the impact type but fineness of pulverization was both inadequate and variable. About 1927 a few direct-fired installations employing tube-type pulverizers were made, which were much more satisfactory. As more efficient pulverizers were developed from 1934 on, equipment for direct firing was installed at a large number of plants, until now 196 of about 900 kilns in use in the United States are direct-fired. Most of these replaced antiquated bin systems. PROCESS OF BURNING CEMENT CLINKERS The process of burning cement clinkers is fundamentally one of heat transfer. In boilers and other heat-exchange apparatus the area of the surface receiving heat from the gases is the best unit for comparing output. This seems to be equally true for kilns. The inside kiln surface is the heat-receiving surface and its area is used as the unit of kiln size in the following comparisons. Heat input is based on British thermal units in the fuel. E. G. Bailey,1 in his work on boiler-furnace heat absorption, has used the unit "B.t.u. available." This is the practical calorific power of the fuel, plus the heat in the air used for combustion. In other words, it is the heat available for useful work in the furnace or kiln. The unit of kiln output is barrels per hour. The composition of the raw mix, the percentage of water in the slurry of wet plants and hardness of burning all affect the output. These conditions, however, are hard to evaluate and probably have less effect on the output than irregularities of raw feed and clinker discharge and inexpert control of combustion. WET VS. DRY PLANTS The study presented here covers 88 plants, of which 41 are wet and 47 dry. Of

Jan 1, 1941

By P Salmon, M Kennedy

Sun Metals Corporation Pty Ltd (SMC), a wholly owned subsidiary of Korea Zinc Co Ltd (KZC) is a company formed to develop, construct and operate a zinc refinery, 11 km south of Townsville in North Queensland. The project opportunity exists because of on-going consumption growth for refined zinc metal, technological, environmental and economic obsolescence of existing zinc processing plants, and a prolonged ædroughtÆ of new zinc processing capacity under construction. The Project will utilise proven technology developed by KZC at the Onsan refinery in Korea. The Townsville Refinery has been designed to be the most environmentally-friendly zinc refinery in the world, and in particular to resolve the issue of secure, long term treatment of the ironbearing content of the zinc raw materials.

Jan 1, 1998

By J. Bongarra

This report describes the development of the instructional design and content of a training program for shaft construction miners and supervisors. The recommended training approach is based on the results of a needs, task, and competency analysis of the jobs performed by conventional shaft sinking and raise drill personnel. Learning objectives were derived from the task analysis and the appropriate training delivery system was chosen using a selection technique which employed learning algorithms. The training described is aimed at improving the safety and efficiency of constructing shafts by new hire and experienced miners and supervisors. A self-paced, self-teaching, modular approach to training, using criterion-referenced tests was proposed. Recommendation was made to divide the training into three parts: Orientation and Safety; Task Instruction; and Practical Exercise. Training requirements for conventional shaft sinking and raise drilling were described. Training program content was detailed in the form of module and lesson design approaches. In addition, the report recommends a method for developing, implementing and validating the training program. The authors conclude that such an implementation would meet the major objectives of improving the safety and efficiency of shaft construction work operations.

Jan 1, 1979

Reliable sampling practices are the key to optimising the market value of a mining or chemical companyÆs stock. As a result, reliable sampling standards are needed. However, current standards on sampling present the æuniversalÆ Pierre GyÆs Sampling Theory in an ambiguous way. For example, the Total Sampling Error is divided into its basic components only in informative annexes, when it should clearly be the main body of the standard. Sampling standards are presently loaded with statistical concepts that actually belong in the annexes. Furthermore, many non-probabilistic sampling procedures are still mentioned which do not belong in a standard. The objective is not to criticise existing sampling standards, but to suggest better ones. Sections on the Sampling Theory should divide the Total Sampling Error into a sum of its nine basic components. Then, and only then, should they be addressed one at the time. Sections for establishing a sampling protocol should address the in situ Nugget Effect, the Fundamental Error, the Grouping and Segregation Error, the Long Range Quality Fluctuation Error, and the Periodic Quality Fluctuation Error. Sections for sampling methods, mechanical sampling, manual sampling, grab sampling, sampling of trucks, railroad cars, bags, and drums should be part of the critically important practical implementation of a recommended sampling protocol, called Sampling Correctness. It includes the increment Delimitation Error, the increment Extraction Error, the Weighting Error, and the Preparation Errors. Unless these errors are addressed one at a time, in an unambiguous way, the standard will remain ineffective in solving sampling problems for the industry. Therefore, a strategy is needed to create better standards required at the early stages of new projects, both by manufacturers of sampling equipment and by engineering firms. A logical sequence of important points that cannot be ignored in any sampling standard is presented. An analysis of the practical use of the words sampling uncertainty versus sampling error is recalled. Finally, as a practical example, an in-depth analysis of the correctness of cross-belt samplers is presented, and emphasis is placed on the correct ways to perform bias-tests for mechanical sampling systems.

Jan 1, 2005

By E. Morrice

This report of the Federal Bureau of Mines presents a laboratory procedure, with the requisite equipment, for electrowinning ingot (liquid) cerium metal from a fused-fluoride bath, the metal purity being about 99.9 percent. Physicochemical studies, including bath properties and electrochemistry, are included, with a speculative model of the mechanisms involved. An historical review of the methods used for electrowinning misch metals and yttrim-group metals, as well as individual rare-earth metals, is presented. The electrolytic preparation of metal from fused salt and nonaqueous media is summarized, along with the unsuccessful attempts at depositing the metals from aqueous solutions.

Jan 1, 1961

By Len Blackman

The Absaroka-Beartooth Study Area is a tract of approximately 1.4 million acres of National forest land in southern Montana, part of the Greater Yellowstone Area. This study evaluated the mineral potential of four mineral terranes containing undiscovered resources in the area. The geological data is probabilistic, with estimates of the possible number: of deposits and their grades and tonnages. Possible future development scenarios range from no development to many mines, including some very large. As two thirds of the study area is within the Absaroka-Beartooth Wilderness, the future development scenarios reflect the area's mineral potential, not what we expect to see in the foreseeable future. Based on the analysis performed on these four terranes, the most likely future scenario for the study area would include the potential for two medium sized, (predominately) gold, mines, each employing a few hundred workers. There is a small chance, less than 5%, that a large Porphyry Copper or Superior Iron deposit would be discovered and be economically feasible to develop.

Jan 1, 1994

By Peter Broad

"Extracting any metal, especially specialty metals and rare earth elements, requires an in-depth analysis of the costs and potential revenue as well as a due diligence study of other stakeholder interests. Rare earth projects are generally in the billion dollar US range or above, and thus failure to accurately predict any loss of revenue caused by impurities within the product or additional effluent treatment costs can destroy an otherwise viable study. Two prime sources of input impurity are considered: impurities in the material feed and from reagents. The effect of these impurities factor on both the product (in reduced revenue) and on residual “tailings” that may incur additional unforeseen costs.INTRODUCTION“Truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident” – Arthur SchopenhauerThe era of unscoped, unbudgeted construction ended about 150 years ago. Today’s engineer must design with confidence; but do so amidst proprietary secrets and unfamiliar pollutants, which present a myriad of interesting challenges. Is it possible to build a viable rare earth plant to a realistic budget, without destroying that which we cherish? Some see this as contradictory but in reality it is the only viable option.WHEN GOOD PROJECTS FAILWithout rare earths the Copenhagen agreement might be null and void. Running a wind turbine with a 30 tonne conventional magnet requires some hefty engineering and prohibitive investment. Despite their ‘Green metal’ applications, production of rare earths have created environmental nightmares, as Folger stated in 2011 when visiting Baotou, or has Jaing Mainheng who has been quoted by Ambrose Evans-Pritchard 6 Jan 2013. This comment is not a criticism of China; the details are from a 2012 white paper published by the Chinese Government that initiated a $6 billion environmental clean-up. Nor is China unique; other plants have had problems as well. There were toxic leaks in the 1990s from Mountain Pass, and the Mitsubishi Bukit Merah Plant (built in Malaysia in 1958) required a $100 million clean-up."

Jan 1, 2016

By A. Z. Dimitroff

An improvised rock-dust disseminator, consisting of a 10-gallon galvanized metal milk can that dispenses rock dust in return air currents by the injection of compressed air has reduced the float dust explosion hazards at the Koehler coal mine, Koehler, N. Mex.

Jan 1, 1965

By S Nowosad, A Binder, O Langefeld, M Bothe-Fiekert, F Apollo

The mining industry faces complex and urgent challenges driven by an increasing demand for raw materials, and a socially demanding globalised world. The extraction of primary raw materials is today more important than ever as one of the cornerstones towards a sustainable future since the increasing demand for the raw materials required for the energy transition. In the last three years, leading countries as USA, China, Canada, Australia, and the European Union (EU) have developed and adopted strategies to enhance domestic extraction capabilities, diversifying sources, fostering innovation in recycling, and promoting international collaboration related to critical raw materials. On 2022, the Inflation Reduction Act was signed into law in the USA, in June 2023, the Australian Critical Minerals Strategy 2023–2030 was published and in March 2024, the Council of the EU adopted the European Critical Raw Materials Act. On the other hand, raw materials extraction is facing higher environmental and safety standards and regulations, as well as scrutiny from the broader public. Regrettable environmental accidents as tailing dam failures or acid mine drainage occurrences have led to a general distrust of mining activities leaving mining companies with the dual imperative of increasing output while implementing sustainability, decarbonisation, and circularity as a core value in their production processes. This challenging environment offers the opportunity to enhance ‘blue mining’ (BM) as a sustainable holistic approach that integrates the principles needed to plan sustainable, reliable, and responsible mines for today’s and future generations by implementing the principles of circular economy (CE). This requires a fundamental shift from the traditional linear economy approach to a sustainable, circular economy strategy. At its essence, BM encapsulates four crucial aspects – energy, ergonomics, water, and circularity and integrates these four aspects into integrative mine planning, defining clear goals and objectives from the ‘blueprint’ of a mine towards a beneficial post-mining activity. Its implementation can lead to maximisation of resources beyond the life of the extractive mine and sustainable use of materials by integrating the principles of circular economy and multiuse mine, see Figure 1. These concepts complement and recognise the need to minimise environmental and social impacts while advancing economic development. Finally, this contribution explains the requirements and challenges of moving from linear to dynamic planning approaches under the BM concept. This way, BM stands as an approach that can contribute to the mining industry receiving necessary approvals and support from society leading to a long-term transformation of the industry’s image.

Sep 1, 2024