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By George D. Raitt

Anyone who has spent any time in and around the drilling and blasting profession knows that probably the most critical part is the drilling portion. A blasthole is nothing more than a cylindrical vehicle designed and strategically situated to hold and contain an explosive charge so that it can be detonated in the most efficient and optimum manner possible. It matters very little if the latest “State-of-the-Art” explosive or detonation system Is employed if the hole is poorly placed; i.e. excessive burden and spacing, sized incorrectly for desired results, insufficient in depth etc.. This is not to mention that the drilling phase is the most expensive, requiring sizeable initial outlays and upkeep. It’s also true that improper drilling can cause costs to skyrocket throughout the remainder of the work cycles such as excavating and hauling, crushing, screening and so on.

Jan 1, 1990

Characterisation of Computer Printed Circuit Boards for Hazardous Properties and Beneficiation Studies

Sep 13, 2010

Investigation of the Classification Operation in a Coal Pulverising Vertical Spindle Mill Coal pulverisation in power plants is a major electrical energy consumer. In 2006 more than 41 per cent of world electricity generation was from coal where pulverisers use 0.5 to 1 per cent of gross generation. Therefore, pulverisers are an important target for optimisation not only for reducing costs of power generation but also for reduction of greenhouse gas emissions. A better understanding of the operation of pulverisers is an essential requirement for their optimisation. However, little information is available, other than operating experience, on the performance of pulverisers and how these react to changes in operational variables. This study investigates the effect of changes in coal and airflow feed rates on the classification performance that occurs in an industrial scale ball-and-race vertical spindle mill in which the pulverisation and classification processes are linked together due to the separator classifier being an integral component within the pulveriser. In order to decouple the breakage and classification processes, samples were cut from upward flowing streams through sampling ports drilled on the pulveriser body at different locations. Specific sampling tools were developed. Samples collected from the pulveriser were size and density fractioned to distinguish the differences in behaviour of the components, namely coal and mineral matter. The coal flow rates on dry basis within the mill and around the separator classifier were calculated by mass balancing the multi-component data. The difference in classification behaviour of components during pneumatic transport was confirmed. The response of the circulating load in the mill (~600 to ~1100 per cent) as well as the dependency of fineness of the streams to the operating variables was demonstrated. The approach taken in this study has proved that development of a classification model for a vertical spindle mill pulverising non-homogeneous materials, eg coal, requires treating these materials as multi-component/composite substances.

Sep 13, 2010

GENERALTHE coal deposit, where it is being worked, consists of a bed of brown coal varying in thickness from 120 ft. to 200 ft., covered by an overburden of clay, drift, loam, etc., of a thickness of 22 ft. to 40 ft., and averaging 28 ft.The overburden is first entirely removed from the coal, and then the coal is excavated by. large revolving shovels which work at the bottom of the hole or open cut in the coal and deliver it in shovel bucketfuls to the transport system. The shovels owned by the Commission and available for this coal excavation are two Bucyrus steam revolving shovels, one being type 150B, weighing 150 tons, having a 21-cub. yd. bucket, and capable of digging a 47-ft. face; and the other being type 175B, weighing200 tons, having a 31-cub. yd. bucket, and capable of digging a 61-ft. face.In addition to these two steam shovels, the Commission has recently obtained a No. 250 Ruston electric revolving shovel weighing 340 tons, and having a bucket of 10 cub. yd. capacity, and capable of digging a 75-ft. face. When this electric shovel has been erected it will replace the steam shovels on the coal excavation, and the permanent transport system has been designed to take delivery of the coal from its bucket.The duty to be performed by the transport system is to take the coal from the shovels, elevate it out of the open cut, transport it to the screening house, deliver it iuto the hoppers at the top of this building, then to take the coal after it has passed over the screens and distribute the required grades to the power house and to the briquetting plant.

Jan 1, 1924

By J. B. Brodie, C. Pelletier

"The vulnerability of Canadian and U.S. companies, their directors, officers and employees to onerous penalties associated with violations of environmental statutes and common law actions has provided the impetus for the increasing use of environmental audits. This trend is developing in direct proponion to the cost and difficulty of obtaining liability insurance. Companies operating in British Columbia should be cognizant of developing legislative and enforcement trends and their implications for individual and corporate responsibility. Canadian mining companies doing business in the U.S. should be particularly aware of the environmental exposure which may be assumed with property acquisition or by operations which produce or use any of an ever-increasing list of regulated substances.The environmental audit is now a key component of prudent business planning which will identify noncompliances and environmental liabilities, outline defensive strategies, and assist in a legal defence should charges be laid. This paper will discuss the purpose and mechanics of an environmental audit with emphasis on those features which will maximize protection against statutory and common law actions.IntroductionThe environmental audit is but one weapon in a comprehensive defensive strategy for corporate and individual survival in an increasingly litigious world. The principles of the environmental audit have been formulated as a logical response by management to an ever-growing list of environmental vulnerabilities, which often have the potential to result in plant shutdowns, prosecutions or fmancial liability of major proportions. Accordingly, the audit may play a critical role in maintaining profitability as well as assisting in the defence of a company and its employees against actions taken by regulatory agencies and citi7.cns under statute and common law. Should convictions result from these actions, the penalties are likely to be ameliorated by the demonstration of due diligence through management policy supporting the audit procedure.An awareness of environmental sensitivities, strict adherence to licensing requirements, and planning for environmental emergencies are now generally considered to be as important to profitable performance as operating costs, metal prices, and labour peace. Why is this so? The increased priority given to environmental matters is partly a result of changing attitudes amongst the mining profession, but perhaps more importantly, it is also a direct consequence of the proliferation of ever more stringent environmental legislation, the targeting of management for responsibility and the draconian penalties imposed for violations of such legislation. Contributing to this trend are recent court decisions involving disputes of an environmental nature in which the standard of care required for a successful defence now requires almost super-human diligence in environmental management. The principle of ""strict liability"" (in which negligence or permit violation does not have to be shown) is also being increasingly applied in the resolution of civil actions."

Jan 1, 1988

By Euler De Souza

Backfilling in Canadian mines has been practised for close to 100 years and evidence anticipates the application of mine fill technology at an increasing rate during the foreseeable future. The evolution of backfill technology is closely related to the advancement of modern mining methods and the development of new backfill technology continues to evolve. The authors, after conducting extensive surveys of backfill practices in underground mines across Canada, have concluded that, because backfill operations employ large quantities of cement and experience large costs associated both with backfilling practice and cement use, opportunities exist for reducing backfill energy costs and enhancing the application of alternative cementing agents in backfill. Consequently, the authors have developed an alternate, equally effective and lower cost binder agent replacement for cement, and incorporated waste glass into the development of a lower cost backfill (glassfill). This paper presents the results of two design stages associated with the development of glassfill: strength development and flow performance. The advancement of this technology has reached a stage that should promote industrial implementation within the Canadian mining industry. A number of Canadian mining operations exhibit potential for plant optimization through possible binder source replacement, and might thus realize associated reductions in backfill and energy costs.

Apr 1, 2005

By Hongfei Li, JianLong Wang

This paper introduces the technical characteristics, transformation scheme and production practice of the project in which Copper P-S Converter was replaced by Bottom Blowing Continuous converting for the first time, and introduces the technical achievements obtained by the project. The application practice proves that bottom blowing copper continuous converting technology can completely solve the problems of fugitive off-gas pollution in the ladle transportation, large amount of flue gas and fluctuation of flue gas caused by P-S converting. Comprehensive energy consumption and operating costs of producing blister copper, safety and environmental risks are greatly reduced, and economic, environmental and social benefits are significant. It is one of the preferred technologies for upgrade and to replace P-S converting technology. INTRODUCTION At present, more than 80% of copper production capacity is still using the P-S converting technology with a history of more than 100 years. During P-S converting process, melted copper matte needs to be transported by ladle, and it needs to rotate the furnace body several times, causing a lot of serious environmental and safety risks such as SO2 flue gas emission and low-altitude SO2 pollution. In addition, the high operating cost caused by low rate of air blowing, the short life of the refractory materials and high energy consumption during P-S converting become big problems. Other problems such as large amount of flue gas, low SO2 concentration, large fluctuation of flue gas volume and SO2 concentration, and discontinuous flue gas cause high cost of subsequent flue gas treatment are also needing to be solved. In order to solve these problems during the P-S converting, metallurgical engineer in various countries has spared a lot of efforts to develop continuous blowing process for decades. The continuous converting that have been industrially applied are flash continuous converting, Mitsubishi continuous converting, Noranda continuous converting, Bottom Blowing Continuous converting and multi-lance top blowing continuous converting

Jan 1, 2019

By D. R. Parrish, F. F. Craig

In some respects, forward combustion (alias: fie-flooding, underground combustion, in-situ combustion, dry combustion) is an efficient oil recovery method. For example, its displacement efficiency (as much as 95 percent in reservoirs with high porosity and high oil saturation) is good. In its use of heat, however, forward combustion is grossly inefficient. Most of the heat generated during forward combustion is wasted. About one-fifth of the heat is picked up by the incoming air and re-used (regenerated); the remainder is left behind the combustion zone and ultimately is lost. Compressed air is expensive, and heat generated from compressed air via underground combustion is too valuable to be thrown away. Improvement is needed. Since the early 1950's, improvements in forward combustion by addition of water injection have been discussed, particularly in the patent literature, with increasing frequency.'-'' These concepts are based on the fact that relatively inexpensive water can be used to pick up much of the heat that is ordinarily wasted during forward combustion, and transport it forward to a more useful place, thereby reducing the amount of air required to move a heat front through the reservoir. Several approaches have been proposed. Merriam and Squires1 taught that a combustible (fuel) gas should be injected along with the air and water. This, however, would give at least a tendency toward reverse combustion instead of forward combustion, and would reduce the velocity of the heat bank, defeating the primary purpose of the water injection. Pelzer2 described primarily a batchwise method of forward combustion and water flooding. He advocated burning part way through a reservoir with forward combustion, then switching from air to water injection alone to push the heat toward the producing wells. Though possible, this method has serious disadvantages, the major one being that, by the time water injection is started, much of the heat has been irretrievably lost to the overlying and underlying formations. We have described what is considered a practical Combination Of Forward Combustion And Water-flooding (COFCAW).3,4 Air and water are injected simultaneously (or alternately) after a small heat bank has been formed by forward combustion. Some of the injected fluid fills up the region behind the heat bank; the rest enters the heat bank. Upon encountering heated rock, the water is converted into steam, which then flows ahead of the combustion zone and displaces much of the oil in place. Only enough air is injected to provide heat for vaporization of the water and to compensate for reservoir heat losses. Since the size of the heat bank is minimized, heat losses also are minimized. Because of more efficient oil displacement ahead of the combustion zone, fuel consumption is reduced. Too, unlike a forward combustion zone that cannot move until all fuel at a point has been consumed, COFCAW leaves some

Jan 1, 1970

By Gábor Csicsovszki

We have developed a novel method - at the laboratory scale - comprising an ion-exchange separation and a membrane-electrolysis step for the purpose of zero-waste regeneration of spent HCl pickling liquors originating from hot-dip galvanizing of common steels. It is aimed at the parallel regeneration of HCl and iron. Experiments revealed that iron can be electrodeposited at high current efficiencies by maintaining the following conditions: 0.04-0.08 M HCl, 500-1000 A/m2, 20°C and stationary electrolyte in a conventional cell. Zinc in the solution did not disturb the deposition of iron, however it contaminated the product and it poisons the anion-exchange membrane required to tackle acidity during electrolysis. For a preliminary separation, anion-exchange tests were carried out to produce pure iron solutions. Beyond the equilibrium studies, column experiments were carried out showing that low flow rates of the loading solution and the ~1.5 M HCl eluent are essential for separation.

Jan 1, 2006

The Ministry of Commerce has been carrying out an evaluation of the resources of the Northwest Nelson region. In part this was to revisit the issues covered in the earlier proposal to close part of Northwest Nelson to mining under section 24 of the Mining Act (1971) initiated in 1990. In addition, the option of using GIS to integrate a variety of spatial data sets to aid policy formulation could be tested. The Northwest Nelson assessment would be a useful trial. The subsequent national park proposal provided a major impetus to the project and resulted in the scope of the study being broadened to include all energy and minerals resources.

Jan 1, 1993

By Roger S. Jackson

"This study interprets vibrations produced by single underground shots, recorded on surface by 135 digital seismographs laid out in four linear arrays. Several vibration anomalies were observed and are investigated. A novel method of displaying the blast-induced vibration iso-contour data relative to the three-dimensional representations of the geological rock units and structures leads to the following interpretations:• The identified faults commonly dampen or amplify vibrations, on the evidence of the peak particle velocity,• Strong anisotropy of geologic formations produces different vibration attenuation in the various directions of interest,• Low-vibration “depressions” can be related to the presence of faults, and• Higher vibration levels than expected based on ‘scaled-distance’ principles are observed close to intersecting faults.The interpretations from this study document a better understanding of the geotechnical influences on blast induced stress wave propagation in a geologically complex area. The practical benefit of this understanding is better control of surface vibrations, experienced from underground mining activities."

Jan 1, 2010

By Roger Frank

"Abstract After noting the importance of standardization for piles, the European system is described (execution, tests and design, etc.). Some important aspects of Eurocode 7 are outlined (like the role of pile load tests). Finally, the calculation methods in the recent French standard for the design of piles following Eurocode 7 are shortly addressed.Importance of standardization for piles Like for other fields of geotechnical engineering, pile engineering is a complex art. For piles, the challenges are particularly numerous and many things must be mastered properly: - the soil investigation must be serious and adequate (for instance, deep enough!);- the choice of the pile type and the assumed behaviour must be assessed in order to reach a safe and economic design of the overall foundation;- the execution itself (construction and/or installation) deserves special attention and must follow strict state-of-the art rules.The geotechnical engineer, in charge of the design of a pile foundation, must have in mind the parameters linked to the variety of soils, of soil conditions and of pile types. A wide range of strong environmental issues are also to be considered: minimum disturbance during the execution processes, long-duration friendliness of the “inclusions” into the ground (to avoid pollution of the soils and waters, for instance) and respect of the neighbouring structures.Pile engineering plays in a world which is constantly moving and progressing: constructions expand in new difficult areas, actions on piles are more and more important, new execution techniques of piles are developed, research into the complex behaviour of pile foundations has no end, etc. Our views on how piles and group of piles really work are constantly evolving!"

Jan 1, 2014

By W. N. Patterson

The three major objectives of this contract were (1) to survey underground diesel-powered mining machinery to determine noise exposure problems, (2) to recommend noise control techniques, and (3) to develop a technique for predicting underground sound levels from surface sound power measurements. The objectives were achieved. The contractor developed information on the severity of the noise problem caused by diesel engines underground and pinpointed the equipment causing the problems. He recommended a number of corrective techniques that can provide relief until long-term solutions are found. A procedure for predicting underground noise levels from above-ground measurements of the machine noise was found valid for several cases tested.

Jan 1, 1975

Mine waste and mine reclamation are topics of major interest to the mining industry, the government and the general public. This publication and its companion volume are the proceedings of a conference held in Pittsburgh, April 19-21, 1988. There were nine sessions (50 papers) that dealt with the geochemistry, hydrology and problems of mine waste and mine water, especially acid mine drainage. These comprise Volume 1. The nine sessions (43 papers) that dealt with reclamation and restoration of disturbed lands, as well as related policy issues, are included in volume 2. Volume 2 also contains the ten papers that pertained to control of subsidence and mine fires at abandoned mines. Poster session presentations are, in general, represented by abstracts; these have been placed in the back of both volumes.

Jan 1, 1988

By B. Anameric

The pig iron nugget process is gaining in importance as an alternative to the traditional blast furnace. Throughout the process, self-reducing?fluxing dried greenballs composed of iron ore concentrate, reducing-carburizing agent (coal), flux (limestone) and binder (bentonite) are heat-treated. During the heat treatment, dried greenballs are first transformed into direct reduced iron (DRI), then to transition direct reduced iron (TDRI) and finally to pig iron nuggets. The furnace temperature and/or residence time and the corresponding levels of carburization, reduction and metallization dictate these transformations. This study involved the determination of threshold furnace temperatures and residence times for completion of all of the transformation reactions and pig iron nugget production. The experiments involved the heat treatment of self-reducing?fluxing dried greenballs at various furnace temperatures and residence times. The products of these heat treatments were identified by utilizing optical microscopy, apparent density and microhardness measurements.

Jan 1, 2007

By R. J. Baumgartner

Sustainability issues are from rising interest and importance for the mineral industry worldwide. In order to bring them into management processes and to improve decision processes, economic, ecological and social aspects of products, services or technologies have to be assessed. In this paper, the concept of integrated sustainability assessment is presented. Each aspect is assessed with quantitative or qualitative methods. The results of these ecological, social and economic sub-assessments are integrated by the means of Fuzzy Logic in order to regard preferences of decision maker and circumstances of decision situation. An example demonstrates the application of this new instrument.

Jan 1, 2005

By D. Imeson, T. Grammatikopoulos, G. Pearse, M. Aghamirian, C. Mohns

"Spodumene mineral is a source of lithium for lithium ion batteries. Thus, the production of a spodumene concentrate with an approximate grade of 6% Li2O is targeted. Traditionally, spodumene is concentrated by froth flotation using fatty acid as the collector. Amine collector can also be used to float mica ahead of spodumene as required or feldspar from the spodumene tailings. Slimes have a negative effect on spodumene flotation and they are commonly separated by scrubbing and de-sliming prior to spodumene flotation. The main losses in spodumene flotation typically occur in cyclone overflow, scrubbing slimes, spodumene flotation tailings and mica concentrate. In recent years, dense media separation (DMS) is the main concentrating process in Australian spodumene operations. In these operations, DMS is efficient at generating coarse grain concentrates and rejecting large portions of silicate gangue, thereby directly reducing the milling cost. The ore should be crushed to 3/8” or coarser while further crushing is possibly necessary on the middling particles to scalp further spodumene. The DMS feed should be classified to remove fines (typically -0.5 mm particles). The final middlings and undersize fractions could then be processed by flotation. The main requirement in DMS operations is to have good spodumene liberation at relatively large grain size. This paper reviews the most significant DMS and flotation parameters in spodumene beneficiation. The treatments of different minerals in the spodumene ore are also addressed.INTRODUCTION A number of laboratory/pilot plant programs have been recently conducted at the SGS Lakefield site, sponsored by different clients. The main objective has been to develop a process flowsheet to generate a spodumene concentrate containing 6.0% or higher Li2O (~75% spodumene) suitable for producing lithium carbonate by a hydrometallurgical process. Depending on spodumene liberation size, dense media separation (DMS) can be an attractive option to produce a final high grade concentrate and to reduce the mass to be treated in the flotation circuit. In such a case, crushing would typically be performed in stages, with DMS separation to recover a spodumene concentrate and reject gangue minerals following each stage. DMS middlings and -0.5 mm fines can be processed by flotation to further recover spodumene. In the flotation process, coarse stage grinding minimizes the grinding cost and formation of slimes. In the majority of cases, a grind size (K80) of approximately 200 microns is sufficient for flotation. After primary grinding, mica, if present in an appreciable amount, should be floated to minimize interference with spodumene flotation. Desliming after scrubbing and high density conditioning are the key process operations prior to spodumene flotation. Spodumene can then be floated from silicate gangue minerals with a fatty acid or a mixture of fatty acid and petroleum sulfonate at slightly alkaline pH. Subsequently, feldspars can then be floated from the spodumene tailings."

Jan 1, 2012

By Fredrick Fränding

In mining and quarrying operations, electric motors can fail for a variety of reasons. Some failures are directly linked to demanding production requirements and contaminant-laden environments and, consequently, are difficult to prevent. A sizeable number, however, are caused by ?offline? factors that have nothing to do with production. These include inadequate or substandard motor repair practices and improper motor shipping, storage and installation. The fact that failures are at times attributable to repair- or rebuild-related errors and problems raises the stakes when selecting an electric motor repair provider. Teaming with high-quality electric motor shops can help a company reduce failures due to offline factors, improving motor reliability and cutting downtime costs. Regardless of location or annual revenues, the best motor shops have similar business cultures and share many of the same characteristics.

Jan 1, 2009

By H. W. Wainwright

.1. The purification pilot plant and the equipment, solution, and gas cycle used for removing hydrogen sulfide and carbon dioxide are described. 2. As sulfur recovery is necessary in any large Fischer-Tropsch plant, pilot-plant runs were made at 300 p.s.i.g. to study the efficiency of tri-ethanolamine solutions in removing selectively hydrogen sulfide from gases containing varying amounts of carbon dioxide. 3. Aqueous solutions of TEA of 20, 30; 35, and 50 percent were investi¬gated. Data indicate that 30 to 35 percent is the optimum concentration if both selectivity and economy are considered. Slightly better selectivity is obtained with the.20 percent solution, but steam consumption is greater owing to the higher solution rates. Results from our pilot plant runs indicate that a 50 percent solution not only produces an acid gas of lower hydrogen sulfide content but also requires high solution rates to effect hydrogen sulfide purification. 4. Data from 37 runs using TEA are presented in tabular form. In addition, the data are correlated and presented in three sets of curves. By using these curves, it is possible to calculate the compositions of the purified and acid gases for various raw gas mixtures. 5. In cooperation with the Southern Natural Gas Co., investigations were carried out at 300 p.s.i.g. on the simultaneous removal of hydrogen sulfide and carbon dioxide, from gases using various concentrations of diethanolamine. 6. Data from 17 runs employing 20, 30, and 40 percent DEA are reported in both tabular and graphic form. 7. A comparison of the data from one DEA run made at 200 p.s.i.g. with those from the runs operating at 30O p.s.i.g. shows float the absorption capacity of the solution, and, hence, the steam requirements per gallon are about the sage for both pressures. .The only real advantage of the higher pressure is the additional volume of gas that can be treated. 8. The quantity of steam needed to reactivate fouled TEA and DEA solutions increased as the reactivator pressure was increased about 1,0 to 1.1 pounds of steam was required for each gallon of circulating solution when the reactivator was operated at 5 p.s.i.g. 9. A curve is included that shows the effect of the hydrogen sulfide con-centration in a lean 35 percent TEA solution on the hydrogen sulfide content of the purified gas and on steam consumption for reactivation. 10. Both TEA and DEA reduced the organic sulfur content of the raw synthesis gas considerably. Analyses of the lean amine solutions showed a gradual build up of sulfur compounds, indicating that the compounds formed by the amines and organic sulfur do not break down under the ordinary operating conditions of the reactivator. 11. Considerable operating difficulty was encountered in the pilot plant owing to foaming of the amine solutions. Laboratory experiments in which the effectiveness of certain antifoam agents was studied showed Alkaterge C to be most promising for the particular conditions studied.

Jan 1, 1952

By M. C. Pietrobon

"A common problem in assessing the applicability of laboratory flotation data is determining how closely conditions during laboratory testing of the ore matches those that occur in a plant. Typical laboratory based investigations do not consider factors such as water quality, pulp temperature and the pulp chemical environment during both grinding and conditioning on laboratory flotation performance. Disregarding these important factors may seriously compromise the validity of conclusions based solely on laboratory experimental results. Furthermore, considering these factors during the flowsheet design stage in the development of new ore resources may reduce financial risk associated with building a new plant. A methodology is described here which embraces these factors in an attempt to bridge the gap between laboratory and plant. The methodology should be considered a vital first step in all laboratory based experimental programs and has implications for fundamental studies on the flotation behaviour of single minerals. This methodology increases the confidence with which findings of laboratory based studies can be transferred to the plant and highlights the effect of variables which may be accessible to manipulation in the plant.Pulp chemical parameters, such as pulp dissolved oxygen demand, pH, Eh, mineral oxidation and solution composition were manipulated in the laboratory by adjusting the duration of gas purging after grinding, the process water input and pulp temperature. A key finding was that matching of the laboratory pulp chemistry to the plant pulp chemistry was dependent upon oxidation after grinding. In turn, mineral oxidation was dependent upon the pH in grinding, water composition and the duration of oxygen purging after grinding. The methodology closely matched the dissolved oxygen demand and surface chemistry of laboratory and plant pulps."

Jan 1, 2002