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By Stephen C. Tadolini, Raymond A. Mazzoni

The International Ground Control Conference in Mining has always provided an open forum for the publication, presentation, discussion, and often heated debate on roof bolting systems mostly with attention to how, when, and why they work. During the last 24 Conferences at least 170 papers have been presented by International Experts on these “simple” devices that range in length from 30-inches to 20 ft and from 5/8 to 2 inches in diameter. Roof bolts are primarily mechanically anchored, glued, cemented, or driven. Bolts are placed vertically, angled, or tied together with special fixtures (trusses and slings). They have been termed active, passive, stick-slip, and several other descriptive acronyms or mining slang expressions. This retrospective paper will present the changes in bolt types and usage, point out some of the biggest myths and hail the most significant advances (according to the authors’ opinions of course).

By Mark Hollingworth

"There is general consensus that as the world continues to change at an ever-increasing pace, companies must continually adapt their operations in order to remain competitive. Those that change fast enough, survive; those that don’t, perish quickly. Today, we hear that it is not worth the time preparing corporate business plans as they are out-of-date before the ink is dry. Within the corporate environment of the 1990s, we must “think” strategically, be a “learning organization”, keep our costs low, focus on our core competencies, stay as flexible as possible and create value. So-called “sustainable competitive advantages” can be obsolete before a patent is issued — if its even worthwhile patenting the advancement. This is industry in the 1990s.Now, while all this radical change has been underway in the global industrial environment, what have Canada’s universities been doing to keep pace with the change affecting one of their major stakeholders? Have they adapted their products and services to suit the new market conditions? Have they built closer links to industry to try to understand how better to serve this important client? Do they welcome industry input as to how to redefine their mission, objectives, strategies or their course contents? Do their students graduate with skills ideally tailored for the global mining industry? In the era of communication, can they write high quality reports in English, never mind speak French or Spanish?In an effort to provide Canada’s engineering faculties with a “blueprint” for the future, the Canadian Academy of Engineering pre-pared a report entitled “Engineering Education in Canadian Universities”, published in August1993, which concluded with the following recommendations:"

Jan 1, 1996

By P. Somasundaran, Tarun Bhambhani, S. Murthy Khandrika, Partha Patra, D. Nagaraj

Fine and ultrafine mineral particles, particularly if, altered mineralogically, can have detrimental effects on selective separation of minerals. Behaviour of altered mineral fines has been investigated in this work by studying the effects of weathered silicate slimes on the selective separation of copper minerals, particularly with focues on effect of the pulp rheological behaviour, which plays a governing role in the process. Physicochemical properties of these altered silicates fines such as morphology and surface charge are proposed to be responsible for the adverse rheological effects and resultant selective separation. Here, the effect of a number of problematic aspects such as water chemistry, froth stability, physicochemical aspects of gangue mineral aggregates on flotation sub-processes has been studied. Processing problems owing to the physical aspects of the gangue minerals, shape and morphology, are primarily due to uncharacteristic increase in the pulp viscosity. While problematic aspects other than impact of pulp rheological behaviour can interfere with each other in their contributions to how they affect the sub-processes, effects owing to pulp rheological behaviour have a direct impact on the flotation performance. Subtle increase in pulp viscosity can interfere with sub-processes in flotation leading to decrease in recovery and grade, and it is difficult to assess the effects due to such subtle changes. Reagent based strategies to overcome the problematic aspects has been explored here.

Jan 1, 2014

By S. Kapusniak

Specialist Machine Developments (SMD) is a design and manufacturing company involved in the design of Remotely Operated Vehicles (ROV?s), ploughs, trenchers and mining machines for use in submerged environments. Established in 1971, the company has made over 500 vehicles for subsea use. These range in size from small remotely operated swimming vehicles with a weight of less than a tonne to heavy duty seabed crawling machines with a weight of up to 310 tonnes (in air). Primarily, these machines have been designed for offshore vessel-based applications, but the machines are equally suited to other submerged mining applications onshore. Many onshore deposits can technically and theoretically be mined using currently available submerged mining ROV technology. Similar equipment to that in use subsea could easily be fast-tracked into use to extend the life of opencast mines facing severe hydrological problems. It could also easily be used to mine vertical ore-bodies where the stripping ratio has become uneconomical due to increasing depth. In some cases mining ROVs could even be suitable for use as the primary extraction method for a new mine. Exploration and extraction techniques used in oil and gas gradually developed and moved from land to offshore in the middle of the last century. Are we about to witness a similar shift with other minerals? This paper describes the design concepts of submerged mining equipment, targetted subsea mineral deposits, the suitability of submerged mining ROVs for onshore deposits, limits to their application and parallel research and development activities which will help to accelerate the use of such equipment in the emerging submerged mining sector.

Aug 1, 2013

By M. M. Kulkarni1

Kaolin clay is used as a filler and pigment in various applications such as paper, paint, rubber, plastics, adhesives, ink and ceramics etc. Major mineral content in crude kaolin clay is kaolinite along with some accessory minerals as quartz, hematite, mica, feldspar, anatase, rutile, illemnite etc. The Fe and Ti bearing minerals play very important role in determining quality of the kaolin, as these minerals impart yellow, pink or darker color to the white kaolin. Conventional beneficiation methods used in kaolin processing are de-gritting, classification and sodium dithionite bleaching, which improves the optical properties of kaolin, wherein reduction of color imparting constituents such as Fe2O3 and TiO2 is marginal. In the present study, these coloring impurities are separated using selective adsorption of water-soluble polymers. Degritted kaolin samples after passing through 45 micron sieve is used in the study for selective flocculation by polyacrylamide based polymers. The effect of pH, zeta potential, and polymer dose on the reduction of impurities is studied. Analytical tools such as XRF, XRD, SEM, and TEM techniques are utilized and results are discussed in detail.

Sep 1, 2012

By Sergey Ulianov, Arkady Senchenko, Alexey Shvets, Arkady Bakotin

"This paper contains description of research results of technology development for copper recovery from weathered tails of iron processing plant. The predominant host mineral that contains valuable component is chalcopyrite occurring in its free form and in associations with ore and rock-forming minerals. Copper grade is 0.26-0.30%. Emulsion inclusions of chalcopyrite in pyrite and sphalerite were noted. Major problem is low copper recovery (30-35%) by flotation. When studying chalcopyrite in primary concentrate it was determined that the surfaces of many chalcopyrite grains are covered with oxide films which prevented collector attachment onto them. Second issue was deep association of chalcopyrite with pyrite and sphalerite. Sulfidizing reagent addition did not help to reach the required level of copper recovery to concentrate. In the result of research performed the technological flowsheet was developed including preliminary treatment of head material in a special unit aiming at oxide films removal, followed by copper rougher flotation on head size tails, crude concentrate regrinding and a number of cleaner flotation operations. After the treatment of weathered tails according to the flowsheet developed, copper recovery to flotation concentrate became 71.53%, at 23.46% copper grade. The suggested technology allows one to solve the issue with treatment of technology-related copper-containing stockpile material, as well as to include the ores where copper is represented by sulfide minerals covered with oxide films into processing."

Jan 1, 2014

By Janine Acasi, Robert D. Rogers, Jonathan K. Trautman, Richard C. Cronn, James H. Wolfram

The demand for phosphate will continue into the future, because phosphate is currently irreplaceable as a plant nutrient and in many chemical applications. Phosphate is not recycled, so the supply must be replenished through a process of mining and purification. The most energy intensive part of the process, separation of phosphate from the ore, requires 54 to 78% (depending on the method used) of the estimated 0.5 quads of energy consumed by the U.S. phosphate industry. This paper provides data from a project designed to determine if a biotechnology can be developed to separate phosphate from its ore. Several hundred microorganisms (both bacteria and fungi) capable of solubilization of phosphate ore have been isolated from the environment. Work is ongoing to determine the mechanism for solubilization. In addition, how these organisms could be used in a bioprocess is being investigated.

Jan 1, 1989

By Robert E. Moore

Renewed interest in olivine refractories has led to efforts to characterize them employing modern techniques of experimentation and data analysis. Initial studies have focused on determination of physical and thermophysical properties. Special equipment for the determination of thermal shock resistance and creep behavior have been constructed. Optimal compositions for maximizing various properties are being identified using appropriate statistical techniques. The overall goal is to develop response surfaces for each of a selected group of engineering design and use properties. Development of ?olivine Refractories? in the United States The term "olivine refractories" is used here because it does appear that domestic deposits of this rock will be the focus of renewed interest and "olivinell is the preferred term in this country. There are extensive deposits of high quality olivines extending through parts of Georgia. North Carolina and in the state of Washington. The eastern olivines are much more localized and extensively altered compared to the western materials. The Washington olivines exist as massive rock deposits in the Twin Sisters mountain area northeast of Seattle and their inaccessi-bility has slowed efforts to develop them. The North Carolina olivines have been used in steel plant applications since the 1930's. Geologists use the term "olivine" to describe assemblages of ortho-silicates. 2RO.SiO2, wherein the RO may be MgO. FeO. MnO. etc. When the RO consists essentlally of MgO and FeO. the material is called dunite and. as such, is synonymous with "refractory olivine." Refractory olivines utilizing North Carolina materials were developed for brick products by Birch and Harvey in this country around the mid-1930's. (I) Their work was completely independent of that of V. M. Goldschmidt and co-workers who used massive dunites located in Denmark. (2) These deposits are currently being mined by A/S Olivine of Denmark for the manufacture of a rather complete line of brick shapes for use in steel-plant. glassplant. and cement kiln applications. Birch and Goldschmidt

Jan 1, 1982

By M. G. Maruma, L. A. Mampuru

"Mill liner wear is a major cost item in the mining industry and there is continuous research to prolong the life of the liners. Over the years it has become apparent that even though high-chromium white cast irons are highly efficient as abrasion-resistant materials, a combination of wear resistance and fracture strength remains difficult to achieve. Increasing the hardness of the high-chrome white cast iron (HCWCI), which improves the resistance to abrasion wear, is often accompanied by a deterioration in fracture strength. Operational conditions inside the mill require that the liner should be made of highly wear-resistant material with some fracture strength. Vanadium additions ranging from 0.2 to 3 wt% were made to HCWCI in an attempt to refine the microstructure. It was found that an increase in vanadium content promotes grain refinement. A content of 1.5-3 wt% gave the best results as measured by the maximum breaking strength.IntroductionOver the years it has become apparent that even though high-chromium white cast irons are highly efficient abrasion-resistant material, a combination of excellent wear resistance and fracture strength remains difficult to achieve. The exceptional wear resistance of highchromium white cast iron (HCWCI) is attributed to hard chromium carbides embedded in an austenitic/martensitic/pearlitic matrix. When the chromium contents exceed 12 wt%, interconnected MC3-type carbides of conventional cast irons are replaced by rodshaped and isolated M7C3 carbides (Powell, 1980), leading to an improvement in the impact toughness, ductility and fatigue resistance. However, the main M7C3 carbides in HCWCI are hard and brittle and can provide an easy path for crack propagation. This limits the applications of HCWCI, particularly in severe impact conditions. Most operations involving HCWCI are in crushing and grinding and the life of a part/liner is limited by its wear resistance. However, improving the wear resistance of HWCI comes at the cost of a significant reduction in fracture strength. Concerns about premature failure of HCWCI mill liners in the mining industries prompted a study to improve the wear resistance and mechanical properties of HCWCI."

Jan 1, 2016

By G. Granata, C. Tokoro, T. Kato

The rare earth elements (REE) are composed of 17 elements that are 15 elements of lanthanide added scandium and yttrium. REE are divided into light rare earth elements (LREE) and heavy rare earth elements (HREE). Although the supply source of LREE is distributed around the world, the supply sources are unevenly distributed. Thus, the development of a new HREE supply source is required. In this study, we focused on the weathered residual rare earth ore as a new HREE supply source. Since so far this weathered residual rare earth ore could not be treated neither by flotation nor by wet high intensity magnetic separation, it was not considered as HREE resource before. In this study, we investigated the leaching of HREE from the weathered residual rare earth ore and elucidated the effectiveness of planetary milling with sodium hydroxide as a method to enhance their recovery. For this purpose, the weathered residual rare earth ore was first grinded by planetary mill in the presence of sodium hydroxide and then leached by sulfuric acid. The influence of planetary milling on HREE recovery was investigated by assisting the leaching experiments with X-ray absorption fine structure (XAFS) in cerium and yttrium K-edge. Since yttrium was the most contained HREE in the weathered residual rare earth ore used in this study, we focused on yttrium in XAFS analysis. Results clearly showed that the recovery of HREE increased by planetary milling with sodium hydroxide. XAFS analysis revealed that a part of the yttrium in the weathered residual rare earth ore was changed to yttrium hydroxide by planetary milling with sodium hydroxide. It is supposed that all HREE were affected like yttrium due to a similar behavior observed in leaching.

Jan 1, 2018

By Nava-Vasquez E, Torres-Torres J, Mendez-Nonell J

The ZA-27 zinc base alloy was poured into cylindrical moulds and solidified under different conditions ie normal freezing and unidirectional freezing. In addition a cylindrical ingot with rheocast material was obtained by stopping the stirring action and, at a specific solid fraction, gravity casting it into a graphite mould. It was observed that the material obtained under normal freezing conditions is likely to present both segregation and inverted pipe. In contrast, the unidirectional solidified and the rheocast cylinders showed the absence of inverted pipe. The segregation pattern was quite irregular in the rheocast ingot while such segregation was more uniform in the unidirectional solidified cylinder. By virtue of these observations, the inverted pipe formation may be ascribed to the interdendritic flow, while the irregular segregation pattern in the rheocast ingot may be attributed to an irregular distribution of the liquid and solid fraction along such a cylinder.

Jan 1, 1993

By Marjorie Benegra

This study aims to compare the wear resistance assessed in rubber wheel abrasion test of nickel aluminide coatings deposited by for Plasma Transferred Arc (PTA) and High Velocity Oxigen Fuel (HVOF) manufacturing, using the same raw material. A nickel aluminide powder was atomized and deposited on 316L steel plate substrate. After deposition, some specimens were submitted to a heat treating (1200 °C for 24 h followed by 760°C for 24 h). The coatings deposited using PTA developed different microstructures due to the incorporation of substrate elements, its performance was better than the HVOF coatings, although their Vickers hardness was similar. After heat treating, a significant variation in hardness and wear resistance was observed. For PTA specimens, there were decrease in hardness of 35%, while for HVOF ones this drop was approximately 20%. Nonetheless, the effect of thermal exposure in wear resistance was quite different: an increase of 21% was observed for HVOF coatings, while a reduction of 20% occurred in PTA ones. Microstructures modifications in PTA coatings were significant for their wear resistance. On the other hand, the reduction of porosity and sintering were responsible for a better performance of heat-treated HVOF coatings.

Jul 31, 2018

By W. N. Roman

This paper will examine the challenges involved in ventilating and cooling South African mines, with particular emphasis on solutions to the issues of heat (generally associated with depth), mechanization and energy efficiency. Comparisons will be made with other international mining areas. Some of the deepest mines in the world are to be found in the South African goldfields. The Mponeng mine is approaching 4,000 m below surface, with virgin rock temperatures (VRT) of between 60°C and 70°C. Mining at these depths has only been possible with the use of large refrigeration plants supplying cold air, water and ice to the workings. In the Bushveld Igneous Complex, where most of South Africa?s platinum mines are located, similar VRTs are being experienced at significantly shallower depths. This is due to the different geothermal properties of the host rock between the two areas. Existing mines are being forced to go deeper and new underground mines are being planned and constructed in other areas with widely differing thermal conditions. South African metal mining has traditionally been labour intensive for historical reasons as well as for the narrow tabular nature of many ore bodies. Due to cost pressures and labour problems, some mines have been investigating the possibility of using mechanized equipment, both diesel and electric, to increase production and to improve efficiency. Studies have been carried out to determine the effect of the additional equipment on the overall ventilation system and some of the conclusions are discussed. The use of diesel equipment adds heat and pollutants to the ventilation air but, although electrical equipment has a lesser effect on the ventilation systems, it is generally less favoured due to claims of lower flexibility/manoeuvrability. Mechanization holds the promise of more concentrated mining activities but, with higher localized ventilation and cooling needs. Systems which will control the provision of air and cooling more effectively are required and are being implemented. In the 1990s and early 2000s, the South African economy experienced significant growth which was not matched by the growth in infrastructure. Consequently, at present there is a shortage of electricity generation capacity which affects large industrial consumers, including mines. Increasing levels of heat and mechanization will require more electrical energy for ventilation and cooling. There are many initiatives underway to save power or to shift consumption to periods of national low demand and these will be described.

Aug 1, 2013

In Mr. Weed's interesting paper, frequent reference is made to the Cananea copper-deposits, which are said to have been so vigorously exploited that they produced 14,000,000 Ib. of copper in 1901. The ore-bodies which yielded this large quantity of metal are described as a product of contact-metamorphism, and in Mr. Weed's genetic classification of such deposits, they receive a place under the sub-heading, "Deposits impregnating and replacing beds of contact-zone."* They are considered by Mr. Weed to represent a special type under this head, and are further classified as: " l. Chalcopyrite deposits: (a) Pyrrhotite ores; (6) Magnetite ores, Cananea type." In condensing much information into a comparatively small space, the presentation of a subject may be so abbreviated as to detract from its clearness. The situation at La Cananea, considering its importance from an economic as well as scientific standpoint, may he worthy of more detailed description. As Mr. Weed rightly remarks, " structural differences are so important, and have SO marked a bearing, not alone on the theory of their genesis, hut also on the working of the deposits and a determination of their value as mines, that they merit a full discussion."† It is my present purpose: (1) to show that it is doubtful whether the copper of La Cananea is mined, except to a limited

Jan 1, 1903

By Ronald K. Riddle

The processing of lateritic ores in rotary drying and preheating/pre-reduction systems has historically been plagued by problems associated with significant dust generation. These problems include handling issues, kiln capacity limitations, negative impacts on furnace stability, a reduction in nickel recovery and higher operating costs. The dust is formed in the rotary devices during heating and tumbling due to the following three mechanisms: (I) mechanical dccrepitation of the ore as a result of tumbling and attrition, (2) thermal decrepitation during rapid vaporization of internal free and bound water, and the (3) loss of free moisture which functions as a binder. This paper investigates the causes of dust formation, provides methods to reduce dust carryover from the rotary devices, and finally offers methods to recover the dust in the existing pyrometallurgical process. Keywords: Laterite, Drying, Rotary, Dust

Jan 1, 2004

By Yongyong Gong, Qijie Zhai, Zhichen Zhang, Qixin Li, Zhishuai Xu

"Microstructure of semisolid slurry of Al-4.5wt.%Cu alloy was investigated with pulse magnetooscillation (PMO) treatment, the results showed that the PMO treatment can refine the crystal structures of Al-4.5wt.%Cu alloy significantly. The discharging frequency of PMO had a great effect on the solidified structure transformation of semisolid slurry of Al-4.5wt. %Cu alloy, and the primary a-Al particles become much finer and rounder with an increase of discharging frequency. However, over a certain discharging frequency, the grains of primary a-Al become coarse.IntroductionOver the last decade, a lot of attentions have been paid on metal rheoforming process [1-4], since it has higher mechanical properties of formed components, strength to weight ratio and age hardenablity. Nevertheless, semi-solid forming is always performed at high solid fractions (40%-60%), so it has the limitation of viscosity, a tends to be difficult to pour semisolid slurry into the hole of the shot sleeve. Therefore, a series of novel semi-solid slurry preparation methods and rheoforming techniques have been invented, such as, semisolid vibration treatment [5], rheocasting [6], pulsed magnetic field process [7], annulus electromagnetic stirring [8], via ultrasonic vibration process [9], equal channel angular extrusion (ECAE) process [l0] and straininduced melt activation (SIMA) process [11].The electromagnetic field is characterized by its effective grain refinement, green, convenient manipulation and without contamination of melt. The mechanisms of dendrite was fragmentation by electromagnetic field have also been largely proposed [12-14]. The broken dendrite arms then undergo a coarsening process to provide the globular structures and obtain much finer and rounder a-Al particles. When compared with other external electromagnetic techniques, Pulse Magneto-Oscillation (PMO) has obtained more fuvors, owing to narrower pulse width and much lower energy consumption. Furthermore, the PMO treatment can reach finer grains with shorter time treatment [16, 17]. This work aims to study the effects of different discharging frequency ofPMO treatment on the microstructure transition of the semisolid slurry of Al-4.5 wt.%Cu alloy."

Jan 1, 2014

By W. F. James

"The property of Siscoe Gold Mines, Limited, comprises about 1,600 acres, including Siscoe island and adjacent claims under water in Montigny lake, in Dubuisson and Vassan townships, Quebec.For many years the property was reached by way of Harricana river and its chain of lakes from Amos, Quebec, about 45 miles distant. In later years a highway has been built from Noranda east through Val d'Or, about 5 miles distant.Gold was discovered on one of the claims on the north shore of Montigny lake as early as 1911, but these gold discoveries have never been economically important. Several years later gold was discovered on Siscoe island and considerable surface work was carried out. Still later, iscoe Gold Mines, Limited, was formed and carried out further work, some of it through shallow shafts. In 1928, larger scale operations were undertaken and a 100-ton mill was constructed. In the years following, production· was on a larger scale with lower grade, until finally a milling rate of over 1,000 tons a day was attained. Approximately 1,500,000 tons were treated between the end of 1940 and mid-year 1945. At present the milling rate is down to about 200 tons a day and work is confined chiefly to some of the less important veins that have been recently developed.The following is a summary of production up to December 31st, 1946:"

Jan 1, 1954

By C. Kennedy, S. Jensen

Traditionally, mineral processing plants are designed to achieve the highest recovery of valuable material with limited regard for the cost of managing waste products-both solid and water components. As an industry, we are confronting ever more stringent environmental standards and lower grade deposits requiring more intensive processing. The most profitable processing route can, in fact, lead to costly issues downstream. Issues or risks associated with waste management include water treatment and handling and storage of potentially acid generating material. The capital and operating costs of dealing with these issues are significant and should be considered as a consequence of plant design and optimisation. The authors of this paper are involved with a number of projects where process operation changes offer opportunities to mitigate risks associated with water and waste management. Examples of these changes will be discussed along with the estimated benefits to the value of the project and reduction of long-term environmental risks. Process changes include 1) the application of in-plant water treatment as opposed to dealing with the entire tailings management facility and 2) the potential to reduce metal leaching and acid rock drainage through the preferential liberation of carbonate minerals in the grinding process.

Jan 1, 2014

The standard procedure of fire refining consists of sulphur removal via air injected through tuyeres, arsenic slagging via soda-lime flux and oxygen reduction by air or oxygen deficient air or a steam fuel mixtures. The use of porous plugs to stir with an inert gas has been mainly considered as a surface renewing agent that increases the product quality and shorten the refining cycle. In the present study the effect of the bottom stirring by nitrogen gas injection through porous plugs for the treatment of the crude copper in the range of 400-150 ppm sulphur, 3,000-2,000 ppm arsenic and 14,000-7,000 ppm oxygen content was investigated. The combined effect stirring-reducing, by the use of air or a steam fuel mixtures through tuyeres for oxygen removal, follows a kinetics of first order where the constant, K, can be represented by the following polynomial expression: K = A * R2 + B * R + C Where A, Band C are constants that depend on the nitrogen flow rate and R is the air-fuel ratio or the steam-fuel used in the reducing step. Depending on the optimization of the flow of nitrogen and the air-fuel or steam-fuel mixture and only if just the oxidation, complexing and reducing steps are considered, the process cycle might be shortened by 45%.

Jan 1, 2003

By C. Acuna

The standard procedure of fire refining consists of sulphur removal via air injected through tuyeres, arsenic slagging via soda-lime flux and oxygen reduction by air or oxygen deficient air or a steam fuel mixtures. The use of porous plugs to stir with an inert gas has been mainly considered as a surface renewing agent that increases the product quality and shorten the refining cycle. In the present study the effect of the bottom stirring by nitrogen gas injection through porous plugs for the treatment of the crude copper in the range of 400-150 ppm sulphur, 3,000?2,000 ppm arsenic and 14,000-7,000 ppm oxygen content was investigated. The combined effect stirring-reducing, by the use of air or a steam fuel mixtures through tuyeres for oxygen removal, follows a kinetics of first order where the constant, K, can be represented by the following polynomial expression: K = A .* R2 + B * R + C Where A, Band C are constants that depend on the nitrogen flow rate and R is the air-fuel ratio or the steam-fuel used in the reducing step. Depending on the optimization of the flow of nitrogen and the air-fuel or steam-fuel mixture and only if just the oxidation, complexing and reducing steps are considered, the process cycle might be shortened by 45%.

Jan 1, 2003