Search Documents

By E O. Foster

When roasting started at Giant Yellowknife Mines in 1949, it became apparent that, to prevent air and water pollution in the surrounding district, it would be necessary to collect the arsenic that was contained in the exit gases of the roaster. The arsenic collection problem was finally solved by the installation of both electrostatic and baghouse collectors. It was realized that a considerable quantity of gold-bearing dust was leaving the roaster with the exit gases. When the collection problem was solved, it was possible to measure this loss. The loss proved to be considerable and it became evident that a substantial quantity of gold could be recovered. Research programs on dust treatment began in 1958, and by May, 1960, the treatment process which is currently being followed was started in the plant. At present, the two electrostatic preci11itators, Operated at temperatures above 600°F, collect the gold-bearing dust.

Jan 1, 1963

By E. Godin, M. Rigaud, S. C. Panigrahy, I. Malinsky

"RésuméDes boulettes de concentres d'hématite spéculaire à basse silice ont été produites en substituant la bentonite par de la tourbe, adéquatement traitée, additionnée d'une faible quantile de soude caustique durant le boulettage. La réductibilité de telles boulettes et leur gonflement pendant la réduction ont été évacues, en utilisant quatre mélanges gazeux différents, formes de H2 - CO - N2.L'influence du pouvoir réducteur du gaz utilise, sur le gonflement des boulettes, à été mis en évidence. Quelles que soient ces conditions réductrices, les propriétés mesurées sur les boulettes liées a la tourbe sont comparables aux propriétés obtenues avec des boulettes traditionnelles liées à la bentonite.ABSTRACTAdditions of peat moss and small quantities of NaOH during balling of low silica specular hematite concentrates have eliminated the need to use bentonite as a binder. The reducibility and swelling of such pellets have been evaluated using four different gas mixtures, consisting of H2 - CO -N2. The influence of the reducing power of the gases, on the swelling behaviour of pellets has been documented. Under the different reducing conditions, this new type of pellets exhibit properties similar to the ones obtained using bentonite."

Jan 1, 1987

By T. G. Joseph

The chicken and egg scenario where adverse truck motions cause ground deterioration and poor ground profiles that in turn cause adverse truck motions is a downward deterioration spiral that dominates in our industry. If we can remove one action, the reaction must stop and vice-versa. A simple 'truck to excavator' load data analysis and wireless communication system is outlined in this paper; that will provide visual assistance to the excavator operator in achieving improved load placement and balance in a truck body. In turn this will reduce the subsequent hauler duty cycle adverse motions and g levels that contribute to structural fatigue, higher tkph, reduced tire life and ongoing maintenance of haul roads

Nov 1, 2011

By Akiyoshi Horiuchi, Manabu Kanno, Shigeki Sato, Taro Aichi

"AKITA ZINC Co., Ltd. (Iijima Zinc Refinery), jointly owned by DOWA METALS & MINING Co., Ltd.(DMM), has used the company’s own hematite process for iron control since the beginning of operations in 1971. The hematite process consists of reductive leaching with SO2 gas and iron removal in autoclaves by high temperature hydrolysis. This process enhances not only zinc recovery but also the recovery of gold, silver, copper, lead and rare metals, which is carried out at another DOWA metallurgical plant. All by-products produced in the hematite process are marketed and sold. This paper presents an overview of the hematite process and the recent process improvements made.INTRODUCTION DMM carries out mining and smelting activities for precious metals, PGMs, rare metals and base metals such as copper, lead and zinc. It owns KOSAKA SMELTING & REFINING, producing copper and lead, and the AKITA ZINC Co., Ltd. (AZC) in Akita Prefecture. DOWA is a specialized smelting company which has established a metallurgical complex for copper, lead and zinc, including a recycling business. AZC was established in 1971 at a production capacity of 72,000 t/y zinc; it is jointly owned by DMM and five other non-ferrous metal companies. AZC has increased its capacity continuously and now produces 210,000 t/y of zinc. Figure 1 shows the changes in zinc production and capacity at AZC."

Jan 1, 2016

By M. E. Coleman, G. Money

Pneumatic Conveying and Process Injection Technologies have been implemented in the metals markets for the last 40 years and have considerably improved the productivity and the performance of many processes. There have been many steps forward in handling technology and this paper seeks to consider those now offered by Clyde Materials Handling who as an established customer-driven solutions provider has turned its attention to supporting the Metals Market. Clyde seeks to utilise its knowledge, expertise and technologies to transform the production processes of its customers, who operate in the ferrous and non-ferrous metals industries.

Jan 1, 2008

By Peter C. Jones, Wanda M. Carter, David H. Watkinson

"Abstract - Pyrrhotite, chalcopyrite, and pentlandite are the dominant sulfide minerals in the 740 zone of the Kelly Lake orebody (Inco Ltd.), Copper Cliff Offset, Sudbury. Petrographic and quantitative electron microprobe analyses of minerals, from sulfide assemblages and host quartz diorite, of the 740 deposit have revealed three processes that have affected sulfide mineralization and associated sulfarsenide and platinum-group-mineral (PGM) distribution: magmatic, hydrothermal, and tectonic. Accessory, zoned cobaltite, and gersdorffite occur in sulfides as a result of these three processes, and PGM occur dominantly in hydrothermally remobilized and deformed ores. Where PGM are present in sulfarsenides they provided nuclei for sulfarsenide growth. Solitary PGM are orders of magnitude larger than those PGM found within sulfarsenide minerals. Five varieties of PGM occur, michenerite and sperrylite being the most common, with lesser froodite, hollingworthite, and ruarsite.The effect of a deformation is a localized fabric in the ore, revealed by pyrrhotite and chalcopyrite bands; pentlandite porphyroblasts also partially define the foliation. The deformed ore is also characterized by alteration of the adjacent quartz diorite, which produced an alteration assemblage including almandine garnet, Fe-rich biotite, and chlorite."

Jan 1, 2001

By E. V. Neelands

THE Canadian Malartic mine is in Western Quebec, about fifty miles east of Noranda and forty miles south of Amos on the Canadian National railway. The recently constructed branch of the railway from Rouyn to Senneterre passes half a mile north of the mine. HISTORY he property was discovered in 1923 'by St. Barbe Sladen, H. S. Kennedy, and J. C. Carroll, who were prospecting for an Ottawa syndicate and found gold in a small quartz vein near the present workings. Five claims were staked and were optioned to an exploration company, who allowed the option to lapse after surface sampling and diamond drilling eighteen holes. Some months later, the property was sold to Malartic Gold Mines, Limited, who carried on development until 1929. A vertical shaft was sunk and exploration work done on three levels, supplemented by diamond drilling 16 surface holes and 62 underground holes. The work indicated that the important ore occurred in two silicified.zones in schisted greywacke which intersected west of the shaft and were believed to be controlled by a drag-fold. The ore grade was not considered sufficiently favourable to war-rant an operation, and work was terminated. With the advance in the price of gold to $35 per ounce, interest was revived and a new Company, Canadian Malartic Gold Mines, Limited, was incorporated for further development. The shareholders of the old Company accepted a new position under which their interests were protected, and sufficient treasury shares were optioned to Ventures, Limited, and Sudbury Basin Mines, Limited, to provide funds for further exploration of the prop-erty to determine whether, under the new economic conditions, profitable operation would be possible, and, if advisable, to provide the equipment for production. Additional claims were acquired, bringing the total area up to 1,029 acres.

Jan 1, 1939

By Redhead Robert J.

"In 1991, the Canadian Council of Ministers for the Environment (CCME) charged its Waste Management Task Group with developing a nationally coordinated strategy to measure, monitor, and achieve the objective of decreasing the generation of waste (solid and hazardous) by50% from 1988 levels by the year 2000.With the encouragement of the CCME, which viewed hazardous waste as largely an industry problem, a committee, the “Industry Action Group”, representing eleven industry trade associations with a strong interest and involvement in hazardous waste was recruited.The Municipality of Markham, Ontario was also recruited (Appendix 1)."

Jan 1, 1996

By H. Paudyal, K. Ohto, H. Kawakita, S. Alam, B. Pangeni

The orange waste after lime water modification was converted into promising adsorbents for fluoride by metal loading reaction. The effectiveness and mechanism of fluoride adsorption on metal loaded orange waste gel from synthetic and real plating solution were investigated. Amount of zirconium(IV), aluminium(III), cerium(III), lanthanum(III), titanium(IV), vanadium(IV) and tin(IV) loaded on orange waste from aquearegia dissolution were evaluated to be 1.62, 1.16, 0.93, 0.95, 1.20, 1.12, 0.97 mmol/g respectively. The maximum adsorption capacity (qmax) of zirconium(IV), cerium(III), lanthanum(III), iron(III) and aluminium(III) loaded orange waste for fluoride ions were evaluated to be 1.74, 0.91, 1.07, 0.98 and 1.01 mmol/g from aqueous solution. The mechanism of fluoride adsorption by metal loaded orange waste was inferred to be ligand exchange reaction. Application of zirconium(IV) loaded saponified orange juice residue(SOJR) for real plating solution showed effective removal of trace concentration of fluoride down to the accepted standard. The negligible interference of co existing anions like nitrate, carbonate, sulphate and chloride makes zirconium(IV) loaded SOJR a promising sorbent for waste water treatment. The adsorbed fluoride from fluoride loaded zirconium(IV)-SOJR was effectively desorbed by using alkali solution for its regeneration. This work shed light on the potential application of metal loaded SOJR to remediate fluoride contaminated water for environmental relevance.

Jan 1, 2012

By A. E. Boudreau

Abstract-It has long been recognized that platinum-group-element (PGE) deposits in layered intrusions preferentially occur in intrusions that crystallized from high-Mg parent magmas. Recent studies suggest that evaluation of any given intrusion for economic PGE potential should also include assessment of the PGE, sulfur and chlorine concentrations in the cumulates and potential parent liquids. PGE: Magmas that contain relatively abundant Pt and Pd are the best candidates for forming economic deposits. Although analyses of coeval sills and dikes are the best indicators of primary magmatic PGE concentrations, analysis of the cumulates themselves is also valuable. For example, within the Stillwater complex, background PGE values in cumulates from the ultramafic sections of the complex contain, on average, several 10s of ppb Pt and Pd. Background concentrations of this order are suggestive that the magma was not depleted in the PGE. Sulfur: Conventional petrogenetic models for the formation of PGE deposits in layered intrusions require the PGE to have been concentrated during a magmatic sulfide-saturation event. In contrast, some hydrothermal models suggest that sulfur and the PGE were mobilized from footwall cumulates by upward- migrating, high-temperature hydrothermal fluids. Both models suggest that significant PGE deposits are likely to occur at and below the level where stratigraphic increases in whole rock sulfur concentrations occur. Chlorine: In both the Stillwater and Bushveld complexes the cumulate sequences below the major PGE-bearing zones contain anomalous Cl-rich apatite. The chlorapatite component of apatite in these rocks may exceed 40% and, in the Stillwater complex, typically exceeds 90%. It is stressed that pristine igneous mineral analysis and not whole rock data be used, as whole rock Cl concentrations may be affected by very localized (grain boundary), low-temperature alteration. Intrusions that crystallized from high-Mg, high-Cl magmas appear to have the best potential to host significant PGE deposits.

Jan 1, 1995

By J. Baz-Dresch

"The most cost-effective method of placement of the high strength fill used in the Cannon Mine' s overhand cut-and-f ill bench stopes was determined to be truck haulage. Constraint s imposed by the mine layout dictated the use of a truck which could dump its load in a fifteen-foot high drift. The Dux Teledumper truck was selected as the most suitable unit for this application based upon operational and maintenance parameters which included a telescoping, tilting dump box; large load capacity; and robust construction. Development of the truck continues through the cooperation between the manufacturer and user. INTRODUCTIONThe Cannon Mine is situated in the centre of Washington state, approximately midway between the cities of Spokane on the east and Seattle on the west. The mine complex is located three block s south of the Wenatchee city limits at the eastern base of the Cascade Mountain range.Asam era Minerals (U.S.) Inc., with 5I% ownership, operates the Cannon Mine. Breakwater Resources, Ltd. holds the remaining 49%.Annual paroduction is 520 000 tons per year, presently on a 21-shift per week operating schedule for both the mine and the mill.All production is presently won by overhand bench stoping with backfill. Stoping starts with 15-ft high by 24- or 30-ft wide sill cuts driven above and below a stope block . A drop rai se and slot are used to open a bench which is then slabbed toward the open slot. Truck-placed backfill is dumped into the mined - out stope from the upper sill cut. This stoping sequence is repeated until the top of the ore block is reached . The top sill cut is then tightly filled with backfill to minimize subsidence and to provide adequate roof support during extraction of the pillars.Mining equipment consists of hydraulic drills and rubber-tired, diesel scoops and trucks."

Jan 1, 1989

"This paper describes an alternative method of vehicle control which uses a micro-processor to control the field current and armature voltage concurrently. The field tests carried out and the conclusions drawn from the basis of the paper.IntroductionIt is generally accepted that the main obstacle to a greater use of electric vehicles is the relatively poor range and performance when compared to alternatives such as diesel and petrol-engine vehicles. Much effort has been applied to the problem of increasing the energy storage density of batteries and considerable improvements are now being reported.Improvements in the efficient use of the stored energy, although unlikely to achieve the necessary increase in range and performance for a widespread acceptance of electric vehicles, can nevertheless make a useful contribution. Because the improvement in efficiency is achieved by a reduction in losses, it follows that the temperature rise in drive-train components is reduced. These advantages, coupled with the increasing cost of energy, make improvements in the efficient use of the stored energy desirable, if not absolutely necessary. To achieve this with the large and rapidly varying loads encountered during the operational use of a vehicle will require a more flexible system of control than that provided by the current limit. This paper describes an alternative method of control which uses a micro-processor to control the field current and armature voltage concurrently.The value of these parameters is selected to supply the power demand at the motor shaft, with the minimum losses in electrical transmission, thus increasing the efficiency with which the stored energy is used."

Jan 1, 1982

By S. A. G. Poppen, J. Konopka

"Petro-Canada's project investigative and experimental underground work in the Galt coal seam at Kipp, Alberta included the construction of an emergency egress and ventilation raise from surface.The Galt coal seam is 206 m below the surface and covered by 8 m of shale, sandstone and clay beds of the Oldman Formation, 128 m of shale, bentonite beds and sandstone of the Bearpaw Formation, and 70 m of glacial till and basal gravel. Free water was encountered from sand lenses in the glacial till and the basal gravel.Excavation for the ventilation raise was a nominal 2 m diameter and it was lined with a welded, continuous, steel liner of 1.2 m 1.D.Excavation in the glacial till was carried out with a surface bucket drill rig combined with hand mining. Ground support in the glacial till consisted of liner plates and backfill grout. The Bearpaw and Oldman formations were excavated by employing standard raise boring techniques. The individual liner sections of the continuous steel liner were assembled on surface and the entire liner column was lowered into the raise by employing hydraulic lift climbers. The liner column was back-filled with concrete.IntroductionThe Lethbridge Coal Field comprises an area of approximately 1 165 square km in the vicinity of Lethbridge in southern Alberta. Pacific Petroleums Ltd. proposed in a Preliminary Disclosure in January 1979 ""to open an experimental mine prior to development of a producing underground mine with an initial rate of 540,000 tonnes per year"". A 2 900-hectare group of leases in the Kipp-Coalhurst area was selected as the primary target for the Kipp experimental mine. The scope of work for the experimental mine included the construction of an access shaft with production capabilities, the construction of a ventilation and emergency exit raise, drive-ages in coal to yield a bulk sample, gathering of geotechnical information and the testing of experimental mining methods."

Jan 1, 1983

By Yuki Tsunazawa, Shuji Owada, Sho Fukui, Chiharu Tokoro

"Since the amount of e-waste has been rapidly increasing all over the world, there is a desire to develop the effective recycling process. E-waste has various kinds of electronic components with valuable and/or hazardous materials. Recycling of them is an important subject from the viewpoint of both the recovery of valuable materials and waste treatment. In common with all mineral processing, the comminution of e-waste is a key process because the liberation states after comminution determine the overall efficiency of metal recovery. Since some of useful critical metals are concentrated in a specific component, a special and selective grinding is expected to be effective. However, the knowledge about the mechanism and the effectiveness of the selective grinding is still limited and unclear.To better comprehend the mechanism, in this study, the investigation of comminution process using the particle-based simulation was conducted. Especially, this study focused on the comminution performance of printed circuit boards (PCBs), which are major components of e-waste. The behavior of PCBs and airflow in a drum typed agitation mill having flexible chains was simulated by the discrete element method (DEM) coupled with computational fluid dynamics (CFD). To model the shape of PCBs, the particle based rigid body model was introduced into the DEM. Since this model could not directly simulate the breakage phenomena, collision energy was calculated to qualitatively evaluate the comminution performance. In addition, the simulation results were compared with the experimental comminution tests using simulant PCBs where some capacitors were solder-mounted. These results indicated that comminution performance was affected by the rotation speed of the agitator. It was also demonstrated that the comminution performance was qualitatively evaluated using the particle-based simulation and this particle-based simulation made it possible to investigate the mechanism of e-waste comminution."

Jan 1, 2016

By Oliver Bowles

Cementing materials of mineral origin were well known to the ancients. Ordinary lime and gypsum plasters were the first to be recorded by historians. The next development was the discovery that certain limes would set under water, but the hydraulic property was not definitely attributed to the presence of clay in the limestone until many centuries later. The Romans advanced a step nearer to modern cement in the development of 'pozzuolana', a mixture of volcanic ash or trass with hydrated lime. The silicate of aluminium in the volcanic rock combined readily with the lime, forming a hydraulic mortar or cement which was widely used. Natural Cement In Europe (1) No further progress was made in the art of manufacturing cement for several centuries, during which the Roman Empire declined and passed away, and the Anglo-Saxon race slowly and painfully evolved through the Middle Ages an ever-increasing prestige. An Englishman, John Smeaton, is credited with the honour of the next important development, for he employed a little-known cementing material-natural cement-in constructing the Eddystone lighthouse in 1756. It was called 'natural' cement because it was made from a natural rock with no additions of other materials. The process consisted of calcining an argillaceous limestone at a comparatively low temperature and grinding the product to a fine powder. Care was exercised to keep the temperature low, and any material burned to the clinkering point was thrown away, although such material was, as learned at a later time, Portland cement.

Jan 1, 1933

By R. M. Clowes

"As part of LITHOPROBE's multidisciplinary earth science research program to understand the evolution of the North American continent, studies have been undertaken in a number of key areas in Canada. In the Trans-Hudson Orogen of Manitoba and Saskatchewan, LITHOPROBE results require re-evaluation of tectonic models related to its origin. In the Abitibi greenstone belt of Quebec and Ontario, results indicate a more complex evolution for the southern Superior province, one that links with the development of gold and massive sulphide deposits. As part of the program, the seismic reflection profiling method is being adapted for the mining industry. Three examples demonstrate the subsurface information that can be obtained. In Noranda, the base of the volcanic Blake River group is imaged and reflectivity is tied to geology through well logs; in Matagami, the zone of mineralization is shown to be downdropped along a majorfault; in Sudbury, a new structural model is developed, one that shows marked asymmetry at depth and indicates that some ore-bearing units on the margins of the igneous complex may be repeated at depth. IntroductionLITHOPROBE is Canada's national, collaborative earth science research project, established to develop a comprehensive understanding of how the North American continent has evolved. Ten transects, or study areas, were chosen to investigate pivotal geological features to their deep lithospheric roots. They span the country from the Pacific to the Atlantic Oceans and from the U.S. border to the Yukon and Northwest Territories, and geological time from four billion years ago to the present. A multidisciplinary approach, which is spearheaded by seismic reflection techniques, is essential to developing complete interpretations and outstanding scientific results. LITHOPROBE also has pioneered the use and demonstrated the value of using reflection technology to determine subsurface geology in mining camps.This paper provides an overview of the transects and their significance for the tectonic evolution of North America. Two specific examples demonstrate how we detennine present three-dimensional lithospheric structure and past geotectonic processes which formed it. The application of the reflection method to imaging complex structures in ""shallow"" crystalline rocks has been developed with funding and other support from the mining industry and provincial geological surveys. Sustaining funds, however, are derived from the Natural Sciences and Engineering Research Council and Geological Survey of Canada. Emphasis has been placed on developing deeper penetrating tools for exploration of deeply buried, but economically retrievable, mineral resources near existing mines, where an expensive infrastructure already is in place. Three examples, Rouyn-Noranda in western Quebec, Matagami in northwestern Quebec and Sudbury in northeastern Ontario, illustrate these developments."

Jan 1, 1994

By A. E. Boudreau

It has long been recognized that platinum-group-element (PGE) deposits in layered intrusions preferentially occur in intrusions that crystallized from high-Mg parent magmas. Recent studies suggest that evaluation of any given intrusion for economic PGE potential should also include assessment of the PGE, sulfur and chlorine concentrations in the cumulates and potential parent liquids. PGE: Magmas that contain relatively abundant Pt and Pd are the best candidates for forming economic deposits. Although analyses of coeval sills and dikes are the best indicators of primary magmatic PGE concentrations, analysis of the cumulates themselves is also valuable. For example, within the Stillwater complex, background PGE values in cumulates from the ultramafic sections of the complex contain, on average, several 10s of ppb Pt and Pd. Background concentrations of this order are suggestive that the magma was not depleted in the PGE. Sulfur: Conventional petrogenetic models for the formation of PGE deposits in layered intrusions require the PGE to have been concentrated during a magmatic sulfide-saturation event. In contrast, some hydro thermal models suggest that sulfur and the PGE were mobilized from footwall cumulates by upward-migrating, high-temperature hydrothermal fluids. Both models suggest that significant PGE deposits are likely to occur at and below the level where stratigraphic increases in whole rock sulfur concentrations occur. Chlorine: In both the Stillwater and Bushveld complexes the cumulate sequences below the major PGE-bearing zones contain anomalous Cl-rich apatite. The chlorapatite component of apatite in these rocks may exceed 40% and, in the Stillwater complex, typically exceeds 90%. It is stressed that pristine igneous mineral analysis and not whole rock data be used, as whole rock Cl concentrations may be affected by very localized (grain boundary), low-temperature alteration. Intrusions that crystallized from high-Mg, high-Cl magmas appear to have the best potential to host significant PGE deposits.

Jan 1, 1995

By Z. Bibak, S. Banisi, A. Ghasemi, E. Nematollahi

"The major importance of liners in grinding is their role in providing an appropriate trajectory for the charge. Since it is not possible to study the charge movement by direct observation in operating industrial mills, this task is accomplished by physical (laboratory), and/or, mathematical (software) methods. Because of the high cost and a longer time required for a physical analysis, mathematical simulations have become more common. Simulation of the effect of liner shape on the charge movement has provided a means to select a proper design based on the operational objectives and conditions. Furthermore, the liner shape changes due to wear and impact during operation, which will influence the charge trajectory. This adds more of an incentive to use simulation. These changes in liner could be predicted through liner profile measurements during operation and/or simulation. In this research, an inhouse developed DEM software called KMPCDEM © was used to simulate the charge movement in industrial plant SAG mills. A geometrical method of implementing the shell liners on SAG mills at the Sarcheshmeh (9.75×4.87 m) and the Gole-E-Ghohar (9×2.05 m) operations facilitated the software simulation. Point by point implementation of the measurements of liner profiles of these mills enabled the study to trend the change in the charge movement as the liners wear. Comparison of the simulation to a laboratory mill (1 m diameter) showed that the difference between the measured and predicted charge impact point, shoulder angle and toe angle were 6, 4 and 3°, respectively.INTRODUCTIONComminution is the most energy intensive operation constituting the major portion of operating and capital costs of a mineral processing plant. In the last decade, a vast number of research was aimed at studying various aspects of grinding with the aim of performance improvements (Davis, 1919; Mishra & Rajamani, 1990; kalala, Breetzke, & Moys, 2008). Mill liners transfer the input power to the charge and play a significant role in affecting the motion of the charge (Mclvor, 1983; Mishra & Rajamani, 1990; Radziszewski, 1997; Van Nierop, Glover, Hinde, & Moys, 2001; kalala et al., 2008). Lifters are usually used with mill liners to extend their life and to enhance the grinding and impact breakage efficiency. Mill lifters are used to raise the grinding media and ore to transfer the energy from the mill to the load (Rezaeizadeh, Fooladi, Powell, & Weerasekara, 2010)."

Jan 1, 2016

By P. H. Riordon

ONE OF the major sources of the world's supply of asbestos lies in a belt of ultrabasic rocks stretching through the Eastern Townships of Quebec where chrysotile asbestos has been mined continuously since 1878. The productive portion of the belt extends from the town of Asbestos in Shipton town-ship northeastward some 60 miles to the eastern edge of Broughton town-ship. (See map). Twelve mines, currently treating an aggregate of over 60,000 tons of rock daily, produce more than one million tons of asbestos :annually. An equal number of mines are now dormant, having for the most part exhausted their reserves. It is evident from the past and present activity, in this belt that it can look forward to at least half a century or more of large scale production. The host rock to the asbestos de-posits is essentially a peridotite which originally contained I 0 to 15 per •cent pyroxene. The peridotite, associated with dunite, pyroxenite

Jan 1, 1962

By Rocky (Yaokun) Wu

Rock burst is one of the biggest challenges to ground control in the mining industry. With increasing mining depth and mining scale, there are more and more industry requirements on yielding rock support. Since 2008, Jennmar has been conducting large scale research and development works to develop a technically reliable and cost effective yielding rock bolt. This paper introduces a new yielding rock support - Yield-Lok bolt. The bolt is characterized by the designed yielding ability to produce 150 ~ 250 mm of deflection at 8 ~ 10 metric tons (Mt) loads for every 16.4kJ energy input. Its performance characteristics are consistent through multiple and varying amplitude of impacts. In this paper, the design criteria of the bolt and the principle of performance are described, the dynamic testing results are discussed; and the features and application of the bolt are presented.

Oct 1, 2010