Search Documents

In the present work, the effect of pH, non-ionic polyacrylamide flocculant and anionic polyphosphate on rheology and settling behaviour of colloidal TiO2 suspensions (15 ? 50 wt% solid) is investigated. Maximum particle aggregation, reflecting in the highest suspension settling rate and maximum shear yield stress was achieved at pH 7.2, the isoelectric point (iep), consistent with DLVO expectation. However, the maximum aggregation condition at the iep also resulted in the poorest suspension consolidation behaviour. Significantly enhanced consolidation was achieved for a more dispersed suspension at pH values away from the iep but at reduced settling rate. Thus, when pH alone is used to control conditions which facilitate strong interparticle attraction, a high settling behaviour which is not conducive to compact consolidation results. Improved suspension consolidation may be achieved at the iep via anionic polyphosphate addition which leads to attenuation of the strongly attractive van der Waals forces and emergence of "soft" repulsion due to weak inter-particle electro-steric forces. The weak repulsion act to lubricate particles involved in the hydrodynamic interactions which controls the compressibility of the sediment bed, allowing a compact consolidation of solids to be obtained. Alternatively, non-ionic polyacrylamide homo-polymer (Magnafloc 333) was fairly effective in flocculating titanium dioxide suspensions leading to high settling rate and acceptable pulp consolidation at the iep.

Jan 1, 2006

By R. E. Eyre, L. P. Landucci

C URRENT practice in the zinc concentrate roasting plant of The Consolidated Mining arid Smelting Company of Canada Limited, at Trail, B.C., involves passing the furnace effluent gases through an electrostatic precipitator for the recovery of dust. After removal of the dust the gas is treated for recovery of sulphur dioxide by conversion into sulphuric acid ( 1). However. as roasting techniques improved, and furnace productivity in-creased, the rated capacity of the precipitator was exceeded and it was necessary to consider various means of improving the dust recovery. A study of methods indicated that a baghouse using silicone-treated glass fabric, might be suitable for this particular application. Glass fabric was chosen because the temperature of the roaster effluent gases would range from 450°F to 500°F and tempering air was undesirable to avoid dilution of the sulphur dioxide gas.

Jan 1, 1962

By H. Al-Kazzaz

The 2-mm butt joints of ZE41A-T5 sand castings were laser welded using 1.6 mm EZ33A-T5 filler wire and a continuous wave Nd:YAG system at a power of 4 kW, surface defocusing and various welding speeds, Compared with the base metal, the fusion zone showed significant grain refinement due to high cooling rate, No grain coarsening was observed in the heat affected zone (HAZ). The porosity area percentage and total solidification crack length in the fusion zone (FZ) were reduced as the welding speed increased from 4 to 7 m/min, Fusion zone area, total penetration depth, and weld width decreased with increased welding speed, The hardness in the FZ was similar to or higher than the base metal after a natural aging of about one year, but there was a drop in the hardness of the HAZ, The HAZ width decreased with increasing the welding speed, Tensile test showed that a joint efficiency of approximately 75 ? 90 % was obtained.

Jan 1, 2005

By W. Holdsworth

The flotation mill of Dentonia Mines, Limited, at Greenwood, B.C., went into operation on April 20th, 1934, and by October 11th a total of 15,000 tons of ore had been treated. It is intended in this paper to describe briefly the operation and to give some of the operating data which have been gathered. The metallic minerals in the Dentonia ore are pyrite, chalcopyrite, galena, and, occasionally, native gold, and the gangue includes chloritic material, vein quartz, and calcite. Pyrite makes up about 90 per cent of the metallic content of the ore, in which it is disseminated as irregular grains and well-formed cubes. An average analysis of the ore is: gold, 0.27 oz. per ton; silver, 1.73 oz. per ton; copper, 0.12 per cent; lead, 0.31 per cent; and zinc, trace. From the mine ore-bin, situated near the portal of the tunnel at the mine, the ore is hauled by motor truck to the mill, a distance of three-quarters of a mile, and there dumped into the receiving bin, which has a capacity of fifty tons. The hauling is done during one eight-hour shift, commencing at 7 a.m. The maximum size of the ore fed to the mill-bin is ten inches. Lumps larger than this are broken by sledge hammer to pass through grizzly bars, spaced ten inches apart, installed above the bin. The ore is drawn from the bin by a 30-inch, 6-ply conveyor belt, 18 feet 6 inches long. In the near future, when the cross-cut tunnel is completed, the ore will be trammed to the receiving bin. This will effect a considerable saving in cost. At the same time, the bin will be set back several feet, so that the length of the conveyor belt may be doubled. This will make efficient ore-sorting possible, and so ensure a minimum of waste rock in the mill feed.

Jan 1, 1935

By W. Rostoker

Packing Experiments The porosity and most of the other physical properties of a coherent mass of any material built up by the packing together of discrete particles will obviously vary with, and be governed by, the manner of association of the particles. The relation of packing to powder metallurgy has been discussed in some detail by at least two authors. Packing Theory Theories of particle packing have been put forward by C. C. Furnas and A. E. R. Westman. Although their approach to the problem is not the same, their conclusions are similar. In the process of packing, they visualize the voids of a uniformly sized material becoming filled with particles of a smaller size, and the voids between these being filled in turn with still finer particles. Obviously, if this process is carried ad infinitum, the resultant mass will have the same density as the constituent particles. In practice, of course, such a density of packing is never attained. In addition, the premise is made that successive particle sizes must fit into the voids left by the immediately larger particles- an assumption requiring definite size gradations and also particle shapes. It remained, then, for theory to correlate relative diameter ratios, and proportions and numbers of sizes of particles, for requisite packed densities. Briefly, the following principles were postulated: (a) For an infinite diameter ratio between largest and smallest sizes, an infinite number of particle sizes in proper proportion is required to give natural density. (b) For a given diameter ratio, there is a maximum number of permissible particle sizes for maximum packed density (Furnas). (c) Provided the particle shape is spherical, or approximately so, the proportions o particle sizes can be calculated. (d) The ratios of successive diameters of particles are in geometric progression.

Jan 1, 1947

By Wei Sun, Xiangsong Meng, Xiaodong Li, Weisheng Huang, Yuehua Hu, Chonggao Cao, Haisheng Han, Wensheng Chen, Runqing Liu, Central South University

"The similar flotability of scheelite, fluorite, and calcite resulted in the difficult separation by flotation. This work revealed the effect of water glass on the flotation of scheelite by FTIR and the wettability change of the usual cleavage plane, and proved that water glass inevitably influenced the flotation of tungsten minerals to a large extend in traditional fatty acid flotation process. A new collector, benzohydroxamic acid complexes, was found to be selective for the separation of scheelite and calcium minerals with little water glass. Hence a novel flotation process was developed for the recovery of tungsten minerals in shizhuyuan mine in China. Normal temperature flotation of tungsten minerals was developed to instead of the classical “Petrov's process” for scheelite-calcite-fluorite type ores. Compared with the traditional process, the recovery was improved by 10% and the grade of scheelite concentrate was above 55%. The disappearance or decreasing of water glass contributed to improving the recovery of tungsten and fluorite and the circulation of water and reagents.INTRODUCTIONChina is rich in tungsten resources and the proved reserves accounted for 60% of the world's reserves (Cai Gaipin et al., 2009). However the wolframite has been dried up and the scheelite resource has become the main resource of the tungsten metal. Scheelite deposits were classified to scheelite-silicate type and scheelite-calcite-fluorite type based on the associated gangue minerals. Scheelite was easy to separate from the silicate minerals. Flotation separation of scheelite from calcium minerals creates difficulties because of the existence of the same cation in the minerals and similar physicochemical characteristics such as solubility, hardness, specific gravity, PZC (point of zero charge) etc.(Arnold & Warren, 1974; Yongxin & Changgen, 1983; Ozcan & Bulutcu, 1993a; Deng et al., 2015, 2016;). The conventional collectors used in the flotation of scheelite ores are generally fatty acids or fatty acid derivatives ( Yongxin & Changgen, 1983; Oliveira & Sampaio, 1988; Sivamohan, 1988; Shi et al., 2014; Bo et al., 2015). It is difficult to separate scheelite especially from calcite with these reagents because the adsorption mechanism of these collectors occurs through chemisorption of the oleate ion onto the mineral surface (Atademir et al., 1979; Changgen and Yongxin, 1983; Hiçyìlmaz et al., 1993; Hu et al., 2011). Therefore, it is almost impossible to separate them by fatty acid flotation without using any selective depressant. Although oleoyl sarcosine was used as a selective collector in the flotation of fluorite and siliceous scheelite ores (Ozcan & Bulutcu, 1993b; Ozcan et al., 1994), this selectivity is not adequate for a low-grade calcitic scheelite ore. Unfortunately, the reagents such as organic colloids (dextrine, starch), quebracho, sodium phosphates, sodium silicate solutions containing polyvalent cations (hydrosols), etc. (Yongxin and Changgen, 1983; Schubert et al., 1990; Shi et al., 2014; Bo et al., 2015) used for calcite depression also depress scheelite to a large extent."

Jan 1, 2016

By A. E. Wraith, R. Harris, J. Qiu, R. Parra

Small pilot scale experiments have shown that it is possible to almost fully eliminate the minor elements (ME), namely As, Sb, Bi and Pb contained in smelter dusts by vacuum calcination of mixtures of the dust with sulphidizing agents such as dirty copper concentrate or elemental sulphur at 900 °C and 80 +/- 30 Pa for 90 minutes. The products of this calcination are a residue comprising a purified mixture of copper containing compounds along with the gangue constituents and a high sulphur condensate comprising a mixture of the minor element compounds. In particular, the Cu:ME ratios of the concentrate and dust were increased from 250 and 50, from 28 and 12 and from 36 and 8 to roughly 3000, 3000 and 100 for the calcine, for Bi, As and Sb, respectively. It has also been calculated that (i) the copper content of the vacuum calcine may be recovered by feeding it into a Peirce-Smith converter during its slag blow, and (ii) the resulting recycling could increase the minor element treatment capacity of a smelter by 100 % while also reducing the blister As content by a factor of three. The experimental results are briefly discussed and a treated dust recycling option is examined. Example operating conditions are presented and available commercial technology for the vacuum calcination of the mixtures is reviewed.

Jan 1, 2007

By Rong. G., T. Q. Lin, W. Du

Based on analysis of the evolutionary history of the valley in Baihetan, the mechanism of asymmetrical evolution, gradual migration-incision evolved from left bank to the right, is revealed in Baihetan river valleys. The process of in-situ stress evolution is carried out by using the Universal Distinct Element Code (UDEC). Consequently, the numerical results which indicate the main regulations of that stress field are as follow: (1) The phenomenon termed "high in-situ stress fold" appears in the bottom of the valley. With the maximum principal stress being 28-34 MPa, the stress increases significantly at a vertical depth of approximately 130 m. (2) The in-situ stress presents zonal distribution along the bank slope. It is apparent that the in-situ stress field consists of stress relaxation zone (SRZ), stress concentration zone (SCZ) and original stress zone (OSZ). The horizontal depth of stress relaxation zone varies from the left bank (roughly 200 m) to the right (about 120 m). Furthermore, the stress evolution of the left bank slope is studied. As a result, it is found that asymmetrical erosion contributes to the difference of the in-situ stress distribution as a critical factor, between the left bank and the right. And for an asymmetrical valley, the evolutionary process of in-situ stress field is a circular procedure, which includes the incision of valley, the accumulation of landslides and the migration of valley.

Jan 1, 2015

By C. G. McLachlan

Abstract This paper deals with the application of the cyanide process to recover gold from a pyrite concentrate produced by means of differential flotation. This concentrate before cyanidation contains from 0.09 oz. to 0.14 oz. gold per ton, of which only about 60 per cent is recoverable. The rest is so fine that it remains interlocked in the pyrite and therefore is not acted on by the cyanide. The concentrate also contains about 15 per cent pyrrhotite and 0.4 per cent chalcopyrite, both of which are cyanicides. The cyanicidal effect of the pyrrhotite is inhibited by preacracing the pulp with lime, and maintaining a high lime alkalinity during cyanidation. The effect of the chalcopyrice is reduced as far as possible by removing those particles which are free by means of a further flotation step immediately prior to cyanidation. This involves the flotation of some very fine material. After nullifying as far as possible these two cyanicides, the concentrate is cyanided directly, i.e., without being roasted. This leaves the pyrite available for subsequent sale as a source of sulphur dioxide and sulphuric acid, and the entire residue of the cyamde plant, amounting to about 500 tons per day, 1s now being disposed of in this way. Prior to deciding on direct cyanidation, a number of laboratory roasting tests were made. These showed chat, 1f proper control were exercised, a better recovery of gold could be effected from the roasted product than by the direct method of treatment. The tests also showed that the capital cost o the plant would be much higher than that needed for the procedure adopted. The possibility of subsequently selling the pyrite for its sulphur content would also have been eliminated. Introduction A previous paper has described in considerable detail the application of the flotation process to improve gold recovery from Noranda's milling ore, and in so doing has covered the production of an auriferous pyrite concentrate. The present paper deals with the recovery of gold by cyanidation from that concentrate. This gold, though intimately associated with the pyrite, can, for metallurgical purposes, be considered as all occuring in the native state.

Jan 1, 1946

By Waldemar W. Koczkodaj, William O. MacKasey

A consistency-driven pairwise comparisons method for mineral potential assessment is presented, using a simpli?ed case of volcanic-associated massive sul?de type deposits as an example. Geological, geochemical, and geophysical criteria are considered on two levels: local and regional. The local geological criteria are subdivided into stratigraphy, lithology, alteration and/or mineralization, and structure. The concept of geomerit index and a procedure for computing this index are introduced. The method of consistency-driven pairwise comparisons can be combined with other quantitative and qualitative assessment methods, enhancing them by incorporation of non-measurable geological criteria (e.g., stratigraphy or lithology) and by computation of weights. The consistency-driven approach allows experts to re?ne at-times subjective judgments concerning exploration and land-use planning, and contributes to the improvement of mineral-potential assessments.

Jan 1, 1997

By Waldemar W. Koczkodaj, William O. MacKasey

Abstract - A consistency-driven pairwise comparisons method for mineral potential assessment is presented, using a simplified case of volcanic-associated massive sulfide type deposits as an example. Geological, geochemical, and geophysical criteria are considered on two levels: local and regional. The local geological criteria are subdivided into stratigraphy, lithology, alteration and/or mineralization, and structure. The concept of geomerit index and a procedure for computing this index are introduced. The method of consistency-driven pairwise comparisons can be combined with other quantitative and qualitative assessment methods, enhancing them by incorporation of nonmeasurable geological criteria (e.g., stratigraphy or lithology) and by computation of weights. The consistency-driven approach allows experts to refine at-times subjective judgments concerning exploration and land-use planning, and contributes to the improvement of mineral-potential assessments.

Jan 1, 1997

By J. S. Stachulak

"The main ventilation design features adopted at Inco to safeguard personnel against the effects of fires are described in this paper. Measures taken to prevent and detect fires due to spontaneous combustion, and fires involving conveyor belts, are described in detail.IntroductionConsidering the over-all picture of present-day mining operations, the expenditure required to provide a proper system of mine ventilation and fife control should be regarded as a sound investment that will pay back in increased mining efficiency, improved safety, health, and morale of the miners.Mine ventilation control and mine fife detection and fighting are inseparable, because a ventilation system can spread deadly products of combustion just as efficiently as it does life-sustaining oxygen. Therefore, the possibility of a mine fife occurring is of particular concern.The first objective is to prevent a fife.The second objective is to design the ventilation system so that a positive fresh air supply can be ensured on each main level regardless of the location of the fife.The third objective is to be able to detect the fife at an early stage and to extinguish it before it can develop into a major fife. Accordingly, at Inco, very extensive measures are taken to prevent fires and to locate, isolate and extinguish them rapidly. To obtain an early warning, it is not sufficient to know that a fife has started, but it is also necessary to know where the fife is burning."

Jan 1, 1994

By J. S. Stacbulak

"The main ventilation design features adopted at Inco to safeguard personnel against the effects of fires are described in this paper. Measures taken to prevent and detect fires due to spontaneous combustion, and fires involving conveyor belts, are described in detail.IntroductionConsidering the over-all picture of present-day mining operations, the expenditure required to provide a proper system of mine ventilation and fife control should be regarded as a sound investment that will pay back in increased mining efficiency, improved safety, health, and morale of the miners.Mine ventilation control and mine fife detection and fighting are inseparable, because a ventilation system can spread deadly products of combustion just as efficiently as it does life-sustaining oxygen. Therefore, the possibility of a mine fife occurring is of particular concern.The flirt objective is to prevent a fife. The second objective is to design the ventilation system so that a positive fresh air supply can be ensured on each main level regardless of the location of the fife. The third objective is to be able to detect the fife at an early stage and to extinguish it before it can develop into a major fife.Accordingly, at Inco, very extensive measures are taken to prevent fires and to locate, isolate and extinguish them rapidly. To obtain an early warning, it is not sufficient to know that a fife has started, but it is also necessary to know where the fife is burning."

Jan 1, 1994

By J. J. Hussey

"Abstract-The ""Brunswick Horizon"" an informally named ore-bearing unit near the top of the Nepisiguit Falls Formation in the Ordovician Tetagouche Group, hosts the Brunswick No. 6 and No. 12 base-metal mines, as well as the former Austin Brook iron mine, in northern New Brunswick. Detailed structural analysis of the No. 6 and No.12 mines led to the prediction that a massive­ sulfide deposit may have been repeated by F1 folding along the Brunswick Horizon. A subsequent drilling program discovered the new massive-sulfide North End Zone at a vertical depth of 1100 m, 1 km north of the No. 12 underground workings. By the end of 1990, Zn-Pb-rich massive sulfides had been delineated over a strike length of 200 m and a down-dip extent of 170 m. Rock units intersected in the North End Zone are generally thinner and vary somewhat from those at the Brunswick No. 12 mine. Thinning of the hanging wall rocks may be primary, may result from attenuation along F2 folds, or may represent truncation by a thrust fault. The newly discovered sulfide zone indicates that significant potential exists for the discovery of other deposits at previously unexplored depths.SOMMAIRE-Dans le nord-est du Nouveau-Brunswick ""l'horizon Brunswick"" est le nom usuel de la zone qui contient les mines de métaux de base Brunswick No. 6 et No. 12, ainsi que l'ancienne mine de fer Austin Brook, toutes situées sur le dessus de la Formation ""Nepisiguit Falls"" dans le Groupe Tetagouche d'âge Ordovicien. Une analyse détaillée de la structure des mines No. 6 et No. 12 à permis a van Staal de prédire qu'un gîte de sulfures massifs pourrait se répéter dû à une déformation F1, au nord de Brunswick No. 12. Suite à un programme de forage, la nouvelle zone de sulfures massifs appelée le ""North End Zone"", profonde de 1100 rn, et à une distance d'un km au nord des chantiers souterrains, fut découverte vers la fin de l'année 1990, les sulfures massifs riches en Zn-Pb ont été délimités sur une longueur de 200 rn et une hauteur de 170 rn le long du pendage. Les unités de roches intersectées dans le ""North End Zone"" sont généralement plus minces et sont quelque peu différentes de celles de la mine Brunswick No. 12. L'amin­ cissement des roches pourrait être primaire ou être le résultat de l'atténuation le long des plis F2, ou soit tronqué par une faille. La nouvelle découverte d'une zone de sulfures indique un potentiel énorme pour la découverte d'autres g ""tes à ces profondeurs inexplorées."

Jan 1, 1992

By Kri Inwood

"IntroductionIn 1879, when the Dominion government initiated its controversial program of industrial promotion, iron smelting in Canada was limited to one company producing coke iron on the mainland of Nov a Scotia and three small charcoal blast furnaces in Quebec. There was no steel production. By the eve of the first great war, iron and steel were being produced in very large quantities, the companies active in 1879 had disappeared and new centres of integrated iron and rolled steel production at Hamilton, Sydney and Sault Ste. Marie had come to resemble the industry as we know it today.The most dramatic change was that at Sydney, Nova Scotia, where in the early 1900s, two steelmaking companies established works. The Sydney developments have been explained as the result of resource discovery and technical change. W.J. Donald, in his authoritative account of the Canadian iron and steel industry, observes:""The most rapid growth of the Canadian iron and steel industry has occured since 1897... The remarkable growth has been caused largely by the new conditions of the industry. The discovery and use of Newfoundland ores, together with the availability of Cape Breton coal, has made the Nova Scotia industry not only possible but profitable ... It is a safe conclusion that the Canadian industry would not have been an important one, had it not been for the discovery of the Michipicoten and especially the Wabana (Newfoundland) ores""Donald also argues that metallurgical progress had been necessary to render the ores valuable,""Newfoundland ores ... contain a considerable amount of phosphorus, and were made available for steel-making by recent inventions.""The purpose of this paper is to re-examine Donald's story. It will be argued that the origin of steel -making at Sydney is somewhat more complicated than Donald has indicated. The difficulty with Newfoundland ore extended beyond its phosphorus content and a resolution required more than the basic open hearth furnace identified by Donald. Moreover metallurgical change was only one of several developments necessary to induce industrial investment at Sydney. Surprisingly, however, the discovery of iron ore in the late nineteenth century does not appear to be part of the explanation."

Jan 1, 1983

The Autogenous milling of ores holds an increasing attraction as the focus moves towards reducing energy usage, both direct and embodied in grinding media. However, most of the early AG mills were converted to SAG for improved stability and increased throughput. This imposes a huge penalty in steel grinding media consumption. The LKAB iron ore operations in Sweden process highgrade magnetite through fully-autogenous milling lines to a final product P80 of about 45µm. The outcomes of P9O AMIRA research surveys, covering a wide range of mill fillings and throughputs and with different feed blends, are presented. Insights are provided on operational strategies, opportunities, the influence of feed size control and balancing the blend of competent gangue and softer magnetite. Areas of importance in the successful operation and control of energy-efficient autogenous circuits are highlighted.

Jan 1, 2012

By W. A. Roliff

The renewed interest of the past few years in the Appalachian and Michigan oil provinces has not, as yet, created any marked increase in activity in Southwestern Ontario. During 1960 development drilling in-creased somewhat over 1959, but exploratory drilling decreased slightly. More attention was devoted to the deeper horizons, but lake drilling de-creased considerably. Oil production reached a new peak and gas production increased slightly. During 1960 an interesting oil and gas discovery was made in the Cambrian and gas discoveries six miles off-shore in the eastern part of Lake Erie were made in the Clinton-Cataract zone of the Silurian. This paper reviews activities during 1960, summarizes the discoveries made to-date and the pertinent exploration data relating to the prospects of the region and discusses some of the economic aspects of exploration and development. D URING the last few years there has •been a marked renewal of interest in the old petroleum

Jan 1, 1961

By D. Vanin

"Conventional single heading track drifting in the hard rock mining industry has not shown any significant improvements in advance rates, despite the advent of modern track jumbos and igh speed muck handling systems .This paper presents Kiena 's experience in using a 7 ft 2 in. diameter larva Mark 6 Tunnel-Boring Machine (TBM) for driving 6000ft of drift.IntroductionKiena Gold Mines is located about 5 miles west of the town of Val d'Or, Quebec, approximately 300 miles north of Montreal. The mine commenced production in October 1981 and has gone through various expansions of ore production with 287 916 metric tonnes in 1982 to reach 453 800 metric tonnes in 1986.Due to the majority of claims being covered by a lake, a grassroots exploration drive of remote areas of the property was required to allow diamond drilling on a yearly basis. High speed sequential excavation methods (SEM) of single heading drifting in the mining industry has not progressed much in the past 20 years despite the advent of electric-hydraulic jumbos, Haggloader and Hagglund type cars. Certain examples of record SEM drifting advances have been performed in the past but only under very specific ground and cost conditions."

Jan 1, 1987

By A. G. Pathan

Rock and soil mechanics investigations were carried out in block VIII at Thar Coalfield, Pakistan. Most of the strata were mainly composed of sand, with an average content of 67.68 %. Laboratory studies of rock and soil samples from drill hole GT-01 revealed that the strata in block VIII are very weak with an average uniaxial compressive strength of 3.59 MPa, an average tensile strength of 0.68 MPa, an average Young?s Modulus value of 0.234 GPa, an average cohesion of 129.19 KPa, and an average friction angle of 55.47°. Slope stability analysis, based on a probabilistic approach, was carried out using Slide-V software. Monte Carlo simulations have been applied to investigate the probability of failure in the slopes of an open pit lignite mine in block-VIII. From the slope stability investigation, it was found that the probability of failure is 0 % at a slope angle of 16°.

Aug 1, 2013

By J. Kalejta

Ever increasing depth of mineral extraction presents a challenging environment for hard rock underground mines. High in-situ stresses and associated seismicity with potential rockburst hazards are the major decisive factors contributing to the choice of a ground support regime. Conventional ground support systems, designed primarily for static loads, are not always capable of providing safe working conditions for underground personnel in seismically active mines. Systems specifically developed to resist dynamic loading and allowing for larger deformations are therefore preferred alternatives. High-tensile chain-link mesh has a proven record of successful use in open cut operations in various rockfall barrier installations due to its high energy absorption capacity. It has also been used in underground operations in various parts of the world. This paper describes a method of mechanized installation of a chain-link mesh evaluated at the Kiruna mine in Sweden and South Deep Mine in South Africa. A purpose-built mechanized roll mesh handler was used in this evaluation. The handler is compatible with all standard multi-boom underground drill rigs and is operated utilizing the hydraulic circuit normally used for the feed arrangement. A number of key performance indicators have been identified as success criteria: ??A 30-50% faster installation compared to the conventional methodology ??The mesh should sustain any blast damage when applied to the blasting face ??No unraveling of the mesh when cut ??No failure of mesh under normal conditions Although the energy-absorbing mesh combined with yielding rock bolts is a ground support system of choice for rockburst prone conditions, the operational upsides recognized during the evaluation imply that this product can also be competitively used in less demanding ground conditions where customarily weld mesh or shotcrete are used as a primary surface support. The main conclusion: a fast, safe and fully mechanized installation.

Aug 1, 2013