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The notes from which this paper has been prepared were set down at the time of the author's departure from Australia in 1935. Mr. Frank Forman, Government Geologist of Western Australia, who has very kindly read the paper in manuscript, affirms that the views here set forth are now accepted by most geologists. Thus, Forman's recent presidential address before the Royal Society of Western Australia (1937) mentions sediments in the Kalgoorlie Series "including banded jaspers and jaspilites."While it may, therefore, be superfluous to belabour the question further at this time, Mr. Forman has encouraged the author to publish this paper as a summary or both past and present views.To those specially interested in the subject of the paper, a study of pertinent Plates attached to Western Australian Geological Survey Bulletin No. 71, 1917, is suggested.The type of rock which is variously called "jasper bar," jaspilite, or "ferruginous quartzite" is familiar to all mining men who have worked in the West Australian goldfields.In its typical form it is a "striped" rock consisting of alternate layers of white or pinkish silica with red to brown bands of iron-bearing silica.In the course of geological work in many parts of Western Australia I studied exposures of jasper bar and was repeatedly impressed with the similarity of much of the material to the sedimentary "banded iron formation" of Canada. It was, therefore, a surprise to learn that the jasper bars were not generally regarded in Australia as sedimentary horizons. It is true that Honman offered convincing evidence of the sedimentary origin of the jaspers...

Jan 1, 1939

By Michael S. Miller

In 1986 and 1987, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied the nine separate parcels that comprise the 4,330-acre South Warner Contiguous Wilderness Study Area in order to evaluate their identified mineral resources. The nine parcels are along the east side of the South Warner Wilderness. They are, from north to south, the Granger, Milk, Cottonwood, Owl, Hornback, Eagle, Emerson, Barber, and Van Riper parcels. The Wilderness Study Area is underlain by basaltic, andesitic, and rhyolitic volcanic rocks and by sand and gravel deposits. Low-grade metamorphism is widespread in the volcanic rocks, with quartz, zeolites, datolite, chlorite, and calcite locally abundant in veins and amygdules. The rocks have been displaced by the mountain-front Surprise Valley fault and by crosscutting high-angle faults.

Jan 1, 1988

By Zay Jeffries

A SURVEY of rare metals and minerals for the past year places uranium as one of two partners, the other being the neutron, in what historians will probably say is the greatest discovery in physics at least during the year and probably for a consider- ably longer period. The uranium atom has been made to divide into parts somewhat after the style of reproduction of the amoeba. When an amoeba divides into two parts, however, it produces two amoebae substantially alike and each substantially like the parent: furthermore, there is no considerable change of energy when this happens. When the uranium atom divides it yields other atoms such as barium and krypton with the complete destruction of the original uranium atom but with the liberation of a tremendous amount of energy. This will be discussed more at length later.

Jan 1, 1940

The only simple sulphide mineral of antimony of importance is stibnite, SbS3, containing 71·8% antimony when pure. It is lead-grey, has a densityof 4·5 to 4·6 and melts at 546°C. It is both friable and sectile (Hardness 2 on Moh's scale) and, as a result, slimes very readily during milling.It is commonly associated with pyrite and arsenopyrite other minerals occurring with stibnite in minor quantities are chalcopyrite, galena, and scheelite. The latter mineral occurs in sufficient quantity at the Yellow Pine Mine, Stibnfte, Idaho, to justify the production of a scheelite concentrate.Stibnite mayor may not contain gold. Other minerals such as pyrite or arsenopyrite may contain gold. At Wiluna at the main mine nearly all the gold is asociated with arsenopyrite the stibnite being almost free from gold, whilst at the Moonlight Mine both arsenopyrite and stibnite carry gold.The mineral, tetrahedrite, which is a complex sulphide of copper and antimony; must also be considered an economic source of these two metals.Part of the copper may be replaced by iron, zinc; silver; or mercury, whilst part of the antimony is often replaced by arsenic.CLASSIFICATION OF ANTIMONIAL GOLD ORESFor the purposes of this paper antimonial gold ores may be conveniently classified as follows: CLASS 1. Ores from which a satisfactory gold extraction may be obtained by fine grinding, followed by cyanidation and which contain insufficient antimony to justify tIie production of an antimonial concentrate.CLASS 2. (a) Ores in which a satisfactory gold extraction may be obtained by straight cyanidation, but which contain sufficient antimony to justify the production of an antimonial concentrate.CLASS 2. (b) Ores from which the gold extraction by straight cyanidation is unsatisfactory. This type of ore requires the production of an antimonial concentrate for reasons which will be considered later.In deciding whether an ore belongs to class 1 or 2 (a) it should be remembered that the normal price of star antimony is about £1.00 sterling per ton and that the value of each 1% of antimony recoverable as metal is worth about £1 per ton.The antimony content of antimonial gold ores is liable to be considerably...

Jan 1, 1944

By S. K. Chaudhuri

With a growing emphasis on maximizing the value by rapidly deploying it across their assets, mining firms are eager to identify any issues that may hinder such efforts and to refine their approaches to overcome them. As such a CDE vision can be considered realized when the following components are addressed and functioning as intended - People: the right resources working together and efficiently to achieve shared goals, Process: well-defined workflows mapped out for key value processes, Technology: availability of the correct tools and applications to increase efficiency in work execution and Locations: regional locations/ sites that need to be linked for collaboration and information exchange. For the above vision, an approach that considers the degree of interaction between the roles in metallurgy operations, mineral resource planning, mine engineering, plant operations, logistics and infrastructure, and which accounts for the current technology states across these groups to determine sub-processes where the impact of a CDE will be the most is critical. In effect, CDE is more about transforming an organization?s operational philosophy than a technology driven project. This paper examines the definition and components of a CDE in a mining context. Real-time operations co-ordination, maintenance interventions, production analysis and optimization processes are examined along with current state technologies and manual processes as candidates which are likely to result in most benefits from collaborative work processes. Finally, the paper examines technologies that can be used to further enable a collaborative working environment.

Sep 1, 2012

By J. F. Henderson

"IntroductionTHE National Advisory Committee on Research in the Geological Sciences was set up by the Privy Council of Canada in 1949. It was set up because you, the Geology Division of the Canadian Institute of Mining and Metallurgy, asked that it be set up. The Committee is, therefore, to a consider-able degree, your offspring. In the role of good parents you, of the Geological Division of the C.I.M., should be interested in the progress of your progeny. How is the Committee organized? What has it recommended? What has it accomplished? On behalf of the National Advisory Committee, that is what I want to tell you about this afternoon.HistoryYou will remember that, in 1946, the Geology Division of the C.I.M. set up a Committee on Geological Research. This Committee, under the Chairmanship of Dr. J. E. HAWLEY, found ""that there is no national organization interested in surveying, co-ordinating, and implementing with financial help, fundamental and much needed geological research. Accordingly, the first and most necessary step to put the geological sciences in Canada on a proper footing .is the recommendation that a National Advisory Committee on Research in the Geological Sciences be formed"" (l).This recommendation was endorsed •by the President and Council of the C.I.M. in 1947 and submitted to the Minister of Mines and Resources."

Jan 1, 1952

"AbstractThe Sedimentary Basin area of Western Canada, which lies between the Precambrian Shield and the Cordilleran mountain area, covers approximately 800,000 square miles. Sediments ranging in age from Cambrian to Tertiary are present and, of these, horizons in the Upper and Lower Cretaceous, Jurassic, Mississippian, and Devonian have yielded commercial oil and gas flows. Producing horizons in the Cretaceous and Jurassic are sandstone, while all those of the Palaeozoic are carbonate rocks such as red limestone or dolomite (bioherms). Shows of oil and gas have been encountered also in the Cambrian and Triassic sediments.The broad structural features of this vast expanse of sedimentary rocks are the Moose Jaw syncline, the Sweet Grass-Battle River arch, the Alberta syncline, the Foothills belt, the Rocky and Mackenzie mountains, the Great Bear-Slave Lake basin, and the Mackenzie Delta Basin area.This contribution outlines the .stratigraphy and structure of the Basin area, and gives examples of present producing oilfield structures and stratigraphic traps.Part 1.-Regional StratigraphyIntroductionThe vast expanse of relatively undisturbed sedimentary rocks of western Canada has long been recognized as prospective territory to search for oil and/ or gas. This search in western Canada dates back before the turn of the century, but, considering the size of area to be explored and tested, the effort an<l money expended upon it, which, before the recent discovery of oil at Leduc, Alberta, appeared large and fruitless, now seems almost ridiculously small. A check-up of effort and money expended prior to and since the Leduc discovery would undoubtedly reveal that more wildcatting and development has taken place during the last two and a half years than during all previous years combined. The figures would astound not only the average citizen, but many within the industry itself."

Jan 1, 1950

By George H. Holmes

The water situation in Nevada mineral and related industries is described in this report. It contains information on the sources and adequacy of supply to current operators, requirements and uses, quality and costs, geography, hydrography, precipitation and evaporation characteristics, and Nevada water laws. Also, information is given on the water requirements of one public utility powerplant, and the source and consumption of water in four major cities. Water distribution at 24 operations is shown on schematic waterflow diagrams. The mineral industries of Nevada in 1962 used 8.6 billion gallons of new&apos; water and reused 3.8 billion gallons for a total usage of 12.4 billion gallons. The copper industry was the major water user. The 1962 value of all mineral production in Nevada was $85.5 million. The large amount of water required to maintain thin high production is obtained principally from ground-water sources in alluvial valleys and the permeable rock formations of some mountain ranges. Some water is also obtained from perennial streams and springs. Sources of water utilized by existing industry ire near most mineral industry operations; however, seven companies are forced to pipe water distances ranging from 2 to 8 miles. Although water supplies of presently operating companies are adequate at most operations, several companies resort to large-scale reuse of water as a matter of conservation and economics. Acquisition of water by new operators is possible but takes considerable negotiation. Water rights, surface and underground, are controlled by the State. The quality of the water is satisfactory for most purposes. Analyses of 19 samples, listed in the appendix, show the range in water quality at various plants throughout the State. Costs of delivering new water to current operations range from 2 to 26 cents per 1,000 gallons with an average of 10 cents per 1,000 gallons for power and maintenance. No firm costs for recirculating water were available; estimated costs range from 1.5 to 2.5 cents per 1,000 gallons. The mineral-product value of the entire Nevada mineral industry in 1962 was equivalent to $10 per 1,000 gallons of new water and $26 per 1,000 gallons consumed. Projection of the 1962 water requirements of the Nevada mineral industry indicates that the demand For new water will increase from 8.6 billion gallons in 1962 to 11.9 billion gallons in 1980, a 43-percent increase. Water requirements in the year 2000 are estimated as 14.8 billion gallons, an increase over 1962 water demand of 78-percent.

Jan 1, 1966

By W. B. Berwald, T. W. Johnson

"The United States Bureau of Mines, in cooperation with the Natural Gas Department of the American Gas Association, has been studying actively for the past several years the flow of natural as through high-pressure pipe lines. 4 This report deals with that part of the study involving the design of pipe-line systems consisting of lines laid parallel to each other. The lines are referred to as the original line and the parallel line. The paralleling lire may or may not extend the entire length &f the original line; however, the parallel line is connected at its two ends to the original line.As a result of the large expansion of the natural-gas industry almost all markets within economic distance, from the developed as fields have at least one pipe line supplying them with natural gas. Small increases in the consumers' demand for natural-gas can be met usually by increasing operating pressures, but any marked increase in demand necessitates paralleling sections of the existing systems. It is believed that to a large extent future expansion in the natural—gas industry will consist of paralleling the present lines. The several formulas given in this report have been developed to aid in the design of such systems. Curves and tables were prepared from these formulas to simplify the calculations materially and to facilitate determination of the sizes of pine to be used in paralleling various diameter lines to give the most economical design. The formulas are presented without detailed derivations, as a complete report on the flow of natural gas through pipe lines is being prepared which will contain the derivations of these formulas. Examples included here show the detail of application of the several formulas to problems of design of parallel lines."

Jun 1, 1934

By A. H. Lang

"IntroductionMUCH PROSPECTING, exploration, and development work was done for uranium in Canada in 1952, chiefly in northern Saskatchewan and in the Great Bear Lake region of the northwest Territories. The outstanding feature of the year was the great amount of work done in preparing for production at the Ace mine of Eldorado Mining and Refining, Limited, in the Goldfields region . of Saskatchewan. Many private companies and prospectors were also active in this region. Most of the other parts of Canada where uranium has been found received less attention than during the last few years, partly because so much interest was taken in the Goldfields region.In presenting this short summary of the year's activities now, the writer is handicapped because the season is not yet over; some discoveries have probably not yet been announced, and there has not yet been time to digest the numerous reports that have been sent in by companies and prospectors. In any case it would be impossible to give details for most of the discoveries and properties, because that would require a long report, and because that information is classed as confidential until released by the discoverers and companies concerned. It is only possible, therefore, to give a few generalizations, a brief out-line of the activities in northern Saskatchewan, even briefer ,accounts of the work in other parts of the country, and a few details that property owners have informed the writer he may publish or that have already been published by the owners."

Jan 1, 1953

By L Lachance, F Flament, D Leroux, S GariTpy

"Considerable metal values are often locked in stockpiles (ore, concentrates, heap leach pads, slags, reverts, etc.) and process equipment (bins, holding tanks, thickeners, etc.). This is more than enough to justify accurate accounting of such in-process metal inventories from both financial accounting and operational perspective. However, accurately determining the metal inventory of an in-process unit is often a challenge in industrial practice. Audits have shown that available indirect or direct measurements often carry large inaccuracies. Sooner or later, ignoring these measurement errors lead to unexpected incoherencies in reported metal balances. In such situations, coherent metal balances are then achieved through subjective and sometimes significant adjustments of in-process inventory levels. While such metal accounting methods applied by mineral processing engineers used to be rarely challenged, they are now being increasingly scrutinised by various stakeholders. Hence, metal accounting procedures that mitigate subjectivity in adjustments while still coping with the unavoidable uncertainty are more relevant than ever.This paper reviews three different metal accounting methods for reporting in-process metal inventory values. Their individual application strongly depends on the available measurements i.e. The indirect method where the metal inventory of a given process unit is determined by subtracting the cumulative reclaim from the cumulative feed carries important flaws. The direct method also comes with challenging accuracy issues so that emptying a process unit is often the best available inventory measurement. This reality is recognised for by further analysing a previously proposed operating mode where two interchangeable process units are alternately used. The third investigated method is the redundant method which combines indirect and direct methods for a given process unit. This paper reveals that the dual process unit operating mode and the redundant method can both significantly improve the estimation quality of in-process metal inventories.CITATION:Lachance, L, GariTpy, S, Leroux, D and Flament, F, 2013. Review of metal accounting methods for in-process metal inventories, in Proceedings MetPlant 2013, pp 102-117 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013

By William R. Wayment, Wayne S. Cusitar

INTRODUCTION The process of mining removes valuable and eco¬nomically recoverable minerals from the earth. In the case of hard-rock mining, this process involves breaking and removing ore, while leaving the waste rock or host rock as intact as possible. Prior to mining, ground stresses exist in the ore and the host rock as a result of weight and tectonic forces; for the purposes of this chapter, the ore is considered to support the host rock on both the hanging and footwall sides. Two basic phenomena accompany mining. First, the hanging walls and footwalls tend to move together as the ore is removed. Second, high stress gradients de¬velop in the rock periphery of the opening; the magni¬tudes of the stress gradients vary widely, depending upon the local geometry and conditions. At various times, mining methods have used square¬set timbers, waste-rock backfill, alluvial sand fill, and tailings backfill materials, with or without cement, to replace the loss of support caused by the removal of the ore. Cut-and-fill mining has evolved to use hydraulically placed tailings for the backfill. In the stope, this fill provides massive support to the walls, thereby reducing stresses in the back. It also provides a floor from which men and machines can work to drill and blast, to haul ore, and to scale and bolt the back. In many cases, the addition of cement provides a competent free-standing wall when the fill is exposed during mining of adjacent stopes or during pillar recovery operations. In most cases, the use of fill does not eliminate standard tem¬porary or local roof control measures such as roof bolts and wire mesh. Fill Characteristics It is important that backfill used for ground support be of maximum stiffness in relation to wall closure. The stiffness of the fill is related to its placement bulk density or void ratio. In the case of cemented tailings, this is enhanced by the cement bonds. During stope closure, individual fill particles experience rotation and crushing at point contacts, but they are subject to little relative translation. The stiffness approaches infinity as the void ratio approaches zero, until the ground forces reach equilibrium, and closure stops. The gradation of particle sizes and minimal segregation resulting from good hy¬draulic placement both contribute to a high degree of early stiffness in the closure history of classified tailings backfill. This also implies that the fill should be resistant to creeping under high static loads. All mines experience shock loading situations such as blasting, and many mines experience rock bursts that can apply sudden and very high loads to the fill. Certain conditions of void ratio, particle size, and moisture con¬tent can result in mass fluidization of unconsolidated fill during such shock loading. Two key factors in avoid¬ing fluid behavior are the provision of a well-drained fill through desliming or classification and the achievement of a small degree of consolidation through the addition of cement in ratios as lean as 40 to 1 (2.4% cement). The acceptance of classified mill tailings as backfill material has been enhanced by its relative economy, including its source, preparation, delivery, and stope distribution. Transportation from the backfill prepara¬tion plant on the surface into the stope usually can be accomplished with low power consumption, with low labor costs, with few capital costs, and at high tonnage rates. An additional benefit is a reduction of the storage volume required for surface disposal of the tailings stream, with a resultant improvement in the environ¬ment. The costs of placing cemented tailings backfill generally range from $1.65 to $6.61/t ($1.50 to $6.00 per st) of fill depending upon the cement ratio used. Scope This chapter examines a major backfill program at a mine and mill complex where the backfill facilities are included as a part of the original planning. The backfill preparation plant is intended to make maximum use of remote controls and automation. The logistics asso¬ciated with material storage, handling, and metering in the plant are outlined. Important considerations in specifying equipment for typical service conditions are discussed. The fill delivery system is described, includ¬ing the boreholes, level lines, and stope distribution lines. Stope preparations for fill confinement and drain¬age are described, as are the techniques of placement and distribution. Methods of controlling and directing the flow of drainage water and slimes are presented, along with the facilities and equipment for clarification, pumping, and sludge removal. As shown in Fig. 1, the fill program encompasses most aspects of the mining and refining facilities, so the discussion is brief in each area. The preparation of backfill of a uniform and con¬trollable quality is presented here as a material handling problem. The balance of the presentation concentrates on the logic of the system, the costs where meaningful (in 1977 US $ unless otherwise specified), and some operating "tricks" that have contributed to system per¬formance and reliability. SURFACE PREPARATION PLANT A backfill preparation plant is required on the surface. This plant generates suitable fill material from the stream of mill tailings. Among the functions of the plant are: 1) Slimes are removed to improve the percolation characteristics of the fill; typically, particles finer than 325 mesh are removed from the tailings. 2) Tailings and sand storages are provided so that the steady stream of tailings produced by the mill can be accepted. Provision is made to accommodate the cyclic high-volume demand from the mine. 3) The plant stores the cement and contains meter¬ing and mixing facilities to provide fill of a controllable and uniform quality. 4) The hydraulic backfill delivery system is a part

Jan 1, 1982

By D. Grobbelaar, A. Cichowicz, D. J. Birch

The Q-coda method for estimating the quality factor Q(f)= Qo(f)n was used to characterize seismic wave attenuation in a region of the Kaapvaal Craton that includes the mining areas of the Bushveld Complex and Witwatersrand Basin. Seismic waveform data, collected by locally distant stations of the South African National Seismograph Network (SANSN), consisted of mining-related events with magnitudes ranging from ML 1.8 to ML 4. Q was calculated for nine different source-receiver pairs spanning the study region. A weighted average Q based on the number of available data gave an estimated attenuation relation for the study region of Q(f) = 327 f 0.81.

Jan 1, 2015

By S. Hopkins, J. Nolan, S. Gillis

"Cast in place concrete shaft linings have been used in many salt and potash shafts sunk in North America over the last 100 years. A large number of these shafts have exceeded their initial design lives and as producers look to extend the life of their operational assets, maintenance costs and shaft downtime will, in many cases, continue to rise unless repair work is undertaken. Successfully implementing concrete liner repair schemes in operating salt and potash shafts is complicated due to their age, environment and time constraints during inspection, detailed design and construction. This paper outlines a general approach to the repair of concrete-lined portions of these shafts, based on lessons learned from the authors’ involvement in a recent repair project. INTRODUCTION Prior to the recent boom in potash mine construction many of North America’s potash mine shafts were entering their sixth continuous decade of production (Table 1). Of North America’s salt mines, one has been in continuous production, for nearly nine decades.As would be expected, considering the environment in which these liners operate and the age of the material, the concrete-lined sections of the shafts outlined in Table 1 have been noted by the authors to have lost both cross-sectional thickness and strength over time. Since construction, three principal factors have contributed to this loss in section/strength; (1) physical degradation (impact, freeze/thaw or rebar expansion), (2) chemical degradation from brine/water inflows (Neville 1969; Bothwell, 1972) and (3) overstressing of the liner. These factors may act in combination, in which case they can produce more significant distress than individually. Physical degradation There are three main causes of physical degradation of concrete shaft liners. The first is impact from falling debris/tools or equipment (whether large or small), which may damage specific sections of concrete lining as they fall through the shaft. Impacts tend to damage infrastructure fixed to the shaft liner more than the liner itself, so damage from this mode of failure is usually localised, for example, where bolts fixing a shaft services bracket to the wall have been pulled away, pulling out the concrete around the bolts with them."

Jan 1, 2019

By C Li, K McDonald an, T Nicholson, C Brown

The relative reactivities of chars prepared from different coal samples at temperatures in the range 500 to 1150¦C were determined by measuring the rates of metallisation of a standard ilmenite concentrate. The results have been interpreted in relation to different measured physical and chemical properties of the chars. Char reactivities were found to correlate with the maximum specific surface area (SSA) of the chars, obtained from plots of SSA versus temperature. Weathering of coal samples gave higher reactivities which correlated with higher SSAs. Experiments using recycled chars showed that the high internal SSAs developed during earlier reduction reactions provide no benefit in terms of increased metallisations. The important role of char hydrogen contents in controlling low temperature metallisation rates was demonstrated. Chars prepared from different rank coals had the same hydrogen content when prepared at the same temperature. Ilmenite metallisation rates had a linear dependence on the hydrogen content of the chars. Large differences in the slopes of the metallisation versus H2 content curves for different chars were interpreted in terms of SSA variations and catalysis of the gas reactions by dispersed metallic iron particles in the chars. A simple test based on magnetic separation of the char was shown to give an indication of enhanced reactivity due to contained metallic iron.

Jan 1, 2001

By Nils Heinke, Stephen M. Collinsorth

To anyone who is responsible for the production of blast holes, who is looked to on a daily basis for drill maintenance and performance, whose bottom line may depend on the survival of the mine itself.. How much awareness should one have on such things that truly impact production, maintenance and overall job cost? Do you know your drill’s maximum capacity?

Jan 1, 1998

By Ross E. BROWNE, Ross B. HOFFMANN

IT seems strange that a theory so devoid of value in its application to our practical problems should attract such widespread acclaim. This appears still more remarkable when one considers the foundation on which it is built. The criticism naturally suggested is as follows: First; the special theory of relativity is based on an assumption which is counter to the fundamental conception of relative motion. Second; the theory claims only a slight modification of Newtonian mechanics-a modification so minute that, even if true, it would have no practical value in its application to any visible occurrence here on earth.

Jan 1, 1931

By Kurt Oakes, Paul Worsey, Braden Lusk, Tony Brasier, Scott Crabtree, Randy Wheeler

Theoretical description of destructive wave interference and the use of sacrifi cial holes is included and is supported by data collected at Springfi eld Underground. Finally, the process by which the reduction in vibration was achieved in practice is described. Results are discussed for several production blasts taking place over a one year period.

Jan 1, 2008

By Ingo Ossenbühl, Wolfgang Dolsak, Vojtech Gall, Axel G. Nitschke

"Yielding support systems for application in underground construction have a long history, primarily in mining. Typical examples are tunnels subject to loading conditions that lead to overstressing of the newly installed support or existing tunnel structures in active fault zones. Recent applications for tunnel rehabilitation projects unveiled the capabilities and flexibility of combined yielding support systems presented in this paper. Frequently, the main requirements for tunnel rehabilitation applications are a fast, safe, and simple installation along with the need for flexibility with regards to existing tunnel geometries. A combined support system consisting of steel sets with yielding connections and special groutable hoses has proven to be an efficient support measure providing a multitude of advantages compared to conventional rehabilitation approaches. The presented yielding support system provides an immediate and active support, while it allows for controlled yielding upon experiencing loads beyond its support capacity. INTRODUCTION The excavation of underground spaces leads to redistribution in the existing stress regime. This load redistribution goes along with deformations in the surrounding rock mass. Magnitude and duration of these deformations depend on the tunnel’s depth and geological conditions, but also on the installed support system. Modern civil tunneling infrastructure has generally an envisioned service life of about 120 years. Conventional tunneling provides typically a dual support system, split into the initial (or primary) and final (or secondary) lining. A typical design principle in civil tunneling is to let the vast majority of deformations acting on the initial lining cease, before the final lining is installed. Based on this approach, the loading on the final lining is significantly reduced and signs of overstressing, such as cracking of the lining, are typically limited to the initial lining. However, special cases in swelling and squeezing ground require different approaches, including yielding support systems."

Jan 1, 2016

By D R. Andrew, K T. Morrison, J F. Tiedgen

Waste blasting in iron ore operations can pose a number of technical challenges, including blasting through variable geology and blasting soft ground in wet conditions. Blast patterns are designed to be loaded with a specific range of explosives with unique characteristics and properties. Each explosive product will produce an optimal blast outcome for a given set of blast parameters and ground conditions. Sites characterised by softer rock typically require low-density, low-energy explosives. Historically, these products have contained a high ratio of porous ammonium nitrate prill and are only suitable for dry blastholes. When blastholes within a pattern are found to be unsuitable for such explosives due to wet, damp or muddy blasthole conditions, a new product is selected. While it is easy to switch products to match blasthole conditions, the different properties of the new non-ideal product can impact blast performance and increase loading times and costs.Flexigel™ is a solids-sensitised emulsion blend suitable for loading at variable densities and energies in dry, damp, muddy or wet blastholes. It is a universal product that can be loaded to match ground and blasthole conditions or complement other explosive products.At Fortescue Metals Group’s Cloudbreak site, Flexigel™ was trialled through a series of matched pair blasts in order to optimise blast outcomes in conditions that were non-ideal for existing explosive products and to reduce the overall cost of drill and blast operations. Flexigel™ yielded improved instantaneous dig rates and improved loading efficiency when compared to a traditional emulsion blend. The results also indicated that variable-density and variable-energy products afford greater flexibility for optimising blast outcomes across all ground and blasthole conditions trialled.Trials of Flexigel™ at Cloudbreak have shown that a variable-density solution is available for conditions where traditional explosive products are non-ideal. As such, Flexigel™ is able to fill a major void at any operation where the desired low-density, low-energy explosive product must be substituted for a more expensive traditional emulsion blend or heavy ammonium nitrate/fuel oil.CITATION:Andrew, D R, Morrison, K T and Tiedgen, J F, 2015. Flexigel™ – a variable-density solution, in Proceedings Iron Ore 2015, pp 413–418 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015