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By Al Campoli

One of the critical variables affecting resin bolt performance is the size of the resin annulus, defined as the difference between the hole and bolt radius. The vast majority of the millions of resin roof bolts installed each year in the United States employ an annulus between 0.125 and 0.188 inch. As the annulus size decreases the resin flow around the bolt becomes more difficult, increasing the resin pressure induced by bolt insertion. As the resin pressure increases the loss of resin into bedding planes and vertical fractures in the rock increases. As the annulus size increases the mixing of the resin paste and mastic becomes less efficient. Thus, the lower and upper limits of the optimum annulus size is determined by insertion pressure and mixing considerations, respectively. Previous U.S. Bureau of Mines researchers have concluded that a 0 125 inch annulus is optimal. However, others have recently reported that a 0.095 inch annulus with special rolled deformation (SRO) bolts provide superior anchorage to standard rebar with a very large 0.250 inch annulus, attributing SRD resin loss in weak ground to oversized holes. The effect of annulus size on unit length pull strength and resin loss to fractured rock was investigated. Short encapsulation pull tests with resin annuluses of 0.125 and 0.095 inch resisted an average of 2.25 tons per grouted inch, with no significant variation. However, annulus size has shown a dramatic effect on the magnitude of resin lost to simulated rock fractures. No. 5 standard . No. 6 standard, and No 7 J-Bar rebar were inserted into two different viscosity resin cartridges designed for 4 foot boll encapsulation into a one inch inside diameter metal tube, To simulate a rock fracture, a 0.250 inch diameter orifice was located near the capped end of the tube Resin loses increased as annulus size decreased, with a minimum loss of 35% and a maximum loss of 60% associated with 0.125 and 0.095 inch annuluses, respectively.

Jan 1, 1999

By John Conway, Gerald Bennett, John Herrick

Research efforts which have led to reduced resin bolting costs at White Pine Mine are described. Key factor was development of the capability to drill small holes (1 1/8 in. diam) in the hard (20,000-30,000 psi) White Pine roof rock. Economic data comparing the 1 1/8 in fully-grouted Resin Bolt to the conventional 1 3/8 in fully-grouted bolt is also included. The development of a method which allows the Resin Bolt to hold itself in the hole thus removing the requirement for the operator to break his "work momentum" while he stops and waits for the resin to set is also described. This technique increased bolter productivity by 23% in a recent full-scale unit test.

Jan 1, 1974

Roof bolting with resin bonded bolts has been developed extensively in French coal mines. There are three aspects of this development: 1. The reason for and the care used in the development of roof bolting from use as a reinforcement in a classical arched roadway to use as the only support in roadways in ad- vance of the working face (the roadway being reinforced behind the face); 2. The problems encountered and studied, such as choice of boltable roadways and determination of the technical data in designing a roof bolting pattern; 3. Only because roof bolting has been controlled by safety rules, and especially by accurate measurement of strata behaviour, has this system of support been expanded aapidly in France since 1967.

Jan 1, 1971

By I Thin, I Sheppard

Resin encapsulated rock bolting practices have been adopted by Mount Isa Mines since the early-1980s. Fully encapsulated rock bolt systems meet designated requirements for long-term ground support in the mines. A variety of rock bolts, resins and installation methods have been utilised over this period in underground mining. As a parallel to this evolving application, Mount Isa Mines have tested various resin encapsulated rock bolt systems. Testing has included routine underground pull testing and the development and implementation of the push test for the entire encapsulated bolt length. The latter test enables a greater understanding and representation to be had of the overall mixing, level of encapsulation and capacity of the system. Rock mechanics at Mount Isa Mines undertake evaluation of new bolt systems that become available, in addition to the maintenance of compliance with quality control measures for the existing systems. Improved methods of installation and systems are also investigated to further the cost-effective nature and minimise risks associated with resin rock bolt practices.

Jan 1, 2002

By W. B. Beerbower

Resin bolting has enjoyed wide acceptance for coal mine roof support. Beginning in 1973, the first year of significant resin bolting in coal mines, we estimate that 2.5MM resin bolts were installed. This grew to 7MM resin bolts in 1974 and 13MM in 1975. Resin bolts are currently being used in over 300 coal mines throughout the major coal producing areas of the U.S. and barring major work stoppage we expect more than 17MM will be installed in 1976. Although not a cure-all, the number of unintentional roof falls occurring in many mines has been dramatically reduced as a result of converting to this "new" method of support. 1 The improved anchorage strength of resin bolts provides better roof support. (Slide #1) This anchorage strength provides a mechanism to resist changing roof stresses along the entire length of the fully grouted resin bolt, thereby assuring stabilization of rock strata over long periods of time. The ability to resist roof displacement is borne out by readings obtained from strain gauged bolts. These findings can be summarized as follows.2

Jan 1, 1977

By S. C. Tadolini, J. M. Goris, J. L. Gallagher

Cable supports offer several advantages over traditional secondary support methods by enhancing stress redistribution to pillars and gob areas, minimizing or eliminating timbers and cribs that reduce ventilation, eradicating material-handling injuries related to placement of crib supports, and providing a cost-effective alternative to secondary support. The U.S. Bureau of Mines (USBM), researching alternatives to traditional roof support methods, designed and installed high-strength cable supports to improve the stability of longwall gate road entries in a western U.S. coal mine. With the cooperation of industry, methods were developed to install and evaluate cable supports in a tailgate area using traditional resin cartridges. The cable-bolted areas successfully maintained roof support throughout the developed entries. Cable supports have replaced wood cribbing as secondary support in the bleeder entry system and have minimized or eliminated the use of cribbing in the longwall tailgate entries. This paper describes the theory, application, and advantages of cable supports and presents some mine measurements made to assess the cable performance during the retreat process of longwall mining.

Jan 1, 1999

By Stephen C. Tadolini

The U.S. Bureau of Mines (USBM) is conducting research to provide alternatives for traditional secondary support methods. These cost-saving methods are proving to afford safer installation, improve entry stability, eradicate material-handling injuries associated with crib supports, and enhance ventilation. In cooperation with Mountain Coal Company, the USBM replaced timber cribbing with high- strength cable supports to provide stability in a gate road that was used for two longwall panels. The support design consisted of 2.1-m (7-ft) full-column resin-grouted bolts and 4.8-m- (16-ft-) long high-strength resin-grouted cable supports. Three support concepts were evaluated: passive, stiff, and tensioned systems. Cable loading and roof deformations were monitored to evaluate the behavior of the immediate and main roofs during panel extraction. The stress and loading histories for both panels and the abutment and yield pillars were monitored to assist in evaluating the stress transfer and pillar performance in conjunction with the roof behavior. The test results indicated that resin- grouted cable support systems successfully maintained the immediate and main roofs during the extraction of two longwall panels. This paper describes the theory, application, and advantages of resin-grouted cable supports and presents the mine measurements made to assess the cable performance during the retreat process of longwall mining.

Jan 1, 1994

By J. B. Hiskey, V. P. Atluri

Resin-in-leach (RIL) cyanidation experiments were performed on a refractory carbonaceous gold ore. The objective of this investigation was to determine if strong-base ion exchange resins could adsorb the soluble aurocyanide complex in preference to natural "preg robbing" organic constituents. Direct cyanidation of the carbonaceous gold ore used in this study resulted in less than 2% gold extraction in 24 hr. RIL cyanidation resulted in about 70% gold recovery onto the resin. Kinetic experiments indicated that 50% of the gold is extracted after 1 hr of leaching. Resin breakage was investigated for as-received and preattrited resins. Similar results were obtained with three different strong base resins.

Jan 1, 1990

By Gregory Owen Lewis, Wendy Bouwer

Various processing strategies have been implemented in an effort to limit the loss of gold, during leaching, to the naturally-occurring carbonaceous 'preg-robbing' constituents present within certain gold bearing ore sources. Certain processing routes include complex and costly pre­treatment steps to reduce the negative effects of the preg­robber prior to dissolution, while others adopt a simpler direct leach/recovery approach. Process selection is largely dependent upon the gold deportment and the nature of the preg-robbing constituents within the particular ore. In the case of carbonaceous ores in which the bulk of the contained gold is available to direct cyanidation, carbon-in­leach (CIL) technology is generally applied with varying degrees of success. The effectiveness of the CIL route is governed by the competitiveness of the preg-robbing constituents in relation to activated carbon for the preferential adsorption of the solubilized gold. Trials have shown that the DOWEX MINIX strong-base gold-selective ion exchange resin has gold loading characteristics superior to those of activated carbon. The faster gold loading kinetics, together with the higher capacity of this resin, favour its use in an in-leach application as a more effective adsorbent for complex ores. This paper introduces the alternative resin-in-leach (RIL) technology, compares the metallurgical responses to RIL processing of different problematic ore sources, and discusses the interaction between various process conditions. Selected results from laboratory and pilot-scale testwork are presented to highlight the discussion.

Jan 1, 2000

"This paper reviews the chemistry involved in the recovery of gold from cyanide solution with anion-exchange resins, and also discusses the most critical aspects of the engineering of an effective resin-in-pulp (RIP) process. As far as the chemistry is concerned, the conclusions reached by a great many researchers, as well as the performance of the only operating RIP plant in the Western World, at the Golden Jubilee Mine in South Africa, support the view that the process is technically viable and, in many cases, could prove to be more attractive economically than alternative processes such as zinc cementation and carbon-in-pulp (CIP). On the engineering side, there is still a need for further development before larger scale ( > 50,000 tpm) RIP plants can be designed, built and operated with confidence. However, the experiences gained during nearly 3 years of operation of the Golden Jublee RIP plant indicate that the process can be engineered with confidence for smaller operations ( < 50,000 tpm), and this will probably be the scope of application of the first-generation RIP plants. INTRODUCTIONThe use of anion-exchange resins in gold processing has, for a number of years, been proposed as an alternative to more conventional processes such as zinc cementation and carbon adsorption, and detailed research programs that have been carried out at a number of laboratories have demonstrated the technical viability of the process. (Burstall et al, 1953, Davison et al., 1960, Tataru, 1973, Laskorin et al. 1978, Hosking, 1984, Riveros and Cooper, 1987 and Palmer et al., 1988)The main incentive for this work was the fact that resins have several characteristics that are quite different from carbon, which make them potentially more attractive substrates for the recovery of gold. The following are examples: -"

Jan 1, 1991

"Some of the tools developed for the processing of nickel laterite ore by resin-in-pulp (RIP) may be applicable to the remediation of metalliferous mine drainage (MMD). In both cases, recovery of metal value and production of a stable waste stream appropriate for long term storage is desired. MMD typically has the additional challenge of management of toxic low-value metals. Seen in this light, innovations in RIP reactor configuration, selective elution strategies and novel synthetic ion exchange resins become useful tools for taking on the MMD challenge in a way that maximizes both environmental and economic benefit. INTRODUCTIONAcid mine drainage (AMD) is a common problem in any country with significant past mining activity. When sulphide containing minerals, tailings or slag are exposed to water, oxygen and sulphur oxidizing bacteria, AMD will result. Abundant and reactive iron sulphide minerals leach first, providing acidity and the ferrous/ferric couple that can enhance the oxidation kinetics of other minerals. If this runoff contacts encounters acid consuming carbonates or silicates, the acidity may be neutralized, but certain heavy metals remain in solution and can continue to be an environmental hazard (Gray, 1997). For this reason, the remainder of this paper will refer to the broader term metalliferous mine drainage (MMD) rather than acid mine drainage. In either case, such drainage, containing high heavy metal concentrations and often significant acidity, is toxic to aquatic life and can lead to significant damage to ecosystems and to public watercourses. MMD is a problem most commonly associated with now defunct sulphide mineral mines, but similarly toxic streams can result from many types of waste, such as poorly stabilized leach tailings, slag heaps, and coal flotation tailings (Johnson and Hallberg, 2005; Lee et al., 2002; Sainz et al., 2002; Schüring et al., 1997). In any case, the management and remediation of MMD is an important ongoing problem for the resource industry, particularly for the many mines in Canada closed before the advent of more stringent environmental standards. MMD remediation represents a significant long term expense for the resource industry. Multi-disciplinary efforts to understand and mitigate this problem range from creation of artificial wetlands (Poulin and Lawrence, 1996; Sheoran and Sheoran, 2006) to sophisticated biochemical reactors and precipitation processes (Hatami, 2010). Certain remediation technologies such as ion exchange offer methods to make a saleable product by recovering valuable dissolved metals. This paper will show how these technologies can help defray the cost of remediation, and offer potential to turn a dangerous waste stream into a useful product."

Jan 1, 2012

By G. P. Richards

RIP is the process of recovering uranium from an unclarified slime pulp which comes in contact with a moving bed of ion exchange resin, T e sand-slime separation of the acid-leach slurry is accomplished through the use of cyclones and spiral, akins type classifiers. Course sands are discarded to tailings and the combined slimes and leach liquor become the IX feed. Uranium in the IX feed is absorbed on the resin and after exhaustion the barren pulp is directed to tails, Following the uranium exhaustion cycle an eluant solution passes through the resin bed stripping the uranium from the beads, The uranium is precipitated from the clarified pregnant eluant, filtered, dried and packaged for shipment to the AEC, Normally, the ore received at the Mines Development plant is a loosely cemented sandstone containing small quantities of clay and bentonite, The ore is easily crushed and requires only a 1/3 load of rods in the rod mill to reduce the ore to grain size, Very little of the ore is recirculated by the 42" spiral classifier.

Jan 1, 1958

By Huang Kong Xuan, Li Yun Teng

Reviewing the development of resin-in-pulp (RIP) technology for the extraction of gold in the world, especially in South Africa and USSR, and the chemistry of interaction between aurocyanide ions and anion-exchange resins. RIP benchtest and pilot plant investigations show that the resin of the weak-base and strong-base can absorb gold in the cyanide pulp and gold can be eluted from the strong-base resin by electro-elution. The possibility of future application of RIP technology in China fa also briefly discussed.

Jan 1, 1998

By Brian R. Green

Resin-in-pulp (RIP) technology has been developed for recovery of gold. It is now time to look forward to the potential for application of the technology to other situations. Some cases have been identified and have merited preliminary testwork. Four examples, which illustrate the potential of RIP, are dealt with in this paper. These include removal of metal-cyanides from pulps, recovery of manganese that is difficult to wash from filter cakes, recovery of nickel from low grade pulps, and recovery of zinc from process residues. The discussion includes descriptions of the problems, factors that affect the choice of resin, and factors that will affect the economics of the process.

Jan 1, 1998

By Ke Yang

Drilled shafts are widely used as foundation system for sound walls to resist lateral loads. The design method based on the ultimate lateral capacity, such as Broms method, is often used for sound wall foundation design. Allowable Stress Design (ASD) is currently used for deep foundation design. However, by October 2007, all states Department of Transportations are required to use the Load Resistance Factor Design (LRFD) approach for the design of foundation in highway projects. There is a need to develop a calibrated resistance factor in LRFD lateral design of drilled shafts supporting sound barrier walls. This paper provides resistance factors for design of laterally loaded drilled shafts supporting sound walls using Broms method based on the study using reliability based method and fitting to ASD method. Additionally, the resistance factors for static lateral load tests are recommended. Furthermore, a methodology to update the resistance factors using Bayesian approach by incorporating the on-site full-scale lateral load test results is presented. To illustrate the Bayesian update methodology, two lateral load tests in Colorado were employed to develop the updated resistance factors.

Jan 1, 2007

By William Griffith

THE purpose of this paper is to make public record of new information in regard to the sustaining power of artificial mine-roof supports (not timber props) the result of investigations recently made in the anthracite coal fields of Pennsylvania. First.-By the "Scranton Mine Cave Commission," appointed to investigate the mining conditions under the City of Scranton. Second.-By the "Pennsylvania Mine Cave Commission," appointed by the Governor to investigate the general subject of mine caves in the anthracite region of Pennsylvania. Third.-By the personal researches and tests made by the author in an effort to secure a better artificial mine-roof or surface support. During the progress of the work of the Scranton Mine Cave Commission, the Engineers for the Commission, Messrs. Conner and. Griffith, being aware of the general lack of exact information in the engineering profession as to the strength of the ordinary artificial mine-roof or surface support, and particularly the stronger kinds, such as mine cogs, rock piers, etc., had tests made at the. Fritz Engineering Laboratory at Lehigh University, to determine the sustaining power under various compressions of the several kinds of artificial mine supports in use in the anthracite region of Pennsylvania. A report of these tests was included in the report of this Commission, which was published as Bulletin No. 25 of the United States Bureau of Mines, Washington. A similar series of tests, more extensive and more elaborately-planned, were subsequently made for the Pennsylvania Mine Cave Commission at the U. S. Government Testing Laboratory at Pittsburgh, Pa. The report of this Commission was made to the Governor, but has not yet been published.

Jan 10, 1917

E.T. CONNER;. Scranton;. Pa-I had the honor of being associated with Mid. Griffith in an investigation of the Scranton mine cave problem several years ago; in the course of which we investigated rather carefully the bearing strength of various materials that might be utilized for, the support of over We found that there were no reliable data as to the resisting strength, for instance, of gob pillars or timber cogs or cribs, nor as to the amount of compression that might be expected under a given burden. We made a series of tests at the Fritz engineering laboratory of Lehigh University, from which we, reduced certain conclusions, subject, however, to further test before they could be definitely recommended. Onr study of the subject was later checked by a commission appointed by the Governor of the State of Pennsylvania, to investigate the same subject the subsidence of the surface, and the danger entailed thereby. The State, commission made a series of tests on a much more ambitious scale at Pittsburgh, in the laboratory of the U. S. Bureau of Mines, and their tests agreed quite closely with those that Mr. Griffith and I had made. As the result of our study, we determined that the most elastic support is the ordinary timber cog or crib, while the most rigid support is a

Jan 1, 1918

By H. A. Bedworth

ALLOYS of copper and silicon have been known for one hundred years or more but the commercial development of this type of alloy has taken place during the past few years. In 1905, Sperry1 proposed the use of copper-silicon alloys for springs and other purposes for which copper-tin bronzes were used. Some attention was given to this proposal at the time but no one succeeded in producing a practical alloy containing more than a fraction of a per cent. of silicon. The equilibrium relations of the copper-silicon system were studied first by Rudolfi2 and later by Sanfourche3 and Corson.4 The constitution of the system has also been recently investigated by Matuyama,5 and in the laboratories of the American Brass Co. by Smith.6 Some of the physical properties of the copper-silicon alloys have been investigated by Norbury7 and by Geiss and Van Liempt.8 Summarizing the results of various investigators of, the constitution of copper-silicon alloys, the solubility reaches its maximum value, 6.7 per cent. silicon, between 721° and 782° C. At 852° C. the solubility is 5.25 per cent., while at 400° C. it is only 4.1 percent. silicon. The copper-silicon alloy begins to get so hard at about 3 per cent. silicon that it is difficult to manage. It was found by Jacobs that the addition of manganese to this alloy considerably improved the working

Jan 1, 1929

By G. B. Misra

Though installations of main mine fans vary widely, the commonest installation is of a surface exhaust fan connected to an upcast shaft some distance below its collar by a horizontal fan drift bending sharply. downwards near its junction with the shaft. The junction of the fan drift with the shaft often causes considerable shock pressure loss if not properly designed. In one of the major coal mines in India circulating 180 m3/s of air through the mine a pressure drop of 229 Pa out of the total fan pressure of 568 Pa occurred at this junction while in a smaller gold mine circulating 9.4 m3/s it was 147 Pa out of a fan-drift pressure of 382 Pa. With larger mines circulating larger volumes of air, ill designed fan drifts can lead to considerable wastage of the power of ventilation. Shock loss at the junction of fan drifts with exhaust shafts depends on (1) the angle of deflection of the bend, (2) sharpness of the corners (both inner and outer) at the junction, (3) the degree of contraction of the flow-stream which depends on the cross- sectional area ratio of the shaft and the fan drift as well as the amount of leakage through the shaft collar. It must be noted here that the friction pressure loss in the bend is negligible compared to the shock pressure loss.

Jan 1, 1980

By T. L. Joseph

THE United States Bureau of Mines has been studying the blast-furnace process for, about ten years. An experimental furnace was developed by the bureau in cooperation with the Minnesota School of Mines Experiment Station, University of Minnesota. Many data have been obtained and published.1 Royster, Joseph and Kinney§(48) found that the particle size of ore had an important effect upon the blast-furnace, process. Kinney(28) stated: Economy in blast-furnace practice depends largely upon efficient gas-solid contact in the shaft of the furnace. If efficient work is not done in the shaft, the hearth and bosh will not function properly. A condition may be readily imagined where the particles of ore in the shaft are so large that the time entailed in the descent of these materials into the bosh is not sufficient to permit proper reduction and preparation prior to the time the ore enters the bosh of the furnace. Another condition may be pictured where the density of the stock column and the flow of stock is such that the ore will take one course and the gas another. Both of these examples will result in insufficient contact between the gas and the ore. Unreduced ore will reach the hearth, and the gas which has not been efficiently oxidized will reach the stock line. The result is the use of an excess of carbon in the smelting process. It is obvious that fine ore particles occurring in the ore as charged, or . formed in the furnace due to heat and mechanical action, place a definite limitation upon the efficiency of the operation. There is also an economic loss of fine material as dust.

Jan 1, 1930