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1. What Is a Rock Burst? . . . . 569 Jack Spalding . . 569 A. F. Robertson . 569 W. R. Crane . 569 G. S. Rice......569 P. J. Shenon........... 569 L. C. Graton........... 569 2. What Are the Causes of Rock Bursts? 573 Jack Spalding..........573 A. B. Yates and P. J. Shenon 574, 578, 592, 596 A. F. Robertson . . . . . 575, 595 W. R. Crane. ... 579 G. S. Rice.........582 Oscar Weiss .........582 P. B. Bucky..........582 P. H. Bird.....588, 592, 593, 595 M. K. Hubbert.........593 G. Wheeler.......... .593 B. F. Tillson........593, 595 T. T. Read............594 3. How Can Rock Bursts Be Prevented?. 597 Jack Spalding..........597 A. B. Yates and P. J. Shenon ... 598 A. F. Robertson.......599 W. R. Crane....... .602 G. S. Rice............602 Page 4. How Can Rock Bursts Be Predicted?. 602 Jack Spalding.........602 A. F. Robertson.......602, 603 A. B. Yates and P. J. Shenon ... 602 W. R. Crane......602 G. S. Rice......602 B. F. Tillson...........603 5. How Can Rock Bursts Be Controlled? 603 Jack Spalding..........603 A. F. Robertson.......603 W. R. Crane...........604 A. B. Yates and P. J. Shenon 604 Oscar Weiss........605 G. S. Rice......- 604, 609 R.D.Hoffman..609, 610 R. D. Hall..........609 R. H. Cromwell . . 609 P. J. Shenon...........609 P. B. Bucky......609, 611 B. F. Tillson.........609, 611 A. B. Yates...610, 611 P. H. Bird.......610 6. General Discussion........ 611 Jack Spalding.......... 611 R. D. Parker....... . 616 C. Baring Horwood........ 618 P. B. Bucky........... 619 Foreword This symposium brings together points of view, experiences and ideas on rock bursts from a goodly portion of the globe. Some conceptions, particularly those regarding the necessity of depth, have been fairly well shattered, as we find that they are present in the water tunnels of New York, on the surface at marble quarries in Vermont, and in the coal mines of the United States, as well as in the deep mines of the South African and Kolar gold fields, and in the nickel, copper and gold mines of Canada. Their occurrence under such a variety of conditions is, therefore, a challenge, which, if successfully met and overcome,

Jan 1, 1946

By M. K. Larson, R. G. Wade

Researchers at the National Institute for Occupational Safety and Health (NIOSH) are studying the time-dependent response of rock stressed along weakness planes. The objective is to improve mine safety by reducing the number of roof falls that cause injuries and fatalities to miners. Researchers conducted direct-shear tests on mud-stoneovercored from a coal mine roof. Results showed frictional strength weakens with displacement along the shearing planes. Results of direct-shear creep tests also showed time-dependent deformation. Test measurements were compared to classical analytical models. Results suggest that risk of roof collapse may be decreased through layout and support design to reduce creep rates and thus slow progression toward failure.

Jan 1, 2000

Industrial minerals by definition are minerals used as part of an industrial process and usually are one of a number of components, eg finely ground Limestone is an extender in the manufacture of paint. They are normally non-metallic and non-fuel, but like all generalisations there are a number of exceptions. Take rutile û a source of titanium, a metal and also the raw material in the manufacture of titanium dioxide pigment. Industrial minerals under this general definition include construction and agricultural minerals. They are included in the same grouping, principally because their sources are similar and in many cases the raw material, example limestone, can be multi-functional. Calcium carbonate raw materials such as limestone, are used in a wide range of applications from industry as an inert filler, to agriculture as a 'lime' source and to construction and as an important component in the manufacture of cement. As far as this paper is concerned I will avoid discussing the agricultural or construction applications, including burnt lime production.

Jan 1, 1985

By P. K. Narasimharaghavan

The major threat to the sustainability of Aluminium Industry is its significant contribution to global warming by way of generation of non eco-friendly gases during its production cycle from Bauxite to the finished product. Though reduction measures are taken in control and effective recovery of values from pot room gases, efforts in use of environment friendly additives in the final products production line is warranted. In this line, the present paper describes our efforts in the use of a new generation refining flux which apart from helping in effective removal of alkali metals, reduction in inclusions and ensure a better metal cleanliness shall also aide in reduction of obnoxious gases generated during the metal refining process prior to casting. The aim of the current work was to reconcile the practical results with the old generation fluxes used. Further improvements to bring in a better metal cleanliness will also be discussed.

Jan 1, 2010

Detrital gold in the Greymouth-Hokitika area has been won from: (a) gravel of the Pliocene Old Man Group, (b) glacial outwash gravel of Middle and Late Quaternary age, (c) raised shoreline deposits of Middle and Late Quaternary age, (d) deposits resulting from the erosion of (a) to (c). The source of the gold was probably widely dispersed quartz veins in great thicknesses of greywacke and low-grade schist eroded from east of the Alpine Fault, with a contribution from veins in Greenland Group greywacke in the south. At times of high interglacial and post-glacial sea level, gold was concentrated along marine shorelines, and subsequent progressive uplift has resulted in a set of sub-parallel beach leads up to 100 m above present sea level. During glaciations, gold was concentrated in outwash streams close to moraines, especially where ice forming one moraine penetrated and destroyed an older one. Worked deposits in the Old Man Group may also be associated with glaciation. Apart from workings that are essentially extensions of past workings, significant new prospects may depend on inferences as to where prospective deposits are completely obscured by younger ones.

Jan 1, 1996

By V. G. Grechanyuk

The paper presents the mechanical properties of Cu-Mo composite materials depending on the molybdenum content. The influence of structural defects on the mechanical-physical properties of the condensates at stretching testing as well as of the lamellar grain dimensions upon the mechanical properties of Cu-Mo composite materials is also presented.

Jan 1, 2008

Resonance re-emission from nickel vapour affords a convenient method for isolating the resonance lines at 3415A, 3515A, and 3524A. The vapour is generated by cathodic sputtering and is illuminated by light from a nickel atomic spectral lamp. The resonance lines thus isolated can be usefully employed for absorption measurements on mineral samples where the nickel concentration is too high for measurements with the more sensitive line at 2320A. A spectrophotometer employing a resonance lamp as monochromator possesses several advantages where a great number of determinations are made under routine conditions. The wavelength setting is stable under even the most rigorous conditions and with the provision for automatic setting of full scale deflection the instrument requires virtually no adjustment. The instrument has been used under routine conditions for the determination of nickel (in the range O· 05-2 per cent) in mineral samples.

Jan 1, 1968

By Elmer Stewart, Richard May

"The Central Mukur deposit was discovered by the Semipalatinsk Geological Exploration Expedition (GEE) during detailed searches from 1977 to 1980. Andas Altyn Ltd., a Kazakhstanian gold mining company acquired the property and commenced mining in 1995. In 1998, Andas-Altyn Ltd. became a wholly owned subsidiary of Eurasia Gold Corporation.The Central Mukur gold project covers a linear series of parallel, discontinuous zones of near surface oxide gold mineralization that covers a distance of 7 kilometers and extends past the property boundaries. The oxide gold mineralization is a result of the regional oxidization of a primary sulfide gold mineralization emplaced in a series of shallow dipping thrust faults. Resources as calculated by the GEE are 3.45 mt at an average grade of 1.84 gmt Au in the C1 +C2 category and 7.52 mt at an average grade of 1.80 gmt Au in the P1 category. The Central Mukur Gold Heap Leach Mine consists of an open pit, heap leach pads, and an ion exchange resin gold recovery plant. Limited gold production (<2,500 ounces/year) has been achieved over the past three years leaching run of mine oxide gold mineralization. Gold recovery utiling cyanide to dissolve the Au and ionic resin technology to recover the Au for the leachate is approximately 60%. Loaded resin is shipped to a treatment plant at Almaty where the gold is stripped from the resin, refined and sold.This paper will describe the geology, mining, and processing of the Central Mukur ore. In addition, it will describe what it is like doing business in Kazakhstan and the transition from a Soviet style operation to a more western style operation.INTRODUCTIONThe Central Mukur Mine is owned and operated by Andas-Altyn Ltd. a Kazakhstanian gold mining company located in northeast Kazakhstan. Andas-Altyn is a wholly owned subsidiary of Eurasia Gold Corp., a Canadian public company listed on the Alberta Stock Exchange. The Central Mukur mine consists of a small open pit, and a heap leach operation that utilizes ion exchange resin to recover gold from pregnant solutions. In addition to the Central Mukur mine, Eurasia also owns the Myaly heap leach gold project which is also operated by Andas- Altyn Ltd."

Jan 1, 1999

Effect of Iron on ash fusion temperature and waterwall deposits FeS, H2S on tube material corrosion and erosion [ ]

Jan 1, 2005

By C. Slotta, F. Charlier, P. Blomen

"Within the energy concept of the German government, the operating time of nuclear power plants was initially extended from about 8 to 14 years. It is planned, however, that every power plant will gradually be decommissioned until 2025 and that simultaneously the amount of renewable energies will successively be expanded. According to the political state, nuclear energy is a discontinued model. Looking at the global energy market, though, an obviously opposed development can be observed. At the moment, 443 nuclear power plants are running worldwide and further 62 facilities are being built. These about 500 nuclear power stations have to be supplied with nuclear fuel right now and in the future. The present paper will describe the worldwide use of nuclear energy, the extraction of the nuclear fuel uranium and in detail the available and predicted resources of uranium. The conclusion of the paper is the statement that uranium as nuclear fuel is no scarce resource but sufficiently available."

Jan 1, 2011

By Kazunori Matsushita, Frank Vespi, Emi Walder, Mitsuo Nozu

During the runway expansion project at the Fort Lauderdale-Hollywood International Airport in Florida (FLL project), therewere complicated geotechnical issues with a number of cavities in the limestone-loose sand mixed ground thatexisted in many areas below the existing ground. Collapsing the cavities and compacting the runway foundation to secure the take-off and landing of aircrafts was a necessary requirement for the project. The Mammoth Vibro-Tamper (MVT) which produces less vibration and noise level, was proposed and accepted as the alternative to the originally specified Deep Dynamic Compaction (DDC) for the runway with its length of 1.5 miles and area of 570,000 square yards. In this report, the shallow compaction effect and reduced ground vibration with the MVT are presented in comparison with the DDC which was utilized on the same project in a different area of the airport. INTRODUCTION MVT was developed by Fudo Tetra Corporation in the 1960’s and has been widely used in Japan (more than 14,400,000 square yards). For example, at the Kansai International airport, a large area including aprons was compacted with the MVT. It is capable of compacting up to approximately 5m in depth by using a heavy steel plate (3m x 3m) and a strong vibrator motor (V-180, 10Hz) on top of the steel thick plate with specified time duration. We were involved in densification work with the MVT at the Fort Lauderdale Airport Project (Figure 1) from June, 2012 to February, 2014. Deep Dynamic Compaction (DDC) was originally specified as the compaction method to secure the relative density over 70% in every 2,000 square yards grids, however, we proposed the application of MVT to reduce the vibration risk and it was accepted as the alternative (Figure 2). The compaction work was completed in February 2014, without causing any delay in regard to the residual settlement due to the high embankment (H=60ft=18m).

Jan 1, 2018

The Barmac autogenous crushing mill is one of the most successful new comminution technologies to become available to the mining and industrial minerals industries in this decade. &nbsp; The Barmac autogenous crushing mill is an innovative Vertical Shaft Impactor which operates in essence like a high intensity dry ore centrifugal pump with the reduction occurring primarily as a result of high velocity rock to rock impact in a fully rock lined crushing chamber. &nbsp; With applications in a wide range of mining and industrial minerals operations the Barmac autogenous crushing mill presents an opportunity to enhance reduction and liberation whilst providing many cost savings and production increases in new and existing plants. &nbsp; This paper briefly describes the operation of the Barmac autogenous crushing mill and reviews its benefits.

Jan 1, 1990

By M. C. Chapman, P. L. Swanson, A. T. Iannacchione

The National Institute for Occupational Safety and Health (NIOSH) evaluated microseismic activity from three field sites to compare and contrast the characteristics of microseismic emissions from very different geologic, stress, and mining environments. Recently, NIOSH has embarked on a research program to evaluate the use of microseismic monitoring information to identify roof fall failure processes and to assess its potential to warn of unstable roof conditions. Large roof instabilities, such as roof falls and certain roof caving events, have proven difficult to anticipate representing an increased risk to miners working in these inherently hazardous areas. When local failure processes are better understood, appropriate control measures can be engineered to mitigate these hazards. This study used microseismic emissions to help identify three local rock failure processes. It was also shown that analysis of microseismic emissions can aid in assessing the degree of instability associated with these local rock failure processes.

By Patricio Santis, Jacopo Seccatore

Artisanal and Small-scale Mining (ASM) is a prominent activity in the extractive industry: considering only gold, it produces about 20% of world market supply. Despite this fact, ASM is generally associated with negative aspects of its environmental impact, and operational research is generally neglected. This paper emphasizes the peculiarity of the drilling and blasting systems of small underground mines in selected South American Countries. Such Countries, while having large mineral deposits and well recognized large-scale mining activities, at the same time still present on their territory ASM activities that are archaic, highly inefficient and dangerous for the safety of its operators. This paper documents drilling and blasting activities from gold mining in Ecuador and Chile. First, are described the outdated and often non-rational techniques employed by miners, to provide a general framework of the current methods. Then, it is shown what can be improved and how the current methods can be modified. Finally, are shown some field applications and the comparisons of the results obtained. One case shows how blast pull efficiency can be increased of from 82% to 98% by changing non-rational applications of explosive products. Another case shows how, by rationalizing blast designs, drilling and blasting costs can be reduced by 9% per month, the advance by blasting increased by 29% and the blasting efficiency increased from 70% to 90%. Finally, it is concluded that examples of application show how operational improvements are easily applicable on the field, relying only on tools and resources of artisanal mining, but combining solid engineering bases with confidence-gain and respect for the experience of the miners.

By Daoxin Wu, Zhong Cao, Yan Shi, Yu Ding, Huanli Yang, Zhongliang Xiao

"2-substituted benzimidazole-zinc and 2-substituted benzimidazole-copper complexes were main components of organic solderability preservative (OSP) in PCB producing process and affect the thermal stability of OSP film. So these four complexes were prepared by 2-substitutedbenzimidazole reacting with zinc ion and copper ion, the complexes crystals were determined by IR, its thermal stabilities were studied by TG method. The results indicated that the thermal stability of 2-substituted benzimidazole-zinc is higher than the 2-substituted benzimidazole copper,and the thermal decomposition mechanism was presentedIntroductionImidazole compounds which is an important heterocyclic compound shows the important value and outstanding prospects[I-3l in field of biological engineering, medicine, and high-performance composites. It's said that imidazole compounds is an excellent new metal surface treatment[4] agent, because it has good reaction activity with metals and can form a chemical layer on the metal surface. The complexes of imidazole were main components of organic solderability preservative (OSP) in PCB producing process and affect the thermal stability of OSP film. The mechanism of imodazole combined with metal and film deposited has been reported, but the opinions about thermal stability of film have bifurcation, let alone the thermal decomposition mechanism of film at high temperature. The complexes were prepared by combining of 2- substituted-benzimidazole with zinc and copper iron, which were studied by IR and TG method, in order to get thermal stability of different complexes."

Jan 1, 2011

By D. R. Shoemaker, H. W. Judges

A 16.5-kt/d underground molybdenum mine is being developed at Questa in northern New Mexico by Molycorp Inc., a wholly-owned subsidiary of Union Oil Company of California. The new $200-million underground project will revitalize mining and milling activity at Questa, where small scale underground mining first began in 1920. Large scale open-pit mining was initiated in 1965 but now, because of the high stripping ratio, surface mining is being phased out. Construction of the underground mine began in 1979, and first produc¬tion is scheduled for early 1983. The company expects full capacity-9 Gg of molybdenum per year-to be reached in 1984.

Jan 6, 1980

By Gabriel S. Esterhuizen, Jarek Jakubec

In 2000, Laubscher’s Mining Rock Mass Rating (MRMR) classification system was updated and published. The new system brought a few fundamental changes that were in direct response to the challenges and problems encountered when applying the classification system in the mining environment, specifically caving operations. The fundamental changes introduced into the MRMR system in 2000 were the abandonment of the Rock Quality Designation (RQD) as an input parameter, accounting for healed and cemented joints, and the concept of rock block strength. The objective of this paper is not to discuss the role and usefulness of classification systems; the fact that classification systems are widely used in every stage of mining projects speaks for itself. This paper discusses some of the experiences gained with the MRMR 2000 system in various mining projects and shows how the changes to the system have resulted in improved assessment of rock mass conditions. Issues related to core logging for rock mass assessment are also presented.

Jan 5, 2007

By Sneddon N

In November, 1975, Aberdare North colliery was sealed at the surface to extinguish an open fire underground.The fire had developed from a spontaneous heating in one of the open goaf areas of the mine.The mine was re-entered with normal ventilation methods following the isolation of the working district containing the fire. The isolation was accomplished by remotely sealing the open roadways with lly ash emplaced through boreholes from the surface. A subsequent re-entry operation similarly closed the roadways close to the fire and enabled the re-opening of the sealed district.Most of the mine and the underground equipment was recovered after clearing of numerous falls and production recommenced on 25th October, 1976.

Jan 1, 1978

By M .. Hori, H. Onishi, Y. Goda

The split-lining structure was newly developed for the air-tight lining of the underground compressed air storage cavern. This structure consists of separated reinforced concrete (RC) segments and air-tight membrane. It is most important for the Compressed Air Energy Storage Gas Turbine (CAES-G/T) system to develop the economical lining. In order to verify the applicability of split-lining structure, CAES-G/T pilot plant was constructed and operated for 6 months. We confirmed the practical usefulness and safety of this system through the operation. This paper presents the mechanical behaviour of surrounding rock mass and the lining structure observed through the operation of CAES-G/T pilot plant. Nous avons mis au point une structure de revêtement modulaire pour le revêtement des cavernes souterraines hermétiques à pression. Ce revêtement est composé de segments de béton armé et de membranes hermétiques. Il était très important, pour le CAES-G/T (Compressed Air Energy Storage Gas Turbine), de développer un revêtement économique. Afin de vérifier l’aptitude d’application de notre revêtement modulaire, nous avons construit un système pilote CAES-G/T et nous avons effectué des essais de fonctionnement pendant six mois. Ces essais nous ont permis de confirmer l’utilité et la sécurité du système. A travers le présent rapport, nous rendons compte de la structure de ce nouveau type de revêtement et du comportement mécanique de la masse rocheuse environnante que nous avons pu observer au cours desdits essais. Als luftdichter Druckbehälter wurde eine gegliederte Belagsstruktur für tief unterirdisch liegende Felshöhlungen entwickelt. Diese Struktur ist aus Stahlbetonabdeckung und luftdichter Plane aufgebaut. Bei der Entwicklung des Pressluftgasturbinen – Stromerzeugungssystems (CAES-G/T) war es die wichtigste Aufgabe, einen wirtschaftlichen Belag zu entwickeln. Deswegen wurde zum Nachweis der Effektivität der gegliederten Belagsstruktur eine Pilotanlage errichtet und 6 Monate lang betrieben. Durch den Betrieb konnten wir die Praktikabilität und Sicherheit des Systems bestätigen. Dieser Aufsatz ist ein Bericht über das Verhalten der durch Betrieb der CAES-G/T Pilotanlage beobachteten Belagsstruktur und umliegenden Felsmasse.

Jan 1, 2003

Jan 1, 1966