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By Gordon Jackson

"There are two accomplishments of air and gas drilling: a new series of economic and mechanical challenges; and, acceptance as a standard drilling and completion tool.The new challenges are related to the concept of using a gaseous circulating medium in drilling for oil or gas. For purposes of discussion, a two part division has been made: the challenge of fluid invasion control and that of equipment and tools. Great strides have been made in the development of materials and techniques to combat formation fluid invasion. Chemicals and the ""mist drilling"" technique, now in use, have the versatility to cope with a wide range of downhole fluid entry conditions.Equipment and tools have been developed to meet the challenges of better, more economic drilling and completion possible with a gaseous circulating fluid. Economic and operational challenges remain.Acceptance of air and gas drilling as a normal operating tool was reached with difficulty. It is now established as a means of reducing costs in exploratory and develop-mental well drilling, exemplified in a recent study of 226 wells covering 419,407 feet of hole in the United States. Air reached the projected depth in 85 per cent of the operations, although formation water was encountered in 48.7 per cent of the holes. Slim hole bit performance and cost all compared for overall bit averages as part of analysis."

Jan 1, 1961

By R. L. Virta

Four companies mined ball call in four states in 2009, H.C. Spinks Clay Co. Inc. (owned by Lhoist Group), Kentucky-Tennessee Clay Co. (owned by Imerys Group), Old Hickory Clay Co. and Unimin Corp. Production, on the basis of preliminary data, was 820 kt (904,000 st) with an estimated value of $39.4 million. That was a 15-percent decrease in tonnage from 967 Mt (1.1 mil-lion st) with a value of $44.3 million that was produced in 2008. Tennessee was the top producing state with 59 percent of domestic production, followed by Texas, Mississippi and Kentucky. About 71 percent of production was airfloat, 18 perc

Jun 1, 2010

By Raymond Rivera

El presente texto describe la evaluación desarrollada por INGEMMET donde se analiza el potencial de los depósitos minerales en el Batolito Andahuaylas, Yauri, así como el potencial de algunas zonas que presenten características geoeconómicas importantes, utilizando herramientas geológicas como geocronología, isótopos radiogénicos, geoquímica de rocas y sedimentos, petromineralogía y geología estructural.

Sep 12, 2011

By A Brzovic, E Córdova

In an underground mine, different mining activities such as undercutting and cave progression generate redistribution in the present in situ stress field, and these changes are represented in the rock mass through induced seismicity.In order to study and analyse the induced seismicity generated in El Teniente, a block model was developed to account for the dissipated seismic energy through different areas of the mine from 1992 to 2015. More than 2.1 million seismic events were unified and classified in 3D in order to be used for the interpolations. The resultant model variables account for the accumulated energy releases in a monthly time resolution, and provide the ability to intersect different 3D entities with the stored information in the blocks, and estimate the energy evolution inside these entities.The generated model was used to analyse the geotechnical variables that determine the seismic response for the rock mass in the mine, such as geometry and direction of advance of the undercut fronts, lithological domains, and to study the ‘work’ the rock mass needed to go through in order to generate caving in areas with different stress settings.A specific area of the mine under high-stress conditions was analysed by studying the seismic energy associated with two subsidence caves interacting around the project, the modelled lithology. Using the same approach two adjacent projects are analysed to understand the released energy from the rock mass based on different stress and geotechnical settings for each project.CITATION:Córdova, E, Brzovic, A and González, R, 2016. Analysis of progressive seismicity and its correlation with geotechnical variables at the El Teniente Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 835–844 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By J. G. Henning

Following completion of planned mining operations at the Goldcorp Dome Open Pit Mine, a high-grade Shaft Pillar located in the pit highwall was recovered. Mining of this Shaft pillar faced numerous rock engineering design and implementation challenges due to its remote position on the highwall and the presence of mine workings within the wall. The case example presented in this paper discusses the geotechnical investigation performed at the site, novel measures undertaken for installation of ground support required for rockmass reinforcement and for worker protection, as well as operational challenges to successful mining of the Shaft Pillar.

May 1, 2009

By Tristan H. Jones

Beginning in 1987, miniature dataloggers approved by the Mine Safety and Health Administration (MSHA) were publicly available for sale. The principal among these was the model CR21XQM, manufactured by Campbell Scientific, Inc. These dataloggers had been tested and were deemed permissible by MSHA and thus could be installed in the return air of an underground coal mine. In 1996, production of all permissible Campbell Scientific dataloggers ceased due to lack of sales. Data collection with these dataloggers has been a staple of ground control research in the United States for decades, and, without them, or a replacement, the capability to monitor ground behavior is severely impacted. Since that time, any party requiring a permissible datalogger has needed to borrow one that was purchased during the production years. In order to fill this technology gap and ensure its own data-gathering capabilities, the National Institute for Occupational Safety and Health (NIOSH) has developed and refined its own miniature data acquisition system (MIDAS). On February 16, 2010, MSHA deemed the MIDAS to be permissible and approved it for use in the return air of an underground coal mine. The MIDAS is an intrinsically safe, 16- or 24-bit datalogger, compatible with a wide range of resistive, single-ended, and differential-type instrumentation. It contains enough data storage memory to operate for over a year with typical data rates and is efficient enough to do this on a single C-sized alkaline battery for that entire period. It is menu-driven and requires no programming knowledge to operate. It supports wireless or hardwired communication for datalogger setup and data download. This paper describes the design, field and laboratory testing, and capabilities of the MIDAS datalogger. While not as fully -functioned as the CR21XQM, it is the only new permissible datalogger available, and there is intent to make it available to the mining industry for purchase.

Jan 1, 2012

By D Crequer

A Peer Review Panel for the Golden Cross Mine in the upperWaitekauri Valley, Coromandel was initiated in December 1989, before mining, as a requirement of the conditions of the Mining Licence and Water Rights. The panel's function is as a technical audit and advisory team - to provide independent technical review of design, construction, and execution of mining operations, slope remediation works, and reclamation/mine closure activities. The primary role of the panel is to act in the public interest by providing assurance to regulating authorities that the design and application of on-site mining operations accords with 'good industry practice'. Panellists are not involved in design nor as advisers, although until 1997 when explicit terms of reference were written, the panellists were a sounding board for some operational proposals. The panel functions to ensure that best mining industry technical standards are met. The costs of the peer review process are met by the mining company. Review of mining operations includes environmental matters such as land rehabilitation and water quality. The focus of this paper is on the process of peer review for environmental management factors rather than for structural and mine engineering.

Jan 1, 1998

By Sakai Kunito, Nigel B. Sugden

If an Earth Pressure Balance (EPB) TBM is operated effectively tunneling can be carried out producing negligible ground movements. Using the methods given in this paper face losses of the order of 0.5% and less are generally obtainable using an EPB. Operating the EPB TBM in this manner reduces the requirement for the building protection measures used to protect surface structures. This can result in a considerable cost saving for the construction of a tunnel under built up areas. This paper to give guidance on the causes of ground movements around a TBM and the methods of running an EPB TBM that will minimize those movements. Details of how this was successfully done during the construction of the Bangkok Metro are given. The paper is split into three parts as below. 1.Causes of ground movements due to TBM tunneling 2.Methods of controlling those movements using an EPB TBM 3.Case history Bangkok Metro (water main)

Jan 1, 2001

By R. R. Sayers

That the maintenance of proper air conditions is a most important factor in the control of occupational hazards is shown by the large amount of material presented each year through the technical journal's on the effects on workers of injurious dusts, gases, and variations in temperature and humidity.. SUMMARY OF RECENT LITERATURE ON EFFECTS ON WORKERS OF EXPOSURE TO DUSTS The subject of the control of dust and dust diseases continues to be a matter of serious concern in most of the industrial countries of the world, as indicated by the following summary of reports published in a number of foreign countries as well as in the United States. Australia. The Workmen's Compensation Act of 1920 for New South Wales3 provided for the promulgation of schemes for the compensation of workers dis- abled by silica or other dust. In 1924 the prevalence of silicosis and tuberculosis among Sydney stonemasons, quarrymen, sewer miners and rockchoppers was investigated by a Technical Committee of Inquiry, appointed upon the recommendation of the New South Wales Board of Trade. The findings of this committee were published by the Government in 1925. No scheme was promulgated by the Government and in 1926 the Act was amended limiting its scope to workmen disabled by disease caused by silica-dust. This was promulgated and gazetted on September 16, 1927, and applies to men working in sandstone as stonemasons, quarrymen, rockchoppers, and sewer miners in the County of Cumberland.

Feb 1, 1931

By S. Yamashita

Recently in Japan, unexpected degradation (surface subsidence) at old underground quarry sites, such as 'Ohya-Ishi' (pumice tuff) pit field has often been occurred. At these quarry sites, the excavation was started 20 or 30 years ago with mechanical chain cutter and the Room and Pillar method, and stopped 7 or more years ago. Therefore, a reliable method has been required for an estimation of long term mechanical properties of the rock and for an observation of a stability of rock-pillars or structures. In this study, creep tests under uniaxial compressive load were carried out on the 'Ohya-Ishi', with the aim of estimating the long term stability of the rock. From these results, a creep mechanism of the rock was discussed using the failure mechanism hypothesis proposed by Bieniawski and by others. On this basis, critical time to failure was predicted by the relationship between the logarithm of life time and stress ratio of the sustained axial creep load. Additionally, outline of the monitoring system of AE/MS activity in the field, which have set by the Ohya Aria Consolidate Public Corporation and the others to predict or to prevent the degradation of those residual pillars, is to be reported. Key words : Ohya-ishi, Pumice tuff, Mine pillar, Long term stability, Creep, Critical time

Jan 1, 1996

By J. I. Mathis

"The failure that was utilized for developing this model was a double bench-scale failure, approximately 20 m in height, in the Misery pit at BHP Billiton’s EKATI mine site. The bench that failed was excavated in biotite schist. Due to previous problems with bench-scale toppling failures, this bench was excavated with a 70° inclined, 30 m deep preshear. Upon exposure, the wall was very clean with half-barrels commonly observed from the pre-shear operation.In August 2003, a bench failure of about 1000 t occurred in this pre-sheared biotite schist (Fig. 1). Upon examination it was noted that the foliation that paralleled and dipped at 70° into the face when excavated was approximately horizontal at the top of the failure (Fig. 2). While the failure mode itself appears complex, the failure was apparently driven by three factors:• a low-angle, low-frictional strength fault or discontinuity at the base of the failure area;• water either contributed meteorically from precipitation and/or from permafrost melt; and• foliation planes providing a viable toppling geometry once toe block motion began to occur.The above details are illustrated in Figure 3.After considerable thought and analysis, a model was postulated for the failure.It is thought that the entire failure had been triggered by displacement of a toe block (Fig. 4). This toe block is bounded on the back by foliation, the bottom by a low-angle, lowstrength fault, and the front by the bench face. Water pressures behind the bench face developed forces on the block as can be seen in Figure 5. These forces were sufficient to induce block motion. As can be seen in the relative shear strength diagram in Figure 6, only a small amount of water is necessary in the face to initiate block displacement. Note that in this figure, a simplistic piezometric pressure distribution was assumed."

Jan 1, 2004

The cyclone, or centrifugal separator, ,is firmly established in industry as a low cost separator of solids from gases.While it will also separate fluids of different densities, and solids from liquids, its main use is to remove relatively fine dusts from gases whose pr~erties are generally not greatly different from those of air. This latter phase of operation is the one that will be dealt with here.The duty of such a cyclone separating system is to take in a supply of dusty gas and separate it into its components of dust and clean gas as perfectly as possible for the least consumption of pressure head. Any separation at all causes pressure loss and, in general, the greater the separation, the greater the pressure drop needed to effect it. The percentage of dust in suspension which is separated from the gas-dust mixture is commonly called the collection or separation efficiency. Overall or "true" efficiency must take pressure drop into account and may be considered as proportional to the ratio of the percentage of dust collected to the resultant pressure drop. For any cyclone It will vary with different dusts.Many commercial adaptions of the simple cyclone are made solely on the basis of pressure drop improvement, without taking into account the effect on separation efficiency, probably because the latter is so difficult to assess correctly. It appears unfortunate but true that the majority of such adaptions and patent gadgets fitted to cyclones which decrease pressure drop, do have an adverse effect on separation. In other' words, the true efficiency is seldom increased but often diminished.Without a knowledge of what actually goes on inside a cyclone, it is impossible fully to appreciate the real effect of a modification. For instance, it is on record that a cyclone...

Jan 1, 1949

By Chris Larsen, Ian Orford, Mike Cooper

"An autogenous grinding circuit was commissioned at the Brunswick concentrator in October 1998. The autogenous grinding circuit replaced existing surface crushing plants, fine ore storage, rod and primary ball mills. The 8.54m diameter x 4.27m long (EGL) AN1 mill is driven by a bidirectional variable speed 6.3MW ABB wound rotor motor with Slip Energy Recovery (SER) drive. The AG mill was subsequently converted to SAG operation in May 1999 for a number of reasons. The mill is operated in closed circuit with horizontally inclined 660mm diameter cyclones to produce a circuit product P80 of 85 microns. Extensive test work and JKSimMet design modeling resulted in a production circuit operating closely within design expectations.The circuit is highly instrumented and controlled via a hybrid Programmable Logic Controller (PLC-5) and Fisher PROVOX Distributed Control System (DCS) that is in communication with the property information highway. An expert control system (Gensym G2) is used for control of the SAG mill load.Engineering and construction were completed in 28 months from the time of management approval for the project. The Brunswick AG/SAG mill circuit was commissioned on schedule at the $M 23.5 forecast budget."

Jan 1, 2001

By Dan Witkowsky

For the 36th consecutive summer, the Colorado Mining Association Education Foundation and the Colorado School of Mines have sponsored “A Total Concept of the Mining Industry” for kindergarten through grade 12 teachers. Teachers from 34 states, plus the District of Columbia and two foreign countries, have graduated from the four-week course. They received six hours of recertification credit. This summer 31 teachers from Colorado, Kentucky, Virginia and Alaska completed the program. The course is unique from other shorter courses in that it solicits teachers of all disciplines from all K-12classes. In addition to the expected earth science and mathematics teachers, the Class of 2004 consisted of educators who teach music, chemistry, biology, social studies, history, basic English and world history. Others in the program included those who teach American history, physical and life science, remedial reading, consumer/family studies, “world of work,” language arts, engineering technology, environmental science, world geography, human anatomy and physiology, and business.

Jan 1, 2004

By A. M. Poston

Introduction of radioactive elements into ore samples and/or pregnant liquors and radiometric tracing thereof have greatly improved control of fusion and extraction studies on beryllium ores and products. Extractive metallurgical research on beryllium, normally guided by the usual laborious analytical methods, is both costly and slow. Recognition of this problem by the Bureau of Mines led to the development and application of radioisotope tracer techniques" as a substitute for chemical analysis at the Salt Lake City Metallurgy Research Center, The result was that much faster progress at significantly lower cost was achieved. This report discusses the problems encountered and resolved in using radioactive tracers and radiometric methods, defines the conditions and techniques for their effective use, and delineates the limitations and flexibility inherent in applying such methods in laboratory-scale beryllium research.

Jan 1, 1962

By A. More, J. M. Míguez, J. Bullón

In 2000 Ferroatlantica started a project with the aim to develop a new casting machine for silicon and other ferroalloys. Until now, it has been cast more than 25.000 tons of silicon for the chemical and metallurgical market. This system has improved the process yield, productivity and product quality which place?s Ferroatlantica at the top of technology development in this field. After the first presentation of the Ferroatlantica?s casting machine at Infacon X, we would like to show the improvements in the control which have permitted us to increase the lifetime of the copper and to obtain, at the end of the machine, the right product size for the customer avoiding the current necessity of crushing and sizing the lumpy metal. Furthermore, we have improved the system in relation to the obtaining of smaller granulometries at the end of casting machine. Not only is this kind of machine cost competitive for special silicon applications but also for other normal ferroalloys with different specifications of size and thickness.

Jan 1, 2007

By T. Mwanza, B. N. Belford, P. Conradie

"Metix has introduced a three-piece ’deep-cooled’ copper slag tapblock into a six in-line copper matte settling electric furnace. The tapblock was designed without any internal refractory; it relies purely on the development and maintenance of a freeze lining on its hot face and within the tapping channel to protect the copper and promote the integrity of the surrounding endwall refractory lining. In addition, the geometry of the tapblock further supports the sidewall refractories, reduces the impact of funnelling and, therefore, the need for premature rebuilding of the furnace endwall, and facilitates easy removal and replacement of the wear components even under ’hot’ furnace conditions. Eighteen thermocouples embedded in the copper components ensure full resolution of the copper condition, enabling plant personnel to identify wear rates, estimate freeze lining thickness and stability, and schedule replacement of spares and wear components well in advance.At the time of writing the tapblock had been in operation for 6 months with approximately 350 000 t of slag having been tapped through it. Every indication is that the design will limit the need for premature relining of the furnace endwall due to rapid deterioration of the tapblock and its surrounding refractories. IntroductionNonferrous furnaces rely heavily on the maximization of refractory campaign life to increase profitability and reduce planned downtime. In large electric copper slag-cleaning furnaces utilizing insulating linings, campaign lives of six or more years are realistic if consideration is given to each aspect that can degrade the refractory lining during the campaign. An area that is particularly vulnerable is the slag tap-hole and the local surrounding refractory. To avoid premature relining of the furnace walls, every effort should be made to consider not only the tap-hole design itself, but also the selection of the sidewall refractory material and its construction immediately adjacent to the tap-hole, and furthermore the interplay between the tapblock and this adjacent refractory. A holistic approach to the design that considers these interdependent features in the slag tapping area can reduce the incidence of accelerated refractory wear (‘funnelling’), support the surrounding refractories to prevent their collapse, introduce easily replaceable wear components that can be exchanged with the furnace still ‘hot’, and encourage and maintain a stable freeze lining at the refractory hot face that maximizes the tapblock and refractory lifetime."

Jun 1, 2019

By Federico Pagliacci, Marco Chiarabelli, Salvatore Miranda

The paper describes the adopted technologies and performance controls related to a special geotechnical engineering solution provided within the scope of the Galataport Project, in Istanbul, Turkey. The scheme is the one applied to the new quay of Salipazari, which is a combination of retaining structure and ground improvement, formed by a combi-wall, a reinforced concrete diaphragm wall and a soil improvement by deep soil mixing (Turbojet). The paper highlights the importance of employing cutting-edge technologies within the foundation engineering field and state-of-the-art electronic control devices, in parallel with the essential human expertise, in order to obtain the desired results in this high profile Project. The results of the in-situ and laboratory tests carried out on the improved soil are also presented. Main discussed points are: • History of Galataport and main Project details. • Design principle and soil condition for the new quay of Salipazari. • Difficulties encountered during execution of DSM. • Preliminary field trial tests conducted to establish the operational parameters, with relevant in-situ and laboratory tests executed. • Preliminary tests on material used for DSM (seawater and CEM IV SR). • Electronic equipment mounted on the rig, which allows the automatic execution of DSM columns. • Final QA/QC tests conducted to verify the performance of DSM, mainly consisting in: coring with relevant laboratory tests on samples (UCS + Es), seismic refraction tomography and seismic cross hole tomography. Correlations between UCS and Es, and between Es and Edyn are also presented. • A cross section of the executed treatment could be inspected on site during excavation. Photos and considerations are also presented.

Jan 1, 2018

ignitions caused by cutting tools have occurred at a rate of some 14 per year in UK coal mines since 1965, mostly on the coalface. The rate has held steady despite reducing output and number of collieries. Investigations were carried out over this period into factors affecting both the concentration of firedamp in the cutting zone and the igniting source. A study into detecting and suppressing ignitions on shearers has been undertaken and it is feasible to prevent certain ignitions from spreading outside the cutting zone. Practical measures have been adopted by British Coal to identify frictional ignition sites and to lay down working procedures to minimise risk.

Jan 1, 1988

By Jose a. Sanchidrian, Ramon G. Eguren, Javier L. Amigo

On December 2013 a MEMU exploded at a blasting site in Norway, after burning for more than two hours. This paper describes the analyses made to determine the actual yield of the explosion, the lessons learned from the event and the actions taken as a consequence. The conclusions of the analysis were the following: - The yield of the explosion was 650-1450 kg TNT. In terms of AN and ANE they correspond to 1300 – 3700 kg AN, or 950 – 2450 kg ANE or ANE/AN blend. These quantities are 8 to 31 % of the explosive precursors in the truck. The burning of the truck and its load for two and a half hours had consumed more than two thirds (perhaps up to 90 %) of the explosive precursor material.

Jan 1, 2016