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By Jeon Jeon, Yong-Kun Choi, Chung-In Lee, Yong-Hun Jong, Hag-Soo Kim

In this study, a computer program to design tunnel blasting pattern has been developed. The program consists of two parts; one is for tunnel blasting pattern design and the other is for blasting modeling to estimate the peak particle velocity, the distribution of fragmentation and the excavation damage zone. We modified the design method of tunnel blasting pattern suggested by Langefors because it provided undesirable pattern in blasting practices such as considerably large center cut and too large burden for Vcut as drilling length increased. As a result, the burden and spacing were reduced to practically appropriate amounts. In addition, the correlation between rock mass rate, RMR, and rock constant in blasting, c, was analyzed based on the data collected from twenty three tests of tunnel blasting. It was concluded that the correlation between them was fairly good enough to be applied in cut design. In order to check the validity of the modified methods and their practical applicability, test blasting was carried out at two different tunnel construction sites in Korea. The results were satisfactory in that the average rate of advance was 90% and the overbreak did not cause additional support. Futhermore, the developed program is capable of estimating peak particle velocity by using (a) the existing vibration equations, (b) the vibration equation obtained by test blasting to check out the practical applicability of the designed blasting pattern. Feedback is implemented into the program to adjust the designed blasting pattern and control the vibration.

Jan 1, 2005

By C. H. Kats, E. G. Meiter, J. J. Bloomfield

"INTRODUCTION.Street manholes for underground power and signal circuits, and for sewers vary in size from small openings that a workman can enter, to large central vaults. As the gas hazards in manholes are similar to those in mines, the mine safety committee of the Bureau of Mines was asked whether the miners' flame safety lamp is a practicable device for indicating inflammable gases in manholes.The coal miner detects firedamp (methane or CH4) with his flame safety lamp by observing the luminous can or the increased length of flame that appears when 1.5 per cent or more of the combustible gas is present. The lamp flame also warns him of lack of oxygen by going out when the oxygen becomes less than 16 to L7 per cent. A tentative rule regarding the proposed use of safety lamps at manholes has been suggested previously as follows: ""Testing for gas: Do not enter manholes until you have .assured yourself that the manholes are free from dangerous gases, by testing with an approved safety lamp, by ventilation, or by other adequate methods."" The Bureau's committee recommended that miners' flame safety lamps are not suitable,testing in manholes because hydrogen gas may be formed therein. The flame safety lamps approved by the Bureau of Mines for use in aseous mines are safe in presence of methane and while not tested against the members of the paraffin hydrocarbon series (CnH2n+2) higher than methane they been have been used therein; the lamps should not be used in hydrogen or acetylene they can initiate explosions in presence of these gases."

Oct 1, 1925

By Carlos F. Perucca

"Potassium is one of the three basic plant nutrients along with nitrogen and phosphorus. There is no substitute for potassium compounds in agriculture; they are essential to maintain and expand food production.Potash is extracted from buried ancient evaporites by underground or solution mining. This accounts for most of the potassium produced. Another important source is brine from landlocked water bodies, such as the Dead Sea, Salar de Atacama or Great Salt Lake.About 95% of potash produced worldwide is used in agriculture. The rest is found in several other industrial uses, including glass manufacturing, soaps, plastics and pharmaceuticals.Currently, three producers: IMC, PCS and Agrium operate 8 conventional and two solution mines in Saskatchewan, five of which run froth flotation circuits, two heavy media-flotation, two run forced crystallization and one natural crystallization.Potash in SaskatchewanPotash was discovered in Saskatchewan in the early 1940’s while drilling for oil. The deposits lie diagonally across the southern plains of Saskatchewan sloping southerly from a 1,000m depth at Saskatoon to more than 1,600 m depth at Belle Plaine and up to 3,000 m in depth in North Dakota. The known deposits are massive, accounting for more than 40% of the world’s known reserves."

Jan 1, 2003

Chelopech Mining EAD and Best Available Techniques for Management of Waste Rock in Mining Activities

Sep 13, 2010

By Gordon King

The site of the First Quality Tissue plant is located on a previous paper production facility in Lock Haven, Pennsylvania. The new development, which included the construction of a tissue machine building, baled building, converting building, various storage buildings and an electrical switchgear building, required the use of deep foundation systems to transfer loads below compressible fill and alluvial soils. Loading details provided by Jacobs Engineering, the project structural engineer, detailed braced steel frame buildings with typical column loads ranging from 75 to 150 kips and slab live loads of 250 to 300 psf. As an exception to this, however, the tissue machine and stock preparation building, which had a roof height ranging up to 85 feet, had column loads ranging up to 800 kips in addition to high dynamic loads. The First Tissue plant is located in a river valley in the hills of Western Pennsylvania. To evaluate the proposed site conditions and to formulate recommendations for the structure foundations, a geotechnical study was performed by the owner. Approximately 30 borings were advanced to bedrock, with wire-line coring performed in the tissue machine building. The borings disclosed a soil profile comprising of the following:

Jan 1, 2004

By E J. Hofmann, J E. Hofmann, A J. Hofmann-Fritz

"With its Head Quarters in Perth, global heavy engineering company Hofmann Engineering is one of the largest family owned engineering companies in Australia. The company has pioneered a number of new manufacturing processes and design improvements for components of large comminution equipment.Some of these innovations are: Innovative design improvements of high pressure grinding roll (HPGR) forged steel tyres. Hofmann Engineering has developed unique patented tungsten carbide stud and edge protection designs which improve wear life and introduce quick and cost effective replacement options to further extend the life of the tyre. Development of forged fabricated mill heads using rolled and welded high tensile steel plate as an alternative to cast conical mill heads. Establishment of Australian capability to manufacture and export up to 42 ft. (12.8 m) diameter SAG mill shells. Techniques for fast track, product improved replacements of cracked or damaged mill gears, including in situ profile & wear measurements of girth gears using portable coordinate measuring machine (CMM) technology, forged rim steel and induction hardening technology. Gear and pinion mechanical drive designs to 24 MW or higher for SAG mills of 38 ft. to 42 ft. (11.6 m - 12.8 m) diameter as reliable alternatives to gearless drives.The paper presents case studies from the Australian heavy manufacturing facilities of Hofmann Engineering on large, high powered equipment for both the domestic and export markets.CITATION:Hofmann, E J, Hofmann, J E and Hofmann-Fritz, A J, 2013. Australian innovations in high pressure grinding rolls and large grinding mill manufacture, in Proceedings MetPlant 2013, pp 141-151 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013

Research of 200 m3 Self-Suction Flotation Machine

Sep 13, 2010

By B. Anameric, S. K. Kawatra, K. B. Rundman

The iron nugget process is an economical, environmentally friendly, cokeless, single-step pig iron making process. Residence time dependent process requirements for production of pig iron nuggets at a fixed furnace temperature (1425 C) were investigated. Three chemically and physically different products were produced after complete reduction to iron, depending on the residence time in the furnace. These products were direct reduced iron (DRI), transition direct reduced iron (TDRI), and pig iron nuggets (PIN). The increase in the carbon content of the system as a function of residence time was detected by optical microscopy and Microhardness measurements. Sufficient carbon dissolution for the production of pig iron nuggets was obtained after 40 minutes residence time. The pig iron nuggets produced had chemical and physical properties similar to blast furnace pig iron. They were liquid state products and slag was completely separated from the metal.

Jan 1, 2005

By G. K. Jorgenson, S. H. Chung

"IntroductionThe SABREX Blast Modelling Program was developed jointly by the companies of the ICI Explosives Group, of which C-I-L Inc. is a member. SABREX (Scientific Approach to Breaking Rock with Explosives) is a modular computer program which incorporates new technology with a number of tested programs that have been in use world wide.SABREX predicts the performance of blasts in terms of (I) fragment size and distribution; (2) muckpile profile and face velocity; (3) grade fracture; (4) collar breakage; (5) a rupture envelope which depicts crack penetration behind and beneath blastholes; and (6) a complete cost analysis including explosives, drilling and accessory costs. The predicted blast results are displayed as dynamic colour graphics and in tabular form.SABREX uses data on the detailed geometry of the drilled and loaded pattern, detonation characteristics of the explosives and the dynamic properties of the rock to generate blast predictions. SABREX blasting calculations take into account the effects that shock and quasi-static pressures exert on the rock around the blastholes. While physical effects occur very rapidly in rock blasting, it is possible to view and model the sequence of events as discrete sections.The program can be run on a microcomputer and is currently operated by C-I-L technical service staff in Canada for the use of drilling and blasting operators.Figure I is a diagram representing the modules of the program and associated technology that is used to complement the program.Any, or all, of the modules may be used in a particular study or blast optimization. Because the BOBCAT module of the SABREX program has been described in previous papers(7.8.9), this discussion will concentrate on the newer modules: CRACK, HEAVE, RUPTURE ENVELOPE and to a limited extent, KUZ-RAM, which present a more detailed picture of the blasting process.Each of these modules is discussed in terms of the information they offer the operator in analyzing the blast. Specific examples of recent usage in Canadian mining situations are included to illustrate the ability of the model to produce practical results that can assist in optimizing actual blasting operations or solving problems that do exist."

Jan 1, 1987

By R. M. Tyler

The importance of the heavy mineral sands to southern African economic well-being cannot be over emphasized. The value of the worldwide titanium dioxide industry is estimated at $7 billion. Six out of eight of the world?s proposed new project areas are in southern and eastern Africa, and a seventh at Tamil Nadu in India is partly owned by a South African company, Kumba Resources. The HMS industry can be highly lucrative; its return on capital is the best in the mining industry. There are, however, problems, particularly in the smelting technology. The often considerable affect of mining on environmentally sensitive coastal dunes is also becoming increasingly important. The medium-to long-term demand for Ti-dioxide pigment and ceramic grade zircon appears very healthy. If, as predicted, the costs of producing titanium metal can be reduced, then there is huge potential for the metal. In summary, the HMS industry is an attractive one to be in, with good returns and generally manageable risks. New business opportunities and their economic implications for Africa are discussed.

Jan 1, 2004

By Peter White

A bridge reconstruction project involved driving pipe piles for the new foundations. Disturbances within soil layers at depth caused sinkholes to open up within the construction site. After a near fatal accident, the pile driving installations were suspended. The solution involved ground im­provement through cement grouting with sleeve pipes and special grout additives to minimize migration of cement grout.

Jan 1, 1997

By R. L. Castro

Block caving methods, when operated under favourable rock mass conditions, can achieve higher production rates and lower operating costs than other various existing underground mining applications. For this reason, it has been considered the preferred method for the mining of deep and large orebodies in current and future operations around the world. One of the key aspects in the design of block caves is the selection of the production level layout, which, among other parameters, is based on the gravity flow characteristics of the caved rock. This is because gravity flow has a large impact on total ore recovery and the amount of dilution in a caving operation. Today, there are a number of computer based methods which aim to emulate the gravity flow pattern of the caved rock. In this paper, the authors present the development of FlowSiman improved model of gravity flow based on the cellular automaton approach, to estimate dilution entry, mixing and ore recovery. As part of the model development, flow simulations were conducted and subsequently compared to full-scale data collected at two mine sectors operated by Codelco Chile. The results indicate that by using proper calibrated parameters, good correlations between simulated and measured grades as well as dilution entry are obtained. The potential use of the numerical tool to evaluate drawpoint spacing in terms of recovery and dilution for block/panel caving operations is also presented.

Jan 1, 2009

By N. L. Ayres

Tendon support systems have been successfully used to stabilize excavations. Tendon support systems are routinely designed using the axial load-bearing capacity of tendons, namely the tensile strength. To attain tensile strength the tendon must be loaded along its length, which often does not occur in practice. Tendons should optimally be installed at 90° to the surface of the excavation to achieve maximum penetration depth, yet this is often not physically or practically possible, and installations at angles less than 90° occur. Furthermore, the intersection of geological features within the rock mass frequently results in complex loading situations on tendons. The position and angle at which loading occurs results in different combinations of tensile and shear forces acting on the tendon, which can impact on the support performance of each unit and ultimately the whole system. All factors that influence the support system should be understood and taken into account to ensure a sound support design. Combination loading situations are further investigated and tested to obtain a better understanding of the mechanisms involved and the effects on tendon load-bearing capacity. Tendon support units were tested at different installation angles to establish the tendon performance, mechanical behaviour, and load capacity during these loading situations. The results and outcomes are aimed at providing rock engineers with additional data and improved understanding of how tendons could perform under certain conditions.

Jan 1, 2014

By Parker A. J, Muir D. M

Solutions of acetonitrile in water dissolve water soluble copper(I) chloride. Removal of volatile acetonitrile from the resulting solutions, by distillation with low grade steam, precipitates pure copper(I) chloride. This is used to purify a crude copper chloride sublimate from the chlorination of nickel matte but is applicable to other sources of copper(I) chloride. The pure product can be converted to pure copper(I) oxide, copper(II) oxychloride or pure copper metal directly.

Jan 1, 1980

A large lab apparatus was designed using a scale-down methodology based on the design legacy of the current FLSmidth commercial forced air flotation machines. This new apparatus, along with a new test methodology, was used to evaluate new rapid prototype concepts. The apparatus was designed to monitor bubble size, power, pumping capacity, Jg, velocity profiles, froth character, and tip speed. The methodology developed follows a sequence that goes from hydrodynamic tests and solids suspension tests to a flotation kinetic test. This methodology has been demonstrated to be a good tool to determine the effect of machine design changes on flotation.

Jan 1, 2012

By Serge Ouellet

Identification and quantification of cementitious phases in cemented paste backfill (CPB) is difficult due to the fineness of tailings and the low binder content used in the mixture. Techniques such as X-ray diffraction and thermogravimetry were ineffective (mainly due to tailing mineral interference) to identify and quantify hydration products in most works reported in the literature. On the other hand, scanning electron microscopy (SEM) was used in many cases but mainly for qualitative purposes. This paper presents the development of a new approach based on a computer program (SEM-XMAP) that combines X-ray dot mapping images acquired by SEM and generates a coloured image representing the mineralogy and the microstructure of a given CPB specimen. The technique is applied to one CPB sample mixed with blast furnace slag (BFS) and acidic sulphated mixing water sampled in a mine dewatering system. The technique allowed identifying calcic matrix, unhydrated and partially hydrated BFS particles, and sulphated phases.

May 1, 2007

By Turnbull A. G

Thermodynamic calculations based on the ideal system NiO - Fe203 - H2(g) - CO(g) - H2O(g) - CO2(g) show that it is not possible to selectively reduce nickel oxide in the presence of hematite because ferronickel is the zero-valent nickel-containing product. The calculations show that temperature, reducing atmosphere composition and oxide to reductant ratio have a marked effect on the nickel content of the ferronickel alloy and the amount of nickel reporting jn the alloy. The general trends based on the calculations correlltte well with experimental observations.

Jan 1, 1980

By Larry F. Drolet

Charleston, SC is anything but boring. The city was founded in 1670 and has played a significant role throughout the history of the United States. Located along the coast of the Atlantic Ocean in the southeastern United States, Charleston was a vital city in America?s early existence. Charleston?s coastal location has helped the city become the fourth largest cargo port in the United States and earn the 2011 designation as the number one travel destination in the United States by the Conde Nast Traveler Magazine. Part of Charleston?s charm and beauty can be attributed to its historic structures and churches that line nearly every sidewalk, roadways that were laid out based on the width of horse carriages, great weather, southern hospitality and coastal living. Now imagine the challenges of installing new, or re-placing aging infrastructure, in this setting. Every shovel full of dirt, every stick of pipe and every roadway sub-surface has its own historic story to tell. For engineering minded individuals, Charleston?s infrastructure has almost as fascinating a history as its more visible surface structures. Charleston was among one of the first American cities to construct separate sanitary and storm water drainage infrastructure. This concept has roots dating back to the city?s founding and is a credit to the foresight of its founding fathers who understood the basic health differences between sanitary and storm water.

Jan 1, 2013

By Rob Thomas

Adequate load transfer is considered essential for optimum ground support and is increasingly important in weak roof and/or high stress environments. If adequate load transfer is achieved not only can this have a positive impact on the resulting roof behavior, but it may also allow the use of lower and hence more economic densities of roof support. A wide variety of post-groutable cable bolts are currently in use in the Australian coal mining industry, each of varying capacity, design, and grouting methodology. Though all of the cables are supplied with the appropriate steel specification, strength, and modulus data, the Australian coal mining industry does not have access to a comprehensive and comparative database on the corresponding load transfer performance, which is a critical problem. On the basis of the above, this paper describes the methodology and results of a laboratory pull testing program that aims to assess the impact of cable bolt design on load transfer, and specifically, the impact on the capacity and stiffness of the anchorage. As part of the testing program, 19 cables were tested including (1) plain-strand cables installed in holes drilled with 28 to 55 mm diameter drill bits and (2) bulbed and nutcaged cables installed in holes drilled with 42 to 64 mm diameter drill bits. Other parameters assessed included the significance of smooth and profiled wire, wire packing, and expanded geometry bulbs. The main results of the testing indicate that in comparison to plain-strand cables, if the cable is bulbed or nutcaged, the capacity of the anchor can increase by up to 400%, and the peak stiffness by between one and two orders of magnitude. The results also indicate that increasing hole diameter may have a positive impact on load transfer in the case of bulbed or nutcaged cables and a negative impact on plain-strand cables. No conclusive results were obtained with regard to the impact of grout strength on load transfer.

Jan 1, 2012

By Gunderson C. T

The use of carbide tipped integral drill steels and detachable bits is discussed in relation to the means of drilling or cutting employed. It is stressed that only by correct use can the full value of these tools be realised.Factors affecting carbide quality, the design of shanking steels and the requirements and techniques of brazing in inserts are considered.It is essential that the brazed jointing between carbide and steel be strong but ductile. The methods used for the manufacture of carbide tipped tools are briefly outlined.INTRODUCTIONIn recent years the application of tungsten carbide to various mining tools in the mining industry, has developed to the stage where it is now regarded as an essential item in the production of coal and metal ores. In fact it is claimed that certain mining operations would not be possible if it were not for the benefits obtainable from the characteristic properties of tungsten carbide. The advantages of this hardmetal have, to some extent, influenced manufacturers to revise design specifiations of some machines, while againsome machines have actually been designed with tungsten carbide as their basic medium for operation.In general the applications fall into the following three categories:(a) Drilling hard rock by percussive means.(b) Drilling soft rock and coal by rotary means.(c) Coal cuttingThis paper is concerned with tungsten carbide tools associated with these three activities in Australia, the effectiveness of their application and significant points in their design and manufacture.

Jan 1, 1958