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The introduction of a new mining method to Australia is not without its risks and challenges. This paper discusses the processes of planning a new operation, with particular emphasis on block caving and its Northparkes adaptation. As well as applying advanced technologies, here also is the opportunity to develop the art and science of block caving for its application to a wider range of geotechnical conditions than previously Envisaged.

Jan 1, 1995

Declines for both access and rock haulage are replacing shafts for mining relatively shallow deposits of down to 1000 m below surface. Where the orebody does not outcrop and where surface access may be restricted, it is often necessary to drive long dead end headings before a connection can be made back to surface and a ventilation circuit created. In hot tropical areas and where large diesel powered equipment is used for mining, heat may also be a problem at these relatively shallow depths. The normal design criteria based on statutory limits and good practice used to evaluate ventilation and cooling requirements in terms of air velocity, dust, gases, diesel exhaust dilution, re-entry after blasting and heat stress are described in this paper. These are then used to design and cost alternative auxiliary ventilation systems that include leakage based on general fan performance curves and typical duct systems. The implications of the current European Community recommendations regarding nitrous fumes are also briefly considered. The actual problem relates to a 2100 m long decline that may have to be extended to 3000 m long without a connection to surface or through ventilation and is located in a hot tropical area where the surface wet bulb temperatures may exceed 25¦C for more than a third of the summer period. Once the preliminary ventilation design is completed, the auxiliary ventilation system can be modelled and simulations undertaken that incorporate heat and moisture transfer routines with the objective of determining the cooling load and amount of refrigeration required. Cognisance is taken of cyclic diesel operations and the thermal flywheel effect of the surrounding rock on the wet and dry bulb temperatures resulting from these operations.A suitable modular cooling system located at the portal is described and optimised with capital and operating costs of both the ventilation and cooling systems provided.

Jan 1, 2005

By P. Malíková, I. Osičková, R. Sousedíková, P. Rys, J. Dvořáček, S. Heviánková

Each mining project goes through the same life-cycle, from prospecting and exploration to closure and post-closure periods. This prompts the question whether the closure of a mine constitutes the end of its life-cycle or whether the decommissioned mine can be employed for some other purpose. Best-practice references indicate that there are many viable options. In our opinion, the production of service water is one such option. Laboratory research was carried out on the water from a flooded underground coal mine in Ostrava- Karviná coal district, Czech Republic, concerning the production of service water from pumped minewater. The research proved the practical feasibility of service or process water production. Given the effect of global climate change with regard to water resources, good prospects for this additional resource can be assumed since the water has to be pumped in any case for safety reasons.

Oct 1, 2022

By Catherine C. Kilgore

The Bureau of Mines investigated the availability of lead and zinc from 104 domestic mines and deposits. Fourteen primary lead and fifty-three primary zinc operations with in situ demonstrated resources containing 27.3 million metric tons (t) of lead and 53 million t of zinc were subsequently evaluated. Potentially 17.5 million t of lead and 2.4 million t of byproduct zinc could be recovered from 14 primary lead operations. Economic evaluations performed in constant January 1982 dollars determined a long-run total cost per pound of recoverable commodity. Including a 15-pct discounted-cash-flow rate of return (DCFROR), 59 pct of primary lead was potentially available at or below $0.32 per pound of lead. Potentially 40 million t of zinc and 5.6 million t of byproduct lead could be recovered from 53 primary zinc operations. Ninety percent of the recoverable zinc is potentially available from currently nonproducing mines and deposits, and a weighted average of their long-run total costs was determined at $0.98 per pound of zinc. At a breakeven (0-pct) DCFROR, these non producing operations had a weighted average long-run total cost of $0.58 per pound of zinc. Sensitivity analyses illustrated that operations that recover byproducts were most sensitive to fluctuating metal prices, producing operations were more sensitive to increased smelter treatment charges, and nonproducing operations were impacted most by the DCFROR.

Jan 1, 1983

By David Smith, Bernie Martin

The Queens Bored Tunnels consist of 11,000 feet of 19'-6" inside diameter tunnels mined through rock, mixed face and dense glacial till, constructed with bolted gasketed one pass reinforced concrete liner. The tunnels are to be excavated with a pressurized face TBM, either EPB or slurry. The construction of the tunnels will require ground stabilization in the mixed face area, instrumentation and monitoring of railway infrastructure, underpinning of bridges, relocation and protection of utilities, demolition of some industrial buildings, construction of open-cut approach tunnels and emergency exits and vent plants. The purpose of this paper is to describe the scope of work, the suggested methodology and the proposed construction schedule.

Jan 1, 2005

By Rob Farnfield, William Birch, Douglas A. Anderson

In the blasting industry, even to the most safety conscious shotfirer, misfires are a constant source of concern. In the United Kingdom, there are two types of misfire, as classified by the Health & Safety Executive. Type A occurs when testing a shot before firing reveals broken continuity that cannot be rectified. However, due to the fact that a majority of quarries use non-electric initiation [i.e. shock tube] that cannot be tested, this type of misfire is very unusual.

Jan 1, 2016

By Donald Koch

The project investigated regional impacts of mining on the ground water system of the Powder River Basin by: 1) establishment of a regional ground water monitoring network, and 2)development of , set of digital computer models to simulate ground water flow and quality, ground water contributions to surface water flow and quality (i.e., baseflow), and watershed run-off and recharge. Over 100 wells were monitored for physical and chemical parameters. Data were used as input to the model; and for the development of a comprehensive data base. The basin was modeled on a regional and subregional scale using a finite -difference model employing an alternating difference technique. Two water-shed models were evaluated for their ability to provide runoff and recharge inputs to the basic ground water model. Application of the regional and subregional models using conservative mining scenarios showed that drawdowns may extend west from the mines as far as ten miles but that impacts would be insignificant on a regional scale. The watershed model could be effectively applied to small watersheds only.

Jan 1, 1982

Flawed mining studies have been major contributors to poor investment decisions in mining for many years, contributing to the long period of poor industry profitability. Most of the major mining houses have now adopted quite formal processes and quality standards for mining studies to reduce the potential for poor investment decisions in the future. Other organisations such as the World Bank also have specific requirements for particular types of studies, such as bankable studies. This increasing requirement for rigour and discipline means a highly structured and phased sequence of studies is now required along with the development and adoption of industry-wide standards in mine ventilation studies. New terms in the study process such as ?independent peer review? and ?hold and review? are assisting in this process. More traditional terms such as ?feasibility study? and ?pre-feasibility study? now have much more precise technical definitions. Specific standards for the ventilation components of the various phases of a mining study are proposed in this paper.

Jan 1, 2009

By D. J. McLaws

"Recent innovations in metal smelting technology utilize continuous oxygen-enriched smelting and converting processes which are capable of producing off-gases containing up to 60% SO2 or more. Other SO2 recovery processes, involving solvent absorption and steam or vacuum regeneration, can produce off-gases with SO2 concentrations nearing 100%.Processing of these high-concentration SO2 off-gases in conventional sulfuric acid plants can cause excessively high catalyst bed temperatures and poor SO2 conversion. In order to avoid these problems, a conventional acid plant design must dilute these high SO2 process gasses with dilution air in order to provide the required oxygen to effectively convert the SO2 and provide a heat sink (via the inert N2) such that the exothermic reaction, SO2 + ½ O2 ???SO3, does not exceed the temperature limit of the catalyst or the converter vessel.MECS, Inc. (MECS) has proven that a high SO2 feed gas design can be a viable option which can increase energy recovery, reduce energy consumption and potentially reduce capital costs."

Jan 1, 2014

By H. Allenius

Today, most requests for quotations force all bidders to follow the bid document to the letter. The choice is then made based on price since it is the only difference in technically identical offers. However, clients allow and even encourage suppliers to come up with alternatives. Overall economy again, is much more than low investment costs. Operation costs may affect the economy of a project far more than a million saved in investment. There is almost always the choice: Should we go for the cheapest solution or should we go for the most economical solution? We strongly recommend the study of the long-term effects on investments as they often surpass any apparent savings in capital expenditure. With high operating costs, time is never on our side. Almost all relevant inputs and outputs in a concentrator have a value that can be expressed in a suitable currency. Unit prices may differ substantially from one operation to the other, but everything has a price tag and globalization has made it possible to move both goods and services to almost any place in the world. Even a rather simple exercise can give a good indication on which process improvements are worth pursuing when investing in new systems or equipment. The ones that do not qualify, as money earners, will naturally appear as clearly. No ?rocket science? is required, just process knowledge, practical experience, an open mind and some common sense and the reward may be the difference of having a good or an excellent project. The model we have developed can be made as detailed as required, but we do not recommend too much detail, as it sometimes tends to distract work and obscure the important issues. Two different process solutions compared in a simplified example illustrate the importance of evaluating a project based on its long-term effects rather than focusing on the investment costs only.

Jan 1, 2014

By Fookes R. A, Bunch K, Gravitis V. L, Watt J. S

The combustible volatile matter in coal mine roadway dusts (CVM) has been determined using x-ray backscatter techniques. The correlation between x-ray and chemical techniques is reasonably good for the 92 samples from collieries on the Bulli seam, and the maximum error expected at the maximum level of 11· 5 weight per cent CVM permitted in the N.S.W. Coal Mines Regulation Act, 1912, as amended, is about ± 2·5 weight per cent. This x-ray technique can be used only when the combustible volatile content of the coal matter (cvm) varies within a limited range, and a separate calibration is required for each coal seam.Portable equipment based on a radioisotope x-ray source ahd digital ratemeter makes possible simple and rapid analysis, and with adaptation to use in coal mines should lead to much more comprehensive testing- ofroadways and hence improved overall prevention of coal dust explosions.

Jan 1, 1977

By Patrick J. Hannigan, Geir Veslegard, Frank Rausche, Rozbeh B. Moghaddam

A common type of deep foundation used in Norway to support bridge structures is the drilled pipe piles (piles) filled with concrete reinforcement after installation. The standard installation practice is the use of down-hole hammers. Complex geology and difficult subsoil conditions in Norway causes a high variability of soil and rock layers which in turn make for differences between actual subsurface conditions and those expected from geotechnical exploratory borings. This situation is strongly noted when the foundations are not fully socketed, and the rock layer is sloped. In this particular case, special testing procedures are required to assess the drilled pile base material and evaluate the rock-socket to ensure full contact between the foundation base and the rock surface. The local standard practice to verify the latter condition, consists of coring and visually evaluating the material recovered at the bottom of the drilled pile. This paper presents a case where the coring and visual inspection were not possible and alternatively the geological material encountered at the base of the deep foundations was evaluated using force-displacement measurements. Two 1016-mm (40in) diameter open-end drilled piles identified as P02-04 and P02-05 were tested and evaluated using in-situ force-displacement data prior to filling the piles with concrete. Test results showed an average displacement of 7mm (0.28in) corresponding to 35MPa (5.1ksi) stress level for P02-04, and 7.2mm (0.28in) corresponding to a stress level of 38MPa (5.5ksi). Based on testing results, both drilled piles were within the established material assessment criterion presented by the local authorities. INTRODUCTION This paper presents a case study in Norway where the material encountered at the base of an open- end drilled pipe pile (pile) was evaluated using force-displacement data. In the deep foundation industry in Norway, it is a common practice to install piles to support transportation structures. Once the piles reach the embedment elevation, and the pile base is assessed, these are filled with concrete. In projects where sloping rock is the supporting layer, and all nominal loads are supported by the pile base resistance, assessing the material encountered at the pile base to ensure full contact with the rock becomes critical. The local practice to make this assessment consists of the use of weighted tape, coring, or inspection cameras. However, similar to any other testing and evaluation methods, these come with their own limitations. The variability associated with the use of the weighted tape, accessibility for the coring equipment to complete a coring process, or the conditions at the foundation base such as murky water or thick drilling fluids could significantly impact the photo or video quality taken at the pile base. In such conditions, it is important to consider alternate testing methods to evaluate the material at the foundation base.

Jan 1, 2018

By P. H. Francis

In This report, factors which currently enter into the design, manufacture, and quality assurance of explosion-proof enclosures are reviewed, with special emphasis given to the sealing concepts and sealants/cements, per se, for lenses. The physical and mechanical properties of a number of representative sealants and adhesives are measured, and found to exhibit great variance, with few discernible trends which might afford a firm base on which to establish minimum property standards. Accordingly, acceptance criteria for adhesives and sealants are suggested based on the survivability of an explosion-proof enclosure as a structure rather than upon the minimum mat real properties of its constituents. Procedures or surface preparation of adherends, and for quality assurance, also are proposed.

Jan 1, 1980

By R. Dippenaar

The emergence of new steel grades is largely driven by the need to produce high quality steel at a competitive price. The principal aims are to attain ultra-high purity, (especially low interstitial elements) and ultra-cleanliness (by the control of the inclusion content and size). Whereas the steel used to build the Titanic contained 650 ppm sulphur, resulting in MnS stringer-inclusions 25 mm in length, modern quality requirements for arctic pipelines would only allow 10 ppm of sulphur and inclusions in ball-bearing steels must be smaller than 5µm. Most developments are aimed at hot-metal treatment before refining and ladle treatment after decarburisation. Because ferroalloys are added during or after the refining step, it is the secondary (ladle) refining production technologies that are of specific interest to the ferroalloy producer. Through ladle treatment, hydrogen and nitrogen contents are reduced, ultra-low levels of solute impurities are attained and the shapes as well as the composition of inclusions are modified. Steelmakers are concerned about the cost effectiveness of the use of ferroalloys such as consistent product analysis and delivery, improved financing arrangements and technical support. Minimal variation in product sizing is vital because it impacts on handling problems and because particle size determines the rate of particle dissolution. The required ferroalloy product quality depends on the specific use but in general sulphur, phosphorous and nitrogen contents are of concern. Apart from the presence of trace and impurity elements, ferroalloys also contain inclusions. For example, ferromanganese may contain MnO-MnS-SiO2 inclusions while high-carbon ferro-chrome may contain different kinds of Cr-Mn-spinels. The presence of these impurities and inclusions has a significant impact on steel production techniques and cost and hence, on the selection and use of ferroalloys. The interrelationship between ferroalloy quality and steel production technology is plant and product specific and hence, effective communication between ferroalloy suppliers and steel producers is essential.

Jan 1, 2004

By Ivette E. Torres

Of the 15 selected non fuel mineral commodities detailed in table 12, only 3 indicated increases in worldwide consumption in 1992. As in 1991, decline in consumption levels of the selected commodities can be attributed to reduced levels of use in the former U.S.S.R. and Eastern Europe. Of the remaining 12 commodities, 2 magnesium and cadmium, stayed relatively the same, while the other 10, including iron and steel, all recorded decreases. Global consumption of iron ore is estimated to have fallen about 3.5 % or about 30 million tons. This is a greater decline than what was estimated for production of iron ore, which is down only 2.7% or nearly 26.5 million tons, suggesting an addition to stocks. The consumption trend for iron and steel has been declining since 1989. This has mainly been due to the continued drops in use in the former U.S.S.R. and Eastern Europe. Even as the European economy begins to turn upward, there may only be a slight increase in consumption of iron, steel, and cement, considering the high cost of construction needed to modernize factories and buildings in Eastern Europe. Many feel that the economies of these countries are limited by the current status of their industries.

Jan 1, 1994

By Chikaosa Tanimoto

INTRODUCTION Bratislava is located at the intersection of important traffic routes, including motor-ways, roads, railways, air traffic, trading, and inland waterway with an important harbour. The construction of the D2 Motorway Bratislava, Lamacska cesta Stare grunty was the last missing section of D2 Motorway and its completion linked the Czech Republic through Bratislava to the Hungarian Republic. Traffic was obliged until its completion to use the Lamacska Road and Mlynska Dolina, which were the most heavily trafficked roads in the city. The section of D2 Motorway to be completed in 2006 was 3,300m in length, of which the SITINA Tunnel was approximately half the length. After putting into operation the transit traffic(motorway) and urban traffic was separated. Transit traffic by passing the town was eased. The junctions D2 with Lamacska Road (Harmincova) and Mlynska Dolina also allowed better use of the motorway for the urban traffic The tunnel construction was specified by the features with the highly weathered and thermally altered granitic rock formation with the overburden of Quaternary sediment of 2?4 m thick, very thin overburden, severely controlled deformation limit and environmental protection. The tunnel had to be excavated beneath and nearby the academic complex area and the zoo, where sensitive facilities exist and animals live in. The tunnel consisted of two tunnels (Tunnel A and B) with the length of 1,415 and 1,440 m, respectively. The overburden thickness was in the range from 10?30 m. The standard cross-section and the one with invert arch were 79.5?81.5 m2 and 92.1?93.3 m2. The excavation took 21 months from September 2003 to May 2005. The construction was based on the concept of NATM. The SITINA Tunnel was the third application of NATM in Slovakia, following the BRANKISKO Tunnel (commenced in July 2003) as the first and the HORELICA Tunnel (in October 2004) as the second NATM practice. To protect the surrounding structures and citizens from tunneling operations, seismic monitoring was performed in association with blasting. The allowable limit of blasting vibration was fixed to be under the particle velocity of 15 mm/sec. The tunnel excavation cleared this limit as expected before construction. In driving through the difficult geological situation the excavation work hit 49 faults, and some of them occasionally caused serious face instability. In principle, the rock formation has been affected by the high hydrothermal effect and the resultant clay filing along faults and joints. The auxiliary reinforcement with the 4?8 m long pipe roofing was needed to protect the vicinity of mining face area. This operation extraordinarily required additional works and time which had not been expected before construction.

By R. L. Attridge

Namibia's newest mining enterprise, the Navachab Gold Mine, was officially opened by President Sam Nujomo during June 1990. The mine is a joint venture between Erongo Mining & Exploration Company Limited, Metal Mining Corporation of Canada, and Rand Mines Windhoek (Pty) Ltd. Erongo has a 70 per cent interest in the mine, while Metal Mining and Rand Mines hold 20 per cent and 10 per cent respectively. Anglo American Corporation and its associates hold two-thirds of Erongo shares and CDM (Pty) Ltd one-third. The Mine is managed by Erongo Mining & Exploration Company. The property is located some 10 km southwest of the town of Karibib and 170 km west-northwest of the Namibian capital of Windhoek (Fig. 1), the name of the Mine being taken from the farm on which the gold deposits were discovered. Navachab is an opencast operation and was brought into production in December 1989 at a cost of around R84 milion-RS,2 million under budget. The plant is designed to treat 840 kt annually at an average gold grade of 2,6 g/t. This wil produce 1900 kg of gold per year, which at today's prices will earn Namibia more than R60 million in foreign exchange.

Jan 1, 1991

By Robert L. de Beauchamp

The Bureau of Mines reviewed aluminum chloride technology to determine the problems associated with its preparation from minerals, and to ascertain the best areas for research to solve these problems. Commercial AlC13 production processes are described and the ?state of the art? for the preparation of AlC13 from aluminous materials is evaluated. Areas for further research are indicated.

Jan 1, 1969

By Tom Ireland, Tony Rock

The proposed 1.83km long twin bore A3 Hindhead road tunnel planned for contruction in 2008 is being delivered under a Highways Agency Early Contractor Involvement (ECI) contract. The proposed construction methodology is progressive mechanical excavation of a horseshoe shaped tunnel with shotcrete installed close behind the face using robotic spraying equipment. The tunneling medium is a ‘soft rock’ sandstone for which there was little previous tunneling experience, requiring extensive geotechnical investigations and an innovative approach to lining design. A 240m long portal section though sandy material utilising a steel pipe umbrella is also required. This paper describes the development of the tunnel planning and design including the most recent developments in UK road tunnels, and the innovation included in the ‘permanent’ primary lining design.

Jan 1, 2007

Traditionally within the mining industry, single models for both grade and geology of orebodies are created upon which all mine development decisions are based. These models provide a single interpretation of the extent and continuity of the mineralization envelope based on solids and sections interpreted from relatively wide spaced drilling i.e. the models infer behaviour of grade and geology at smaller/local scales based on data available at wider scales. The variable behaviour of grade and geology cannot be derived from single kriged resource models. In recognition of this, Newmont Mining Corporation typically uses Sequential Gaussian Simulation (SGS) to quantify grade variability and to determine its effect on some of these mine development decisions. In most of these studies the mineralized envelope remains fixed and grade simulations are generated within a fixed volume. To account for uncertainty in the geology/ mineralization envelope Newmont Mining Corporation has been experimenting with Multiple Point Statistics (MPS). Multiple-Point Statistics is an emerging technique, which can be used to generate multiple, geologically realistic, realizations of data that displays complex non-linear features. MPS uses a conceptual model of the geology, called a Training Image (TI), to infer these high-order spatial relationships. The multiple realizations allow for an assessment of the geologic uncertainty, which can be further combined with grade simulations to generate a more complete picture of the true uncertainty of a mineral deposit.

Jan 1, 2011