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By D. Waite

The Chairman opened the session by wondering why so few papers on Maritime Structures had been received for this conference. Perhaps because the marine environment is so hostile and the access so difficult that engineers tend to be more prudent about new ideas and designs. Dennis Waite noted the number of grey hairs in the room - grey hairs which could be equated with experience gained the hard way. He hoped that this experience would be passed on in the discussion period of this session. The Chairman was delighted to welcome two authors from China, Mr Sun and Mr Liang. He was most grateful on behalf of the conference for their efforts both in preparing their papers and for being able to present them. He regretted that Messrs Noce and Fedolino were not able to present their paper and then welcomed Mr Christensen from Denmark who would present the first paper.

Jan 1, 1991

By James Ridenour

This report represents the first comprehensive accounting of lode mining sites in the Loon Creek mining district, Custer County, Idaho. Thirty-five mine and prospect locations have been added to the Bureau's Mineral Industry Location Subsystem (MILS) data base as a result of initial phases of a mineral appraisal of the River of No Return Wilderness; previously known locations were field checked and the updated information added to the data base. The district's major deposits are gold-copper-silver fissure-fillings hosted by biotite schist intruded by dikes ranging in composition from rhyolite to lamprophyre. These deposits contain a trace element suite similar to Tertiary pink granites and may be related to intrusion of the nearby Casto pluton. Continued firm gold prices could stimulate the search for precious metal occurrences in this and other mining districts in central Idaho.

Jan 1, 1983

Detailed mineralogical investigation of a tailing sample from the Juno plant circuit at Tennant Creek was carried out to determine the nature of the unrecovered bismuth and whether any possibility existed for improving bismuth recovery. The investigation showed that the Ibismuth was present in a complex mixture of Bi-Pb-Ou-Se-S minerals (termed "bismuthinite"), of which about 74 per cent was locked (mainly with magnetite) and 26 per cent was liberated (18 per cent in the minus 7 µm slime). The results suggested that attention should be directed to both finer grinding and improved flotation of slime "bismuthinite", and testwork carried out by Peko Mines N.L. on the basis of these recommendations led to a significant improvement in bismuth recovery.Detailed mineralogical investigation of two Juno concentrates was carried out to determine the nature of the selenium present and whether any possibility existed for improving the selenium grade. The investigation indicated that virtqally all the bismuth, selenium, and lead was present in "bismuthinite", which showed a composition range of 32-82 per cent Bi, 0-42 per cent Pb, 0-24 per cent Se, and 5-18 per cent S. Differences in the Bi/Se ratios of the two concentrates could be attributed to different average Bi/Se ratios of the constituent "bismuthinite", and the relatively low selenium grade of the "bismuthinite" precluded the possibility of obtaining a high grade selenium concentrate with high selenium recovery.However, differential flotation and/or low intensity magnetic separation to remove chakopyrite, and magnetite, the main diluents of the concentrate, could be expected to upgrade the selenium content byup to 80 per cent (relative) and .festwork carried out by Peko Mines N.L. on the basis of the recommendations of the mineralogical investigation confirmed that depression of chalcopyrite in the flotation circuit could produce significantly improved selenium grades.These investigations illustrate the application of mineralogy to the practical problems of improving plant performance. Mineralogy has an important role to play in providing quantitative data on which the metallurgist can evaluate plant performance and base a programme of metallurgical testwork, and early mineralogical investigation of feeds, concentrates, middlings, and tailings can lead to the avoidance of much abortive and expensive metallurgical testwork.

Jan 1, 1974

By A N. Kasnanto, D A. Sims, J Pocoe, B Pulungan

In this case study we compare the sampling quality of diamond drilling (DD) and reverse circulation (RC) drilling at the high sulfidation Purnama gold–silver (Au-Ag) deposit located in northern Sumatra, Indonesia.There was a systematic bias of 23 per cent gold metal under-call in the diamond drilling based Ore Reserve estimate compared to the mill reconciliation over three years of production. The RC based Grade Control data and mill production data were in much closer accord. Investigation led to quantification of the significantly reduced sampling imprecision (or improved precision) of RC drilling samples relative to diamond drilling samples and the determination of a grade bias between the drill types caused by sample volume and metal distribution in the mineralisation. An infill RC drilling program was undertaken to improve data density across the pit for inclusion in the Mineral Resource estimate. This subsequently increased Au metal in the estimate by 16 per cent.The sampling imprecision of primary diamond drill sampling is rarely tested. Duplicate sampling can be used to quantify sampling imprecision at each stage of subsampling. In diamond drilling it is tested at the primary sampling stage via second half core sampling, while RC sampling is tested with field duplicate sampling at the rig. Duplicate data can be compared in a number of ways to determine imprecision including Thompson-Howarth plots which quantify imprecision to allow comparison between different methods and protocols. Comparing sampling imprecision between data sets and data types allows determination of optimum drilling and sampling protocols and can reflect upon the underlying validity of Mineral Resource input data and estimation outputs.CITATION:Sims, D A, Pocoe, J, Kasnanto, A N and Pulungan, B, 2017. Why combine reverse circulation and diamond drilling in Mineral Resource estimation at Purnama?, in Proceedings Tenth International Mining Geology Conference 2017, pp 413–422 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By W. Mackenzie

The development of a resource project inevitably requires the investigation of a vast range of issues across most engineering disciplines - mining, metallurgical, chemical, civil, electrical, mechanical and environmental - as well as the geosciences. It is also a characteristic feature of the resource industry that no two orebodies - and hence no two development projects - are the same. So these technical issues have to be addressed to a greater or lesser extent in evaluating any resource project's development potential. Not surprisingly then, technical issues tend to predominate when assessing the development potential of a project in the process typically referred to as `doing a feasibility study'. But the principal purpose of a `feasibility study' is to determine whether a development opportunity makes good business sense, not just whether it is technically possible. Resolution of technical issues is often seen as the primary focus of a feasibility study, whereas in reality, these technical issues are the basis upon which an asset delivery and business plan is built. This is not to say that technical issues are unimportant - they are a prerequisite to the demonstration of a project's viability. The feasibility study process must therefore demonstrate that not only have the technical issues been satisfactorily addressed, but also that the broader commercial, economic and social issues have been considered in the development of a comprehensive business plan, which includes an assessment of the risk-reward profile of the proposed development. This paper will present a framework for the conduct of `feasibility studies' and provide guidance to minimum standards and best practice.

Jan 1, 2007

CAPTAIN JOHN H. BALLAMY John H. Ballamy, Captain on the Regimental Staff of the 103d Engineers, was killed near Fismes, on August 9, 1918. Captain Ballamy was born at Plymouth, Pa., in 1886 and graduated from the High School of that town in 1903. In the following year he began work as a coal miner, and at the same time began the study of mining engineering in the evening and any other spare time. He continued this diligent and energetic practice for many years. For sixteen years he continued in the employment of the Delaware, Lackawanna & Western Railroad Company's coal mining department, first as a practical miner, next as rodman on the survey corps, of which he soon became chief, then draftsman and mining engineer in the company's office. In January, 1916, he was promoted to the position of district engineer in charge of mining engineering work. He became a member of this Institute in September, 1917. CAPTAIN JOHN H BALLAMY. Captain Ballamy's military experience began at the same time as his engineering practice. He was a charter member of Company A, Engineers, N. G. P., which was organized ten years ago. He saw service on the Mexican border as First Lieutenant of this Company, and remained in that position until November, 1916. In July, 1917, he was again called into service and was sent to Camp Hancock, Ga., with the 103d Regiment of Engineers. Before joining this regiment he attended a school for officers at Fort Sill, Okla., where he received special training in field fortifications. In December, 1917, he was commissioned Topographical Captain on the Regimental Staff, and in April, 1918, preceded his regiment by about six weeks to France, where he again attended an officers' training school. He rejoined his regiment on July 15, near Chateau Thierry and was killed near Fismes on August 9, 1918.

Jan 11, 1918

By S. Ngidi

Palabora Mining Company operates a low grade underground copper mine situated in the Limpopo Province, South Africa. Full production was first reached in May 2005 after a successful transition from an open pit operation to an underground block cave operation. The operation faces a number of technical and operational challenges, not the least being fragmentation of a competent rock mass and external dilution. The cave is subdivided into three main sectors being the east, the west and the central sectors. Caving was initiated from the weaker central sector, which has the majority of its drawpoints located directly under the open pit bottom currently filled with about 130 million tons of waste material from the pit wall failure incurred in 2004. About 48% of the ore reserve has to be extracted from the western sector, which has a much courser fragmentation compared to the other two sectors and only 25% from the central sector with the finest fragmentation. The main constraint during the ramp-up stage has been secondary breaking of drawpoint blockages. Ground-breaking secondary breaking and cave management initiatives and practices have made it possible for Palabora to realize and sustain high production rates.

Jan 1, 2007

By Steve Kral

Amax Coal Industries Inc.'s Delta Mine is a medium-sized. high-sulfur coal producer that has lived up to the challenges posed by nearly six decades of a highly competitive domestic coal market. The mine now faces one of its biggest challenges - the same one staring at the dozens of other high-sulfur producers in the Midwest - the Clean Air Act Amendments of 1990. The 59-year-old mine, located in the coal fields of southern Illinois, has remained one of the state's oldest continuously operating mines by rolling with the ups and downs of the coal market and by incorporating new technologies and innovative productivity improvements into its operation.

Jan 1, 1993

By Lukasz Maciag, Ryszard Andrzej Kotlinski, Ryszard Krzysztof Borówka, Dominik Zawadzki

Concentration and composition of rare earth elements (REE) and major elements in the sediment samples from the IOM H11 Fe-Mn nodule deposit, eastern part of the Clarion-Clipperton nodule field (located between the Clarion-Clipperton Fracture Zone - CCFZ; tropical Pacific), have been studied. We show the controls on REE concentrations and described vertical/horizontal variability of selected metals in pelagic sediments from the CCFZ. According to Kato et al. (2011), who analyzed 2000 seafloor sediment samples at 78 sites of the Pacific Ocean, deep-sea mud shows high concentrations (2230 ppm maximum) of ?REY and could be potential resource of these elements in the future. However, our work does not fully confirm that sediments in the IOM H11 are significantly enriched in REE.

Sep 1, 2014

By W. L. Hunter

The research on this report was conducted to obtain information on the feasibility of producing ferro chromium of varying silicon and carbon contents from domestic chromite. Concentrates from the Mouat deposit were chosen because they typify the chromite found in the Stillwater complex, the largest domestic reserve, and are similar in composition to other extensive North American and foreign deposits. Batch-smelting tests designed to produce high-, medium-, and low-carbon ferrochromium were made in single phase and three-phase, electric-arc, steelmaking furnaces. Agglomeration studies were made in a rotary kiln. Continuous smelting tests were made to yield data on the production of high-carbon ferro chromium and low-carbon ferrochromium-silicon. The carbon content of high-carbon ferrochromium was lowered to the medium-carbon range by oxygen injection. Mouat stockpile concentrates were nodulized in a gas-fired rotary kiln using quartz, limestone, and fluorspar additions in the proportion necessary to flux the slag. The nodules were smelted in a continuous test using coal, coal char, and mixtures of the two consecutively as reductants.

Jan 1, 1961

By Derek T. Novotny

Blasting cap precision is of major importance to advanced blast design. New technologies have introduced the use of microchips within detonator casings in the hope that the electronic control of the timing element will increase the accuracy of the cap and therefore improve the results of perimeter control blasting applications. The electronic detonators have proven to be accurate in timing tests done to date. They boast cap scatter results to microsecond accuracy, but the question is, does this degree of accuracy actually prove to be beneficial during practical use in the industry, or are conventional technologies applicable.

Jan 1, 1998

By Bali. D. D., S. Chattopadhyay

"The planning and construction of prime coking coal beneficiation plants in the nationalized mines in India are reviewed. Flow schemes, construction practice, materials consumption, and costs are detailed.Medium-capacity beneficiation plants with multiple loops are recommended under Indian conditions.IntroductionThe reserve of high-grade and easily washed metallurgical coal in India are quite limited. Prime coking coal constitutes approximately 22% of the total resources and occurs exclusively in the Jharia coalfield in the state of Bihar. Bharat Coking Coal Limited (a subsidiary of Coal India Limited (CIL) the nationalized mining sector of India) owns 80% of the Jharia collieries. The development of Jharia coalfield in the pre-nationalized period before 1971 has been characterized by a large number of small mines with primitive mining methods and low productivity. The production of prime coking coal to meet the demand of the steel industry in India has to increase from the existing level of 11.1 million tonnes to 43.4 million tonnes per annum by 2000 AD, thereby producing 5.61 million tonnes and 22.7 million tonnes of clean coal respectively. An ambitious program has been undertaken for development of bigger mines with an average production of 1 to 3 million tonnes per annum. With the fast dwindling reserves of good quality coking coal, more inferior grade coal seams, having difficult washing characteristics, are now being mined. All the coal from the future mines will have to be beneficiated to make it suitable for consumption of steel plants; the following washeries are being planned for construction by 2000 AD:"

Jan 1, 1986

By Hugo Cabrera-Real

This work investigated the chemical and mineralogical properties of CaO-SiO2-CrOx-CaF2- MgO slags. Synthetic slags were prepared and the effect of the slag basicity (CaO/SiO2) and MgO contents on the stability of the mineralogical species formed was analyzed. The morphology and composition of the slags were analyzed by XRD and SEM-EDS, whilst their chemical stability was evaluated by leaching with an aqueous acetic acid solution. It was found that in slags with CaO/SiO2 = 1, the main Cr-compound was MgCr2O4 spinel, which forms octahedron crystals. Small amounts of CaCr2O4 and CaCrO4 were also observed. It was found that increasing the slag basicity from 1 to 2 the compounds MgCr2O4 and CaCr2O4 were formed together with the Cr(V)-containing compound complex Ca5(CrO4)3F which forms hexagonal crystals. The results showed that the highest chromium concentration levels in the leaching liquors corresponded to slags with CaO/SiO2 = 2, probably owing to the formation of Ca5(CrO4)3F.

Jan 1, 2010

By X. Bai

A new heuristic sublevel mining stope optimizer is presented. The optimizer seeks the best locations and lengths of a series of vertical raises that, together with the blocks linked to each raise, define a mining stope. Five design constraints ? the footwall angle, the hangingwall angle, the number of raises, the maximum distance of a block from a raise, and the minimum width required to move the farthest block towards the raise ? allow the shape of the sub-stopes associated with each raise to be controlled. The optimization is done on the locations and lengths of raises using a genetic algorithm to efficiently sample the parameters? space. For each raise, a local network is defined in cylindrical coordinates around the raise such as to impose the design constraints. A maxflow algorithm on the local network is used to determine the optimal sub-stope for each raise. All substopes are combined to define the global stope for the entire deposit. The best global stope is obtained using a genetic algorithm to find the raise parameters providing the best profit over the entire deposit. Two synthetic cases and one real deposit are used to evaluate the new algorithm and compare the results with the single-raise optimizer. The multiple raises approach leads to significantly improved economics compared with the single-raise stope optimizer, and the dilution is also substantially reduced compared to the single-raise case.

Jan 1, 2014

By R Bertuzzi

This paper presents a three-dimensional analysis of a trapezoidal-shaped segmental tunnel lining for a recent tunnelling project in Sydney. Two- dimensional analyses, hand calculations and equipment selection defined the lining geometry and loads. The analysis, which was undertaken using 3DEC (Itasca), included a complete ring of six segments bolted together to assess the impact of imperfectly built rings. Asymmetry was induced in the analysis by unfavourable positioning of segments within construction tolerances. Model output includes displacement and stress within the entire ring and normal, shear and bending moments at the joints. For the case analysed, the results suggest a 10 mm construction tolerance increases normal and shear stresses along the radial joints by approximately 25 per cent and 15 per cent, respectively and up to a doubling of the induced moments.

Jan 1, 2008

By B. W. J. van Rensburg, M. J. Schmidt

Bulk materials handling systems are extensively used in the mining and minerals industry, where a fairly high incidence of structural failure is experienced, notwithstanding design compliance with appropriate standards. A number of case studies are explored to demonstrate how insufficient controls or protection systems have contributed to structural failures on mobile bulk handling equipment. The importance of design integration across engineering disciplines is highlighted. The revision of ISO 5049-1 (1994) is proposed to provide specific rules and guidelines pertaining to machine protection systems. It is further recommended that the structural design engineer of the original equipment manufacturer(OEM) fulfils a more prominent role during the final acceptance and handover of mobile bulk handling equipment, with specific reference to protection systems.

Jan 1, 2015

By N. D. L. Burger

An effective prototype face support system to minimize rockfalls in rockfall-prone mines was developed and patented during a project sponsored by the Mine Health and Safety Council (MHSC). An experimental development model (XDM) roof support unit was developed and evaluated. Mines with rockfall problems in the face areas can use the roof support system to reduce fatalities and injuries in the face area of stopes. The roof support system consists of two similar support units connected to each other via two crank mechanisms. Each unit consists of a headboard supported by a ?wishbone? structure (top and bottom leg). In the first design a threaded bar with struts similar to a scissors jack keeps the legs apart. (In the final version that was field trialed, the threaded bar mechanism was replaced with a hydraulic cylinder). All the components are manufactured from steel. To move the system forward the first support unit is collapsed, the second remaining in the loaded position. The first unit then hangs from the second unit to which it is connected. The first collapsed unit is then manually cranked forward and prestressed. If the required position is still not achieved, the other unit is released and moved forward. The specification for the system was determined and presented at a workshop with industry participants. Different concepts were developed and evaluated against the system specifications. A technology demonstrator was then developed and tested on surface. The technology demonstrator development process included detail design, building and testing of components and subsystems, design reviews and the building and commissioning of the technology demonstrator. The testing of the technology demonstrator was done in a 500-ton hydraulic press, in a mock-up stope and underground. A risk analysis, in which technical, logistical and economic aspects were assessed, was done to determine the critical areas of the system. During the next phase of the project working prototypes were developed for underground tests and evaluation. This process indicated that it was necessary to adjust the system specifications and a redesign was called for. In an iterative process test units were built for purposes of evaluation, specification verification and field trialing. After the successful conclusion of the trials the equipping of a complete production stope started for purposes of integrating the system into the current mining process.

Jan 1, 2008

Heavy mineral deposits are becoming more complex in terms of their compositional variation, particle mineralogy and size distributions, and present challenges for the operation of separation equipment to achieve the required grades and recoveries. Changes in equipment design and concepts potentially provide new opportunities for the beneficiation of heavy mineral sands deposits. The development of a framework for the fundamental understanding of separator performance issues is a first step to develop new machines. This paper will present a first step analysis of electro-static and magnetic separation machines with their application to real separation scenarios.

Jan 1, 2010

By C Ferron, R Massimi

There is approximately 240 000 tonnes of arsenic trioxide dust stored in underground chambers at the Giant Mine in Yellowknife, Northwest Territories, Canada. To minimise the amount of arsenic released to the environment, a number of closure alternatives are being considered. One alternative is to mine the dust, encapsulate it and dispose the mixture into a secured landfill. The potential leaching behaviour of the encapsulated dust was examined in a laboratory programme. Cylinders of arsenic trioxide dust mixed with cement/aggregate and bitumen were prepared. The dust content varied between zero per cent and 60 per cent of dry weight charge. The cement cylinders were tested for strength, leaching and freeze/thaw durability. The bitumen cylinders were tested for leaching only. The results show that increasing dust content in the cement cylinders negatively impacts the strength and the freeze/thaw durability of the samples. A contributing factor is likely the high water to cement ratio in the samples. Leaching tests show that arsenic release from cement cylinders increase with increasing dust content. Arsenic concentrations in leachates do reach a plateau at a certain point in time. Arsenic release from bitumen cylinders was significantly lower compared to cement cylinders. Arsenic concentrations eventually were less than 0.05 mg/L in samples containing up to 25 per cent arsenic trioxide dust. Arsenic leaching rates were found to decrease by an order of magnitude over the course of three months.

Jan 1, 2003

By A. Kevin Beaton, Robert W. Laakso

The desire for dry passageways promotes the NATM as it provides a final support system most suitable for the installation of a waterproofing membrane. Waterproofing during construction is a cost effective way to enhance safety and function as well as increasing the life of an underground structure. The NATM approach utilizes the surrounding mass as an integral element of the "ringlike" support system. At the Pennsylvania Turnpike Commission Lehigh Tunnel No. 2 various rock classifications were determined to require support measures ranging from 2 to 12 inches of shotcrete along with spiling, wire mesh, deformed bar, lattice girders and rock bolts as needed. Field instrumentation and monitoring programmes are a key factor for the success of the NATM. When the support "shell" stabilizes smoothing shotcrete, waterproofing and a final liner can be placed.

Jan 1, 1991