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By John Babcock, Gregory Poole, Ron Hudson

In January 2007, Fultondale Alabama opened a new elementary school. Site work at the old school location included blasting activities and the old school building was scheduled for demolition. With help from Apache Construction, blasting was scheduled to be performed in close proximity to the old school building prior to the demolition. Arrangements were made to perform extensive monitoring on the old school building during the blasting activities. The monitoring plan for the project included: • Pre and post blast inspections were performed on the structure; • Conventional crack monitors were installed at 22 locations throughout the structure; • Digital displacement monitors were installed at 6 locations on the structure; and • Seismographs were used to monitor structure vibration at 6 locations and ground vibrations at 9 locations. Blasting activities were allowed to produce vibration levels well above the safe levels established by the U.S. Bureau of Mines (USBM). Vibration levels up to 7.44 in/sec were recorded with no damage noted. Permanent deformation was recorded on vibration levels of 9.68 and above. Not only did this project reinforce previous studies which indicate that concrete block walls can withstand vibration levels well above 2.0 in/sec, this study was also a good example of employing new technology to help determine if/when damage occurs on a specific structure.

Jan 1, 2009

The notes from which this paper has been prepared were set down at the time of the author's departure from Australia in 1935. Mr. Frank Forman, Government Geologist of Western Australia, who has very kindly read the paper in manuscript, affirms that the views here set forth are now accepted by most geologists. Thus, Forman's recent presidential address before the Royal Society of Western Australia (1937) mentions sediments in the Kalgoorlie Series "including banded jaspers and jaspilites."While it may, therefore, be superfluous to belabour the question further at this time, Mr. Forman has encouraged the author to publish this paper as a summary or both past and present views.To those specially interested in the subject of the paper, a study of pertinent Plates attached to Western Australian Geological Survey Bulletin No. 71, 1917, is suggested.The type of rock which is variously called "jasper bar," jaspilite, or "ferruginous quartzite" is familiar to all mining men who have worked in the West Australian goldfields.In its typical form it is a "striped" rock consisting of alternate layers of white or pinkish silica with red to brown bands of iron-bearing silica.In the course of geological work in many parts of Western Australia I studied exposures of jasper bar and was repeatedly impressed with the similarity of much of the material to the sedimentary "banded iron formation" of Canada. It was, therefore, a surprise to learn that the jasper bars were not generally regarded in Australia as sedimentary horizons. It is true that Honman offered convincing evidence of the sedimentary origin of the jaspers...

Jan 1, 1939

By Nikhil Dhawan, Shrey Agrawal, Veeranjaneyulu Rayapudi

India’s steel vision of 2030 requires a huge amount of quality iron ore. The utilization of low-grade iron ores such as banded iron ores will play an important role to achieve the same production. The absence of alumina impurities in the banded hematite jasper (BHJ) ore provides it an edge over other low-grade iron ores. The conventional beneficiation techniques such as magnetic separation and washing were found to be ineffective to produce suitable feed (Fe ~ 60%) for the blast furnace. It was found that microwave exposure provides significant enrichment to the low-grade iron ore and can be used as a pretreatment step in the beneficiation of similar low-grade iron ores. The above study reveals that hematite phase is susceptible to microwave exposure which enhances the separation of iron values from impurities. Under optimum conditions, an iron-enriched concentrate with 61% Fe, 85% Fe recovery at 50% yield can be achieved from BHJ feed ~ 38% Fe. The pretreatment process for BHJ beneficiation includes only microwave exposure without any chemical additive and may prove economical and industrially feasible.

By H. B. Menardi

The history, geology, ore deposits and current mining operations of the Huitzuco district have been described by C. W. Vaupelll and the current mill operations by David Segura.2 This paper completes the story of Huitzuco with a description of the reduction of the flotation concentrates. The predominant ore mineral in the Huitzuco deposit is livingstonite, a rare, mercury-antimony sulphide (HgS.2Sb2S3). Other associated minerals include cinnabar, stibnite and elemental sulphur. The gangue is largely limestone and gypsum. Former operators mined a selected grade of ore, from which the mercury was recovered by an expensive, inefficient operation. A considerable tonnage of rejects and fills, carrying mercury and antimony, was left in the mine. In order to recover both mercury and antimony from these fills and also from newly developed ore, a combination method has been developed, by means of which the livingstonite is concentrated by flotation and the flotation concentrates subsequently reduced to metallic mercury and antimony. An essential part of the flotation treatment, as developed by Segura, is the use of copper sulphate as an activating agent. A typical analysis of concentrates now being produced at the property is as follows: Hg, 7.73 per cent; Sb, 26.40; Fe, 1.20; S, 29.68; CaO, 11.50; MgO, 7.25; SiOz, 1.63; A1203, 0.65. PRocess foR Treatment op Concentrates In the development of a process for treatment of these concentrates, three different methods were investigated: (1) roasting in a Dwight-Lloyd sintering machine with an excess of air; (2) separation of mercury and antimony by distillation in a reducing atmosphere; (3) a third method, which ultimately developed into the present process. The third method involved a slow calcination at a closely regulated temperature with a limited admission of air, which separated the mercury and antimony, the raeroury passing out of the kiln with the furnace gases and the antimony remaining in the calcine or "sinter."

Jan 1, 1944

By Francis D. Leathers

Four friction pile load test programs, including 23 tension tests and 9 compression tests, have been performed as part of the Central Artery/Tunnel Project in Boston, Massachusetts. The tests, performed on both precast, prestressed concrete (PPC) piles and steel piles, yielded the following adhesion values: [Soil Type Clay Clay Glacial Till Interbedded Sand and Clay Interbedded Sand and Clay Pile Type PPC Steel Steel Steel PPC Adhesion (psf) 610 to 1,200 230 to 900 220 to 550 680 1,280 ] The adhesion appears to be affected by differences in pile material type, with PPC piles having higher adhesion than steel piles. However, part of the apparent difference for the clay may be due to differences in time between driving and testing. The significant range of test data means that the need for site specific testing to determine or verify design values of adhesion should be considered during design. Creep rates at loads near failure ranged from about 0.02 to 0.18 inches per log cycle of time, with most values in the range of about 0.04 to 0.08 inches per log cycle of time.

Jan 1, 1994

By Yi Luo, Jian Yang, Hua Jiang

Surface subsidence events induced by underground longwall coal mining operations can cause various disturbances to surface structures ranging from integrity and stability to functionality problems. Highway bridges, as a kind of special road construction that can only tolerate smaller movements and deformations than road pavements, are particularly susceptible to severe influence caused by subsidence-induced ground movements and deformations. However, based on accurate subsidence prediction and correct influence assessments, efficient and effective mitigation and remediation measures can be designed and implemented to ensure the continuous service of bridges, safety of the travelers and smooth mining operations. In this paper, based on the predicted final and dynamic surface movements and deformations, the techniques to assess subsidence influence on the integrity, stability and functionality of bridge structures (e.g., decks, beams, abutments, etc.) are presented. A number of mitigation measures to protect the bridge structures are recommended along with an actual application case.

By S. S. Peng, C. T. Holland

Mountain Top Removal (MTR) mining started in West Virginia nearly thirty years ago. This surface mining method can extract multiple coal seams as thin as a few inches thick with total recovery and minimum rock dilution in very steep mountainous terrain. It is highly efficient even if coal seams are in close proximity and small in aerial extent. Consequently, MTR has been widely used in the Central Appalachian Coalfield (mainly Kentucky, Tennessee, Virginia and West Virginia) for the past thirty years with great success. In that respect, there has been no demand for research and little scientific research has been performed to investigate its impacts on the surroundings in the history of MTR mining. However, in the past two years the debate over the MTR mining has grown quickly and in times become very intensely. This paper describes chronologically the issues raised by various parties, legal actions, its impacts on mining permit application and research projects developed to address the issues.

Jan 1, 2000

By N. Coli

The exhausted Santa Barbara open pit mine (Tuscany, Italy), owned by the main electric power company in Italy (ENEL S.p.A,) extracted lignite as a fuel for the Santa Barbara thermoelectric power plant. The mining activity led to the excavation of a wide slope (with maximum height of 200 m and a planar extension of about 1300 m x 500 m) in the Shale Limestone Chaotic Complex (SLCC) (Figure 1). Since the beginning of its excavation the slope underwent rotational landslides and diffuse instability phenomena. From a geotechnical point of view the SLCC represents a typical bimrock (block-in-matrix rock) (Medley 1994, Medley 2002, Medley 2007) characterized by a mixture of a highly sheared, scaly-fabric, clayey matrix and calcareous blocks ranging from a few millimetres to tens of metres in size. Since the geometrical properties of blocks (grain-size distribution, shape, orientation and volumetric proportion) have been proved to influence the mechanical behaviour of bimrocks (Lindquist & Goodman 1994, Goodman & Ahlgren 2000, Kim et al. 2004, Sonmez et al. 2006), the aim of the present study is to investigate the geometrical properties of calcareous blocks in order to properly characterize the mechanical behaviour of the SLCC bimrock and to further assess the stability of the slope. Block size-distribution and shape were investigated by means of advanced image analysis techniques of SLCC pictures taken in the field. Geostatistical semivariograms and variographic maps were also used in order to investigate the anisotropy of block spatial distribution. Finally, in-situ large sized sieving tests were carried out to investigate the volumetric block proportion within the clayey matrix.

May 1, 2009

By Clarke E. Schuetze

This project had as its objective the experimental investigation of water capsule production utilizing the Southwest Research Institute's submerged nozzle encapsulation apparatus (U.S. Patent 3,389,194). Initial efforts on this project involved nozzle configuration and shell formulation optimization. The shell formulation developed on a prior program was modified during the course of the project to obtain the best balance of capsule breakage resistance and water retention. Subsequent effort centered on determining operating conditions which would produce the best quality capsules for each candidate shell formulation as determined by laboratory tests. Some preliminary work was done to increase the production capacity of the encapsulation equipment. The program was extended with major emphasis concerned with scale-up studies of capsule production capacity and the treatment of problems associated with grouting cartridge fabrication. During the course of the program, water-containing capsules were produced which have good long-term water retention, block resistance and adequate strength. Using a single-nozzle design, a production capacity of 15.9kg (35 pounds) per hour was demonstrated to give acceptable capsules based on initial results.

Jan 1, 1978

The Porgera Joint Venture commenced production during September 1990. A small tonnage underground mine extracts high grade gold ore using small scale stopes. Conventional drill and blast methods are used for development and production mining. Ground support is effected with Splitset anchors, grouted rebar bolts and grouted cable bolts. Splitsets and grouted rebar can be installed by mechanised means. Vertical crater retreat, slot and massfire, and modified VCR stoping tech- niques are used at Porgera. Stopes are backfilled with a relatively strong cemented rockf ill. Future stope sequences require recovery of pillars beside and under filled stopes.

Jan 1, 1991

Taking the third meridian as the eastern boundary of proved payable auriferous country, there is a stretch of country, nearly 600 miles in width, in which no appreciable amount of gold has yet been discovered. Many prospectors have attempted to .penetrate or traverse it, but comparatively few have thought it worth while proceeding with the examination.The desolate stretch of waterless desert-the very few and insignificant outcrops through the sand and the almost total absence of feed for horses have, combined, presented such a barrier as to preclude prospecting. The few who have traversed the country are eloquent in denunciation, yet their investigations, necessarily hurried, are not quite satisfactory. The absence of water utterly debars a thorough examination being made. Gold may exist in quantity, yet it would have to be extraordinarily plentiful to render its obtaining profitable. Too fantastic is the idea of its ever being a mining district; shifting sand to traverse, utter absence of wood and water render the notion absurd. Likely looking belts occur, but these in all "cases are small and remote from water. Gold has been obtained from likely look ing quartz reefs, but only by fire assay, and then but a few do to the ton. Without wishing to be pessimistic, I would unhesitatingly declare that east of the third meridian, and between the parallels 25 and 30 degrees in West Australia, there is no gold in payable quantities.

Jan 1, 1901

Base metal sulphide mineralisation on the northern end of Great Barrier Island is spatially associated with hypabyssal intermediate to acidic intrusives, in transgressive structures in indurated, complexly deformed greywackes and argillites. Copper predominates in the mineralisation, with minor accompanying lead and zinc and also some gold and silver. However, in some cases lead or zinc may be the dominant constituent. The mineralisation is generally characterised by only narrow envelopes of weak alteration (propyliticassemblages dominated by chlorite and epidote) and with only minor amounts of quartz accompanying the sulphides, which form a cement in zones of hydraulic fracturing. There are two distinct structural settings to the mineralisation: at MinerÆs Head, in a structurally complex situation in a shell-like zone of crackling in hornfelsed greywacke, in association with both north- and east-striking fractures and rubble breccias associated with the apical part of a large intrusive; and in very narrow, but very strike-persistent, 1inear steeply-dipping fracture zones, exposed on the north coast and inland areas near Tataweka.

Jan 1, 1984

Research into the mechanisation of ore winning from the very narrow reefs characteristic of South African gold mines has been conducted from as early as 1964 through the Chamber of Mines Research Organisation (COMRO) but with limited success. However, the Council for Scientific and Industrial Research (CSIR) has recently re-evaluated the potential for the mechanisation for the narrow tabular gold mines. It has been determined that there are approximately 22 000 tonnes of gold left in-situ in channel widths of less than 500 mm in thickness. The extraction of ore from such reefs requires a complete paradigm shift in that the current mining cycle (drilling, blasting, cleaning and supporting) is not feasible since such a stoping width would not allow the workers entry into the stope. Consequently, a non-entry form of mining is required. With this target in mind CSIR has invested in a project called the Nederburg Miner which seeks to identify new technologies for drilling, rock breaking, cleaning, and materials handling, the application of which will enable non-entry mining of very narrow ore bodies. The intention is to develop a fully automated system that will not require human involvement at the stope face. The outcomes of research into this proposed system will not only extend the life of South African gold mines but will also enhance South Africa's reputation for excellence in mining research. This paper presents the new technologies under consideration and potential methods for their application into an integrated non-entry mining system.

Jan 1, 2008

By Ovidiu Pasca

The Phelps Dodge Miami Smelter utilizes four Hoboken converters to process molten matte from the Isasmelt vessel. This paper presents past and present improvements in operation, maintenance and process optimization, based on data collection, which has led to increased converter campaign life and copper throughput.

Jan 1, 2005

Traditionally, capital costs of major resource development projects have been estimated as a single amount to which a percentage accuracy has been assigned based on the method of preparation of the estimate, that is, on the amount of information available to develop the estimate.However, there is a growing recognition of the importance of a probabilistic approach to capital cost estimates, and of a more rigorous calculation of estimate accuracies and of the presentation thereof. Accuracies can be expressed with more certainty as a percentage of the estimate amount where the percentage represents one standard distribution on the probability curve for the capital cost of that specific project. Thus confidence levels can be stated for various estimated amounts - for example, it can be stated that there is an 85% chance that a stated amount will not be exceeded, or a 90% certainty that a (higher) amount will not be exceeded. Moreover, the right skewness of the probability distribution curve for most projects can be readily recognised and reflected in the evaluations. This enables senior executives and board members to have a clearer understanding of investment uncertainties, and the possible magnitude of commitments.

Jan 1, 1990

Water rights and availability are extremely contentious issues in many mining regions around the world, in some instances leading to violent confrontation. This situation has the potential to only get worse because competition for 'scarce' water resources will increase with population growth. In this environment the dilemma facing the mining industry is how to generate confidence in developing a responsible, sustainable and transparent water management strategy that is recognised as such by all stakeholders. Whilst the water needs of the mining industry are minor compared to those of agriculture, an operating mine requires a relatively large quantity of water on a daily basis to carry out operations. Another contentious aspects of new mine development is the debate between all stakeholders on the amount and quality of water that a mine is able to discharge into the environment should this be required. There are a multitude of water resources available to the mining industry for operational needs however much of this water is saline and over the last two decades there has been a continual decline in water quality (ie salinity has increased). In today's world there are enormous internal and external pressures to reduce water consumption at a mine and/or alternatively use water not considered a resource by the local community (ie sewage, saline or salt water, desalinated water). Strategies to meet these objectives can be achieved by implementing good water management practices, by recycling process water, reducing water losses by evaporation and seepage (ie by increasing and improving dewatering practices) and employing new technologies such as dry stacking and dry processing. Recycled water, acid mine drainage water and water collected in the mining area have the potential to impact mineral processing performance, unless they are treated, because of the build up of mineral salts and decomposed chemical products in these types of waters. Besides this the regulatory requirements of any water discharged from a mine site (quantity and quality) have also become more stringent. For these reasons there is now some form of water treatment practiced at most mining operations around the world. This paper provides an overview of water stewardship undertaken in the mining industry over the last two decades and provides examples of water treatment practices that have recently been installed at mining operations that may be of interest to the reader.

Sep 13, 2010

By John Watson

The earliest known records related to mining document in dramatic terms the fact that mining methods have undergone significant change over the centuries. Wooden wedges, hammers and chisels, “fne setting”, to name a few, were the frst tools used to extract ore .or quarry rock for civilization. These inefficient tools and unsafe practices have been replaced today with some of the highest technology known to man. At the heart of most mining operations is the blasting program which utilizes one of the most efficient tools ever invented.. . explosives. Ever since they were invented, miners have been searching for more efficient products and methods with which to harness this “tool” and make it safer, reliable, and more eficient to use.

Jan 1, 1997

By McKenzie P

The techniques of geological control developed by the Coal Geology Sections of the Broken Hill Proprietary Company Limited and Australian Iron and Steel Proprietary Limited in providing geological service in the coilieries operated by these associated companies cover the provision of geological control for both planning and production in each of which the significance of geology has in the past been only poorly appreciated by the coal mining industry.While the adoption of similar techniques is well within the capacity of major companies there is considerable scope for the development of government geological services providing specialized assistance of this nature for smaller scale producers.INTRODUCTIONThe coal mining industry in Australia can instance many notable mistakes caused by failure to obtain sufficient geological information or by incorrect interpretation of available geological evidence both before the commencement of mining and during the progress of operations. Substantial development undertaken in, areas with insufficient or inferior coal reserves, difficult mining conditions caused by failure to adjust operations to geological circumstances, and the irregular development of mine workings caused by unexpected geological features, all bear witness to the lack of geological foresight by the industry.Along with the more widespread general use of applied geology, an increasing acceptance has developed during the past ten years of the valuable contribution which can be made by this science to the exploitation of coalfields. In spite of the advances which have been made, there is still a wide scope for further detailed application of geology throughout the coal mining industry in Australia.

Jan 1, 1963

The selection of the best comminution circuit for the preparation of concentration feed is a compromise based on economics, energy efficiency, labour costs, steel consumption, availability and other factors specific to each case. It is postulated that the selection must be a choice of one of the eight basic comminution circuits which can be divided into two basic groups, (1) autogenous or semi-autogenous primary mills with or without a secondary grinding stage and (2) fine crushing usually in cone crushers followed by a rod mill-ball mill circuit or a single stage ball mill circuit. The accuracy of selection may be improved by pilot plant and laboratory tests which are described in this paper. For (1) above, testing includes media competency tests with standard impact crushing, grindability and abrasion tests followed by pilot plant tests. For (2) above, bench scale crushability, grindability and abrasion testing is available. It is suggested that, through these tests, it should be possible to eliminate all but one in each group of basic comminution circuits. Then engineering and economic studies should lead to the best comminution circuit for the specific requirement.

Jan 1, 1984

By Jia-Shyan Shiau, Chung-Ken Ho

An uneven gas distribution through the burden layers inside a blast furnace (BF) results in abnormal gas resistance or pressure changes. Rapid variations in the abnormal gas resistance will lead to the occurrence of channeling. A visualization technology mainly made of pressure distribution was developed to predict BF channeling phenomena in this study. The real-time data of BF shaft pressure was used to create a 3D visual model by neural network algorithms and 3D real-time BF pressure changes were observed. The root mean square deviation (RMSD) of the BF shaft pressure was used as an index to set up the predicting criteria of channeling occurrence with the opening of BF Annular Gap Element (AGE), and a predicting system based on the criteria was built. The two criteria for the channeling alarm are the RMSD of the BF shaft pressure (> 0.15 kg/cm2 ) at the upper two levels, and the AGE opening being greater than 60%. This system has been installed in the China Steel Corporation (CSC) BFs, and the test results showed that a prediction can be obtained 8 to 16 min ahead of channeling allowing sufficient time for the operator to adjust the BF operation in order to avoid the occurrence of channeling.