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By Paul C. Schmall, Arthur B. Corwin, Derek Maishman

Ground freezing occupies a unique and important niche in underground construction, fulfilling a geotechnical need that is difficult, or sometimes impossible, to fulfill through other groundwater control and excavation support methods. Where complete groundwater cut-off and in-built ground support are required, and deep excavation is planned or the work occurs in difficult or disturbed ground, ground freezing offers the assurance critical to safe and timely construction. Compared with other groundwater cut-off or excavation support methods, a frozen wall is easily connected to underlying bedrock and will also adhere to adjoining subsurface installations or obstructions, if necessary, to provide a composite cutoff structure. Ground freezing is effective in all soil and ground conditions and has been used for emergency situations in disturbed, displaced or loose ground, where detailed soil characterization could not practically be performed.

Jan 1, 2005

By Zuhair A. Nawab, Muhammad A. Al-Marhqun, Mehmet Guney

"The Atlantis-Il-Deep is a stratified metalliferous deposit located along the median valley of the Red Sea at a water depth of about 2200 m. The metal-bearing mud contains sulphides of zinc, copper and iron with significant amounts of silver, gold and cobalt. A variety of oxide, siliceous and carbonaceous gangue material is also present. Long sediment cores indicate that the thickness of the deposit may reach 25 m, but the average kriged thickness of metal-rich sediments is about 11 m.Mining geostatistics was applied to estimate the Red Sea offshore mineral resources. Experimental semi-variograms were computed along 0 ± 180 degrees and then models were fitted to analyze the mineralization phenomenon. Kriging estimates indicate that 696.330 million t of bulk sediments contain 1.891 million t of zinc, 0.425 million t of copper and 3. 75 thousand t of silver. Gold and cobalt contents were calculated from the analysis of solids in flotation concentrates as 47 t and 5368 t respectively. The significant outcome of implementing geostatistics to the Red Sea brine precipitates is not only for the evaluation of metal resources, but it also provides a useful tool in the optimization of selective dredging of appropriate areas to be mined. IntroductionThe discovery and extensive exploration of hot brines and hydrothermal sediments in the Red Sea median valley revealed the fact that the Atlantis-II-Deep is a potentially exploitable metalliferous mud in the economic sense. Sediments in the mineralized deep are composed mainly of oxides, various types of silicates and sulphides with considerable concentrations of zinc, copper, cadmium, silver and gold. The mineral-rich deposit, located at a mean water depth of about 2000 m, has an average thickness of 11 m, and is covered by a brine layer having a temperature of 60°C."

Jan 1, 1988

By Jacques B. Wertz

Both the San Andreas fault complex and the Murray fracture zone are apparently found to be contemporaneous with the Laramide mineralization period. Their compounding effects certainly have disturbed the Texas lineament belt and its components with serious lateral offsets and most probably have been instrumental in allowing intrusives to be emplaced as well as mineralization to accompany these intrusions at some of the fracture intersections. While the main fracture centers can be almost accepted as being structurally linked together, the Texas lineament trend definitely predominates, exerting a prevailing direction to graben (Silver Bell) and to elongated depressions (Bisbee). That this lineament belt also influenced the concomitant mineralization seems a logical inference. The orebodies are generally found at intersections near the most centrally-located intrusive with a distance varying from contiguity to one or two miles. The Southeast Arizona copper province owes its existence primarily to a particularly favorable structural setting of broad semi-continental scope. Thus, various regional structural elements are to be considered as possibly direct or remote cause for the widespread mineralization, although the one or the ones really responsible may never be singled out. There arc three basic regional elements: (1) The north-northwest-trending anticlinorium that diagonally crosses Arizona is quite obvious because many mountain ranges follow this direction. This anti- clinorium, which merges northward into the Wasatch-Jerome Belt, marks a broad zone of weakness where tension seems to prevail. Mineralized trends such as Jerome-San Manuel-Bisbee may give some weight to the economic value of this structural element. (2) Northeast-trending fractures, parallel to the Colorado Mineral Belt (Landwehr, 1967), appear troincident with mineralization as evidenced by the Questa-Grants-Morenci and the Lordsburg- Tyrone-Santa Rita alignments. This structural direction is accepted as one of the most economically significant in the Southwestern United States. (3) The Texas Lineament.

Jan 1, 1970

By Gang Chen

Conventional methods designate a factor of safety, a deterministic number, to indicate the stability of a mine excavation. However, this deterministic description of excavation stability is frequently insufficient or inaccurate and, sometimes, misleading. Employing the probabilistic analysis to determine the likelihood of mine excavation failures will lead to a better understanding of ground control problems and result in more rigorous designs of the excavations. Based on the theory of probability, two approaches are taken in this study for the probabilistic analysis of excavation stability. The first one utilizes direct integrations for the estimation of failure probabilities of mine excavations. Due to the complexity of the integration, this approach can only be applied to solve relatively simple problems. In order to overcome the limitation of the direct integration method, the second approach employs the first-order second-moment approximation of the failure probabilities for more complex ground control problems. The probabilistic analysis offers a deeper insight into the uncertainty associated with the stability of mine excavations. The study indicates that the distributions of parameter values play a significant role in the mine excavation stability, which can not be disclosed by the conventional methods of stability analysis. Greater dispersiveness of the parameter values will lead to a different probability of failure, although the factor of safety estimated by conventional methods stays the same if the mean values of the parameters are constant. By taking consideration of the probabilistic distributions of the parameters, the probability model can provide more reliable designs of mine excavations.

Jan 1, 1996

In conjunction with steady increases in production levels, longwall operators have applied greater quantities of ventilating air and spray water in an effort to control respirable dust and/or methane. Air velocities greater than 7.6 m/s (1500 fpm) have been measured on longwall faces. Operators have expressed concern over the potential entrainment of respirable dust at these high velocities. The greatest likelihood for entraining dust into the high velocity airstream may occur as shields are advanced allowing relatively dry particles to fall from the shield canopy directly into the airstream. Laboratory tests to simulate dust liberation during shield movement were conducted at the Pittsburgh Research Laboratory of NIOSH at velocities ranging from 2.0 to 8.2 m/s (400 to1600 fpm). Airborne dust samples were obtained with personal impactors to quantify the size distribution and concentration of the dust entrained at the various air velocities. Statistically significant increases in both total and respirable dust concentrations were measured as test air velocities were increased.

Jan 1, 2001

By A. Yazadni-Chamzini

Risk ranking of projects is one of the importance parts of the complicated risk management procedure. Recognizing the riskiest criteria enable the managers to plan for risk reduction. The first stage for meeting this aim is defining the risky parameters and then working to establish order between them. There are variety methods for risk ranking. The ELECTRE method is one of the best among the multi criteria decision making methods. In this paper with implementing the fuzzy ELECTRE, The risky criteria in the Tehran Subway project are being ranked. The result of this research presents damage and accident of machineries as well as the lack of labor and equipment safety is located in the first order. Collapse factors and local prices are in second rank. Also wrong design, pollution, urban facilities damageable are in third to fifth respectively. Delay and ? are located in the last positions.

Jan 1, 2012

By Christoph Müller

Information exchange for mine process optimization is essential. Today, modern mining equipment uses the IREDES standard to exchange production plans and reports for easy management and storage. To gain further benefits from process optimization, a mine wide access to real-time information is needed as e.g.: The current status of a machine, operational details etc. Presently, real-time data exchange systems are developed by machine producers. Each machine producer uses its own way of gathering, managing, and storing production data. These proprietary mining processes increase the complexity of cross platform data exchange and management for mines which involves machines produced by different vendors. Casting and unifying the data requires much effort. For this purpose, ?IREDES On-line? currently is being introduced. The standard defines an open, web based method for the exchange of volatile real time machine information. Two different principles are used: Web Services for cross platform information exchange within the IT world and the optional OPC UA for use with automation and process control systems. With such a standard information from machines of different vendors may be managed by using one common platform without spending the effort for dedicated interface development. Additionally, information management and storage will become straight forward since all the data are of the same format. The IREDES On-line standard utilizes the latest IT technologies as well as the knowledge and experiences gained from the previous IREDES standard. The paper explains the benefits, the use, as well as the technical design of the standard and gives application examples from the practice.

Oct 1, 2009

By Stuart St. Clair

EARLY in 1936, when the American Petroleum Institute issued -J "American Petroleum Industry," which was a survey of the current position of the petroleum industry, and its future outlook, and the figures for petroleum requirements .for 1950 and 1960 were widely publicized by the several oil journals, the impression was given that the petroleum- industry must be nearing maturity and would by 1950 have passed the high' point of its obligations to business progress in the United States.`' Let -us look at the figures which might conduce, this thought. Referring to p. 32 of the report, the total indicated crude-oil requirements in 1940 are 1,099,000,000 bbl-; for 1950, the peak, 1,109,800,000 bbl.; for 1960 a decline to 1,071,020,000 bbl. This downward trend, then established, is probably expected to continue. And this in the face of a crude production in 1935 of 993,942,000 bbl., 38,858,000 bbl.

Jan 1, 1936

By D. Kachongo, Y. Cheng, A. Kashala, D. Samal, G. Mitshabu

Many copper processing flowsheets in the Democratic Republic of Congo include the leaching of oxide ores containing copper and cobalt, copper solvent extraction, copper electrowinning, and precipitation of cobalt salt. Recently, cobalt price gained momentum, driven mostly by the fast-growing electric vehicles battery market. The ore blending scenarios tend to prioritise high cobalt grade ore, whatever the content of copper and other impurities. Therefore, many copper solvent extraction circuits are running below design capacity. The variability of feed induces a variability of the leach solution with respect to copper, manganese, and silica contents. It is thus important to adjust hydrodynamic and metallurgical parameters of the solvent extraction plant to optimise metallurgical performance, production cost, and the quality of the copper electrolyte. This paper presents some results on how solvent extraction plant parameters have been managed in two solvent extraction plants running with lower than designed copper input. INTRODUCTION Referring to a report of the chamber of commerce of the Democratic Republic of Congo (DRC) the online publication Agence Ecofin (2019) indicated that the DRC ranks in the fifth position of the world top copper producing countries with over 1.2 million tons produced in 2018. The same year, 66% of the world’s cobalt was produced in the DRC at over 106,000 tons. If the political situation remained stable and the new tax regime introduced in 2018 did not deter private investors, copper production could reach 1.4 million tons/a in 2020 as pointed out in Mining.com (2019). Forecast figures for DRC cobalt production vary widely depending on analysts. The DRC online magazine Actualité.cd (2018) referring to a ministerial source forecasts over 141,000 t cobalt/a for 2020. The reality will depend on many factors, including the selling price, the supply compared to the demand, and finally the reaction of investors to the new DRC tax regime. The growing electric vehicle batteries market has been the major key driver of the price of cobalt. The five years historical cobalt price graph in figure 1 from infomine.com (2019) shows that the price of cobalt peaked at over 40 USD/lb in the first quarter of 2018. Cited by the online Magazine Creamer Media, Smith (2019) has indicated that the long-term demand of cobalt will likely remain strong.

Jan 1, 2019

By M. B. Shongwe

Pt-based alloys are being developed for high-temperature applications with the aim of replacing some of the currently used Ni-based superalloys (NBSAs) in the highest temperature applications. The Pt-based alloys have a similar structure to the NBSAs, and since Pt is more chemically inert than nickel and has a higher melting point, they can potentially be used at higher temperatures, up to 1300°C, and in more aggressive environments. Several experimental Pt-based alloys were studied at Mintek, and an optimum composition was found to be Pt84:Ahi:Ru2:Cr3 (at.%). On the basis of hardness and microstructure, a later study identified a new optimum: Ptr8:A111:Ru5:Cr6 (at.%). There are at least two Pt3A1 allotropes, and the high-temperature cubic structure has better properties than the lower temperature tetragonal form, and so needs to be stabilized. This work describes the latest results obtained in transmission electron microscopy (TEM) studies of the quaternary Pt-based superalloys. These results are both interesting and important, because the samples have a higher precipitate density compared to those from earlier work. The precipitate morphology is mainly cubic, with minor areas having irregular-shaped precipitates. The high volume fraction of the precipitates is a major breakthrough, since the objective of this work is to improve the alloys. A prior disadvantage was that the proportion of the precipitates was too low in samples before this work, especially compared with the work from Germany on Pt-Al-Cr-Ni¬-based alloys as well as the NBSAs. TEM -Pt3A1 diffraction patterns were studied, and for each diffraction pattern, many possible lattice point combinations were tried, with the angle between the lattice spots as well as interplanar spacings being calculated for each phase (cubic or tetragonal) to match the measured results. An overall analysis of the diffraction results indicates that the cubic phase fitted the experimental lattice points with much lower errors compared to the tetragonal phase. Thus, with the close match achieved with the cubic structure, the structure of -Pt3A1 precipitates is likely to be cubic. X-ray diffraction has been carried out on selected samples, and the results confirmed the presence of cubic -Pt3A1 and (Pt). Different X¬ray diffractometers were used to further verify the results, and the results were also compared with those from TEM.

Jan 1, 2012

By Chas. F. Jackson

The work of the Mining Division is divided among seven sections, each in charge of a supervising engineer, as follows: 1. Metal-mining methods section, the supervising engineer of which is also supervising engineer of the Southwest Experiment Station at Tucson, Ariz. 2. Metal-mining research section. 3. Nonmetal-mining section. 4. Coal-mining section. 5. Mine-ventilation section. 6. Mineral-industries survey section. 7. Electrical section. The names of the sections indicate broadly the fields covered by each, and in the following, pages the objectives and type of work of each section will be summarized briefly and their active problems listed. The work clone during the fiscal year 1937 will also be summarized.

Jan 1, 1937

By R. R. Allen

[The utilization of Western coals and lignite is a continuing study of the Bureau of Mines, and storage of these fuels is of paramount importance. Since the seasonal demand for coal in the Western States triples between the summer and winter months, successful storage of these low-rank fuels would tend to level out this variation and should reduce fuel costs. The time is rapidly approaching when the West Coast States, particularly California, will annually import several million tons of coal from the Rocky Mountain States for additional power production. This will necessitate storage of large quantities of coal, and it is thefore important to develop experience in such storage. Dry surface storage, by virtue of its flexibility and low cost, is particularly adapted to the stockpiling of large quantities of coal. This report will, therefore be primarily concerned with such storage. Inasmuch as the problems of dry, open-pit storage are quite similar to those of surface stockpiling, experiences in pit storage will be discussed briefly. Although spontaneous combustion is a hazard in storing coal, experience has proved that heats can be avoided by proper stockpiling procedures. The purpose of this report is to show that the most reactive coals can be stored satisfactorily on the surface by avoiding segregation and by thorough compaction.]

Jan 1, 1954

By W. R. ARGYLE, R. A. SHERMAN, Henry Kreisinger, John Blizard, B. J. CROSS, A. R. Mumford

On entering the World War the United States was confronted with the necessity of building in a short time a large number of ships of tonnage adequate to transport troops and war materials to Europe and to carry food supplies to the allied countries, whose merchant fleets had suffered greatly by submarine warfare. The necessity of building ships quickly led to the formation of the United States Shipping Board, which was charged with the duty of developing an efficient organization for the purpose. Such an organization was developed under the name of the Emergency Fleet Corporation; it was under the control of the Government, but could conduct its business in the most direct way, like a private corporation. In order to build the largest- number of ships possible without drawing too heavily on the steel industry, which was already taxed heavily by the production of munitions, it was decided to build wooden as well as steel ships. These ships were built from a few standard designs to enable a large number of duplicate parts to be fabricated in inland shops and transported by railroad to the shipyards on the seacoast, where they were assembled into ships. In other words, the plan was to manufacture the ships rather than to build them. The shops on the seacoast were reserved to make those parts of the ships' equipment that could not readily be transported. The inland shops made the parts that could be transported to the seacoast by railroad. Among the more important parts of the ships' equipment to be standardized were the boilers. As the Scotch marine boiler in large units is bulky and can not be transported by railroad, and as, for the same capacity,much more steelis needed in its construction than for water-tube boilers, a few simple designs of water-tube boilers were developed that inland shops having ordinary equipment could make in large quantities.

Jan 1, 1924

By L. C. Graton

[CONTENTS PAGE INTRODUCTION AND ACKNOWLEDGMENTS. By George M. Fowler2 Question 1-Is Structural Deformation of Some Character Always Necessary for the Migration of Mineralizing Solutions, Especially in Limestone or Other Dense Rock? DISCUSSION by: A. M. Bateman 10 S. F. Kelly 15 C. H. Behre, Jr 8, 13 G. B. Langford 13 T. M. Broderick11 H. E. McKinstry6 R. H. Clarke 13 D. H. McLaughlin8 J. D. Forrester for M. H. Gidel . . . 4 W. H. Newhouse13 G. M. Fowler 2, 6, 11 R. H. Sales 6 L. C. Graton 11 Edward Sampson 12 R. D. Hoffman 10 J. S. Stevenson 7 I. B. Joralemon11 L. B. Wright 2 Question 2-What Are Some of the Chemical and Physical Characteristics in Certain Beds within a Limestone Formation that Determine Their Favorable or Unfavorable Aspects as Reservoirs for Ore and Other Introduced Minerals? DISCUSSION by: G. W. Bain 17G. M. Fowler 21 C. H. Behre, Jr21L. C. Graton18 J. S. Brown 16G. F. Loughlin18 E. L. Bruce 19R. H. Sales 19 R. H. Clarke 20A. K. Snelgrove 20 Question 3-Are There Any Criteria by Which One Can Determine When Mining Operations Have Reached the Roots of an Ore Deposit? DISCUSSION by: J. M. Boutwell29G. B. Langford 29 T. M. Broderick28G. F. Loughlin25 E. Y. Dougherty27R. H. Sales 24 G. M. Fowler 22F. A. Thomson 26 I. B. Joralemon 22Edward Wisser 30 General S. F. Kelly35 References36

Jan 1, 1940

By H. Verakis, M. J. Sapko

The Pittsburgh Research Laboratory (PRL)1 of the National Institute for Occupational Safety and Health (NIOSH) in collaboration with the Mine Safety and Health Administration (MSHA) Technical Support Center has devised a prototype hand-held instrument which can provide a direct assessment of the potential explosibility of a coal and rock dust mixture. Current Federal regulations require that rock dust be applied in all underground areas of a coal mine to mitigate the propagation of a coal dust explosion. To determine compliance with the Federal regulation, mine inspectors collect dust samples from sections of underground coal mines for an MSHA laboratory analysis of incombustible content. However, the laboratory analysis may not be completed for more than a week or two, during which time the mine area from which samples are taken may be inadequately protected. The operation of the Coal Dust Explosibility Meter (CDEM) is based on the difference in optical reflectance between light rock dust and dark coal dust. For a given coal volatility, the optical reflectance of such mixtures is relatively constant at the limit of explosibility, independent of the coal dust particle size. The CDEM is not intended to replace the current MSHA laboratory analysis of coal mine dust samples for incombustible content, but to serve as a supplemental device for enhancing mine safety through improved rock dusting practices.

Jan 1, 2006

By Bassam Kattaa

"Abstract - A heavy mineral survey of beach and dune sands including geochemical analysis for trace elements was undertaken to evaluate the economic potential of the sands and to understand the nature and distribution of the heavy minerals relative to potential source rocks. Results indicate that heavy minerals are generally derived from outcropping volcanic rocks that comprise a proportion of the hinterland in the south part of our survey area. The most abundant minerals are magnetite and pyroxene. The morphologies of the heavy mineral grains are angular to subangular, suggesting that they were transported short distances from the source rocks. Factors controlling heavy mineral distributions include wave and wind action, proximity to provenance, the fluvial drainage network, and longshore currrents.The most economically important mineral is ilmenite. Zircon and rutile concentrations are relatively minor and thus have lower economic potential."

Jan 1, 2002

By K. Biswas, S. Iverson, S. J. Jung

Computer modeling of rock flow in ore passes is being investigated and compared using MSC Soft-ware’s Working Model 2D1 (WM2D) and Itasca Corp.’s Particle Flow Code in Two Dimensions (PFC2D). This work is being carried out by the Spokane Research Laboratory of the National Institute for Occupational Safety and Health to determine the usefulness of computer modeling to improve ore pass design. The types of tests included pendulum tests to validate WM2D simulations and simulated single-rock drop tests in both WM2D and PFC2D to understand their contact models. Simulated rock impacts at the ore pass chute and the use of inclined ore passes and doglegs were investigated in both programs. A PFC2D simulation showed that dynamic loads at the chute gate were reduced significantly when a dogleg transition was used, and simulations in which the ore pass was inclined showed significant reductions in chute impact loads compared to simulations of a vertical ore pass. A released hang-up was simulated using PFC2D.

By K A. Bunker, A D. Campbell, E Ah Mu, A R. Penney

The Ernest Henry mine is a transverse sublevel cave (SLC), which is relatively unique due to the 45 degree inclination of the orebody. To economically recover ore, each sublevel is horizontally offset from the previous level by around 25 m, depending on the orebody geometry. Mine development, slotting and initial production within this zone occurs in a high stress abutment that increases in magnitude at depth. These areas are seismically active and close to the hanging wall where cave propagation is yet to initiate. High stress conditions and the close proximity to the cave seismogenic zone results in challenging geotechnical conditions in the step out zone of each level and requires management of hazards including stress driven rockfalls, rock bursts and pillar failure.This paper outlines how these hazards were forecast using numerical modelling and geotechnical monitoring. Risk management techniques included dynamic ground support design, development of a new mine layout and extraction sequence as well as delayed re-entry into seismically active areas. Ongoing monitoring, instrumentation measurements and field observations were used to track the effectiveness of the controls.Future production levels are forecast to experience increasing stress and seismicity, which will increase demand on excavations and installed ground support. Ensuring the techniques and controls for monitoring, measuring and mitigating stress and seismic hazards are enforced is essential for continued safe production.CITATION:Campbell, A D, Bunker, K A, Ah Mu, E and Penney, A R, 2016. Managing stress and seismicity in an inclined sublevel cave, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 319–328 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By P. C. Fletcher, E. Kaya

The Bond grindability testing procedure has been standardized to measure the same grindability values, i.e. Bond work index (BWi), for the same ore when tests are performed in different laboratories or by different operators. This is accomplished by the standardization of mill dimensions, tumbling speed, grinding ball charge weight and distribution, sample ore charge weight in the mill and operating practice. The results of this investigation reveal that the Bond work index grindability values may differ substantially with different standard Bond ball mills. This paper will review the results.

Jan 1, 2002

By Ralph Spickermann

UK Seabed Resources (UKSR) signed a manganese nodule exploration contract with the International Seabed Authority on 8 February 2013 for a 58,000 km2 tract on the eastern edge of the Clarion Clipperton Zone (CCZ). UKSR is a private company based in the United Kingdom and established primarily to develop the commercial potential of the CCZ deposits. This is the first of many anticipated regulatory, market and technical milestones that are requisite for (1) environmentally responsible commercial scale production of nodule derived metals and (2) generation of revenue through their sale in the global commodities market. This presentation will describe the progress made to date in this effort and an industry-based perspective on the tasks and challenges that may lie ahead.

Sep 1, 2014