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By Joshua Taylor Drake

This report answers specific questions concerning underwater blasting considerations, and blasting safety. The blasting considerations discussed consist of basic blasting principles, and new variables to be accounted for. Blasting safety will include the safety of personnel and structures. The environmental considerations will also be discussed with mitigation methods. To be most effective, this document requires the reader to be familiar with key fundamentals of explosive engineering. In order for a blasting professional to benefit from this report, the following questions will be asked:

Jan 1, 2015

By D Pilone

The Tyrrhenian micro-nodules, findable at low depths (200/600 m under s l) are a reasonable reserve of manganese. They can be easily and cheaply recovered but do not contain valuable metals as in the case of oceanic nodules. In this work a hydrometallurgical process for manganese recovery from Tyrrhenian nodules is presented. The studied treatment includes the following operations: magnetic enrichment, reducing leaching, leach liquor purification and electrowinning . The study shows that the most important step in the process is the preliminary manganese enrichment. It can be done directly on the platform reducing not only the transport cost, but also the residue mud in the metallurgical plant. The leaching parameters such as status and size of nodules, temperature, composition of leaching solution and S/L ratio have been investigated. After purifying the leach liquor by iron precipitation as ammonium jarosite , the conditions to electrowin manganese have been investigated. The yields of both manganese leaching and iron precipitation together with current efficiency and specific energy consumption in the electrowinning step are given.

Jan 1, 2000

Drill blasting is a widely used method for rock fragmentation in mining, quarrying and construction industries. Environmental effects such as air shocks, dust, flying rocks and ground vibration are unavoidable results and undesired effects of blasting. Among these ground vibrations can have a damaging effect and may influence on long distances. Therefore various researchers have developed mathematical models to predict ground vibration after blasting. These models take into account the amount of explosive, distance and several coefficients related to the field under investigation. The developed models to predict ground vibration may yield different results for the same case. Selection of the most suitable model requires engineering judgment and evaluation of models. At this point, a computerised system helps the engineer to evaluate and select the most suitable model in order to design and plan a blasting pattern. The safe charge of explosive and magnitude of vibration after blasting should be predicted beforehand. Therefore a computer program namely 'prediction of blast induced vibration' (P-BIV) has been developed. This paper introduces and presents a computer program (P-BIV) which includes the set of models developed to estimate ground vibration to provide blasting engineers a tool to determine the amount of explosive for safe blasting.

Dec 6, 2010

By Rolf Schillinger

Blasting activities on the surface or underground necessarily involve the most sensitive aspect of environment remediation, human response or annoyance. Such effects are unavoidably characteristic of those activities. For this reason, blasting activities are governed by law and official regulations under surveillance of authorities, where companies and explosives engineers have to proceed within proper limits. Subject of the paper is a practical way of handling some necessary vibration standards being focused on blasting activities. The paper is based on the German Standard DIN 4150, Part 1 - 3, “Vibration in buildings”, Part 1: “Prediction of vibration parameters”, June 2001, Part 2: “Effects on persons in buildings”, June 1999 and Part 3: “Effects on structures”, February 1999.

Jan 1, 2006

By Arun .. J. Basu

The paper introduces Intelligent Air Management (IAM) as the core activity of M&I Group of Companies (M&I) for providing a total solution to any air management problems for mining and mineral processing operations implementing a comprehensive systems approach through a world-wide network of strategic alliance partners and in-house engineering team and manufacturing facilities in Mississauga, Ontario, Canada. Recommendations for energy-efficient ventilation in a vibration and noise free environment are made with the patented and innovative solutions supported by extensive computational fluid dynamics (CFD) studies. The solution scope extends from an intelligent and integrated exhaust silencer to a complete ventilation sys-tem solution including inlet and outlet control design and ducting for diffusers and silencers.

Apr 1, 2005

By O. Bouaziz, O. Magnea, P. Cugy, E. F. Rauch

The experimental difficulty to perform Equal Channel Angular Extrusion (ECAE) of a bulk sample of hard material such as steel was overcome. The original method proposed in this paper consists in replacing the bulk sample by a stack of alternated hard metal (steel) and soft metal (aluminium) sheets. By applying this procedure to an Interstitial Free steel (IF steel), 2.7µm grain sized material was obtained after recrystallisation. Its mechanical properties (hardness, formability in shear, hardenability and faigue limit) were investigated and compared with the properties of the same IF steel with conventional grain sizes (12m and 25µm).

Jan 1, 2004

By Jonathan Taylor, Irwan Halim, Frederick (Rick) Vincent

The new underground facilities for the LINAC Coherent Light Source project at the Stanford Linear Accelerator Center in Menlo Park, CA, are constructed in very weak sedimentary rock interspersed with uncemented zones. In addition to several 21-footwide (excavated) tunnels, the NATM excavations include a large, 49-foot wide (excavated) cavern, an unprecedented size in this geology. The critical design issues include characterization of the weak rock, some shallow rock cover areas, and very stringent criteria for final invert slab movements within the tunnel. The design also incorporated severe seismic criteria, since the site is in close proximity to the San Andreas Fault.

Jan 1, 2007

By C. Bise, A. Seal

Excessive noise has long been a hazard in the coal-mining industry. Studies conducted during both the mid-1970s and the mid-1990s consistently show that hearing hearing loss within the mining industry persists, in spite of regulatory requirements and sampling technology advances. When MSHA’s new health standards to protect miners from hearing loss took effect in September 2000, the potential developed to re-evaluate sampling approaches with regard to noise-source hazards, such as task-based methods. This paper describes results from a Penn State research project currently being conducted at an underground coal mine. Each occupation was reviewed, and a list of tasks or processes performed by each was generated. Traditional personal noise dosimetry, static sound pressure levels, and equipment sound mappings have been performed. Job tasks indicating the greatest levels of daily noise exposure and contributions to noise dose have been identified and will be discussed.

Jan 1, 2001

By K. Wongaew, R. F. Cook, J. E. Carlson, T. Cleys, C. R. Smith

Steel fiber reinforced concrete segmental rings are the final tunnel lining for approximately 85% of the alignment for a 6.706-meter (22-foot) internal diameter tunnel being built as part of the East Side Combined Sewer Overflow Tunnel Project. This paper describes the approach adopted for the design of the steel fiber reinforced concrete segments, the development of the performance criteria for the segments, and the testing program used to confirm the performance of the materials and segments in the laboratory and in the field.

Jan 1, 2007

By Walter Frank

The purpose of the work covered by this contract is to develop a ground and pilot conductor connector which will significantly improve mine trailing cable splice performance. This work compliments the work completed under Contract 00357100 on the development of crimp connectors for the phase conductors of trailing cables. A brief discussion on splice problems is presented as an introductory means and substantiates the need for the development and test programs outlined in this report. As with the phase development work, the ground and pilot connector work is essentially of an empirical nature. As a result time is devoted to explaining the derivations of the test procedures used. In order to familiarize the reader with connector terminology a section is devoted to a glossary of pertinent terms. The connector design effort includes connectors for splicing ground and pilot conductors. A distinction is made between connectors suitable for splicing round and flat ground configurations. The same also applies to the pilot conductors. During the course of this work, much time has been devoted to the question of suitability of round cable configurations for trailing cable applications. This is discussed in detail along with resulting conclusions and recommendations. A field test program was conducted in order to confirm ground and pilot connector laboratory data. This testing also determined the viability of the connector designs and recommended installation techniques in a mine environment.

Jan 1, 1979

By Paul Staples, Chris Morley

"The development of the Cerro Verde, Amplats Mogalakwena and Boddington projects over the last few years has helped to establish the use of high pressure grinding rolls (HPGR) in comminution circuit designs in large-scale hard-rock applications. The increasing acceptance of this innovative and sometimes controversial technology has had the natural effect of prompting many other new projects to examine HPGR as an alternative to the established, usually SAG-based, comminution circuit design approach.At the current stage of development of the technology, HPGR-based circuit capital costs are generally higher than for the equivalent SAG-based circuit, so that HPGR must offer sufficient operating cost benefits to offset the additional capital costs over an acceptable pay-back period. It is usually necessary to undertake comprehensive project-specific trade-off studies to quantify this effect.This paper describes the processes involved in the execution of a typical SAG-HPGR trade-off study, from the preliminary assessment of ore characteristics and project criteria, through testwork, circuit modelling, equipment selection and cost estimates, to a project-economics comparative assessment of the options. The trade-off study determines both the technical feasibility of the respective technologies and their commercial viability in the given project setting.The paper concludes with a cautionary note to the effect that, while HPGR has many potential benefits, it is not a panacea, and that, for some ore types and project conditions, the more established conventional technologies are often more appropriate."

Jan 1, 2010

By Andrew K. hg` Officer, A. L. Griffiths, J. Andrew Hindmarch, Gert Wittneben

Durban Harbour in South Africa is one of the continent’s busiest ports however the harbor entrance is currently too small for the new generation of container ships. There-fore it is to be deepened and widened by the National Ports Authority in the near future. An existing immersed tube tunnel carrying major sewer, water and other utilities under the harbor first needs to be removed and replaced by a deeper 4.4 m ID ser-vices tunnel. Construction of the deeper tunnel saw the first use of a slurry machine in South Africa and was required to negotiate grades up to 20%.

Jan 1, 2007

By Montaser S. EL Salmawy, Takahide Wakamatsu, Eishi Kusaka

"The effect of ethoxylation of long chain alcohols on the quartz and feldspar flotation behaviors was investigated for surfactants of the octylphenol polyoxyethylene family. The tests were carried out with an average of 7.5 (Triton X 114), 9.5 (Triton X 100), 30 (Triton X305), 40 (Triton X 405) and 70 (TritonX 705) oxyethylene units. Electrokinetic and flotation studies on quartz have shown that at low pH values, quartz could be floated with polyoxyethylene octytlphenols. The possible mode of adsorption of these nonionic surfactants may be suggested to be due to hydrogen bonding between the oxygen of ether and hydrogen in the free hydroxyl groups on quartz surface. It was anticipated that the selectivity between quartz and microcline would decrease as oxyethylenic chain length increases.Electrokinetic methods were used to elucidate the mechanism of surfactants adsorption and to correlate these findings with the optimum flotation conditions. The polymeric surfactants would reduce the negative values of zeta potential of quartz while the reverse is true for feldspar. After treatment of microcline with HCl, its electrokinetic behavior in the presence of Tritons X surfactants became similar to that of quartz.The obtained results would suggest that separation of quartz from feldspar using nonionic surfactants of octylphenoletoxylated alcohols having shorter oxyethylenic chain length at low pH could be achieved"

Jan 1, 2003

By D. A. Grieve

"Mineable coal seams in the East Kootenay region belong to the Mist Mountain Formation of the Jurassic -Cretaceous Kootenay Group. Three structurally separate coal fields (Crowsnest, Elk Valley and Flathead) are recognized, all of which are characterized by compressional tectonic features such as f aiding and thrust faulting, and by /ate-stage normal faulting. Tectonic history has greatly influenced coal mineability and quality. Coals range in rank from low to highvolatile bituminous, and reactive maceral content ranges from less than 60% to greater than 90%. A wide range of metallurgical and thermal coal qualities is found. Measured reserves (up to 1981) include 1.03 billion metric tonnes metallurgical and 165 million metric tonnes thermal coal. Introduction a) Location -Coal fields of the East Kootenays region occur in the Front Ranges of the Rocky Mountains, within 30 km of the Alberta -British Columbia boundary (Fig. 1). They extend over 175 km north from near the U.S. border, and occupy the regions of the Crowsnest Pass and Elk and Flathead River drainages. The deposits are accessible from Highway 3 (Fig. 1) and various secondary roads. The towns of Fernie, Sparwood, Elkford, Coleman and Blairmore serve the coal industry. East Kootenay coal deposits are contained in three structurally separate coal fields, the Crowsnest, Elk Valley, and Flathead coal fields (Fig. 1). Coal is currently being produced by B.C. Coal (now Westar Mining Ltd.) at Sparwood, by Fording Coal 20 km north of Elkford, by Crows Nest Resources at Line Creek 15 km southeast of Elkford, and by Byron Creek Collieries at Corbin. Westar Mining has also constructed a new mine on the Greenhills Range 8 km northeast of Elkford. Pre-requisite engineering and environmental studies have been carried out on the Elco Mining property, 35 km north of Elkford, and on the Sage Creek coal property near the U.S. border (Fig. 1). b) Coal land tenure -Coal rights in the East Kootenays are either held as freehold land, or are licensed from the provincial government. The former category includes lands acquired under the Railroad Act of 1890. Shortly after this the federal government also obtained 50,000 acres of coal-bearing lands from the Crown Provincial, the so-called Dominion Government Coal Blocks. Major holders of coal rights in the area are Westar Mining and Crows Nest Resources. Large blocks are also held by Fording Coal and related companies, Sage Creek Coal, and Canada Permanent Trust Company as trustee for Elco Mining, and small blocks are held by Byron Creek Collieries and Coleman Collieries. In addition the provincial government holds an area in reserve for possible future use of B.C. Hydro at the extreme north end of the Elk Valley coal field."

Jan 1, 1985

By David P. Lindroth

The objective of this research by the Bureau of Mines was to determine the technical feasibility and associated pilot data for drying minus 1/4-in coal with microwave energy at a frequency of 2.45 GHz. The drying data were obtained experimentally on three coal types: bituminous, subbituminous, and lignite. The experiments were performed with a custom-designed conveyorized microwave oven having a continuous power capability of 12 kW. Drying efficiencies near the theoretical maximum of 1.54 kg of water per kilowatt hour of energy input were achieved for two coals and two sizes; overall drying efficiencies averaged 77 pct.

Jan 1, 1986

By G. B. Hudson

Previous papers (1, 2) pertaining to the treatment of uranium-bearing ores were concerned with the flotation of the radioactive minerals. In this investigation, the application of flotation to the removal of acid-consuming minerals from uranium ores was considered. Two pitchblende-bearing ores, which, because of the presence if dolomite were abnormally high acid consumers, were studied. In both in-stances commercial reagents of widely varying fatty acid composition proved satisfactory as flotation col-lectors, particularly at a pH of 10.5, for the carbonate minerals. From an economic viewpoint, however, Neo-Fat 42-12 was favoured. A mixture of sodium tripolyphosphate and citric acid was an effective depressant for the pitchblende in the ores. The tailings remaining after the removal of the dolomite by flotation contained, in one case, 88.5 per cent of the uranium in the original sample, and, in the other, 93.8 per cent. Analyses conducted on these tailings and on the original ores showed that

Jan 1, 1963

By PHILIP N. MOORE

THE development of the power of the Tennessee River at Muscle Shoals has become a matter of political interest as well as engineering possibility. The controversy over it has been so active that the facts have been obscured, the possibilities exaggerated. Although the members of the American Institute of Mining & Metallurgical Engineers are not generally specialists in hydroelectric development, those who visited Muscle Shoals in October, following the Birmingham meeting of the Institute, were interested, and many of them surprised to learn the actual conditions. These have long been familiar to those who have studied the matter through the reports of the U. S. Engineers on the subject. The approved plan contemplates three dams-No. 1, a low dam close to the City of Florence, planned in the interests of navigation, since the construction of the other dams has rendered impossible the use of the river without it. No. 2-named the Wilson Dam is now under construction. Concerning it political argumentation has waged. No. 3 Dam-much smaller, is planned to be erected several miles above No. 2.

Jan 1, 1925

By L. Scott, M. A. Goncalves

Effective communication is a sought-after non-technical skill in the health, safety, and environmental (HSE) function and is fundamental in achieving an organization’s safety objectives. While different channels are used to communicate HSE matters, many organizations employ posters, videos, and/ or signs containing images to convey information. Communication through signage and graphical hazard symbols has been regulated in standards, but vast sections of HSE communication are bespoke communications and exist outside the sphere of standards. Effective HSE communication through images requires an understanding of the organizational culture in which the images will be used, as well as an understanding of the semiotics of the images themselves. Creative interpretation within HSE communication can create situations where the message that was received is not the message that was intended, leading to confusion and misinterpretation. This paper is aimed at elucidating the semiotics of South African HSE visual content. It was found that the indexical mode of images was most preferred in visual communication, and text-only designs the least preferred. Senders and receivers of messages differ in their opinions on the complexity of HSE communication.

Feb 2, 2021

By Siavash Mahvelati, Alireza Kordjazi, Joseph Thomas Coe

Deep foundations are often constructed as end bearing members with a significant amount of their capacity derived from bedrock. Sites with highly variable bedrock conditions therefore present a unique challenge when attempting to estimate the design elevation of deep foundations. Typical subsurface characterization techniques such as drilling, standard penetration testing (SPT), and cone-penetration testing (CPT) may fail to adequately establish top-of-rock elevation in geologic settings prone to karst and/or significant amounts of residuum, saprolite, and deformed bedrock. Seismic surface wave geophysical methods have been increasingly used to map bedrock topography in such settings. However, the current standard of practice for these methods introduces resolution limitations in spatially variable subsurface conditions due to averaging effects from the analytical framework used to process the acquired data. This study explores the use of a tomographic approach with full waveform inversion (FWI) to map top-of-rock elevations at a numerically simulated site representative of highly variable bedrock topography. Comparisons are made with seismic refraction (SR) and a dispersion-based multichannel analysis of surface waves (MASW) approach as more commonly used in geophysical subsurface investigations. The results highlight that FWI provides a superior estimate of top-of-rock topography than SR and MASW at a cost of a significant increase in the required computational resources and time.

Sep 8, 2021

By Siavash Mahvelati, Alireza Kordjazi, Joseph Thomas Coe

Deep foundations are often constructed as end bearing members with a significant amount of their capacity derived from bedrock. Sites with highly variable bedrock conditions therefore present a unique challenge when attempting to estimate the design elevation of deep foundations. Typical subsurface characterization techniques such as drilling, standard penetration testing (SPT), and cone-penetration testing (CPT) may fail to adequately establish top-of-rock elevation in geologic settings prone to karst and/or significant amounts of residuum, saprolite, and deformed bedrock. Seismic surface wave geophysical methods have been increasingly used to map bedrock topography in such settings. However, the current standard of practice for these methods introduces resolution limitations in spatially variable subsurface conditions due to averaging effects from the analytical framework used to process the acquired data. This study explores the use of a tomographic approach with full waveform inversion (FWI) to map top-of-rock elevations at a numerically simulated site representative of highly variable bedrock topography. Comparisons are made with seismic refraction (SR) and a dispersion-based multichannel analysis of surface waves (MASW) approach as more commonly used in geophysical subsurface investigations. The results highlight that FWI provides a superior estimate of top-of-rock topography than SR and MASW at a cost of a significant increase in the required computational resources and time.

Oct 1, 2021