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By Mark R. Svinkin

Construction vibrations may be harmful to adjacent and remote structures, sensitive instruments and people. Construction vibration sources have a wide range of energy, displacement, velocity and acceleration transmitted on the ground. Effects of different dynamic sources and soil conditions on construction vibrations is analyzed. Consequences of construction vibrations are developed in various ways. It is important to assess intolerable vibrations before the beginning of construction activities. Guidelines for preconstruction survey are presented. Pre-construction survey and prediction of anticipated vibrations by IRFP method, monitoring and control of measured vibrations are important steps in preventing intolerable vibration effect.

Jan 1, 2000

By T. Bajpayee, L. Prosser, A. Iannacchione

Reducing the number of roof fall injuries is a goal of the NIOSH mine safety research program. Central to this effort is the development of assessment techniques that will help to identify the nature of the risks associated with working under potentially hazardous roof conditions. This paper discusses a method to determine the roof fall risk using a qualitative risk analysis technique. The ability to determine roof fall risk has been a long-standing goal of safety professionals and can provide the kind of information, needed by on-site personnel responsible for worker safety, to mitigate roof fall injuries.

Jan 1, 2007

By Wayne E. Kilker, Michael J. McBride, William P. Levy, Thomas J. Lamb

Between 1989 and 2004 the Massachusetts Water Resources Authority (MWRA)constructed several major wastewater and water tunnels associated with three major projects in the Boston area of eastern Massachusetts. There were many similarities and differences in the bedrock conditions encountered and among the contractual approaches for these independent projects. Through a clarification of the approach similarities and analysis of the contract differences, this paper addresses and presents what are considered to be valuable lessons learned. In doing so, the paper follows the evolution of such disparate issues as contract conditions, baseline reports and dispute review boards. The authors believe that the lessons learned even represent what, in certain cases, could be referred to as “universal truths” that are intended to have application to the next generation of tunneling contracts.

Jan 1, 2005

Ammonium nitrate-fuel oil (ANFO) explosives are unstable in hot, reactive sulphide-rich ground at Mount Isa. Under certain conditions associated with background heat, moisture, and chemical impurities from natural oxidation, ANFO composites in contact with hot ground disproportionate and the ammonium nitrate can undergo rapid exothermic reactions with sulphide.Reactions can occur in confined charges from prolonged contact with reactive sulphides, or by contamination with sulphide in loading. Partial interaction can result in misfires or premature detonation. Spilt, scattered and unpropagated explosive will undergo further reaction in sulphide-rich environments. ANFO-sulphide interaction is invariably exothermic and causes an irreversible chemical transformation of the ore.The heat generated during reaction may be dissipated, heating the environment, or rapidly accumulated to yield hot spots or areas in excess of 400°C. These can result in forced ignition of bulk sulphide and sustained combustion.Thermal analysis was used to define the critical conditions for ANFO-sulphide interaction and sulphide combustion.The occurrence of incandescent ore is attributed to the thermal interaction between exothermic hydrolysis oxidation, ANFO-sulphide, and combustion processes.Chemical agents and control methods have been developed to prevent ANFO-induced oxidation and combustion.

Jan 1, 1968

By D. R. Hanson, H. Lawson

In this study, NIOSH researchers conducted a machine learning analysis to examine whether a model could be constructed to assess the probability of dynamic failure occurrence based on geochemical and petrographic data. Random forest, cluster analysis and dimension reduction were all applied. The objective of dimensionality reduction was to explore patterns and groupings in the data and search for relations between compositional parameters. Cluster analyses were performed to determine if an algorithm could find clusters with given class memberships and to what extent misclassifications of dynamic failure status occurred. A random forest analysis performed on data from the Pennsylvania Coal Sample Databank cross-referenced with accident data from the Mine Safety and Health Administration (MSHA) determined that 7 parameters of the 18 examined exerted the most influence on results. Cluster analysis on data after dimensionality reduction resulted in a hierarchal clustering algorithm finding four clusters, with one relatively distinct dynamic failure cluster, and three clusters consisting mostly of control group members but with a small number of dynamic failure members.

Feb 1, 2023

By C Laming, P M. Hetherington, F A. Pym, M P. Murphy, K E. Crook

Reconciliation is a powerful tool used by mining operations to compare the mass and grade of ore produced with what was estimated before mining. The primary objective of reconciliation is to verify that the estimated planned metal production is achieved during processing, allowing issues to be identified for which adjustments can be made throughout the mining value chain to improve recovery and maximise efficiency. Traditionally, the mine plan is based on estimated mine grades using sampled exploration drill hole or blasthole grades. Reconciliation discrepancies between the mine plan and mill are common due to such factors as insufficient or non-representative sampling, poorly conceived models, or unrecognised blast movement. MineSense Technologies Limited® (MTL) has developed an X-ray fluorescence (XRF) sensor-based ore classification system that is installed on mining equipment to provide real-time grade estimates of run-of-mine material at bucket, truck, or belt-scale. Bucket level grade estimates provide insights into grade variations at the mine face that were never before available. This data set eliminates some of the leading causes of reconciliation discrepancies and enables tracking of tonnages and grades from the mine face to the processing plant at bucket resolution with confidence. Bucket-by-bucket grades at the mine face enable dynamic optimisation of the mine plan to stabilise the mill feed grade through blending of mine and stockpile loads. Beyond stabilising feed grade, Mine to Mill reconciliation combined with the full XRF spectrum response can generate proxy relationships to ore characteristics like hardness and recovery. These properties can then be predicted at the mine face, enabling further optimisation of the downstream mill feed, not only for grade, but also for power and water consumption, reagent addition, and recovery. This paper presents the benefits of MTL technology for grade reconciliation and mill performance optimisation at a Cu Mine in BC (Canada).

Mar 22, 2022

The kinetic and practical aspects of the extraction of copper from copper-rich solutions by cementation on iron was investigated. Tests were made on the effect of stirring speed, cupric sulphate concentration, acid concentration, temperature, and ferric sulphate concentration on the reaction rate and excess iron consumption.Most kinetic investigations were conducted under a nitrogen atmosphere to prevent any oxidation of the iron or copper metals. The stirring mechanism for all tests incorporated the use of a rotating impeller above a static disc in the solution. The activation energy for cementation on the steel disc at high stirring speed was 8·6 kcal/mole, indicating a predominant chemical control.Increasing the pH first decreased, then above pH 3, increased the reaction rate. Additions of sodium sulphate also significantly increased the reaction rate.The use of high temperature and high pH under an inert atmosphere has been suggested for increasing the reaction rate and producing a high purity sponge copper product.

Jan 1, 1972

By Daniel W. H. Su

The importance of incorporating fundamental principles of rock material response and failure mechanics into a pillar strength design model has been demonstrated. To accurately assess pillar strength, a model should account not only for the characteristics of the coal, but also for those of the surrounding strata. The interactions between the pillar and the surrounding roof and floor dictate ultimate pillar strength. Confinement, or the lack thereof, provided by roof and floor frictional end-constraint is one of the most significant factors in the strength of very wide pillars. The best conditions for end-constraint occur with ideally strong roof and floor. In this paper, it will be shown that weak roof and floor may decrease the ultimate pillar strength by as much as 30% compared to ideal conditions. Field observations confirm this pillar strength reduction in the presence of weak roof and floor. Furthermore, rock partings within the coal have a variable effect on pillar strength, depending on the parting strength. A competent shale parting within the coal reduces the effective pillar height, thus increasing the ultimate pillar strength; a weak claystone parting slightly decreases the strength. Imposed load distribution also has a significant effect on pillar strength, such that asymmetric pillar loading, similar to that observed in pillars adjacent to high extraction mining, reduces the ultimate pillar strength below that of equivalent pillars subject to uniform load distributions.

Jan 1, 1997

By Gary A. Kingston

Low-cost hydroelectric energy in the Pacific Nortnwest has been an important factor in the development of a ferroalloy industry. Eleven companies, employing approximately 1,000 persons, produce about 116,000 tons (1954-58 average) annually of ferrosilicon, ferrochromium, ferromanganese, ferrophosphorus, silicomanganese, and ferronickel. About 7,500 tons (1954-58 average) of these ferroalloys is consumed in the Pacific Northwest States of Washington and Oregon; the rest is used principally in other western and mid-western markets. In 1959, the Bureau of Mines began a study to determine the current status and to evaluate the potential of the ferroalloy industry in the Pacific Northwest. The Bureau gathered information from operating alloy plants in Oregon, Washington, Idaho, and Montana; from published materials; and from consumers of ferroalloys.

Jan 1, 1962

By A. B. Hooker, Ilsley. L. C.

"Several writers have called attention, in the technical press, to the possible failure of flame safety lamps in coal-dust laden atmospheres. Such writers question the safety or a flame lamp that has been proved only in atmospheres containing methane, believing that the resistance of the lamp to explosion would be lessened it coal dust constituted a part of the explosive mixture.If this be true, it follows that any series of tests devised to prove the safety of flame lamps for use in gaseous and dusty coal mines should not only embrace tests in mixtures containing various proportions of methane, but also in some of the tests the effect of adding coal dust to the explosive gaseous mixtures should be investigated.Some attention has been given this question by investigators, but the more common practice has been to make all tests in gas and air mixtures only, using methane when it was readily available. Apparently the English Accident Committee (1879-1886) who conducted tests upon 250 different lamps did not use coal dust in their tests. The first British requirements for the testing of safety lamps, issued as a result of the Coal Mine Act of 1911, made no mention of tests with coal duet.The Austrian Fire-damp Committee (1890) conducted a series of tests in which coal dust was used in some of the tests. In certain tests, the addition of coal dust apparently lowered the resistance of the lamp 1 meter per second. The Belgium investigators, Messrs. Watteyne and Stassart, conducted a series of tests in 1904 in which coal dust was used in a few tests without any marked difference in safety."

Dec 1, 1920

The discussion which followed the publication of my paper by the formert has, I think, enhanced its value. It may therefore be of interest to members of our Australasian Institute, who are not members of the Institution of Mining and Metallurgy, if I give a synopsis of the discussion.My attention was drawn to the fact that my paper did not make clear the extent of the improvement in furnace operations, which followed the use of coke of high quality; this comment applied more particularly to the lead content of slag. My failure to supply comparative figures in regard to the lead content of slag was governed by a condition which, I think, is of interest to metallurgists. As a result of industrial...

Jan 1, 1932

By Boden A

A procedure was developed for recovering metal values from copper-smelter fume. The fume is first leached to neutrality with dilute sulphuric acid to obtain a solution of zinc sulphate containing a low level of impurities. The tailings from this leach are treated with hydrochloric acid in two stages, in which tin and zinc are quantitatively leached and recovered as a tin concentrate and a zinc sulphatelzinc chloride solution.About 80 per cent of the lead sulphate is converted into lead chloride, which can be recovered as a pure product.Data on the effect of temperature, acid concentration, aeration, and solid/liquid ratios on the hydrochloric acid leach are presented, and the fate of the most important metals during the recovery process is described. Alternative treatments of the tailings from the neutral sulphuric acid leach were briefly investigated.

Jan 1, 1977

In a field test at Mount Isa Mines Ltd., a system developed by ICI Australia Ltd. for bulk loading "MOLANITE", an ammonium nitrate slurry blasting agent into ring drilled holes of wblcvel open stopes, was shown to be satisfactory. The fragmentation produced by the slurry was a significant improvement over ANFO and the stope production rate was increased by approximately 50%. Indications are that the charging rate and labour costs will not be greatly changed if a slurry system is used.

Jan 1, 1973

By R. Larry Grayson, Joel R. Warneke

The mining industry has searched for a message that will resonate with the public while focusing on the industry’s positive contributions to society. So far, environmental groups remain unconvinced and the public is still largely uninformed. In the authors’ opinion, a number of recent events and experiences have converged to help shape a more effective public communication on mining’s important role. This article presents a perspective on coal’s role in sustaining society by anchoring the message in a transparent way, including a material flow analysis, that links coal’s impacts across a range of social and environmental aspects. Past and continuing image problems In her 1994 paper, Nancy Bingham, with Caterpillar, outlined what the public thought about mining. Based on extensive interviews, the following results were found: • The public believed mining harms the environment. • The public believed mining harms people in nearby communities. • The public believed mining exploits workers. • The public believed mining has little personal benefit to the individual.

Jan 1, 2006

In the extraction of level bridge pillars in the South Mine by square-setting methods the general practice is to work transversely from the hanging wall in narrow sections three or four sets wide to the depth of the bridge-usually three sets. When the working block attains an area of twelve square sets, sand filling is run in, either by pneumatic (Proceedings No. 123, 1941) or hydraulic methods, in order to control the settlement of the general area and prevent the development of undue weight in the stope. Upon completion of the filling operations, or coincident with them, ore breaking is resumed and the transverse section of the bridge pillar gradually reduced. A number of these parallel sections may be working at the same time.In preparing a block of sets for filling a great deal of paddocking is required, both to contain the filling and to preserve access to ladderways and ore chutes which may be situated at some horizontal distance. Stope paddocking until recently was constructed of 10 in. x 2 in. boards nailed...

Jan 1, 1942

By T Atchison

The Vale Ferro Carajßs S11D project in northern Brazil is based on the movement of unprecedented volumes of waste and ore for mobile in-pit crushing and conveying or ætrucklessÆ systems. In peak years, the system is intended to handle a combined 160 Mt of material.The planning and implementation of the first such system for Vale, in a remote greenfield site, utilising the services of a range of international study, design and supply partners has provided a unique set of technical and project delivery challenges. The lessons from these are of value to the industry as the trend to remote and high-volume operations continues.This paper describes the key features of the mining system and documents the challenges and mitigations for important technical, cultural and project delivery issues that have arisen. It is a combined description of the journey taken by both Vale (as owner) and SKM (as delivery partner) over the course of many years.CITATION:Atchison, T, 2013. Lessons from the S11D truckless mining project, in Proceedings Iron Ore 2013 , pp 177-184 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By Matthew S. Sanchez, Richard J. Lee, Matthew D. Zock, Drew R. Van Orden, Yumi Kamiya, Edward B. Ilgren

In many developing countries, asbestos is still used for friction products, insulation, and asbestoscement products. However, there is very limited modern data evaluating the airborne concentrations of asbestos fibers in operating asbestos plants. We have conducted an Industrial Hygiene survey, using state of the art PCM and TEM analysis, of a Bolivian asbestos cement plant that uses crocidolite during the production of roofing shingles and water tanks. The study is the first to use modern analytical measurements in an uncontrolled asbestos environment. Thus, this study offers insight into the historical airborne exposures at asbestos plants operating before modern dust control measures were introduced or airborne fiber levels regulated. The results suggest that fiber concentrations are far in excess of those for which current models would predict the onset of asbestos disease and mesothelioma. Significantly, the plant and community do not have an elevated incidence of asbestos disease or mesothelioma. Airborne fiber levels during comminution and fiber sizing ranged from 100 to as much as 1,000 f/cc. Fiber levels in the mixing, forming and finishing areas ranged from 0.5 to 9 f/cc. Based on the number of overloaded samples and estimates of their concentration, historical estimates of exposure may be underestimated by an order of magnitude. Also, an excellent correlation (1:1) between the PCM and TEM fiber concentrations (for fibers _0.25 um diameter) were obtained, raising questions about the conventional wisdom that the PCM systematically undercounts fibers. The results of this study further indicate that current models may overestimate the risk of asbestos disease and mesothelioma.

Jan 1, 2012

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 Larry DeGraff

With the increase of new mine development in the past several years, many coal mines have decided to self- perform the design and construction for their slope development projects. The development process of determining the proper configuration is challenging, and a major economical consideration. Greenbrier Smokeless Minerals engineering staff and consultants, along with DSI/American Commercial, developed a support configuration that was best suited for their slope. The developmental process took into consideration the length of slope, depth of slope at the high-wall transition, economics of a single or multiple entries, waterproofing, stresses on the steel supports and lagging during the backfilling operation. This paper describes the developmental concept of using a single entry, side by side configuration, using steel ?Banjo String? supports with steel plank lagging, to develop a long term permanent installation in a cut and cover application.

Jan 1, 2009

By M. E. Volin

The tungsten potentialities of the Combination mine were examined by a mining engineer of the Bureau of Mines in 1947. A report based upon his personal knowledge of the mine and the results of the examination contained recommendations for further investigation. This report presents factual data from Bureau of Mines field investigations begun in August 1947 and continued until December 1948, except for a 5-month recess during the first winter. The Combinat.ion mining property of 52 patented claims and 15 patented mill sites is in the Black Pine mining district, Granite County, Mont., 11 miles northwest of Philipsburg. The altitude in the mine vicinity is approximately 6,500 feet.

Jan 1, 1952