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By Nikolaus Schneider

"Abstract: The combination of failure in joints of diaphragm walls and their exposure to water pressure may have far reaching effects ranging from water leakage to the risk of catastrophic loss of stability for the retaining wall and civil structures behind it. Investigations of imperfect joints in diaphragm walls have led to the development and testing of a quality tool to monitor the joint integrity of diaphragm walls during construction. By applying independent mechanical sensors (“joint inspector”) to the steel frame of hydraulic or mechanical grabs, it is now possible to record the surface conditions of exposed primary joints during the construction of secondary panels. This allows for the implementation of corrective action during the construction process should joint quality not indicate a watertight connection to the adjacent panel. The joint inspector, used for different types of stop ends, was tested on a full scale test field at several construction sites. The implementation of this new quality tool drives a new quality standard for deep excavations in inner city areas.General introduction to diaphragm wallsDiaphragm walls are reinforced concrete elements constructed using bentonite slurry to temporarily support an open trench in the ground. They are used in two main fields of application in civil construction, as foundation elements for vertical and horizontal loads (barrettes) and as retaining walls for excavation pits.Particularly for deep excavation pits in inner city areas, diaphragm walls are used as temporary or permanent walls of retaining walls. Alternative retaining wall systems would be secant pile walls, sheet piles or soldier piles, but these have disadvantages in structural strength when compared to diaphragm walls. If the vertical load of existing buildings next to the excavation pit has to be accommodated, the most practical solution can be found using diaphragm walls supported by prestressed anchors, steel struts or slabs."

Jan 1, 2014

By M. C. Bétournay, J. E. Udd

"The legacy of abandoned mines in Canada creates issues that impact on both the health and safety of Canadians and the environment. Solutions to the problems of abandoned minesites require a detailed understanding of site conditions, the engineering solutions which may be relevant, and planning for effective use of the land. In this paper, the authors outline the basic thrusts that have been developed at CANMET to address this problem. These include: multiprovincial agreements to develop a national database; methods of site rendering; a ten-year research program to develop engineering approaches; the review of a large number of case studies; and outlining the associated risks. Examples of the applications of this research are provided in the areas of: municipal, provincial, and federal co-operative projects; site-specific applications; and international linkages."

Jan 1, 1997

A study of the electrolysis of PbS in molten PbCl2 showed cathode efficiencies which increased with current density at fixed sulphide concentrations, and decreased with increasing sulphide concentration at fixed current densities. The anodically produced sulphur dissolved rapidly in the melt, the rate increasing with temperature and sulphide concentration. Experiments with diaphragm cells, made to determine the relative effects that dissolution of lead and sulphur have on the cathodic current efficiency, demonstrated that dissolution of sulphur was the major contributor to the lowering in efficiency.

Jan 1, 1973

By G. Tiess, S. Mujiyanto

Indonesia is a fast growing democratic developing country comprising more than 17,000 islands, founding member of ASEAN and a member of the G-20 major economies. It is one of the most highly mineralised countries in the world, the mining sector playing a pivotal role in the country's economy. In 2001, the Decentralization Law No. 22/1999 came into force and caused a transfer of authority and responsibility from central to regional and local administrative governments. The new Mining Law of 2009 substituted its 40 year old predecessor, but lacked detailed regulations for its implementation. These were only issued in 2010, which lead to a period of great uncertainty for investors in the mining industry. The new legislation intends to foster domestic economic development, which may be interpreted as protectionist policy. For the development of a sustainable mineral resources policy, further endeavours will have to be made.

Jan 1, 2011

By Zach Ellis, Dusty Fisher

The Office of Surface Mining, Reclamation, and Enforcement (OSM) cited a large surface coal mine for a series of flyrock incidents that occurred when blasting close to the mining lease perimeter. The OSM placed the company on a pattern of violation status. It was determined through analysis of blasting practices that flyrock could be controlled at the mine by drilling a smaller diameter hole and stemming with crushed rock when blasting within 1,000’ (304 m) of the lease line. The procedure to install and remove the small diameter drill steel was cumbersome and dangerous because it was a manual transition. The drill carousel could only hold one diameter at the time the project was initiated. The process was very time consuming, involving a mechanic to transport the steel to the drill and spend up to 1.5 hours of downtime switching the steel. In addition, the hydraulically operated break-out wrench and break-out fork on the SKS Infinity Redrill® is only designed to work with one diameter, so these tools could not be used to disconnect subs and steels on the string. At the time, the mine’s breakdown was between 30-40% small diameter (6 ¾” (171 mm)) versus large diameter drilling (10 5/8” (270 mm)). The drill and blast group was challenged with the task to implement a 6s (Six Sigma) project that would reduce the amount of time spent on steel change-outs on the rotary drills while improving the safety of the task. A solution was proposed to carry the small diameter drill pipe, lower small diameter sub, and small diameter bit on board the drill at all times. The goal of the project was to carry the steel in the carousel after modification so that the driller could change the diameter himself on board the drill in less than 45 minutes without any assistance from a mechanic. The drill had to be modified so that the hydraulic operated break out wrench and deck fork could be utilized on both diameters. The drill accessory supplier and the mine worked together to design and implement design changes and new equipment onto two rotary drills, and new standard operating procedures (SOPs) were created for the new process. The project has been in the sustaining phase for approximately three months now and all steel diameter changes are completed by the operator under the allowable time limit.

Jan 1, 2015

By A. W. Dougall, T. M. Mmola

"SynopsisThe global resources and commodities market has become highly competitive. While southern Africa’s abundance of minerals resources is still unrivalled, it has lost considerable dominance in terms of production output. The sustainability of southern Africa’s mining industry is increasingly becoming dependent on its ability to manage the performance of its operations well. A valuable tool for monitoring and managing performance is the use of key performance areas (KPAs) – which are those areas of performance that are reflected explicitly or implicitly in the vision and strategies of an organization and reflect the critical success factors of the organization. This paper is a review of key performance areas in the southern African mining delivery environment. The KPAs discussed in this paper have been identified by comparing KPAs of the several mining houses engaged in surface mining operations in southern Africa and then extracting those KPAs that are common to most of them. Although the authors support the view that each organization should develop KPAs to specifically fit its needs, the study reveals that five KPAs – safety and health, costs, product quality, fleet management, and delivery should form a default list that covers the key areas that any organization should consider when choosing KPAs. KPIs are those subsets of KPAs that we measure in order to manage KPAs.IntroductionThe global resources and commodities market has become highly competitive. While southern Africa’s abundance of minerals resources is still unrivalled, it has lost considerable dominance in terms of production output. The sustainability of southern Africa’s mining industry is increasingly becoming dependent on its ability to manage the performance of its operations well. A valuable tool for monitoring and managing performance is the use of key performance areas (KPAs), which are ‘those areas of performance that are reflected explicitly or implicitly in the vision and strategies of the organization’ (Barker, 1997). The terms KPA and KPI (key performance indicator) are often used interchangeably – whether correctly or erroneously is debatable. KPIs are ‘quantifiable measurements, agreed to beforehand, that reflect the critical success factors of an organization’ (O’Neill, 2007). Each KPA probably has multiple KPIs associated with it."

Jan 1, 2015

By David Kwietnewski

Roadheaders are gaining widespread acceptance in North America as a means for mechanical tunnel excavation. Until recently, almost all of the large-scale North American tunnel projects were excavated one of two ways ? the tried and true drill-and-blast method or with the use of tunnel boring machines (TBM), the hi-tech super-excavators. TBMs enjoyed fast-growing popularity worldwide as TBM manufacturers offered greater technology to meet the demand of the civil tunnel industry in the late 20th century. Recently, though, more tunnel projects, large and small, can thank the brute force of a roadheader for getting the job done.

Jan 1, 2011

By E. P. Youngman

This paper presents one of a series of digests of foreign mining legislation and court decisions that is being prepared in advance of a general report relative, to the rights of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the mining laws of British Guiana has been prepared from the best available sources in Washington and is, released subject to amplification and correction, if necessary, by United States foreign-service officials. INTRODUCTION The sources of information available in the preparation of this paper are the following: 1. The Crown lands ordinance, No. 32 of 1903, September 26, 1903.

Jan 1, 1934

By James J. Anderson

In this talk I will report on an effort to reassess the risk of pile driving to juvenile salmonids migrating through Puget Sound. The study was motivated by the concern of the construction industry that provisions restricting pile driving during the spring migration is resulting in an unbalanced burden to the industry. In simple terms the industry wants to know if some construction can be conducted in the spring without harming the juvenile fish. Fisheries agencies have agreed to reconsider their regulations in the context of additional studies. So, in this talk I will present some thoughts on risk assessment in general and the results of our study to assess the impact of pile driving on Snohomish River juvenile pink and chum salmon that migrate through the Navy Homeport construction site at Everett. The research, which is being carried out by the Fisheries Research Institute at the University of Washington, was planned and is supported in a joint effort including: the Washington Department Fisheries, National Marine Fisheries Services, U.S. Fish and Wildlife Service; General, Manson, and Hurlen construction companies, the Department of Transportation and a number of Puget Sound ports authorities. I will first briefly discuss the early life history of the juvenile salmon the regulations are designed to protect Second, I will outline the legal criteria required for risk regulation and some specific thoughts on how a reassessment of pile driving risk might be approached. With this basis I will report on our research and how it can be applied to a new risk assessment.

Jan 1, 1990

By Neil Westoll

But First, An Overview of the Selwyn Basin and Its Resources ?World-renowned sedimentary-exhalative (SEDEX) deposits of zinc, lead, silver +/-barite ?Significant reserves/resources remain and vast tracts of prospective stratigraphyremain under-explored and untested. ?More details are at the Yukon Geological Survey?s Selwyn Basin Metallogenysite:http://www.geology.gov.yk.ca/metallogeny/selwyn/ Overview of Metal Price and Demand Trends ?The pace of economic change in China has been extremely rapid since the start of economic reforms just over 25 years ago. According to official statistics, economic growth has averaged 9.5% over the past two decades and seems likely to continue at that pace for some time. National income has been doubling every eight years. Such an increase in output represents one of the most sustained and rapid economic transformations seen in the world economy in the past 50 years.? Organization for Economic Co-operation and Development 16-Dec-2005

May 1, 2006

By Mark S. Sanders

The present study was designed to explore the contribution of organizational climate and management practices to the injury experience in underground coal mines. A cross-lagged panel design was used in which miners from 22 mines completed questionnaires assessing 27 organizational climate, structure, and function dimensions on two occasions, The results strongly support the hypothesis that climate and management practice have casual effect on the incidence of disabling injuries.

Jan 1, 1976

Oil sands processing generates huge volumes of slurry, known as tailings, that is being stored in tailings ponds. The volume of produced tailings is a very important factor in oil sands surface mine planning, because the available area for dam construction is limited to the lease areas. On the other hand, oil sands operators cannot leave mine sites without reclaiming the tailings ponds. Since most of the reclamation material is generated in either oil sands mining or processing, it is reasonable to include reclamation material requirement as part of long-term mine planning. In this paper, an integrated optimization framework is proposed to maximize the net present value (NPV) of the produced oil sands, with respect to tailings capacity constraints and reclamation material requirements. A mixed integer linear programming (MILP) model is developed to find the optimal solution for long-term mine planning problem. A sample bitumen processing flow sheet is used to formulate the volume of produced tailings, based on Clark hot water extraction method. To verify the proposed model, it is coded in Matlab and run using CPLEX. Run results for real-case oil sands dataset show that the optimal production schedule meets material requirements for reclamation, tailings volume is within tailings capacity range in all periods and the production schedule follows the predetermined horizontal direction.

Feb 27, 2013

Precast prestressed concrete piles designed to be end-bearing in a sand stratum at Drax Power Station met with extremely variable resistance during driving. Some piles came to virtual refusal almost immediately on entering the sand whereas others were driven to considerable penetration with very low resistance. Redriving and load tests on piles experiencing low resistance on initial drive showed that take up in strength occurred over a relatively short period of time. Investigations involving the use of pneumatic piezometers revealed the development of significant excess pore pressures during driving. Samples from boreholes showed that piles met the least resistance when the sand had a high silt content. Comparison with the original site investigation data demonstrated the difficulties in predicting detailed pile behaviour. The varied behaviour could not be related to the original borehole logs or to SPT or static cone penetrometer results. The factors controlling pile driving behaviour were essentially geological and could only be explained with reference to local soil grading.

Jan 1, 1989

By R. E. Head

[This paper embodies the data obtained by a detailed statistical, microscopic analysis of the composite mill feed concentrate, and tailing from the Magne and Arthur mills of the Utah Conger Co. for 1 month in 1929. It is one of a series of papers by the same authors5 dealing with the mineralogical characteristics of the ore and concentration products from various well-known plants. The work was done in the cooperateive microscopic service laboratory at Salt Lake and represents the results of cooperation between the United States Bureau u of Mines, the Utah Copper Co. and the University of Utah.]

Jan 1, 1935

By R. E. Head

This paper embodies the data obtained by a detailed statistical, microscopic analysis of the composite mill feed concentrate, and tailing, from the Magne and Arthur mills of the Utah Conger Co. for 1 month in 1929. It is one of a series of papers by the same authors dealing with the mineralogical characteristics of the ore and concentration products from various well-known plants. The work was done in the cooperative microscopic service laboratory at Salt Lake and represents the results of cooperation between the United States Bureau of Mines, the Utah Copper Co., and the University of Utah.

Jan 1, 1935

By R Goater, P Kirsch, S Goater, I Goater

With staff productivity and retention a crucial factor in the longevity of AustraliaÆs mining industry, some mining companies are increasing their focus on the health and well-being of their people, to minimise the risks of deteriorating health in an ageing workforce. Many of AustraliaÆs mining operations rely heavily on long distance commuter (LDC) rosters, which are argued to have a significant impact upon worker health, wellbeing and lifestyle choices. The potential impact of workforce health on mine safety performance, efficiency and operating practice is an interesting additional line of enquiry. Food choice, exercise and recreation initiatives offer living and working conditions that æempower healthy choicesÆ in the shift worker community, but do not guarantee improved worker wellbeing. This paper explores first-hand the experiences of one individual over two and a half years of employment at different mine sites, under different shift conditions and across different operating crews. Novel insights and recommendations concerning the LDC lifestyle are offered through integrating reflections on one individualÆs fly-in, fly-out (FIFO) experiences in open pit mining operations from personal, family, professional and academic perspectives.CITATION:Goater, S, Goater, R, Goater, I and Kirsch, P, 2012. This life of mine - Personal reflections on the well-being of the contracted fly-in, fly-out workforce, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 31-40 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By P. Tolvanen, A. Jalili

"When hard times strike in the mining cycle, sites tighten their belts and focus on lowering their unit costs. Lower unit costs can be achieved by reducing expenditure, increasing production, or by a combination of both. Faced with these requirements, site personnel must turn to areas where they can focus their effort for maximum return. For many sites, both in Canada and overseas, focusing on improving flotation cell maintenance is one of the areas where gains can be made for minimum outlay. Due to resource limitations and/or lack of equipment understanding, maintenance on many sites is only conducted on a reactive basis, once equipment fails. This paper will promote the idea that mineral processors should become more familiar with their equipment so they can ensure that the plant’s ability to produce is not compromised. By better understanding the flotation equipment and ensuring the critical components are maintained, it should be possible to unlock value in an operation. Flotation equipment inspections will be discussed in detail, including key items to look for during these inspections. Potential approaches for predicting wear and change-out time for flotation equipment components will be also demonstrated. An example of one approach used at a South African nickel site will be given.INTRODUCTIONWith metal prices decreasing and operating costs rising, concentrator operators are looking for ways to improve their bottom line. Lower unit costs can be achieved by reducing expenditure, increasing production, or by a combination of both. To meet the expectation of shareholders, mineral processors must turn to areas where they can get the best return for their efforts. One area where there is a large opportunity for improvement is in the maintenance of flotation equipment.On many mine sites, both domestically and around the world, it is quite common to see the philosophy applied of repairing equipment only once it has failed. Though some sites have advanced enterprise management systems and monitoring programs, in the authors’ experience, the decision on flotation equipment maintenance is rarely made on a proactive basis. Two common trends that are evident in the mining industry are that operations are under pressure to keep the plant producing, and maintenance managers generally have very strict budget targets to meet. In addition to these factors, few sites have a good understanding of the financial implications of running with worn or broken flotation equipment. Knights, Jullian and Jofre (2006) summarize this situation well, stating that the lack of correlation between some commonly used maintenance performance measures and key business drivers can lead to maintenance being seen only as a cost center (that needs to be reduced) rather than a tool for productivity improvement."

Jan 1, 2015

By Philip R. Whitney

Precipitation of hydrous manganese/iron oxides in streams can be readily observed in much of the northeastern United States, and is apparently a common phenomenon in other glaciated areas (1,2,3,4). Deposition occurs when Mn-enriched ground or surface water enters the stream environment and encounters conditions of higher Eh and pH. The preferred location for deposition is in shallow, fast-flowing segments of stream; the oxides usually form as coatings on detrital material. The experimental studies of Hem(5) and a considerable amount of work on marine and lacustrine manganese nodules(6,7,8) suggest that given an appropriate substrate, deposition of manganese oxides may occur even when the water is undersaturated in Mn with respect to the oxides, due to catalysis by organisms or by silicate, carbonate, or ferric hydroxide surfaces. Once begun, manganese oxide deposition is autocatalytic (9). Studies of the distribution of oxides in various size fractions of stream sediments indicate that the thickness and prevalence of the coatings commonly increases with increasing particle size in the coarse sand and gravel size ranges. Figures 1 and 2 show a fairly typical distribution of leachable metals over nine size fractions from 62 microns up to 8-16 mm. The leaching solution used was neutral ammonium citrate with hydroxylamine hydrochloride, which effectively removes the oxide coatings without significantly attacking most silicates, carbonates or sulfides. Figure 1 shows metal content as ppm of the total sample; figure 2 shows' the same data as micrograms of metal per square millimeter of surface area.

Jan 1, 1975

By W. W. Adams

With greater production of coal per man-hour of work than ever before achieved, the coal-mining industry of the United States established a better safety record in 1941 than in any year since 1930, the earliest for which complete reports of nonfatal as well as fatal injuries were collected by the Bureau of Mines, United States Department of the Interior. In only one year (1933) of the 12-year period 1930-41 was the fatal-accident rate better than in 1941, whereas the rate for nonfatal accidents was better in 1941 than in any previous year. Accident and employment reports received from mine operators, together with fatal-accident reports received monthly from State mining departments and inspectors, showed that 546,692 men were employed in and about the coal mines of the United States during the calendar year 1941. This number does not include office employees or coke-oven workers. The increase of 1.3,426 over the number of employees in 1940 was accompanied by a gain in man-hours of work performed at the mines and an increase in average number of hours worked per man during the year.

Jan 1, 1944

By Kerry Gee, Gary Colgan, James Fricke

Introduction Elevated zinc concentrations are observed in groundwater within alluvium adjacent to Silver Creek east of Park City, Utah. The study area is located in a small valley one and one-half miles northeast of Park City, Utah in Summit County, Utah (Figure 1). Although surface water concentrations in Silver Creek are typically less than 1 mg/l, groundwater concentrations have been measured as high as 85 mg/l in a near neutral pH environment. The elevated zinc concentrations in groundwater result from several factors including: (1) dissolution of zinc from tailings exposed at the surface and within the alluvium, (2) oxidizing conditions created by surface/ground-water exchange, and (3) ideal geochemical conditions for the dissolution of zinc-containing minerals. These ideal conditions include readily soluble minerals, available anions for complexation, and lack of available surface adsorption sites.

Jan 1, 2005