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By Morris Loshinsky, George Ziegler

The New York City Transit System is celebrating its Diamond Jubilee this year. In 1904, 9.3 route miles of New York's first subway was placed in operation in lower Manhattan. Since that date the system has grown to 230 route miles and 458 stations (See Exhibit #1). The age of the system immediately provides a clue to the nature of our construction activity. While we must always plan for the future and expand the system in the direction of the future needs in New York, a substantial amount of time and money must be channeled towards the modernization and maintenance of the existing system which provides vital transportation for 3-1/2 million passengers a day. This paper however will be directed to our New Route's Construction and, specifically, to three rock tunnel and cut and cover sections presently under construction. Currently, New York is engaged in the construction of about 9 New Route miles of structure. Briefly, the 3 Sections we will discuss are as follows: Route 131-A Section 5A is a 4 track structure in Manhattan and includes the new Lexington Avenue Station. This 1240 foot long section is located between Park Avenue and 3rd Avenue and is a combined cut and cover and rock tunnel section under 63rd Street. Route 131-A Section 5B is an intricate 2423 foot long 4 track rock tunnel section extending from 3rd Avenue to the FDR Drive under 63rd Street in Manhattan.

Jan 1, 1979

By R. M. Clowes

LITHOPROBE is a collaborative, multidisciplinary research project that is providing new insights into the tectonic evolution of the North American continent through its work within 10 study areas across Canada. For the mining industry, such results provide a well-constrained regional framework and better understanding of the tectonic processes that lead to the development of ore deposits. In mining camps, seismic-reflection methods have proven effective in imaging shallow to moderately dipping lithologic contacts as well as structural features and, in some cases, have been used for the direct detection of orebodies. Here, short case histories are provided for the Abitibi greenstone belt (VMS deposits) in Quebec and the Thompson nickel belt in Manitoba.

Jan 1, 2002

By Thomas de Lange

Extensive test work performed on the Coalscan 3500 ash analyzer at the Grootegeluk Coal Mine has led to the successful implementation of on-line ash monitoring to control the quality of coking coal and power station coal. Test work results are given and the advantages of on-line bias compensation discussed. Some details of the quality control systems subsequently implemented are also highlighted. Finally, the economic benefit of on-line ash monitoring based on the Mayer curve is demonstrated.

Jan 1, 1992

By M. Scherbakov, W. Shi

Abrasion is an important mode of performance for any element of an engineered product that involves material contact for example, a conveyor belt cover. Abrasion resistance is considered to be one of the leading factors in belt cover design and improvement. Various types of abrasion testing are reviewed by and compared to actual belt applications. A new quantitative screening torsional abrasion test is developed by Goodyear to mimic a dynamic contact between belt cover and differently shaped stones of various weights dropped onto belt at any angle, velocity and height.

Jan 1, 2004

By Stephen G. Whittaker, Rosalind A. Schoof, Martha J. Steele

In determining remedial action objectives for metals in soils, the U.S. Environmental Protection Agency typically assumes that the metal concentrations in house dust are the same as the metal concentrations in soil. Data now available from several studies that were conducted in mining communities suggest that for some metals, concentrations in house dust may be lower than those in soil. This paper reviews available data on the relative soil and indoor dust concentrations of arsenic and cadmium and examines how changing assumptions regarding indoor dust concentrations of arsenic affects risk assessments and determination of cleanup levels.

Jan 1, 1992

By Mark W. Springett

The examination of relatively well behaved distributions subject to truncation by a cutoff grade in the mine clearly demonstrates that a bias is inevitably introduced when the selection is based on the results of samples which are subject to even the most idealised error distribution. The idealised error used in this paper is assumed to be normally distributed with a mean of zero and is thus unbiased. The bias introduced can be minimised but it cannot be eradicated. A better understanding of the bias can lead to improved procedures for mine sampling, sample preparation, assaying and estimation of selection units which will not only reduce the discrepancy but more significantly will increase the efficiency of mining selection and hence profitability.

Jan 1, 1989

By L. S. Leal Filho, L. A. F. Barros, S. M. Assis

Zeta potential determinations and microflotation tests (with starch, sodium oleate and flotigan EDA-B) versus pH, pCa and pMg were performed with apatite and typical silicate minerals that occur in Brazilian phosphate ores: schorlomite, diopside, quartz and micas. Unlike quartz and micas, schorlomite and diopside were depressed by cornstarch during anionic flotation with sodium oleate (pH 1 9). The selectivity of the separation apatite/quartz and apatite/micas by flotation with sodium oleate was adversely affected by the presence of calcium (pCa) and magnesium (pMg) in flotation pulp. Solubility/cation exchange capacity of micas is an important source of dissolved calcium and magnesium in the system.

Jan 1, 2002

The purpose of this paper is to describe two systems designed to provide estimations in stratigraphic orebodies for the purposes of detailed mine planning. The first is a completely geostatistical approach and the second is a combined geostatistical/deterministic approach. The essential features of both systems are the estimation of stratigraphic ore boundaries and the subsequent use of those boundaries to provide stratigraphic (or zonal) control for block and point grade estimation (kriging). Both systems are illustrated by application to a section of, the Hilton orebodies, Queensland, Australia.

Jan 1, 1989

By T. P. Weldum, B. J. Mahoski, R. S. Rasmussen

A case study of a systematic approach to grinding circuit steady-state optimization is presented. After an overall review of the flow-sheet, two operating circuits were prepared for detailed testing. Functional performance analysis was chosen as the primary modeling system, and, on this basis, a quality-assurance program for data gathering was implemented. A number of circuit-design and operating variables were investigated. Statistical analysis of plant-test results revealed relationships previously unquantifiable by any other modeling technique. Improvements in the classification system and in mill grinding efficiencies were demonstrated. As a result, there was significant energy cost savings.

Jan 1, 2000

By Joe M. Bryan, George E. Rodger

The development of small precious metal mines in the western states has been directed at heap leach operations. Crushing plants are an essential adjunct to heap leach operations. They must meet environmental air quality regulations which generally follow a similar pattern from state to state. Prior to mine construction a permit must be obtained and an operating permit granted during or shortly after the start-up period. The typical construction permit application consists primarily of drawings, specifications and an explanation sufficient to indicate that the mass of particulate matter entering the atmosphere is below minimum standards. The operating permit may be granted following demonstrations that air emission control equipment or methods comply with information submitted in the construction permit application.

Jan 1, 1987

By D. G. Millette, A. J. S. (Sam) Spearing

The design of a cost effective backfill system involves many aspects and various inputs from different engineering disciplines. Backfilling is a very significant mining cost and efforts need to be made in the design stage to maximise efficiency and flexibility whilst minimising costs. The aspects that need to be considered include the following: Required fill performance underground Peak and average fill tonnage requirements Backfill scheduling in the mining cycle Material selection, testing and preliminary costing Plant design and storage needs Infrastructure requirements Implications on surface waste/tailings disposal and costs Total backfill costs In order to produce a cost effective and efficient backfill operation, a multi-disciplinary project team is required that should include the following skills and functions: Mine Planning Rock Engineering Metallurgy Mechanical Engineering Environmental Health and Safety Tailings Disposal/Waste Management This paper discusses the above and indicates important aspects that should be considered.

Jan 1, 2001

By James E. McTurk, Sheldon B. Bland, Roger E. Melley

During the first fifteen years of operation at the Syncrude facility in northern Alberta, numerous improvements have been made in the field of ore conveying. The unique nature of the material conveyed coupled with the wide range of environmental conditions encountered results in a number of unparalleled challenges. Most of the improvements have been brought about with the use of detailed field evaluation. This paper outlines some of the programs which have been run to optimise belt and system construction, and conveyor performance and utilization.

Jan 1, 1993

By H. Cho, P. T. Luckie

A study was undertaken to investigate the liberation behavior of coal macerals through size reduction and density separation. It was seen that the liberation of coal macerals could be achieved by size reduction, allowing selective separation of coal organic components. However, the degree of liberation was dependent upon the comminution history. Even for the same fineness, the extent of liberation might not be the same depending on how the material was generated. The liberation of coal macerals was analyzed by examining the liberation index. It was seen that, although comminution produced fine particles enriched in inertinite (primarily fusinite and semifusinite), these particles were less liberated than coarser particles. However, the liberation of macerals increased when all the feed was ground to a finer size.

Jan 1, 1999

By M. Li, J. D. Miller

Recently water insoluble alcoholic solutions of alkyl hydroxamic acid collectors have been shown to be particularly effective in the flotation of coarse feed material sampled from phosphate operations in Florida, North Carolina and Utah (Miller et al., 2000). The experimental results indicate that high separation efficiencies can be achieved in single stage flotation with these new collectors. In some cases the concentrate grade reached 34% P2O5 with 93% recovery from single stage bench scale flotation experiments. Critical aspects of the composition and structure of these new collectors are discussed with respect to their effectiveness in phosphate flotation. The wetting characteristics at fluorapatite, francolite, dolomite and quartz surfaces are being investigated with the new collector. Finally, other surface chemistry considerations in the development of these new collectors for phosphate flotation are discussed.

Jan 1, 2002

By Kenneth S. Graham, S. C. Gambrell

A short term, simple roof bolt load cell which uses a birefringent (photoelastic) coating as its sensing element has been developed. The load cell is installed between the bearing plate and the nut/washer and measures the initial force after installation by the bolting machine. The load cell can be removed from the bolt and used again to measure initial force in another bolt if desired. Because temperature and humidity changes in the mine cause creep/relaxation of the coating and/or adhesive, the load cell is useful for accurately measuring force for a period of only two weeks after installation. Force in the bolt is determined by referring to a calibration curve for the load cell.

Jan 1, 1992

By Andrew J. Neale, Brian C. Flintoff

A review of the current literature, combined with the authors' knowledge of the western Canadian coal industry, indicates that the development and implementation of process control in coal preparation, particularly in flotation applications, is significantly lagging behind that seen in mineral processing. The reasons for this include the lack of inexpensive and reliable sensors, incomplete understanding of the flotation process, limited experience of process control in the coal preparation industry and depressed coal prices, all of which have combined to hinder plant automation. This paper illustrates the benefits of process control in coal flotation, provides a general discussion of the control problem and concludes with two examples drawn from Australian experiences.

Jan 1, 1989

By Z. T. Bieniawski, Christopher Mark

A new method for the design of long- wall chain pillars, called Analysis of Longwall Pillar Stability (ALPS), is described. The method provides estimates of the relative stability of different longwall pillar designs during all stages of their service life. The key issue addressed by ALPS is the magnitude and time-of-arrival of the longwall abutment loads applied to chain pillars. A field study was conducted and other available field data were analyzed in order to develop an approach for estimating the abutment loads. An example based on longwall experience in the Pittsburgh seam is used to illustrate how ALPS can be used in mine design.

Jan 1, 1986

By Dave Willis

In ME'S 1994 Powder River Basin (PRB) coal transportation article, the lead author described some destinations pursued by the railroads. As with many destinations, though, they turned out to be merely stops on the way to places that have yet to be reached. Along the way, the railroads discovered that making it better is a continuous process, not just something done in several phases. This was always known but not at the awareness level that exists in 1998 railroad environments. This update of the 1994 article includes railroad companies' plans for the future of rail transportation in the PRB.

Jan 1, 1998

By D. B. Dreisinger, H. J. Sohn, J. S. Sohn, G. A. Kordosky

The transport of lithium through a supported liquid membrane was studied with a mixture of D2EHPA and TBP in kerosene as a mobile carrier. In the flat- sheet supported liquid membrane(SLM) system, experiments were carried out to investigate the effects of concentration of mobile carriers in the membrane solution, hydrogen ion in the feed solution, and temperature on the transport of lithium. Experimental results agreed well with a transport model for permeating lithium across the liquid membrane. The permeation rates of lithium can be explained in terms of diffusion of a Li-complex through the membrane phase. For a practical application of an SLM method, a hollow fiber module has been used and lithium can be concentrated more than three times in 24 hours.

Jan 1, 1993

By Dilip K. Sinha

In the paper some interesting cases of applications of Operations Research and Computer Methods as worked out by the author and accepted by the management of some of the newly formed Indian mining organisation for implementation are highlighted. The main emphasis on the application cases was to use simple techniques and methods which yield the result in shorter time period, The case problems mainly deals with the production system optimisation in unit mines, areas/divisions and at the corporate levels. Also the management decisions regarding reorganisation of transport and distribution system of material and mineral are attempted to be optimised. Further, the case of management system development with computer aided decision making worked out for single large Iron Ore Project captive to a steel plant is outlined. Finally, the case of a large mining company having decentralised units and divisions geographically dispersed throughout the country, computerised management decision-information system designed on the basis of inputs and outputs of decision models relevant for different levels of management in the organisation is depicted.

Jan 1, 1986