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By Jon Y. Kaneshiro, Ed Walton, Stephen J. Navin, Robert M. Sergeant, Storer J. Boone

The Coronado Traffic Tunnel is a proposed two-lane, reversible, road tunnel, which will relieve severe peak hour congestion problems on surface streets. The tunnel will take traffic from the Coronado Bay Bridge to Naval Air Station North Island. The project will include 12.5 m (41 ft) inside diameter by 1,112 m (3,650 ft) of tunnel, 552 m(1,815 ft) of cut and cover box structure, and 400 m (1,315 ft) of open cut structure. The geology consists of predominately clean and silty sand, saturated sand, with some clay layers, requiring Earth Pressure Balance or Slurry Shield tunneling technology.

Jan 1, 2001

Suddenly, mining has been thrust into the limelight. It has a large image that casts its shadow over New Zealand. Is it any wonder that resistance has heightened and that an almost unprepared populous is currently struggling to protect the very land they hold dear. Next to the atomic bomb, mining has the demonstrated power to massively change the land and its side effects can pollute many miles beyond the operation. During the past year, New Zealand concern over the possible effects of the mining proposals has become acute. This was specially so in the areas of special environmental quality, such as the Coromandel, and here a very unhappy situation has arisen.

Jan 1, 1981

In this address I look back over the past 40 years of mineral exploration in New Zealand û essentially the period since the Second World War (ie since 1945). It was the period of my personal involvement, and indeed of the personal involvement of a number of you. Luckily it was aperiod of great interest and activity. In the previous 50 years, virtually nothing had happened, and it is kindest to draw a veil over that period. In the very important earlier 40 years (1855 - 1895) the New Zealand gold rush occurred. That must have been a fascinating, rewarding period, which has been thoroughly documented by better historians than myself. I will simply comment firstly that its mineral explorers (gold-prospectors) were very successful indeed, and found most localities of the minerals they sought, in spite of using very different methods from ours of today. Secondly, they were preceeded by one of Maori exploration, which searched for a much restricted list of minerals, but succeeded in finding virtually every locality we know of today. The explorers of both of these early periods were obviously highly successful, but, in the time available, I must restrict myself to the period since 1945. I am currently editing the effective up-dating of Gordon WilliamsÆ 'Economic Geology of New Zealand' (1974). It covers the last 12 years or so. Many of you are contributing to that volume û both as authors and as referees û and I would like to take this opportunity of thanking you all. Although this new volume excludes the energy field, many of us have been involved in it, and I am therefore including energy minerals in this review, as Williams did in 1974.

Jan 1, 1987

By Carl-John Grävare

This paper deals with some of the systems and equipment that are being developed and/or are in use in Scandinavia. The main subject is the development of loading tests on the piles using monitoring equipment. This paper also describes ground improvement using lime-cement columns, expander body piles and steel core piles.

Jan 1, 2000

By Roberto Busato Belger

- Fertilizer Business Overview - Supply -Demand Balance in the World - Supply -Demand Balance in Brazil - Brazilian Market Growth Opportunities - Fosfertil Operations - Fosfertil Expansion Plan - Salitre Project - Project Characteristics - Technical Challenges and Solutions - Technical Support Studies Conclusions

May 1, 2010

By COLIN A. LAWRENCE, Anthony Del Vescovo

All Rights Reserved. Printed in the United States of America. Information contained in this work has been obtained by SME, Inc. from sources believed to be reliable. However, neither SME nor its authors guarantee the accuracy or completeness of any information published herein, and neither SME nor its authors shall be responsible for any errors, omissions, or damages arising out of use of this information. This work is published with the understanding that SME and its authors are supplying information but are not attempting to render engineering or other professional services. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Any statement or views presented here are those of individual authors and are not necessarily those of the SME. The mention of trade names for commercial products does not imply the approval or endorsement of SME.

Dec 1, 2017

By W. T. Reid

A shortage of anthracite for home heating indicates the necessity of using other fuels for this purpose; low-volatile bituminous, or "soft" coal is the most feasible supplementary fuel, either burned alone or when mixed with anthracite. Comparison of Bituminous Coal and Anthracite Whereas anthracite is clean, burns without smoke, and requires little attention, bituminous coal is dusty, tends to burn with a smoky flame, and forms coke in the fire pot that must be broken up to maintain a continuous high output of heat. When properly fired, however, bituminous coal responds more quickly than anthracite to changes in damper settings and consequently can supply more heat in a short time. It is generally less expensive and usually contains less ash than anthracite.

Jan 1, 1943

By W. F. Dietrich

1. On St. Thomas and St. Croix, and possibly also on St. John, low-quality red-burning clays probably can be developed to provide the major part of the raw materials for structural clay products and earthenware pottery. 2. The potential sales volume for structural clay products is too small to sustain a plant in the Virgin Islands to manufacture such products in competition with Puerto Rico; however, handmade patio tile might be produced successfully. 3. The market for pottery utility wares in the Virgin Islands is too small to justify a plant devoted solely to the production of such wares; but it may be feasible to evolve a diversified community activity to make jugs, pots, casseroles, bowls, charcoal burners, patio tile, and other items.

Jan 1, 1955

By G. W. Jones

In cooperation with the Edison Electric Illuminating Co. of Boston, Mass., and the Boston Consolidated Gas Co., a survey has been conducted continuously since 1929 by the Bureau of Mines to determine the general hazards of combustible gases and vapors in manholes of the Edison Electric Illuminating Co. The New England Telephone & Telegraph Co. also has cooperated in the investigation, and tests have been made in its manholes since May 1, 1933. Yearly reports6/ on the results obtained since the beginning of the survey have been published. The method and procedure of conducting the survey in 1936 were the same as heretofore.

Jan 1, 1938

By F. V. Meriwether

The Bureau of Mines, in cooperation with the Federal, State, and local health services, and the mining companies, and miners? organizations, has for several years been carrying on sanitary surveys of mining districts in various states, with the purpose of collecting information on good and poor practices in mine sanitation, construction of approved wash-houses and change houses, the measures being taken to combat preventable diseases, the essential features of good houses for mining towns, and other conditions affecting the health and efficiency of miners and their families. The knowledge thus gained is disseminated for the common benefit of the mining industry. The sanitary conditions in the coal-mining districts of Alabama, as found by a recent survey made by the writer, are presented in this report. In addition to the towns on which this report is chiefly based, at least twice as many were visited where no details :were taken, but their general conditions are taken into consideration in summing conditions in the coal districts.

Jan 1, 1926

By V. F. Parry

[Approximately 7-1/2 million tons of subbituminous coals are mined annually in Colorado, Wyoming, and Montana, of which 50 percent probably reaches domestic consumers. The moisture of these subbituminous coals is high, averaging about 25 percent when they are mined. The coals are non-caking end stack to a variable degree when exposed to normal atmospheric conditions. They are good domestic fuels, are considered to be smokeless in most furnaces, and have been used for many years in hand-fired domestic furnaces in which the practice is to employ large lutes for efficient combustion.]

Jan 1, 1941

By D. H. Pulling

Statistics for copper consumption from various sources show that the importance of production from secondary sources is increasing. This is of particular significance in countries such as the U.K ., which are totally dependent on secondary material for the supply of home-produced copper . A brief survey of the U.K . industry has shown that, in the past, relatively high profit margins have not encouraged high cap ital investment and development of more sophisticated operating techniques, but set against a background of rapidly escalating operating and energy costs , together with an ever-increasing demand for copper , it is anticipated that the industry will see great changes in the near future. With this in mind, an experimental furnace for continuous smelting of copper-bearing scrap has been developed at the University of Birmingham. This furnace has been designed to combine the conventional operations of blast furnace or reverberatory smelting, usually followed by converting, in one unit, and incorporates many of the features of the WORGRA and Noranda processes for continuous primary smelting . It consists of a long, sloping channel, constructed of chrome-magnesite refractory, which: is churned near the top. Smelting is effected lower down the channel, where iron, etc., in the scrap is oxidized and slagged off with silica flux. Provision is made for oil injection to increase oxidation rates. Metal can flow from the bottom of the channel, and slag from the top, so that a counter-current flow is achieved. The approximate molten capacity is 25 kg. Various scrap charges, both synthetically made and as supplied from various industrial smelters, have been successfully smelted. Metal of 83 -95 % Cu has been produced, depending on the original charge composition and the degree of air injection, although air injection was also found to considerably increase the copper loss to slag. Recoveries of other valuable non-ferrous metals in the charge were good.

Jan 1, 1977

By Milton Hood

The Copper Flat Property is located approximately 6 miles NE of the small town of Hillsboro in Sierra County, N. M. (Fig. 1). Hillsboro was the center of considerable mining activity in the late 1800's and early 1900's following the discover, of gold bearing vein deposits and later discovery of, placer gold along the east slopes of the Animas Hills. The Copper Flat orebody is a porphyry type deposit occurring in a small quartz monzonite porphyry stock that has intruded the center of a circular andesite plug (Fig. 2). The primary ore mineral is chalcopyrite. By-product values are contained in gold, silver and molybdenum.

Jan 1, 1983

By John C. Hartley

Large areas of the anthracite beds in the Wilkes-Barre, Pa., region have been first-mined in such a manner that over half of the original coal has been left underground as pillars to support the overburden. To recover the maximum amount of this remaining coal, improved devices to support the roof while pillars are being extracted are needed. Also needed are suitable backfilling systems that will stabilize the strata during the mining and effectively limit the inevitable subsidence after pillars are removed. Accordingly, the Federal Bureau of Mines furnished 400 yielding steel props that had been purchased abroad, where this type of prop had been used successfully. The cooperating company arranged for concurrent tests with a mechanical stower designed and built by an American manufacturer. In the area in which the experiments were conducted, pillar removal, using conventional timbering, was most difficult because the roof fractured badly, the installation of timbers consumed a substantial part of the work effort, and some coal nearly always was lost. With the application of the yielding props, the time needed for securing the roof was reduced 33.9 percent; production per man-shift was in¬creased over 33 percent; coal recovery was improved more than 9 percent; and the convergence between roof and floor, during mining and backfilling, amounted to as much as 8.03 inches without any break in the roof. However, in September 1953 some roof rock fell in pillar 10 owing to insufficient props in a small area where the ends of three top holes drilled in the coal face extended up into the roof rock.

Jan 1, 1956

By J. T. Matson

This paper describing the mining practice at the Pecos mine of the American Metal Co. of New Mexico, a subsidiary of the American Metal Co., Ltd., is one of a series being prepared by the Bureau of Mines on mining methods, practices, and costs in the various mining districts of the United States. The mine is producing about 18,000 tons per month of zinc-lead-copper ore, chiefly by the square-set and cut-and-fill methods. Costs are given for 1927, 1928, and 1929, the whole producing life of the mine to date.

Jan 1, 1930

By Norman A. Jull

"IntroductionThe scope of this paper is intended to deal mainly with cyclones in grinding circuits. However, the section on Cyclone Equipment, contains more general descriptions, to cover most of the cyclones used in mineral separation plants.Cyclones as heavy media separation vessels are discussed by Mark Freberg (this volume). Their use in tailings deslirning is discussed by P.C. Lighthall, eta/. (this volume).Cyclone EquipmentCyclone TerminologyApexObviously, the apex of a cone is the smallest end. However, with cyclones the term is usually used for the fitting which is attached there to control discharge of the underflow stream.Note that the cyclone need not be so mounted that the apex is the lowest point, although that is the most common method. Keeping the apex below the rest of the cyclone helps avoid plugging when the underflow contains very large particles and the tonnage of underflow solids can fluctuate.Various devices for adjusting apex diameter or otherwise controlling the underflow are discussed later under ""Cyclone Construction"".BypassingThe transport of a portion of feed slurry directly to underflow so that classification is bypassed by that portion of feed.This action is fundamental in any hydraulic classification, whether gravity or centrifugal, because the large particles going to underflow have some void volume between them, which remains filled with feed slurry.D50By definition, D50 is that particle size which has an equal probability of going to overflow or to underflow.It is calculated by drawing a curve of recovery vs particle size and noting the size at which 500Jo recovery occurs.This may be done equally with corrected or with gross recovery (see below) and the resulting value should therefore be identified as d50c (corrected d50) or as d500 (gross d50).Note also that it is common in industry practice to plot size analysis data on the retained size rather than on the average of passing and retained (the middle of the size band). To portray sizing alone it makes no difference, but to read a D50 value off a curve of corrected or gross recoveries, it is essential to plot those values on the average size of each band."

Jan 1, 1989

By Donald R. Simon

Money... not many subjects are as personal or as emotional. Hessiod said it well in 700 B.C. "Money is life to us wretched mortals". Are you getting paid enough? Does your company reward its top people? Does coal or copper pay more? Production or engineering? How is the synfuels industry going to influence mining salaries? Do high salaries attract and retain the best people? Do modern compensation systems ensure fairness or destroy entrepreneurial spirit? With our tax system and high standard of living why are we so salary conscious? Salary is not only important for what it can purchase but it is also a yardstick, measuring how well we are doing. We all need money to pay the bills and maintain our standard-of-living, but once we reach a certain point the psychological ramifications become more important than the purely practical side. Even necessary payments like the mortgage and the car are a function of our egos. Are our choices of cars and homes based on simple transportation and shelter?

Jan 1, 1980

By R. D. Parker

Location The Frood ore-body is expressed on surface as a prominent gossan ridge, with a total length of approximately two miles. The original Frood (the old No. 3 mine of the Canadian Copper Company) is at the southwest end of this gossan; adjoining it on the northeast is the Frood Extension (until 1929 the property of i:he Mond Nickel Company), while at the extreme northeast end is the Stobie mine. The first two of these divisions of the ridge form the Frood mine as it is known today.? This lies in lots 6 and 7 of the sixth concession, township of McKim, and is two and a half miles north of the city of Sudbury. The general elevation is 1,000 feet above sea level. The Ore-Body The Frood-Stobie parallel offset(l), as its name implies, has no connection in the field with the main mass of the Sudbury nickel eruptive-a norite. It lies one mile to the southeast of that body, and, in general, parallels it in strike. The ore occurs as a more or less tabular structure in what is known locally as the Sudbury series. They are the oldest rocks of the district, and have been placed by Collins(2) as earlier than the lower Huronian, of pre-Cambrian time. The series is comprised of sediments, volcanics (both acid and basic flows), tuffs, agglomerates, breccias, and basic intrusives, all highly metamorphosed, yet all forming a more or less regular picture. The controlling feature of the area has been the attitude of the sedimentary strata, from which has arisen the present sill-like character of the flow rocks, the basic intrusives, and the ore-body itself.

Jan 1, 1932

By G Malherbe, J Gonzalez, D C. Franklin, J Bassan, C T. Farrelly

To respond to ever-increasing challenges, mining companies have been experimenting with new business models and technologies in order to speed mine development, production, processing and transport. The various experiments involve mobile access to data, intelligent sensors, advanced analytics, virtual collaboration, virtual reality, automated equipment, remote operations centres and strategic partnerships. A synthesis of all these components creates a ænetwork effectÆ that can dramatically improve the overall effectiveness the entire operation. The concept of the Network Centric Mine borrows from a variety of industries, including defence, aerospace, aviation, petroleum, utilities and manufacturing. Central to the concept are improvements to the way we connect people, process, information and technology, resulting in a more highly collaborative business model, with roles and processes designed to take advantage of new technology. The components of the mining operation act as a connected network aimed at a common goal, regardless of the boundaries of organisation and location.The design of this new organisational ecosystem needs to take into account the recent advances that enable the æplug and playÆ integrated collaborative environment, including cloud computing, mobile devices and social networking, as well as advances in augmented reality, robotics, geo-location, digital labelling, simulation and analytics. However, the most consistent lesson from other industries is the need to properly enable the behaviour and process changes necessary for success.Benefits from adopting a network centric approach include the more effective use of scarce expertise, improved data and information analysis, reduced process variance, and more informed and faster decision-making. The future of mining will see more technology savvy workers who will drive the adoption of new processes. The operations will shift from a relatively static and disparate set of functions, to a digitally aware, dynamic, automated, integrated and interactive environment, with increased agility, lower operating costs, higher productivity and improved safety.CITATION:Farrelly, C T, Malherbe, G, Gonzalez, J, Bassan, J and Franklin, D C, 2012. The network centric mine, in Proceedings International Mine Management 2012, pp 143-160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By Dale L. Pitt

Introduction In opening up a new country, one of the most vital problems is that of transportation Without roads, railways, or water routes, development is very slow because these are the arteries through which the life-blood of the country flows. British Columbia is unusually fortunate in having along its western coast, for some 600 miles, a stretch of inside water unequalled, for comfortable and safe navigation, by any other similar stretch of ocean in the world. This solves in a general way the major north and south transportation problem for the coast section, and offers comparatively cheap rates for the shipping of all commodities. The principal cities and centres of distribution will naturally grow up on the coast. These cities, however, must have methods of communication with the hinterland, and it is the necessity of supplying these, as feeders to the principal ports, which presents problems of considerable magnitude.

Jan 1, 1930