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By Henry Louis

THE work performed by, the Royal Commission on Mining Subsidence is likely to prove of permanent value, less perhaps for the conclusions it has reached and for the recommendations it has based upon these than for the admirable exposition which it affords of the law concerning mining subsidence and of the legal status of the person who has suffered damage by reason of such subsidence, as also of him whose working has caused the damage. The Commission was appointed by Royal Warrant in the middle of 1925 and delivered its final report in the middle of 1927. The terms of reference to the Commission were as follows: "To consider the operation of the law relating to the support of the surface of the land, and of buildings or works on or under the surface, by underlying or adjacent minerals; to enquire into the extent and gravity of the damage caused by subsidence owing to the extraction of minerals and the incidence of the resulting liability; and to report what steps should be taken, by legislation or otherwise, to remedy, equitably to all persons concerned, any defects or hardships that may be found to arise in existing conditions."

Jan 1, 1929

SINCE I told you in the preceding chapter how the potter's art is followed in practice, now in this following one I wish to tell you how mortar* and bricks are made, and how and to what purpose they were discovered, although I know you will answer that you know it, inasmuch as it is an art known not only to skillful men but also to the unskilled ones by whom it is practiced, and that bricks and mortar were made and always will be made for the purpose of building. This I admit, but probably everyone does not know it as you do, and you perhaps, do not know its beginnings, although I remember having told you of them. Wishing to repeat it better now I shall begin with long ago, so that both you and I may be better satisfied. Therefore I tell you that you should know that all the arts that men practice in the world have been learned by them either through the process of reasoning from the principles of natural phenomena, from the actions of animals, by chance, or when forced either by some necessity or

Jan 1, 1942

By R. E. Allen

One of the most unusual oil-field engineering accomplishments of the past two years is the development and rapid advance in the directed drilling of wells. Directed drilling as referred to herein is the controlled steering of the drill stem in the required direction to a given location in the oil sand. The deliberate drifting of holes is an act so far removed from what has been considered good drilling practice that all of the old questions of correlation, drillability and production difficulties are revived. Only a few years ago, during the boom days of Seminole and Santa Fé Springs, the crooked-hole problem, as it was then called, occupied a primary position among the topics of the day in the fields of California and the Mid-Continent. The net result of all the discussion and study at that time was the conclusion that oil wells should be drilled with as little deviation from the vertical as possible and that crooked holes with elbows and dog legs were to be avoided because of the drilling and producing difficulties encountered therein, but that many nonvertical holes were slanting or angling rather than crooked and were not a serious problem.

Jan 1, 1934

By Richard M. Foose

WOULD you like to find a large new ore deposit next year? The answer is as obvious as the question is foolish. But perhaps the question does have some merit if we alter it slightly and ask: What are you doing about finding new ore? This one is more difficult to answer. Possibly you are doing nothing about finding new ore because you have proved reserves for many future years of production. Others may be investing some small percentage of time, effort, and money in mineral exploration, and reserves may be currently adequate, or inadequate, in terms of many future productive years. Still others may be engaged in large-scale mineral exploration programs involving large expenditures of time, personnel effort, and money. In whatever category you may be, a final question might well be asked. Is your current mineral exploration program, or lack of program, consistent with the long-range needs and objectives of your organization and of the mining industry as a whole, and is it designed to stimulate the growth of the industry in future years, or is it only a short-range program in response to some current situation?

Jan 3, 1958

By P. F. Mataich

When the subject of plant computers is brought up most people visualize the computer's con- trolling the entire plant with very little operator intervention. Actually, this picture is true today in only a limited number of cases and will certainly not be true in the minerals industries for many years to come. There are several ways in which a plant computer can significantly contribute to improving plant operation and closed loop control is only one of these. First of all, for good plant control, two basic requirements must be met. First, the operator must get good information feedback from the process and then he must know what action to take in response to this information. Control information can be obtained through instruments, laboratory analyses, or through simple visual observation. If it is timely and accurate and the operator knows how to use it, then we have the makings of a good plant control system. The computer can be of help in both these areas by getting good data back to the operator and in helping to develop a good control scheme for the plant.

Jan 12, 1966

By I. J. Jansen

Introduction The Surface Mining Control and Reclamation Act (PL 95-87) lays a new challenge before the surface mining industry by requiring that prime farmlands must be reclaimed to equivalent or higher levels of yield as nonmined prime farmland in the surrounding area (section 510d). We must now evaluate the situation and plan a mining and reclamation program that will achieve that objective. We must recognize that soil and land needs vary with intended land use and climatic setting. Also, various site conditions determine the potential for constructing a productive soil and the best procedures to accomplish that end. It is necessary to plan the land reconstruction program on a site by site basis in order to achieve the best results. Discussion The Prime Land Concept Terms like prime agricultural land have been used loosely for many years to refer to lands that are highly productive and well suited to agricultural use. The concept of what qualified as prime land varied considerably from one geographic area to another and from one person to another. The term prime farmland, as used in PL 95-87, has recently been defined quite

Jan 1, 1982

By S. A. Ronlov

The importance of recognizing vibration problems during the plant design stage is emphasized in this paper. Often an experienced designer can recommend what type of support to use and how to tune the structure. However, obtaining sufficient information is a serious problem dealing with vibration. Vibration is a well known phenomena which, simply and generally, can be defined as a periodic motion. It is experienced in nature as caused by eerth- quake, wind, or ocean waves, and must be dealt with in the design of structure or ships. It must be realized that wherever there are moving or rotating elements, it is possible that unbalanced forces may induce vibration in the elements themselves, in adjacent parts, or in the supporting structure. Under certain circumstances, vibration will destroy machines or structures quickly and totally. The most widely known case is the total collapse of the Tacoma bridge when subjected to a wind of only 42 mph. Failures due to vibration of machines and/or their supports may occur in industrial plants where heavy equipment employed in the process must be supported and several machines are combined in close proximity. In the Metallurgical and Chemical Div. of The

Jan 1, 1962

By F. G. Hill

The paper reviews the restrictions imposed by the Department of Mines (now the Department of Mineral and Energy Affairs) on the surface use of ground that has been undermined at shallow depths (down to a depth of244m). The reasons for the restrictions are discussed, with special reference to the early records kept by the Department of Mines on subsidence and fracture of the surface. A discussion of the nature of the strata overlying the ore-body, and the effect of undermining, is followed by a detailed account of investigational work, particularly since 1970, on the stability of shallowly undermined ground. The significance of the data collected during the investigations is considered next, with special reference to the social and economic implications. These are so farreaching, that it is proposed that the already flexible approach of the Department of Mineral and Energy Affairs in considering what structures may be built on undermined ground should become even more flexible. To this end, the appointment of a Commission is proposed to collect as much information as possible on the stability of ground undermined at shallow depth, and to revise the current overrestrictive conditions or guide lines that are in use.

Jan 1, 1981

By C. P. Hood

"The amount of ash in anthracite coal interests every buyer, and occasionally produces caustic comment, but there is a lack of authentic figures that will take the subject out of the realm of opinion and agitated fancy and. give a true picture of the quality of coal actually delivered. What per cent ash is to be expected when the coal is good, and when have we a right to make serious complaint?During the past summer the Bureau of Mines took 127 samples of 1000 pounds each, representing nearly 30,000 tons of anthracite is dealers' yards in seventeen cities in the State of Massachusetts. There were three objects in view, to discover the average and the variation in amount of ash in anthracite in some easily described area; to demonstrate standard sampling methods, and to learn something about the feasibility of itinerant coal sampling. Massachusetts was selected because its principal cities could be visited in a single season. There also appeared need for demonstration of standard sampling of coal, since a coal quality law had been passed in the State, to be administered by those unfamiliar with coal sampling."

Feb 1, 1924

By H. l. Burghoff

DURING the course of preparation of crystals of alpha brass for an investigation of their creep characteristics, a number of critically oriented crystals were produced. In each of these specimens, P0, the specimen axis, lay near some important crystallographic direction or on or near the border of two possible slip systems. Because of the unusual nature of their orientations, it was considered of interest to deform these speci-mens in simple tension and to study orientation changes and any unusual occurrences, different from what would be expected for specimens in which only one slip system had distinctly the highest maximum resolved shear stress. Choice of actual operating slip system in a crystal offering an immedi-ate possibility of two slip systems would be expected to be due to chance, defect, or some inhomogeneity. Even in an ideally perfect crystal so oriented, the natural oscillations of the atoms about their lattice positions would give rise to a condition wherein one slip system would be favored over the other at the critical shear stress. In the large, nonperfect crystals of the present investigation, slip on both systems, but in different portions of the specimen, might occasionally be expected.

Jan 1, 1940

Over the past few years, the School of Mines of Paris has carried out a program of research* on the grade-tonnage relationships in the border zones of porphyry copper deposits. The initial problem was quite difficult : how does the grade vary at the border of the known orebodies? Does it decrease regularly, or do some thresholds exist, where the grade diminishes abruptly? The answer to these questions have important repercussions on the prediction of the future reserves in the fringe of the orebodies. If the grade decreases regularly, very important reserves could exist; if not, there would be strong limitations to the possible recoverable reserves. The first step of our study was a critical study of previous work done on the subject. It appeared that, following Lasky's pioneering paper (Lasky, 1950), most of the authors used what we can call an historical approach to the problem. In this, the grade-tonnage relationships are calculated from the available figures for production and reserves and the results are then extrapolated to the future. The strong limitation of this model are brought out in this article.

Jan 1, 1982

By N. E. Norman, R. Stier

The mining industry is continually seeking out new and better underground mining techniques. One of the most recent-also, perhaps, the most significant-of the new concepts in underground mining is the use of mechanical rock-boring machines. And one of the problems that concerns us all in this matter is the cost of mechanical rock tunneling. To help answer the oft-quoted question "What will it cost me?" the following pages deal with the operating costs of so-called "medium to medium hard rock" boring machines-i.e., those designed to meet the drilling requirements in 8000 psi to 25,000 psi rock. A few machines are capable of drilling hard rock above 25,000 psi, but the economics of mechanical tunneling in rock that hard is limited at the present time. [ ] For mechanical rock tunneling, there are five main cost factors influencing the expense: Capital Investment, Cutters, Labor, Power Requirements, and Maintenance. These factors give us a good basic picture of the cost of excavation, although muck handling, erecting supports, and other costs directly related to conventional tunneling and mechanical boring enter into the final picture.

Jan 6, 1967

By William E. Bruce

This paper is intended to provide an improved understanding of natural draft (natural ventilating pressure) and the effect of natural draft on underground mine ventilation circuits. Attention is focused on measurement of natural draft pressures during ventilation surveys in mechanically ventilated mines and on different methods for modeling natural draft using the measured data. A number of examples are presented which utilize data collected during absolute air pressure surveys made by personnel of the Ventilation Division of the Mine Safety and Health Administration's Safety and Health Technology Center, Denver, Colorado. Examples are used to illustrate how the data from absolute air pressure surveys may be interpreted to determine whether natural draft pressure is present and what its magnitude is. In addition, two different methods are described for mathematically estimating the magnitude of the natural draft pressure. Comparisons are made of results obtained using the different methods. Different procedures are described for modeling natural draft using the MSHA-modified Penn State computer program. Use of the routines is described and illustrated relative to drafts that aid or oppose the mechanical ventilation system. Tabulations of results facilitate comparison of outcomes obtained using the different modeling procedures.

Jan 1, 1982

Carlisle: This is April 19, 1961. My good friend Dave Irwin is sitting on the other side of the tape recorder. We are at Rose Dhu Island, Savannah, Ga. Now, let's begin with your first job, where and what was that? Irwin: I started out to Arizona, looking for a job and wound up in Morenci. The next morning I applied at the mine office and was put on as a sampler. I worked as a sampler and as an assistant to Frank Pelton, the geologist, for a year, after which I went back to New Haven to take my last year of postgraduate work. After getting my degree, I went back to the Southwest with W. Rowland Cox and Staff, supposedly as a geologist. Q: But that was not when he was with Spurr? Irwin: That was after he had left Spurr. Henry Smith was with the Spurr end of the outfit and I happened to drop into the W. Rowland Cox end. My first job with him was to do some work on a prospect above Metcalf, Ariz., and from there I would go out on short reconnaissance trips in Arizona, New Mexico and old Mexico.

Jan 6, 1964

The visible portion of accounting-record keeping and preparation of financial statements-suggests a lack of sophistication and imagination. In reality, accounting is based on a large body of theory. Accountants philosophize, theorize, judge, create, and deliberate as a significant part of their professional practice. The subjective aspects that are so critical to current accounting practice, such as searching for truth and fact, judging what is fair presentation, and considering the behavior induced by presentations, are often overshadowed by the appearance of exactitude, precision, and objectivity that accompanies the use of numbers to express the financial results of the enterprise. * Fundamental accounting principles are hypothesized in the same manner as mathematical principles. These principles are justified by acceptability and intuition. Accounting theory is built upon these hypotheses, resulting in a coherent set of standards and rules. Although it does not specifically address every situation that may be encountered, this conceptual frame- work enables the manager or analyst to resolve specific situations. This framework also aids in the understanding and confidence in financial statements and ensures comparability between statements from different companies. This framework is referred to as "generally accepted accounting principles," or GAAP.

Jan 1, 1999

Early experiences suggested autogenous mills were difficult to operate and consumed substantially more energy than conventional rod/ball mill circuits. As our understanding has increased and the technology has matured this perception has changed to the point where most new comminution circuits are ag/sag based. In addition many operators have replaced existing conventional circuits with this technology. The JKMRC has been studying ag/sag mills for over 20 years. During this time it has amassed what is probably the single largest and most detailed data base of pilot and full scale mill operations in the world. This has been used to help develop and refine its cur- rent commercially available mathematical model of ag/sag mills. A decade of its application has greatly helped simplify both design and operation of ag/sag milling circuits as well as helping to promote the effective use of recycle crushing, secondary crushing and closed-circuit operation. This paper describes the development of ag and sag milling in terms of our understanding and the evolution of the technology. In addition the application of mathematical modelling and simulation in designing and operating efficient circuits is described with the aid of practical examples.

Jan 1, 1998

By Philip B. Dettmer

Up to now we have spoken optimistically of the many potential savings in capital and operating costs to be obtained from the selection of larger diameter and horsepower grinding mills. Such mills may well be the correct choice for one grinding plant but could be absolutely wrong for another plant. It is emphasized here that many significant factors other than the capital cost, labor, grinding media and power savings are involved in the sizing and selection of the optimum grinding circuit. The following discussion covers some of these factors and their relationship to larger mill design. The first consideration is: What is the grinding circuit supposed to do? In most instances it is one or both of the following: 1. Grind the feed material fine enough to liberate the desired minerals but with a minimum of over- grinding. Examples are preparation of ore for flotation, gravity separation, etc. 2. Grind to some pre-specified particle size or particle surface area. Examples of this are cement manufacture or the preparation of feed material for pelletizing; other examples are preparation for chemical reactions or ceramic manufacture.

Jan 5, 1965

By Gerald G. Griswold, James O. Greenslade, Cherie Tilley, Richard Reseigh

INTRODUCTION The Harrison Western Corporation, a leading Denver based mine contracting and engineering concern, is presently engaged in sinking two 1,006 m (3,300 ft) shafts for the Phillips Uranium Corporation at their Nose Rock Project, approximately 13 miles northeast of the small community of Crownpoint in McKinley County, New Mexico. The Nose Rock Project is the first attempt by the Phillips Uranium Corporation to tap the deep uranium reserves in what has become known as the Grants Mineral Belt. (See Figure 1) Project Description Phillips Uranium Corporation's plan for the large 2700 metric ton per day (2950 tons/day) mining facility calls for a series of deep access and ventilation shafts ranging from 4.27 m (14 ft) to 5.49 m (18 ft) in diameter to approximate depths of 1,006 m (3,300 ft). The initial pair of shafts consists of one production shaft and one ventilation shaft separated by a distance of 91 m (300 ft). The interbedded layers of sedimentary sandstones and shales to be penetrated by the shafts contain several major water producing aquifers, the deepest being the mineralized zone called the Westwater Canyon Member of the Morrison Formation.

Jan 1, 1981

By Hae-Moon Choi, Sang-Don Lee, Hee Soon Shin, Choon Sunwo, Chang-Ha Ryu, Hyun-Koo Lee

Building tunnels means dealing with what rock is encountered. Relocation of the site of the underground structure is rarely possible. Tunneling engineers and miners have to cope with the quality of the rock mass as it is. Different tunneling philosophies and different rock classification methods have been developed in various countries. Most of the rock classification methods are based on the response of the rock mass to the excavation. Tunnel support requirements could be assessed analytically, supplemented by rock mass classification predictions, and verified by measurements during construction. Rock mass classifications on their own should only be used for preliminary, planning purposes and not for final tunnel support. Design of blast pattern in tunneling projects in Korea is also for the most part prepared according to the general rock classification methods such as RMR or Q. It, however, does not take into account the blast performance, and as a consequence, produce poor blasting results. In this paper, the methods of general rock classification and blast design for tunnel excavation in Korea are reviewed, and efforts to develop a new classification method, reflecting the blasting performance, are presented. Copyright ©

Jan 1, 2004

As desirable as it may be to a geologist to have maximum detail in any geological report, the task of doing so for an area as vast as British Columbia within six average size magazine pages is clearly impossible. As a result, it has been necessary to draw a fairly broad picture of the geology on the following pages, but it is one which should be adequate to give the reader a concept of what rock is where in the Province. In preparing this horseback ride over the strata of the Province, much reliance has been placed on various reports appearing in trade and Canadian Government journals. Of these, one in particular stands out. Entitled "The Cordilleran Region", this report has been authored in three parts by H. S. Bostock, R. Mulligan and R. J. W. Douglas, respectively, and is included as a major chapter of the book Geology and Economic Minerals of Canada. Published in 1957 by the Department of Mines and Technical Surveys, the book has provided the extensive quotes, taken from each of the three authors, which appear on the following pages.

Jan 12, 1963