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By Norman J. Gibbs, John Sroka

INTRODUCTION At the point a company decides to begin mine development and wishes to convince lending institutions that the proposed operation will return their borrowed funds, plus interest, over the terms of the loan, communications between lender and borrower are crucial. The importance of the mine feasibility presentation should not be underplayed, especially as new projects continue to increase in size, complexity, and cost. While the content and emphasis of a report to the lender will vary according to the particular project and type of debt financing sought, there is a general base of information upon which all such studies are built. THE PROJECT'S TECHNICAL ASPECTS Here, the object is to satisfy the lender that he will not be unduly exposed to technical risks as a result of the physical scope of the project. Reserves The feasibility report submitted to financial institutions should include an adequate description of the geologic setting, mineralogy, ore types, and reserves broken down into such recognized categories as proven/probable/possible or measured/indicated/inferred. Rather than a bald statement of reserves, lenders prefer to have detailed information on: History of exploration Drilling, both percussion and core, with core recovery, drill hole spacing, analyses, and continuity of mineralization Bulk sampling, with core assay comparisons Overburden, with stripping ratios Specific methodology of reserve calculation, and Geologic reserves vs. mineable reserves. As a rule of thumb, a lender would prefer to see that reserves in the proven class alone are sufficient to support operations at the design rates until the borrowed funds are repaid. (See also Schreiber above in this Chapter.) Mining The rationale for adoption of a particular mining technique should be presented as well as descriptions and justifications for: Preproduction development Preliminary mine plan, with forecasts of grades and material movements Geotechnical test work which influenced decisions Mining recoveries and efficiencies Major equipment, with type, model, rating life, spares, replacement schedules, utilization, and productivity Manpower requirements and work schedules Design assumptions Ore stockpiling and blending Environmental requirements, and Waste disposal Processing If a new ore body is to be developed or a new process used, it is important to provide details of test work, scale up, and extrapolation factors. A basic process description with a summary of the studies which justify the intended processing route should be included with the following data:

Jan 1, 1985

During the year 1915-16, the Mining Engineering Society of the, Massachusetts Institute of, Technology had five meetings, at which the following gentlemen addressed the society on the subjects Mentioned: Professor Richards-Memory and the Business World. Mr. Hutchinson-Mine Examinations. Mr. Packard-Mining Law, Necessity of Amendment. Mr. A. H. Rogers-Organization of Mining. Property. Mr. C. Hurter-Explosives. Mr. W. Macgregor-Organization of a Gold Mine and Mill. During the year 24 new members were admitted, making the present active membership 54. There was an average attendance of 34 members at the meetings. HAIG N. SOLAKIAN, Secretary, 1915-16. The Pick and Shovel Club, Case School of Applied Science, has elected the following officers for the current year: President, G: D. Welty, Secretary, C. E. David, Vice-President, E. G. Hollman, Historian, L. S. Kuehn, Treasurer, C. E. Althouse, Sergeant at-Arms, H. H. Smith.

Jan 2, 1917

By G. W. Brownell, H. T. F. Lundberg, R. W. Pringle, K. I. Roulston

The rapid improvement of the airborne scintillometer and the perfection of its efficiency for counting low energy gamma radiation has made it possible to work out a technique to map in great detail the radiation pattern at the earth's surface. On such maps low radiation over certain areas appears to indicate the existence of oil accumulations, forming a pattern similar to that obtained by the geochemists.

Jan 12, 1953

By Daniel T. O’Brian

Exploration targets and results in the mining industry are commonly summarized in terms of tonnage and grade. Business appraisals require, as additional information, the expected profit or loss implied by the physical summary. The early incorporation of knowledge gained through financial analysis computations can provide a means for economically resolving many common exploration and development problems. Examples of such applications from the activities of exploration planning, reconnaissance, land acquisition, and development planning are presented in this paper.

Jan 1, 1969

By E. M. Furness, A. S. Henderson

ORIGINALLY the Babbitt experimental plant grinding circuit consisted of one rod mill 101/2 ft diam by 12 ft long in open circuit followed by two ball mills 101/2 ft diam* 12 ft long in parallel cir- the slow-speed ball mills. The next step was to improve rod mill operation by changing the speed of this mill. Such an attack would affect only one mill and would allow slower speed on the ball mills. The rod mill, as originally purchased, operated at 15.45 rpm. Additional pinions were purchased to test this mill at 16.45, 17.45, and 18.45 rpm. When the mill speed was increased by the use of these pinions, rod breakage with this short mill increased out of all proportion to the improved grinding, until at 18.45 rpm breakage became as high as 7 lb per

Jan 1, 1958

By F. M. F. Cazin

In my first paper, relating in general to the movement of solids in a medium, I stated a newly-discovered natural law, and explained its application to mechanical ore-concentration. This law, as applied primarily to the motion of ships in water, had been announced, demonstrated and defended by me in the Journal of the Franklin Institute for March, April and May, 1893, and has not been controverted since then. I therefore contented myself in my first paper with the simple statement of it; and in order to avoid unnecessary repetition, I refer the readers of this paper to that statement (ante, p. 81) and to the earlier publication already mentioned.*

Jan 1, 1895

By V. G. Mooradian, John T. Norton

THE diffusion of metal atoms into the crystal lattice of another metal and the assumption of regular positions to form a homogeneous alloy are some of the most fundamental phenomena of structural. metallurgy. The mechanism of this process has been the subject of a great deal of study from many viewpoints, but the picture is still far from complete. It is generally believed that if one metal is to diffuse into another, the first must have some solubility in the second1. This means that the solvent must be able to accommodate the stranger atoms, either on points of its own lattice or in the interstices between, without losing its own crystallographic identity. It is also a general observation that cold-working is a distinct aid in the diffusion process, causing it to take place with greater rapidity at the same temperature or with the same speed at a lower temperature. There is considerable doubt, however, as to the real significance of the deformation in its effect on the diffusion mechanism. Several factors associated with the cold-working. may be responsible for the increased diffusion rate. The plastic deformation causes a distortion of the solvent lattice, which may be an aid in the assimulation of atoms of another kind. There are many references2 in the literature that suggest that some distortion or "loosening" of the lattice is necessary for atomic migration and that diffusion cannot take place in the undis-

Jan 1, 1935

By Jeffrey W. Nelson

Predictions of creep closure for periods ranging up to more than 1,000 years are needed for designing a radioactive waste repository in a salt formation. Such long-term predictions must be based on the use of laboratory and field test results extrapolated by numerical modeling. Laboratory test results are presented which show highly variable creep behavior for salts from different sites as well as salts from the same site. Comparisons of measured creep closures against predicted closures are presented for two deep boreholes in Louisiana salt domes and for an exploratory shaft and drift in southeastern New Mexico bedded salt (WIPP). These data illustrate the significant uncertainties involved in long-term closure predictions and indicate the critical need for site-specific, in situ closure measurements over extended periods of time for repository design.

Jan 1, 1984

By Harry Warren

THE Geology Department of the. University of British Columbia has undertaken the task of examining the ores from as many as possible of the gold mines of British Columbia. The object of this work is two-fold. First, it is known that detailed mineralographic studies are useful in attacking ore-dressing problems, and these studies are intended to be helpful to mill operators. Second, it is hoped that mineralogical and mineralographical studies will prove useful adjuncts to those of lithology and structure in throwing more light on problems related to the origin of the deposits. The paper shows that gold, for all practical purposes, is not present in an ore mineral in solid solution nor as a eutectic with any mineral; if the latter were true the gold particles would be distributed equally throughout that mineral. The gold occurs either as native gold or as a gold-silver telluride and is not distributed regularly through any mineral or minerals: The relationship between the gold or gold-bearing telluride and the associated minerals affords a means of classification that is not only simple but also appears to be directly related to the geological nature of the deposit, which may be summarized as follows: 1. Disseminated Gold Type. ;-Precious minerals in extremely small grains, which are distributed without regard to grain size, fractures or grain boundaries: (1) Hedley variety-gold in native form; (2) Surf Point variety-gold predominantly as telluride. 2. Veining Gold Type.-Precious minerals in grains of various sizes, which occur mainly along fractures and grain boundaries: (1) Cariboo gold quartz-gold in native form. (2) Waneta variety-gold as telluride.

Jan 1, 1937

By Louis Cates

AT THE annual meeting of the American Institute of Mining and Metallurgical Engineers in February, 1923, the Chairman of the Committee on Ground Movement and Subsidence appointed a subcommittee to work out a form of questionnaire and to collect data on subsidence and ground movement resulting from underground metal- and coal-mining operations, and on ground movement and safe slopes in connection with open-cut metal-mining operations. The author was requested to take charge of the collection of data and the preparation of a questionnaire in connection with the Committee's studies of open-cut metal-mining operations, this paper is a summary of the work carried on and information received therefrom up to February, 1924. The first approach to the problem of safe slopes is to gather all information that pertains to finished slopes; in other words, the steepest economic angle from the horizontal that will stand in order to uncover the ores to be mined and be safe while the extraction of the ore at the base of these slopes is in progress. Whether or not this angle is 35° or 45° depends on many factors. The number of benches maintained to take care of falling rock and their height and width are direct functions of this overall slope. The slope is here taken to mean the angle from the top edge of the pit through the edges of the respective lower benches to the bottom of the pit. If we accept this definition of the slope, it might save some confusion as there would be a difference if one took the line from the top edge of excavation to the toe of the bottom slope. This latter slope would not be constant, but would vary with the number of benches. The depth of the various ore faces will vary, of course, depending on the deposit; Table 1 shows this to range from 50 ft. to 1100 ft. The geology is an important factor, as are the climatic conditions under which one is operating. A saturated condition in some rock structure causes rock flows; in the Panama Canal excavation, slides have run on a ratio of as low as one on ten, which is a 10 per cent. grade, or a slope of less than 6° with the horizontal. Slopes as steep as 60° have been noted in the Utah Copper operations, so that a wide divergence will possibly be

Jan 8, 1924

The new saw mill at Cache Bay of the Geo. Gordon & Co., Ltd., a subsidiary of International Nickel Co., of Canada, is equipped with the first fully electric saw carriage drives in Ontario. It has a capacity of 120,000 ft of lumber in an 8-hr shift. About half of the mill's production is high grade white pine lumber which is shipped to the general market. The other half, red pine is used in the mining operations of International Nickel in the Sudbury district, 55 miles west of Cache Bay. [ ] Inco with a potential need of 77 million board ft a year, gets only part of its supply from the new mill. The milling firm became an Inco subsidiary Jan. 1, 1948.

Jan 1, 1952

By Homer E. Harris, William C. DeSieghardt, William A. Burgess

Under sponsorship of NIOSH, Eastern Associated Coal Corp., with the Harvard School of Public Health acting as a subcontractor, has determined for the first time the effective protection provided to working underground coal miners wearing approved half-mask dust respirators. This was done by conducting 187 man-shifts of in-mine testing in four different coal mines; included in this testing were 37 different test subjects representing 11 different job classifications and 5 different models of respirators. Presently available respirators on average provided significant protection levels to working miners even though on an intermittent use basis. However, "average" protection values were well below those achieved under laboratory conditions. Protection levels varied from man to man in a given work crew and from day to day for a given man. In addition, some of the factors affecting use and effectiveness of presently used respirators are discussed, as are areas in which improvements are needed, and the need to consider these improvements in context of a systems approach.

Jan 1, 1975

SMALL things are customarily moulded in two ways (unless they have undercut parts which hold them in the moulds); that is in clay, or with natural or which artificial earthern powder made in halves in either wooden boxes or bronze frames. This also depends on whether the object is larger or smaller. Now if you wish to mould with moist clay, you must grease your relief with oil or pig fat; apply a dusting of charcoal, ashes, or cuttlebone on it; or gild or silver it dry with gold, silver, or tin foil. Then, first make with moist and somewhat firm clay a plate as, thick and large as can conveniently hold your relief, and carefully set the latter halfway into this and let it dry. Then, greasing or dusting it again, make the other half. When both are well dried, take out your relief and at the top make its gates and vents. If plastering is needed, do it. Finally, bake the halves, fit them together, and tie them well, as you wish, using the procedure that I taught you in the discussion of brass. But if one has to make a large quantity of works of one kind, he should for the sake of convenience use the method with powder [120] because it is short and requires less time and expense. Therefore if you wish to do this, you need to have several pairs of bronze frames or wooden boxes, higher than half the relief that you wish to mould, and of convenient length. On a flat board always keep half of one of these frames full of powder that has been slightly moistened for moulding, as I told you, so that by pressing with the ends of the fingers and with the hand it holds together as well as possible. Level it off with a cutting tool and when leveled put a flat board over it and turn it over. Turn it on to a dusting of ashes so that it will not stick, dust it on the other side, and remove the excess by blowing it off Then mould the thing that you wish to mould, pressing it halfway in once or twice, always taking it out and putting it back again. Then the other frame is fitted in its place and filled with earth by pressing and squeezing it carefully. Then it is leveled off on the outside with a sharp tool as you did with the other part, and then one of the parts of the frames is lifted up with the point of a knife or some other tool and,

Jan 1, 1942

By R. K. Agarwal

Transforming from a mere novelty field of science to a well-recognized branch of engineering, the scientific discipline of rock mechanics continues to mature. The past decade has witnessed an unprecedented in- fusion of scientific research approach into mine design. In the preceding year alone, there were six national and international congresses which also indicated the increased interest, in rock mechanics and participation by scientific personnel with diversified backgrounds. It may be presumptuous to conclude that the time, effort and money spent thus far on procedures for mine structure design have necessarily resulted in the evolvement of design techniques; but certainly the prospects of evolving such techniques art: more promising at present than ever before.

Jan 1, 1970

By S. P. Singh, V. J. Hucka

There are a number of problems associated with underground coal mining, but the most serious and important are often related to the ground control. The influence of the prevailing geological conditions and features on the stability of underground mining has been outlined in this paper. Special emphasis has been given to the importance of geological techniques in the evaluation of coal mine roof conpetency prior to and during the mining operations. In addition to this, typi- cal ground control problems owing to the geological abnormalities have been depicted by appropriate case histories from coal seams in the State of Utah. The interdependence between longwall design and road- way stability on the one hand and geologic features on the other hand are shown in this study.

Jan 1, 1983

By C. H. Page, Brenne

Theoretical modelling of a proposed sub-level open stoping mining system was carried out to assess pillar instability and potential for hanging wall caving. This modelling was done, at first, without detailed information concerning the rock mass structure and classification. After mining commenced, the deviance in behaviour from that predicted by the modelling indicated that the structure was having an appreciable modifying effect on behaviour. Further analysis was carried out with detailed engineering geological information and a recently developed pillar design method. The outlined procedure produced results for pillar size and strength that explained the behaviour that had been recorded.

Jan 1, 1983

By Charles Hart

THE art of electric smelting came with the turn of the present century and owes its existence to the introduction of alter-nating current, which found its first wide use in the establishment of the great power plants at Niagara Falls, N, Y. Prior to that time current was largely direct. The fur-naces were electrolytic in nature and found their first metallurgical use in the produc-tion of aluminum, and this process still prevails. The normal production of pig iron up to that time was carried on in blast furnaces in which charcoal, coke and anthracite were used as the fuel. This new electric process called for sufficient carbonaceous material to reduce the oxides and impregnate the pig iron with sufficient carbon, but the remainder of the energy was to be supplied by electric power. The chemical reactions are essentially the same in electric smelting as obtains in the older blast furnace. All of these data are so well known in both methods as to need no discussion at this time, for they can be found in scientific publications and books written during the first two decades of this century.

Jan 1, 1940

By P. E. Queneau

This study confines itself to an examination of the two million square miles of the northern hemisphere which the geographer defines as the terrestrial Arctic, a land region in which the mean temperature of the warmest month is below 50°F-in effect, the area lying north of the tree line. The engineering and human problems there are of a different order of magnitude than is generally true of the sub-Arctic. Whether in Dawson Creek or Matanuska, in Mo i Rana or Skelleftea such problems are of the same general order as in Hibbing or Noranda. The same is not true in Kong Oscar's Fjord or Lancaster Sound.

Jan 7, 1961

By Y. C. Liu

IN the study of the rolling recrystallization of face-centered-cubic metals, a most unusual observation is the frequent occurrence of a sharp re-crystallization texture of cube orientation. Although the general conditions under which this texture occurs are known,2,3 its origin is still not well understood. Based on the observed relationship between the {110}<112> deformation texture and the (113}<211> recrystallization texture, regardless of the effect of alloying elements2,4,5 or the symmetry of the deformation texture,&apos; there is a strong indication that a specific component of the deformation texture is related to a specific component of the recrystallization texture. Using the rotational reorien-tation relationship as a means of correlating the deformation and recrystallization textures, it was proposed that the deformation component which related the cube texture has {358)<523> indices."&apos; The investigation reported here was undertaken to seek experimental evidence for the validity of this proposition. Experimental Procedure Two copper single crystals having an initial orientation within 2" of (358) [523] indices were prepared in the manner described in Ref. 5. The purity of the copper was between 99.94 and 99.97 pct. The original dimensions of the crystals were as follows: specimen A, 0.465 in. thickness, 0.844 in. width, and 0.955 in. length; specimen B, 0.535 in. thickness, 1.120 in. width, and 1.36 in. length: Rolling was done on a laboratory rolling mill according to the following schedule: 0.010 in. per pass to 50 pct reduction in thickness, 0.005 in. per pass to 70 pct reduction inthickness, 0.002 in. per pass to 85 pct reduction in

Jan 1, 1958

By George W. Mansfield

My plan in this paper is, first, to prove three general points, and then to take up the specific applications of the electric motor to nining work. The three poinb are: 1. The electric system is the simplest method known for transmitting and distributing any amount of energy from one locality to another, irrespective of the intervening distance. 2. The electric system with its applications is not in its infancy.

Jan 1, 1888