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By William E. Roscoe

"Valuation methods are well established for mineral properties with production or imminent production, and include discounted cash flow and comparable transactions. Valuation methods for non-producing mineral properties, however, are more subjective. Non-producing mineral properties include those at various stages of exploration, properties at the prefeasibility or feasibility stage, properties with currently uneconomic mineral resources, and past-producers. Different valuation methods may be appropriate for different types of mineral properties.Income approach methods such as discounted cash flow and option pricing are generally not applicable to properties at the exploration stage. The market approach is generally appropriate to all types of mineral properties, although it is difficult to find good comparables because of the unique nature of mineral properties and the small number of transactions. Cost approach methods, such as appraised value and geoscience factor, are commonly used for exploration stage properties.Canadian standards and guidelines for valuation of mineral properties are in the process of being finalized by a Special Committee of the Canadian Institute of Mining, Metallurgy and Petroleum (CIMVal Committee). The CIMVal Standards are intended to be consistent with National Instrument 43-101, which sets regulatory standards of disclosure for mineral projects, and with International Valuation Standards. The intent of the CIMVal Standards and Guidelines is that mineral property valuation be carried out by appropriately qualified individuals and that all relevant information be disclosed."

Jan 1, 2003

By Charles A. Beasley

Increased technical and legislative analysis by all parties of interest could result in more efficientand better directed regulatory legislation in the mining industry. Efforts to forestall or frustrate legislation through massive lobbying and public relations efforts are seldom effective over time and often lead to more stringent and far reaching legislation than necessary. The Federal Coal Mine Health and Safety Act of 1969 is perhaps an outstanding example of such insufficiences; a future example may well be regulatory surface mine legislation. Although a lack of extensive hard data seldom enables rapid or sophisticated analysis early in the legislative process, even preliminary analysis may be sufficient. Simple statistical analyses of available data, assessment of the legislative rationale, and subjective appraisal of other non-quantifiable constraints to improved mine safety. An average of 115 underground fatalities at an exposure frequency rate of 0.67 can be reasonably expected in the immediate future, under existing levels of technology, degree of regulation, and economic conditions. If gross unrefined estimates of 6 preparation plant, 5 surface, and 30 strip mining fatalities are assumed, the total fatality industry level could be expected to approximate 156 Serious professional, economic, and technical constraints within the the industry probably preclude any major decrease of these accident levels within the near future

Jan 1, 1972

By P. P. Gregory

ESTIMATION of re- serves in prorated sand fields has been discussed by S. A. Judson, H. D. Easton, Jr., and W. A. Schaeffer, Jr., in a paper that appears in Vol. 114 (1935), of the A.I.M.E. TRANSACTIONS. The purpose of this present paper is to extend the investigation to prorated flush limestone fields and to outline a method of procedure in determining the amount of oil originally in place and the amount of oil that can be recovered from such fields. Although it is possible to use the decline curves to estimate the amount of recoverable oil in certain limestone fields that are allowed to produce the oil at or near capacity production, such a method cannot be used in fields under severely restricted production rates. The problem is exceedingly complex due to fluctuation in the allowable rates of oil production over a wide range and at frequent intervals, and especially because of the heterogeneous nature of the reservoir itself. A well completed in a large solution cavity, capable of producing great quantities of oil per day, may be offset by a well of very limited capacity. Also, it is di5cult to arrive at an average figure for porosity in a given limestone reservoir due to abrupt variations in the character of limestone, in many instances even between two ad- joining wells. It is a safe statement that uniformity of porosity and permeability in limestone reservoirs .is nonexistent. It is evident, therefore, that the method of estimation of re- serves on the basis of per-acre content can give only approximate results.

Jan 1, 1935

By S Zheng, Y Zhang, Z Wen, S Ma

Red mud (RM) is a solid waste product generated during alumina refinery process, and is usually stored in SFs (SFs) because it canÆt be disposed of easily. In this paper, environment degradation caused by RM-SFs was systematically assessed by the method of single factor pollution index based on the analysis data of water, soil and atmosphere sampled around one newly-built and one decommissioned RM-SFs, which are managed by an alumina production company in China. The results revealed that the ambient environment around RM-SFs is seriously polluted by alkali and mercury (Hg). The pH value of RM leachate, surrounding surface water and groundwater are all higher than the limit of water quality standards in China. And as a possible result of overflowing of high alkaline leachate, soil pH value for the decommissioned SF decreases with increasing distance between the sample collection points and the closest side of RM storage facility (RM-SF). Total Hg concentrations in RM leachate, surrounding surface water and groundwater all exceed Grade III limits of ChinaÆs Environment Quality Standards for Surface Water and Groundwater. However, the air quality was little affected as the daily average of TSP in the air is below grade II values of Chinese Ambient Air Quality Standard.CITATION :Wen, Z, Ma, S, Zheng, S and Zhang, Y, 2012. Assessment of environmental quality impacts caused by red mud storage facilities in China, in Proceedings Life-of-Mine 2012, pp 51-58 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By J. H. Adkins

The goal of the project reported in this paper was to make recommendations for changes in roof bolting procedures and bolter design that would reduce roof bolter accident rates. To that end the project identified the major hazards associated with each task a roof bolter operator per-forms, normalized task accident frequencies. by the time spent on each task, reviewed equipment design features and operating procedures related to the identified hazards and developed recommendations for equipment and procedural changes that would reduce, if not eliminate, the hazards. The research steps completed during the project were: a. A review of related literature and re-search including roof bolting time studies b. The collection and analysis of 1975 accident data pertaining to roof bolter activities c. The normalization of the accident frequency data on the basis of time/task data d. A review of roof bolting equipment e. The development of a field data collection instrument f. The selection of mines for bolter observations g. The collection of field data h. Data analysis and problem specification i. The development of recommendations for corrective measures

Jan 1, 1978

By D. Scott Scovira, Thomas Gustavsson

Exiting WW2, the potential of nitrates and hydrogen peroxide for application as industrial explosives both became known. The technology stream advanced the development and uptake of nitrate-based explosives to the point that they are the current global standard for blasting. Recently environmental issues are influencing the strategic agenda of extractive industries. The mid-2010s saw renewed interest in hydrogen peroxide explosives to eliminate NOx fume. Carbon reduction initiatives in the 2020s provided additional impetus to investigate hydrogen peroxide-based explosives. Hypex Bio is at the forefront of developing and delivering bulk gas sensitized Hydrogen Peroxide Emulsion (HPE) for blasting. HPE consists of hydrogen peroxide along with smaller amounts of fuel and emulsifier. The consistency of HPE is similar to industry- standard nitrate-based emulsions. It is compatible with existing priming and initiation systems. HPE does not contain nitrates and thereby does not produce post blast nitrous oxide fumes nor discharge of nitrates or ammonia to mine water. Importantly, HPE contributes to reduction in total carbon emissions as compared to nitrate-based explosives.

Feb 1, 2025

By Edmund S. Leaver, Charles E. Van Barneveld

In response to numerous requests from metallurgists and operators for information regarding the status of the sulphur dioxide leaching process , developed at the Southwest experiment station of the U. S. Bureau of Mines , Tucson , Ariz . , the following statement has been prepared . A more complete report is now in course of publication and will appear as Technical Paper 312. This process was devised to provide a cheap and efficient method for treating the so- called "porphyry " copper ores of the Southwest which generally contain both " sulphide " and "nonsulphide " copper minerals , mixed in such proportions that they can only be satisfactorily treated by a method which will concurrently recover both the sulphide copper and the nonsulphide copper . The latter term has been adopted to include all the minerals commonly referred to in operating phraseology in the mills of the Southwest as " oxidized" , " oxide " , or " soluble " copper . confident that the sulphide dioxide leaching process , as developed by us with the cooperation of the Miami Copper Co. and the Arizona Copper Co. , is suitable and commercially available for a wide range of ores .

May 1, 1922

I have sketches of the radiators, and on this sketch up in here (indicating) we show the line from the fan-exhaust steam from the fan, and the trip spray at the mouth of the mine, which is usually near the tipple, the set of radiators on each side of the entry, exhaust steam exhausting in by the radiators, the small atomizers which I mentioned, and the man sprinkling at the hose. There are times, when at different times we have a man sprinkling during the day time, when he is out of the way, and during the night, sprinkling on the motor roads. I will leave that print up here and let you look at it and if you have any questions you wish answered, Mr. McAllister and myself will be glad to answer them. (Applause.) PRESIDENT PRYDE: . I am going to ask Mr. Hair to leave the sketch on the wall. From the back part of the hall, it is hard to see what is there. The figures are very important. I think one member of this association will be glad to know the cost of water, Friend Littlejohn. MR. LITTLEJOHN: I don't know as I want to ask any questions. The only thing I' would say about the cost there, it is very close to that cost that we tabulated for the Utah Fuel Company at the Utah mines here some time ago. We have not tabulated lately. It may be a little over that at the present time if you take the. labor costs and the material. costs. As I remember, some time ago we did get up some figures and it was, as near as I can remember, exactly two cents per, ton for the labor and material. We haven't got the radiators, etc., that the C. F. & I. have in their mines there, probably due to the fact that we have no shortage of water. We have plenty of that there, and our system is absolutely nothing more nor less than pipe lines, hose and nozzles and the man at the end of the nozzle. PRESIDENT PRYDE: I would like to ask Mr. Hair about the cost of the steam. MR. HAIR: That steam we use there in exhausting, of course, is from the fan, and we have a back pressure valve set right here (indicating), from three to four and sometimes five pounds, and the exhaust from the fan was a five or six inch exhaust, and our exhaust into the mine is nothing less than eight inches, and is practically low back pressure you might say, and all those large radiators, that I spoke of, are heated by live steam, and these probably take a little more coal, but as to just what that cost is I couldn't say. As far as the exhaust steam is concerned, you might as well use it in the mine as discharge it outside. MR. HARRINGTON: Mr. Hair, I would like to ask, is this installation on an intake haulage-main haulage course? MR. HAIR: Yes, sir. MR. HARRINGTON: In the winter time, when it is, say between five or ten degrees below zero, how far into that haulage road does the fogging go? MR. HAIR: Well, that goes in half a mile, sometimes in 3,000 feet. MR. HARRINGTON: Wouldn't that interfere pretty seriously with the motor? MR. HAIR: To some extent, but I wouldn't say seriously enough to interefere with the production of coal. We have one mine we are working in two and three-quarters miles. Our mines are all pretty deep, and we don't find it objectionable. I don't believe that it interferes in the production of coal. I don't believe it makes any more difference between a real cold day in winter time than it does in the summer time. MR. HARRINGTON: I was down at Dawson, and in their mines they have an installation very much like Mr. Hair describes, but we went in there one night and stayed all night, getting a certain amount of data, and the fog was intense for-a full half mile; so intense that you could hardly see your hand in front of your face-see your hand that far (indicating) dis-

Jan 1, 1924

By Zabetakis M. G.

This Bureau of Mines report presents a brief summary of the explosion trends in United States coal mines for the past 160 years. These trends show that in spite of the overall improvements in mine safety, the number of fatalities from ignitions of methane has actually increased in recent years. Suggestions are made of procedures that can be utilized to reverse this trend.

Jan 1, 1973

By W. I. Garms

This paper, describing the milling practices at the Hayden concentrator of the Nevada Consolidated Copper Co. is the first of a Series being prepared by the Bureau of Mines on milling methods and costs in various districts of the United States. The Hayden concentrator is located at Hayden, Gila County, Ariz., 20 miles from the mine at Ray, Pinal County, Ariz., and approximately 1-1/2 miles north of the junction of the Gila and San Pedro Rivers. During the fourth quarter of 1928 the concentrator treated daily by flotation an average of 10,336 tons of ore containing 1.25 per cent of copper. The average recovery during this period amounted to 87.84 per cent of the total copper. The concentrates contained 19.88 per cent of copper.

Jan 1, 1930

Mineral processing is at the hub of the exploration-mining-metals production system. Because of the large volumes of material processed, incremental technology investments can pay off better than for other parts of the system. However, much of mineral processing remains a 'black art', because we are behind in investing in modem technologies. Consequently, we have one of the best opportunities to improve efficiency and competitiveness through the application and transfer of technologies that have already been developed for other industries. The reluctance of minerals companies to place priority in our area is not because we lack new ideas; our senior management has not been convinced, based on our previous results, that such investments will pay off as well as other investment opportunities competing for the same resources. The key is the proper establishment of technology strategy and more effective transfer of technology. The presentation will identify the failure mechanisms of technology transfer and will present a model for improving the success rate, a prerequisite for raising the priority of mineral processing investment. Topics emphasised include strategy formulation, human resources planning, and total quality management principles applied to improving technology transfer.

Jan 1, 1993

By Louis A. Turnbull

An investigation of coal deposits near Cerrillos Santa Fe County, N. Mex., was undertaken 14 the Bureau of Mines in 1943 as part of a general program to determine sources of metallurgical coal for western steel plants. Almost all of the coal used for metallurgical purposes west of the Continental Divide Is mined from the Lower Sunnyside bed in, Carbon County,, Utah. Coke used in western steel plants that is produced from Lower Sunnyside a coal is weaker, structurally, than coke used elsewhere in this country. For this reason, western coal operators and steel manufacturers are anxious to develop new areas of coking coal of better quality then the coal produced from the Sunnyside bed. The objective of investigations of western coals was to (a) develop additional reserves of coking coal to supplement proved reserves in the Sunnyside bed. and (b) develop; if possible, reserves of coal with coking quantities superior to those of Lower Sunnyside

Jan 1, 1951

By L. Zhou, A. Martikainen, G. Goodman

Continuous airflow monitoring can improve the safety of the underground work force by ensuring the uninterrupted and controlled distribution of mine ventilation to all working areas. Air velocity measurements vary significantly and can change rapidly depending on the exact measurement location and, in particular, due to the presence of obstructions in the air stream. Air velocity must be measured at locations away from obstructions to avoid the vortices and eddies that can produce inaccurate readings. Further, an uninterrupted measurement path cannot always be guaranteed when using continuous airflow monitors due to the presence of nearby equipment, personnel, roof falls and rib rolls. Effective use of these devices requires selection of a minimum distance from an obstacle, such that an air velocity measurement can be made but not affected by the presence of that obstacle. This paper investigates the impacts of an obstruction on the behavior of downstream airflow using a numerical CFD model calibrated with experimental test results from underground testing. Factors including entry size, obstruction size and the inlet or incident velocity are examined for their effects on the distributions of airflow around an obstruction. A relationship is developed between the minimum measurement distance and the hydraulic diameters of the entry and the obstruction. A final analysis considers the impacts of continuous monitor location on the accuracy of velocity measurements and on the application of minimum measurement distance guidelines.

Jan 1, 2012

By D. R. Wilburn

The Bureau of Mines investigated the potential availability of magnesium from 45 properties in market economy countries (MEC's). The 38 significant deposits evaluated have demonstrated resources of approximately 29 billion short tons (st) magnesium-bearing material containing 416 million short tons (MMst) magnesium oxide (MgO). Using data it gathered, the Bureau determined the magnesium production potential for each property including a 15-pct rate of return on invested capital. Total and annual availability assessments for the next 30 yr were completed for magnesium (Mg) metal, deadburned MgO, and caustic calcined MgO. At a January 1984 market price of $1.34/Ib Mg metal, the properties evaluated could economically produce an estimated 13 MMst Mg metal. At a market price of $400/st nonmetal magnesium product, these properties could economically produce 109 MMst deadburned MgO and 43 MMst caustic MgO. These properties could produce approximately 301,000 st Mg metal, 3.0 MMst deadburned MgO, and 430,000 st caustic MgO annually at current full production levels and 1984 market prices until at least the year 2000. Total 1984 MEC production assessed in this study was 153,000 st Mg metal and 4.3 MMst nonmetallic MgO products.

Jan 1, 1986

By Jack I. Paige

In this Bureau of Mines study, two fluidized-bed reactors were designed, built, and operated, one as a sorber for S02 and the other as a contactor for the regeneration of the sulfur-laden alkalized alumina. The target of 90 percent removal of S02 from a flue gas stream containing 0.3 percent S02 was attained by using a sorbent feed of 10-15 grams per minute into a 5-inch bed depth of alkalized alumina. The sorption unit was operated at about 330° C. Complete regeneration of the laden alkalized alumina containing 5 to 10 percent sulfur was accomplished in approximately 1/2 hour. An excess of reformed propane at about 730° C was the regenerating gas. Attrition losses, a major problem with this sorbent, ranged from 0.9 to 7.9 percent of the inventory. Data from these tests demonstrate, within experimental error, the validity of equations developed from short-term, thin-bed tests related to sorption and regeneration rates.

Jan 1, 1970

By Slavoljub Makslmovic

One important element of the U.S. Bureau of Mines computer-assisted mining research program is the development of a reliable coal interface detection (CID) system. Several candidate CID concepts currently being investigated by the Bureau include use of natural gamma radiation (NGR), vibration, passive infrared, video, and radar. To help establish which CID sensor technologies need to be developed for a given seam, the Bureau has collected geological and mining practices data from over 460 underground and surface mines in the United States. Also, over 500 coal and rock samples have been obtained for laboratory analyses of ash content, sulfur content, heating value, and NGR. The Bureau's findings indicate that the immediate roof strata in 81% of the underground mines and 93% of the surface mines are made up of shale, draw slate, or claystone. The immediate floor strata in 88% of both the underground and surface mines consist of fireclay, shale, draw slate, or claystone. The results of the NGR testing indicate that the NGR method appears to be a potentially useful CID tool, provided that the immediate roof and floor are both composed of a high percentage of shale-type material.

Jan 1, 1993

By Heinrich Majewski, Rob Jameson

"Careful review of site conditions and constraints is essential to select the appropriate shoring system for each project. Key evaluation criteria include the geotechnical profile, groundwater and environmental conditions, adjacent buildings and utilities, schedule and any project specific access or other constraints. Typical earth retention schemes range from rock or soil nail walls, through conventional anchored pile and lagging walls to deep internally braced cut-off systems. The Owner’s design team will often develop the conceptual approach under their design studies, and this is refined with Contractor input through Design-Build or Design-Bid-Build procurement. In downtown San Francisco, underground construction must accommodate a unique combination of variable fill, soil, rock and groundwater conditions, potential for severe seismic loadings, and constrained sites within a dense urban environment. The quarter square mile of San Francisco’s Transbay and Rincon Hill districts has seen repeated cycles of development, destruction and re-building through earthquakes and the economy, and has been intensely redeveloped over the last decade. Over 50 acres of this land has been reclaimed from the Bay since the Gold Rush and within 3 city blocks the bedrock slopes from over 250 FT depth below the fills up to outcrops over 100 FT above sea level. A series of project examples from within this small area illustrate how varied shoring systems have accommodated the highly variable subsurface conditions while offering best value in terms of cost, schedule and appropriate protection of adjacent facilities.INTRODUCTIONA walk of 3 blocks from Rincon Hill on San Francisco’s Harrison Street, north through the Transbay area to Mission Street will traverse an urban zone which has been reinvented twice within its 150 year history in response to major seismic events. This small area highlights the range of subsurface conditions and urban environments which are encountered and accommodated in shoring schemes throughout the city. This route down the north side of Rincon Hill overlies a steep bedrock slope, outcropping over 100 FT above sea level at its south end and dropping to over 250 FT below sea level at Mission Street. A complex overburden soil profile, shaped by seismic activity and changing sea-levels has created layered soils ranging from soft estuary muds, dense sandy strata and deep clay layers, in turn topped with urban fill, frequently contaminated with debris from the Great 1906 earthquake. This route runs parallel to, and 350 yards inland of, the San Francisco shoreline resulting in groundwater elevation close to sea level with almost limitless recharge within granular layers. On the higher slopes of Rincon Hill, groundwater is typically observed flowing on top of and periodically within the fractured bedrock formation. The Transbay and Rincon areas were developed early in the Gold Rush era of San Francisco. After destruction in the 1906 earthquake and fire, they became a transit gateway into the city throughout the 20th Century. Demolition of the Embarcadero Freeway in response to earthquake damage and social pressure has opened this large area to redevelopment within the last 20 years, creating a new commercial and residential hub for the city. In its latest wave of building, planners are developing taller structures with deeper basements, in turn creating new construction challenges. Selection of shoring systems appropriate for these developments requires detailed evaluation. The process must address both the rapid spatial changes in subsurface conditions and the constraints surrounding, and specific to, each site in order to define shoring performance requirements. This paper presents an overview of the subsurface conditions and land use development of the Transbay and Rincon Hill areas, with examples of the shoring systems selected to meet site-specific conditions and requirements. The projects cited range from soil nail wall"

Jan 1, 2017

By T. F. Witherbee

It is proposed to give, first, a description of the works; second, a report of the first six months of the present blast; and third, such improvements as have been suggested by the practical working. The site selected for this furnace was, at the time of commencing work, October, 1872, entirely covered by the navigable waters of Lake Champlain. A coffer-dam was first built of cribs of round timber filled with stone, forming three sides, while the shore answered for the fourth. Considerable excavating was done with a steam-dredge, a hole being left for it to pass out. The opening was then built up, and the cribbing banked up with blue clay from the bottom of the lake, to render it water-tight and the dam pumped out; the remainder of the excavating being done by hand. All of the foundations, with the exception of the elevator-tower, and fifteen feet of the east side of hot blast, rest on the Potsdam sandstone, which forms the shore line, dipping into the lake at an angle of fifteen degrees. Owing to jogs in the formation, a much greater depth was found necessary than was at first anticipated, the foundation under the stack

By L. B. Berger

Each winter brings its toll of deaths and serious accidents from the deadly gas, carbon monoxide. Newspapers carry warnings to the public of the dangers of this gas, and frequent now items retort the finding of persons dead or unconscious from the effects of carbon monoxide, yet these accidents continue. Either those warnings are not read, or they are unheeded by people who feel that "It can't happen to me." It can happen to you - carbon monoxide is no respecter of persons, as evidenced by items appearing daily in newspapers all over the country. Carbon monoxide has been a threat to human safety as long as man has used fire to keep himself warm and to cook his food. The burning of any fuel that contains carbon may produce carbon monoxide. This is true of solid fuels such as coal, coke, and wood; of liquid fuels such as oil, gasoline, and kerosene, and of gaseous fuels such as natural or manufactured gas. In the process of combustion the carbon in the fuel unites the chemically with tat oxygen of the air to form carbon dioxide (CO2), however, if the supply of air is not adequate, combustion is incomplete and carbon monoxide (CO) will be formed.

Jan 1, 1943

By Robert E. Wood

The compressibility factors, Z, of helium, nitrogen, and helium-nitrogen mixtures in the three-dimensional space of temperature, pressure, and gas composition have been related to the Leiden form of the virial equation of state. The dependency of virial coefficients through the fifth on temperature and gas composition has been established for the temperature range 133.15° to 748.15° K. Compressibility factors, Z, have been computed from the equation of state and tabulated as functions of gas composition, pressure, and temperature. Tabular values of Z are presented for 30.00 through 100.00 percent helium for temperatures from 240° through 700° R for pressures from 14.696 through 3,050 psia and for temperatures from 720° through 1,300° R for pressures from 14.696 through 1,500 psia. Tabular values of Z are presented at increments of 5.00 percent helium and 20° R, and, for pressures greater than 50 psia, at increments of 50 psi.

Jan 1, 1967