Search Documents

By H. Warlimont

In recent investigations of the microstructure and crystallographic features of martensite by electgon microscopy,', '9 thin films (about 50 to l000A in thickness) have been used as specimens. It was found by W. Pitschl ,2 that the lattice relationships between the supefiaturated fcc matrix and the martensite formed in thin films were different from those observed after transformation in bulk material. Corresponding differences are to be expected in nucleation and in reaction kinetics in the formation of martensite in thin films, but have not yet been reported. In the course of the preparation of thin films of iron-base alloys for investigation by electron microscopy it was observed that films of alloys, whose martensite formation temperature (Ms) was below room temperature, formed martensite during the electrochemical thinning process conducted at or above room temperature. The chemical compositions and approximate bulkM,-temperatures of the three materials on which this observation was made are listed in Table I. The alloys were vacuum-melted from high-purity metals. It can be seen that the effect occurred in alloys that contain only sub-stitutional components as well as in alloys that contain carbon as an interstitial solute. The appearance of martensite formed in this manner is illustrated in Fig. 1, which represents a polished film of alloy No. 1 at XI0 magnification. The martensite plates can be recognized by their surface relief effects. In addition, heavily strained (owrinkledo) austenite can be seen near the edges of the film where it is thinnest and transformation stresses or strains can be accommodated by plastic deformation most easily. The nonuniform distribution of transformed regions is probably due to the varying thickness of the film. These observations were common to all materials listed in Table I. Because effects of supercooling or straining can

Jan 1, 1962

Jan 1, 1970

?General Facts:Barrick?sFirst Mine in Peru Production started in November 1998 ?The Facilities:Open Pit, Primary and Secondary Crusher Valley Fill Heap Leach PadMerrill Crowe PlantRefinery Environmental Facts: High Rainfall - Average Annual Precipitation of 1,200 mm (47 inches) Rainfall Events: Common 20mm daily events High Altitude Site - Elevations range from 3900 to 4250m. Steep topography - Terrain ranges from 3:1 slopes up to cliffs. Water Issues: Sediment Control - Open Pit PAG Encapsulation - Waste Dump Stormwater control - Leach Pad Erosion Control Techniques ? Offsite impacts mitigation Social Issues: 11 communities surrounding the property Town of Huaraz

May 1, 2003

By P. H. Tumialán

Dado que la veta El farallón del batolito de la Costa en Huarochirí, Lima, fue alimentada por flujos hidrotermales horizontales, se prevee que la mineralización de los flujos horizontales forman parte final del flujo de ascenso vertical, que en los yacimientos anteriores no se pudo hallar. En esta perspectiva, para la veta señalada, el zoneamiento con eje horizontal en sentido contrario al flujo mineralizante, es de plata, cobre, plomo, zinc y oro. En consecuencia, el concepto genético y el zonamiento hallado se convertirá en una guía para la exploración geológica de estos yacimientos, donde no solo hay flujos horizontales hidrotermales en rocas volcánicas estudiadas en Julcani por U. Petersen, sino también en rocas sedimentarias e intrusivos.

Oct 14, 1980

By R. W. Stahl

An emergency is defined as an unforeseen combination of circumstances that calls for immediate action. When applied to a coal mine, an emergency may call for prompt removal of the men to the surface through travelways other than the haulageway or intake airways, which are generally contaminated with irrespirable air as a result of an explosion or fire. Therefore, maintenance of adequate and travelable escapeways from all working areas of a mine is vitally important insurance against disaster. Several mine disasters could have been avoided if well-defined escape routes had been provided and made known to all mine employees. Such occurrences, unnecessary as they generally are, unfairly indict the industry when only a small segment thereof is involved. As a result of a rather recent disaster, which might not have happened if good escape routes had been provided, the Bureau of Mines decided to delve into the escape procedure to determine (1) what is being done in the industry and (2) what might be done at reasonable cost.

Jan 1, 1962

By Matthew Janes

The installation of piles and casings is becoming increasingly difficult as restrictions on vibration become common in major urban areas. The use of high frequency, resonant excitation of a pile or casing permits ease of installation of sections to great depths with near imperceptible vibrations as close as 1 pile diameter. The new Resonant Driver is able to excite a pile at its resonant frequency (up to 150 Hz or 9000 VPM) to produce elevated levels of acceleration, force and displacement in the pile. The combination of extremely high acceleration and controlled levels of displacement allow the pile to slice through varied soil with almost no vibration translated into the ground. In direct comparisons between conventional vibrators and impact hammers the Resonant Driver produces less than 1/50th the vibration. The Resonant Driver results in ground vibration of between 1/20 and 1/40 of common limit levels (1 cm/s or 0.5 in/sec) as close as 1 pile diameter. At a distance of 5 m (16 ft) from the pile or casing vibration levels approach imperceptible levels. The Resonant Driver uses a proprietary algorithm to tune the drive vibration to the changing natural frequency of the pile as it is driven into the ground. By maintaining resonance the energy in the pile is built up like in a flywheel on an engine or a child on a swing. This build up of energy aids in driving and significantly reduces waste. Recent experience using the Resonant Driver is proving the technology can drive a variety of steel pile and casing sections through varied soils. Continued use of the Resonant Driver will create a data base of various pile and casing sections, soil types and achieved capacities.

Jan 1, 2008

By Curtis G. Kremer, Jeffrey L. Brummert

Blue Circle Cement's Ravena, New York quarry mines approximately 6.7 million tons of limestone per year. Blasting occurs approximately twice a week on three separate benches. Shots average 60,000 tons but can range up to 140,000 tons. Ongoing scrutiny of the drilling and blasting program allows for maximum blast efficiency which results in lower overall mining and crushing costs. Close cooperation between management and explosives supplier assures Blue Circle Cement's objective, "To develop, implement, and continuously improve a measurable drilling and blasting system that will optimize the total mining and crushing costs while ensuring compliance to safety and maintaining or reducing the environmental impacts of blasting".

Jan 1, 1994

By Paul Sainato

Recruiting and retaining students in the explosives industry is becoming increasingly important each year. With no undergraduate degree in explosives engineering currently available in the United States, it is from other industries and degree disciplines we must recruit. The 2014 annual ISEE conference saw the first anonymous online survey distributed to members of SEE student chapters of the International Society of Explosives Engineers. The survey contained questions about future job and career plans, ideal job placement, expectations of salary and current academic degrees. The purpose of the survey was to determine what these students expect or require from a career in the explosives industry, and their current path to pursue this. This information can help steer recruitment activities and job offers for graduating students. The success for both student response rates and interest from the industry has allowed space for a yearly update of this survey. A second survey was distributed in 2015 and included international students. This paper provides the data from a third online survey distributed to all student members of the International Society of Explosives Engineers, globally. Understanding the main incentives for a student to accept a graduate position as an explosives engineer can help us, as an industry; position ourselves to remain competitive in recruiting against other major degree disciplines.

Jan 1, 2016

In addressing the need for non-degree tertiary training, let us examine some recent reviews of engineering and geoscience education. The Finniston Report (1) criticised the formation of engineers in the UK and stated that this was largely due to the narrow British conception of engineering as a branch of applied science which militates against an effective marriage between theory and application. It also criticised the system for not giving students sufficient grounding in the synthesis of technical, human and financial considerations within their undergraduate courses. As we all know, this report has led to the restructuring of engineering education in the UK. More recently, a Review of the Discipline of Engineering was carried out in Australia by a committee chaired by Professor Sir Bruce Williams (2). The report stated that: Australia has a fairly good system of engineering education that should be made better. more should be done to develop the communication skills of both staff and students. more attention should be paid to changes in engineering practice and the human element in technology. there is a serious shortage of state of the art equipment in most engineering schools. female enrolments in engineering courses should be increased from the current level of about 7% to 20% by 1997. employers should develop a better understanding of the need for continuing education. staff in engineering schools should develop closer relations with employers of engineers. higher education institutions with engineering schools should give financial and other inducements to staff to increase the proportion of study leave or professional development leave spent working as engineers in the business sector. there is considerable room for improvements in the teaching process and in the development of evaluation schemes for assessing the teaching contributions of staff. In its recent report to the Council of the Institution of Engineers, Australia, the Task Force on Engineering Education(3) makes the following points: managerial, entrepreneurial, professional and interpersonal skills should be introduced and integrated into the undergraduate courses but studied in depth as part of continuing education. the continuing education policy of the Institution should be promoted and strengthened with all engineers required to pursue continuing education. the Institution should develop a comprehensive guide to continuing education available from universities, colleges and other public and private sector organisations.

Jan 1, 1989

Montana's coal reserves are estimated to be more than 120 billion tons, 24.6 percent of U.S. reserves. Montana's reserves are the largest in the nation. Coal fields are located throughout the state, primarily east of the Continental Divide. Three of the state's 17 coal fields have producing mines. Coal resources range from lignite to high volatile bituminous; however, most of the coal currently mined is subbituminous. Although Lewis and Clark mentioned the presence of coal along the banks of the Missouri River in Montana in 1805, the first major mine was not opened until 1867, at Chestnut, Montana, near Bozeman. The mine at Chestnut served Fort Ellis until the mine was bought by the Northern Pacific Railroad in 1883. By 1900, underground coal mining had developed throughout the state, primarily to supply fuel to the railroads. In the 1920s, large-scale surface mining began in Colstrip to fuel railroad steam engines. Currently, all coal mined in the state is produced from surface mines. The Office of Surface Mining granted the Montana regulatory program conditional approval April 1, 1980, followed by final approval February 1 1,1982. Montana's Abandoned Mine Lands Program was approved November24,1980, and its emergency program was approved August 18, 1983. A Federal Lands Cooperative Agreement was approved May 8, 1981.

Jan 1, 1992

By Tugba Kami?oglu

Hydromagnesite (Mg5(CO3).(OH)2.4H20), one of the sedimentary deposits in Salda Lake Basin, is developed under the control of active tectonics regime. Since the occurrence and deposition mechanism of hydromagnesite are unstable under atmospheric conditions, in order to evaluate the precipitation process, systematic host rock, lake water (surface, 20m, 40m, 60m) and hydromagnesite sampling were carried out. Macro, micro, XRD and chemical investigations were done in detail. Not only the results and formation and crystallization mechanism but also hydromagnesite's St values were evaluated. Main resources could be ultramaficmafic surrounding rocks for hydromagnesite formations. However, hydromagnesite development is considered in different phases, because it has showed various characteristics in Kayadibi and Köpekcayin areas. In Kayadibi area Huntide-Dolomite-Aragonite-Hydromagnesite paragenesis has been realized. Hydromagnesite has also formed in Köpekcayiri area, large amount of hyrdomagnesite occurrences and levels various are noticeable. Actual position of hydromagresite levels exhibits tectonic influences in and around the lake. Therefore, the levels seems to exhibit secondary formation properties. In addition, the formations are being still maintained sedimentation as products of a peripheral deposition phases. Resolving and redifferentiation sedimentation processes probably improve in periods of lake water chemistry especially Ca/Mg proportional changes, and also SI variations indicate the mentioned precipitation mechanism. Similarly, side and into the lake hydromagnesite is stored different levels and ultramafics-mafics rocks fallow indicated stages. It is postulated that hydromagnesite formation, which is existed by result of determined developments and multiphase sedimentation, could be originated from probable crack zones on the lake bottom.

Jan 1, 2005

By Barnard Foo

Topics of Discussion ?Location ?Production & Mining Operation ?Mineralization ?Mining Method ?Rock Mechanics Issues ?Ground Control Problems ?Numerical Analysis ?RockmassBehaviour ?Conclusions & Recommendations ?Discussion

Feb 1, 2008

By E. E. Carpenter

(San Francisco Meeting, September, 1915) BELIEVING that the results accomplished in the mill of the Churchill Milling Co., Wonder, Nev., during the fiscal year ended Sept. 30, 1914, will be of interest, I am presenting the more prominent facts and figures showing the progress made in treating this ore with especial reference to tonnage, supplies, costs, and extractions. The mill is situated at Wonder, Nev., in the Wonder mining district, 55 miles east from Fallon, Nev., the nearest railroad point. All supplies are hauled this distance by freight teams, this method of transportation having been found more reliable for continuous service than trucks, the price paid for hauling being slightly under one cent per pound. In this mill are treated the ores of the Nevada Wonder Mining Co. ,

Jan 6, 1915

The following notes apply more especially to the purchase of silverlead ores produced in the neighbourhood of Zeehan and Dundas; for it is this class of ore that is principally mined in those parts, and which creates competition among the ore buyers.In the early days of this field, most of the ore passed through the hands of the first buyer who had sufficient enterprise to establish himself at Zeehan but in more recent times, competition has been so keen that there are generally three or four buyers tendering. lf the output was large this would not matter so much from the buyers' point of view but when we consider that the output of the field is only some 1,650 tons per month, and that of this 70 odd tons are produced by the Western and Montana mines, aud being sent home for realization, is withdrawn from local purchasers, there is really not enough for four buyers, especially at the present exorbitant prices they pay the miners.Some of the mines have a fixed sampling day, on which it is tacitly understood that the ore buyers will attend. Others, such as Grubb's Silver Mining Oompany, No-Liability, send round a printed reminder, stating the quantity of ore, and the date of sampling.

By W. Lorenz

The responsible treatment of natural resources, including mineral raw materials, contributes to the protection of the environment. The management of resources and the environment encompasses reduction of emission through application of environmentally friendly processes, economical use of resources, recycling and substitution, application of energy saving processes, land reclamation and recultivation, as well as a well balanced regional and land use planning. A variety of materials are needed for measures to protect the environment. Many of these materials are, or to a large percentage consist of, mineral raw materials, which become effective either directly or indirectly in their natural state or after an appropriate industrial treatment. We call them environmental minerals. Although extraction and processing of these mineral raw materials destined for use in the protection of the environment, may have a negative impact on the environment on one hand, preventive or curing measures to protect the environment on the other would not be possible without them. We have to accept certain smaller burdens of the environment, which naturally will have to be kept at the lowest possible level, in order to avoid or minimize greater damages to nature. In the broad group of industrial minerals and rocks there is a wide variety of mineral raw materials, which lend themselves for countermeasures in favor of the environment. To hamper their production and processing through excessive environmental regulations would make the protection of the very environment more difficult or even impossible.

Jan 1, 1995

By George Smith

IN the utilization of natural resources owner, operator, and consumer should share the attendant benefits. Development needs to be planned under terms recognizing fully the interests of all concerned, for any undue advantage given to any one of these participants is apt to involve even greater and disproportionate injury to one or both of the others. For this reason it is well to preface any consideration of needed reforms in legislation affecting the disposition of public land with a survey of certain fundamental principles that determine the general conditions of all land transfers preliminary to development, utilization, and production. The disposition of any undeveloped natural resource, whether timber, oil, coal, or water power, as a transaction to which hand owner and prospective developer are parties, must be based in theory upon a division of expected returns. Whatever the terms of such disposition, neither party can reasonably ask for anything other than an equitable division of the returns. Under this analysis three and only three questions need to be discussed ; namely, what are those profits, how is this division to be accomplished, and what is the equitable basis of division ? The answer to the third question should probably be found by applying to the problem the principles of theoretical sociology, and' the question need not be mentioned further at this time, inasmuch as it does not involve the practical considerations to be kept in mind in connection with the other questions, which are concerned with only the measure of returns and their division. That is to say, whether the land owner's equity is to be stated as 95 per cent. or as 5 per cent. of the profits attending the development of the particular resource, no change would be necessary in the method to be adopted of arriving at the closest approximation of the prospective total profit.

Jan 10, 1913

Refractory gold ores have been the subject of intensive metallurgical study in order to achieve more efficient recovery of contained values and at the same time to minimise environmental impact. Considerable innovative gold processing technology was introduced in New Zealand last century, the most notable being the first successful commercialisation of the cyanidation process by the Crown Mines Company at Karangahake in 1889. The Karangahake gold-silver deposit was second only +to the Waihi Martha mine in total bullion production from the region with active mining from 1882 until about 1920 and sporadic production between 1930 and 1944. Reevaluation at Karangahake with associated metallurgical testing has continued since that time becoming particularly active in the last decade as a result of increasing gold prices. Gold processing technology is reviewed and results of some recent test work are presented and discussed in the context of Karangahake history and future development possibilities. This work confirms the variability and complexity of the Karangahake deposit both mineralogically and metallurgically and suggests flotation followed by new and innovative smelting is the most appropriate processing route for the recovery of gold from the high grade ore which could be produced from the Karangahake workings in moderate tonnages.

Jan 1, 1993

By Jake Gibson

"As one of the most pressing and important political debates of this century, climate change has captured global attention and is forcing governments to take action toward decreasing greenhouse gas (GHG) and carbon emission levels below what was previously thought to be necessary. With the ever-increasing price of diesel fuel, accompanied by the popular topic of carbon taxes and greenhouse gas emissions, the mining industry is looking to industry specialists for assistance. The benefits of a no-idle policy reach far beyond carbon reduction and fuel savings, ranging from decreased maintenance to increased engine life. With products like battery-powered ac systems and diesel-fired heaters, going noidle is easier today than ever before. With both systems being manufactured to withstand the harsh environments of the mining industry, the end user will see a seamless change from conventional, inefficient belt-driven systems to future, standalone mobile equipment HVAC.The history of GHGs and climate changeIn 1896, Svante Arrhenius first claimed that the combustion of fossil fuels may eventually result in enhanced global warming, but not until 1955 did Gilbert Plass draw global attention to global warming by summarizing that adding carbon dioxide to the atmosphere would intercept infrared radiation and thus warm the earth. Then in the early 1960s, Charles Keeling developed modern technology to produce concentration curves for atmospheric CO2 (Fig.1).In 1988, the Intergovernmental Panel on Climate Change (IPCC) was founded by the United Nations after acknowledgment of a rising global annual temperature. The IPCC consists of more than 2,500 scientific and technical experts from more than 60 countries. Because climate change could not be solved by a single country, the Kyoto Protocol was negotiated in 1998, requiring all participating countries to reduce their GHG emissions by at least 5 percent from the 1990 levels. The Protocol was signed by 186 countries in 2001 (since then several countries have retreated from the agreement, including the United States). In 2002, the Bush administration announced a policy for climate change relying on domestic, voluntary actions to reduce the "greenhouse gas intensity" of the United States economy by 18 percent by 2012. The U.S. still attends the Kyoto conference of parties (COPs) but does not participate in negotiations, as it is not bound by its terms."

Jan 1, 2014

By R. Patterson

Tracer gases have been utilized successfully in a variety of industries, each with specific releasing and sampling methods. The various attributes of tracer gases are dependent on the industry the tracers are utilized in. Tracers must be chemically and thermally stable, safe, odorless, detectable at low concentrations, have a low background concentration, and should not be naturally occurring in the environment if they are utilized in underground mining applications (Thimons et al., 1974). In addition, the tracer gas should be inexpensive, non-corrosive, non-toxic, easily transportable, readily attainable, and non-radioactive (Kennedy et al., 1987). Sulfur hexafluoride (SF6) met many of these above requirements and therefore was introduced as an ideal tracer gas to use in mining industry in the early 1970?s (Thimons et al., 1974). Due to the nature of underground mining including complicated geometry, irregular flows, turbulent flows, obstructed airways, and leakages it is difficult to use conventional anemometer and smoke tube techniques to accurately measure the effectiveness of ventilation controls (Thimons et al., 1974; Klinowski and Kennedy, 1991). There have been several applications of SF6 as a tracer gas in underground metal/non-metal and coal mines. Thimons et al. conducted early testing of SF6 in an underground limestone mine and determined that it is an effective technique for evaluating auxiliary fans, estimating volumetric flow rates in large areas, and measuring low flow velocities. A rapid face ventilation measurement method (FVM) utilizing SF6 was developed by the Bureau of Mines to make face measurements in underground coal mines (Timko and Thimons, 1982). When measuring the effectiveness of jet fans in dead headings SF6 was proven more effective than smoke tubes (Timko and Thimons, 1982). Experiments related to determining methane liberation in the gob were also conducted by injecting SF6 into a borehole (Timko and Thimons, 1982). Also, in an emergency situation where the gob had to be sealed due to a fire, SF6 was released to determine the effectiveness of the seals (Timko and Thimons, 1982).

Jan 1, 2011

By D. C. Carter

"The Nova Scotia Department of Mines and Energy located a drillhole at Riverside Corner, Hants County, Nova Scotia, to examine the stratigraphy, structure and potash potential of the Kennetcook River gravity low. This evaporite-related gravity anomaly is one of the largest virtually unexplored gravity anomalies in Nova Scotia. The drillhole intersected a structurally complex sequence o flower Windsor Group ('B' Subzone) evaporites. Downhole geophysical wireline logs were used, in conjunction with detailed lithological descriptions, to interpret the structure and stratigraphy of the sequence. Similar application of total gamma ray, density, caliper and neutron-neutron log responses allows stratigraphic correlation of Windsor Group carbonate marker units separated by up to 35 km in Cape Breton. This work confirms the value of downhole geophysical logs as a tool in the exploration of evaporite deposits regardless of the presence or absence of high quality core. INTRODUCTIONThe exploration methodology for evaporite (specifically salt/potash) deposits in eastern Canada (and worldwide) is relatively simple: identify a negative gravity anomaly within a favourable geological setting, Windsor/Cordroy Group sediments in eastern Canada, and drill it (Anderle, 1980). Although this is an obvious oversimplification of the necessary expertise in the planning and complet ion of an exploration program, those familiar with potash exploration drilling can attest to the risks and expense, in terms of time and problems , associated with the location and drilling of diamond-drill wildcat holes. Potash exploration programs in eastern Canada, their results and inherent difficulties, have been documented by Anderle et al. (1979), Cooper (1981), Dekker (1982), Carter and Boehner (1986), Carter (1988) and Carter and Anderle (in prep .).Downhole geophysical wireline logs have become an important tool in the stratigraphic and structural interpretation of evaporite sequences in eastern Canada and, in many cases, represent the only information recovered or the only information available due to the drilling method (rotary) and/or the long term instability of evaporite cores. This paper documents examples of downhole geophysical log responses which, combined with detailed lithological examination of drill core, or in the absence of core, are used in the interpretation of the complex lithology and structure of a deformed evaporite deposit. Geological and geophysical data from the Nova Scotia Department of Mines and Energy (NSDME) Riverside Corner 85-1 drillhole are presented here as a partial case history and prime example of the use of this method to interpret the complex structure of an evaporite deposit. Drilling of NSDME Riverside Comer 85-1 was conducted in late 1985and early 1986by the Department (Carter and Boehner, 1986) under a program to assess the potash potential of selected areas of the province as part of the Canada-Nova Scotia Mineral Development Agreement 1985-89. A reinterpretation of a portion of the available data from two exploration drilling projects on Cape Breton Island in the Canso-Bras d'Or area is also presented (see inset, Fig. I). Several drillholes have intersected the Windsor Group evaporite sequence in these areas and the available geophysical logs are a valuable tool in the interpretation of the structure of the deposits. However, no attempt has been made to present or discuss the detailed geological investigation and comparison of these two deposits. They are presented here as an example of the reinterpretation of existing data and their application to stratigraphic correlation and structural interpretation of complex evaporite deposits. Further work is necessary to document the stratigraphic and structural correlation of these two areas."

Jan 1, 1989