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By Earl C. Redman

The Juneau Gold Belt, centered on Juneau and approximately 120 miles long by 10 miles wide, stretches from Berners Bay on the north to Windham Bay on the south (fig. D-l). Access within the Juneau Gold Belt is provided by the Glacier, Thane, and North Douglas Highways. The Glacier Highway extends northwest from Juneau for approximately 40 miles to Echo Cove, and the other two roads end 5.5 miles southeast and 12.6 miles west from Juneau, respectively. None of these roads connect with other highway systems and access to other areas is restricted to airplanes, the State ferry system, and commercial barge lines. BUREAU ACTIVITIES The majority of lode gold produced in Alaska came from the Juneau Gold Belt portion of the Juneau Mining District. To evaluate the economic potential of the Gold Belt, the Bureau located 173 mines and prospects within the area. A total of 263 ad its and shafts were found and 56,650 feet of underground workings were mapped. The Bureau collected and analyzed 1,557 samples during the study. In addition, considerable detailed geologic map-ping was done in the vicinity of the mines and prospects from which ore control models were developed.

Jan 1, 2012

This manual is limited to Augered Cast-in-Place (ACIP) piles constructed using a hollow stem continuous flight auger. 1.1SCOPE AND LIMITATIONS The intent of this manual is to provide guidelines for observing and documenting the installation of ACIP piles. The manual may also serve as a guide for the training of inspection personnel. It is expected that the general guidelines and procedures described in this manual for the inspection and installation of ACIP piles will be supplemented by engineering judgment, local practice, and experience. ACIP pile construction procedures will vary depending on soil, rock, and groundwater conditions. This manual represents a wide range of possible applications in a variety of projects. It is not intended to be applicable in all situations nor replace engineering judgment for any given project. Therefore, an all-inclusive inspection manual is not considered practical or desirable. This manual should not be used to interpret or replace project specifications. It has, however, been prepared to complement the Augered Cast-in-Place (ACIP) Piles Manual model specification (DFI, 2003).

Jan 1, 2010

By G. ALBORNOZ, S. Utili, A. AGOSTI, C. VALDERRAMA, R. PELL, N. Morales

The steepness of the slopes of an open pit mine has a substantial influence on the financial return of the mine. The paper proposes a novel design methodology where overall steeper pitwalls are employed without compromising the safety of the mine. In current design practice pitwall profiles are often planar in crosssection and the profile in between ramps especially tend to be planar and defined by a constant inter-ramp angle. Sometimes rock layers exhibiting different strengths require the inclination of the profile to vary with depth, but the inclination across each layer is usually constant. Here instead, a new geotechnical software, OptimalSlope, is employed to determine optimal pitwall profiles of depth varying inclination. OptimalSlope seeks the solution of a mathematical optimization problem where the overall steepness of the pitwall, from crest to toe, is maximized for an assigned lithology, geotechnical properties and Factor of Safety (FoS). Bench geometries (bench height, face inclination, minimum berm width) are imposed in the optimization as constraints which bind the maximum local inclination of the sought optimal profile together with any other constraints such as geological discontinuities that may influence slope failure. The obtained optimal profiles are always steeper than their planar counterparts (i.e. the planar profiles exhibiting the same FoS) up to 8 degrees depending on rock type and severity of constraints on local inclinations. The design of a copper mine is first carried out employing planar pitwalls, secondly adopting the optimal pitwall profiles determined by OptimalSlope. The adoption of optimal slope profiles leads to a 34% higher net present value and reductions of carbon footprint and energy consumption of 0.17 Mt CO2 eq and 82.5 million MJ respectively due to a 15% reduction of rockwaste volume.

Mar 2, 2022

By John Pfisterer

Leadership Priorities in a New Business Environment ?Komatsu Equipment Company ?Health and Safety of Our Workforce ?The Green Economy & Market Challenges ?Equipment Trends ?Our Business Approach

Jan 1, 2009

Jan 1, 2001

The propensity of coal spontaneous combustion can be evaluated using various laboratory testing methods such as R70 adiabatic tests, thermal gravimetric analyzer (TGA) and critical self-heating temperature (CSHT) methods. Each of the methods has its unique characteristics and index for classifying the propensity of self-ignition of coals. Accountable relationships among the propensity indices of different methods should be established. Using the newly established R and TGA testing setups in our ventilation laboratory, samples from US coal mines have been collected and tested. 70 The TGA is a relatively new quantitative method. A test can be conducted in a relatively short time. The temperature and weight of the sample can be measured with high precision and then used to determine the activation energy of the coal which is a good indicator for potential of self-heating. Under a specific experimental design, the TGA technique could perform the proximate analysis for determining coal quality parameters (e.g., moisture, volatile matter, fixed carbon and ash content). These parameters can be used in an empirical equation for assessing the potential of coal self-ignition. The trend of activation energies determined using TGA techniques and adiabatic tests are reasonably consistent with each other. As a case study, a comparative analysis of these two methods for determining activation energy was made on coal samples collected from Indiana. The kinetics of the spontaneous combustion mechanism has been explained. If the functional groups of a coal are easier to be activated with a small amount of activation energy at a relatively low temperature, the coal will has a higher potential of self-heating. With the kinetic and coal quality parameters determined by the TGA setup, it has been found that the coal with low potential of self-ignition has low self-heating rate, high activation energy and high minimum self-heating temperature.

Jan 1, 2012

By T. F. Anstett

The Bureau of Mines evaluated the potential availability of chrysotile, amosite, and crocidolite asbestos from 42 properties in market economy countries. This resulted in the development of tonnage-cost relationships indicating the quantity of grades 3 through 7 asbestos at various average total costs of production at 0% and 15% rates of return on invested capital. The availability of grades 2 and 8 was also evaluated, but since each is produced at only one property, no analytical results were given. Total demonstrated recoverable chrysotile fiber potentially available of grades 3 through 7 from the 42 properties evaluated follow: 1.59 million t, 21.00 million t, 16.74 million t, 15.54 million t, and 19.27 million t, respectively. The total amount of crocidolite is 1.69 million t. Owing to the good potential for discovery and development of new deposits, long- term availability of fiber of all three types is not in jeopardy. However, many of the crocidolite properties evaluated in the northern Cape crocidolite field of South Africa have relatively small demonstrated resources, and new deposits will have to be exploited by the late 1990's to sustain projected levels of production.

Jan 1, 1985

By Bryce T. Tripp

Utah's abundant industrial rock-and-mineral resources support a relatively small but important sector of the State's economy. In 1983, six of the top 10 nonfuel mineral commodities (by value) were industrial commodities. Portland cement was ranked fourth, potash fifth, halite sixth, phosphate seventh, construction sand and gravel eighth, and lime tenth. Portland cement was produced by three operators, principally from the Jurassic Twin Creek Limestone. Potash was produced by three companies from Pennsylvanian beds in the Paradox Basin, surface brine of the Great Salt Lake, and subsurface brines of the Great Salt Lake Desert. Halite was produced by eight operators, primarily from surface brine of the Great Salt Lake. Additional production came from salt beds in the Jurassic Arapien Shale, solution mining of the Pennsylvanian Paradox Formation of the Hermosa Group, and subsurface brines of the Paradox Basin. Phosphate was mined by one company from the Permian Meade Peak Phosphatic Shale Member of the Park City Formation. Construction sand and gravel were produced by dozens of operators, primarily from Quaternary Lake Bonneville beach and nearshore deposits. Lime was produced by four operators from Paleozoic formations in the Basin and Range physiographic province of Utah. The future production of these and other industrial commodities, though individually uncertain, is expected to increase gradually as a group. Factors favorable for the future of the industrial commodities industry in Utah include large to almost unlimited resources for the major commodities, a healthy projected population growth, an abundant local supply of relatively inexpensive energy from coal and natural gas, and a favorable corporate tax structure and business climate.

Jan 1, 1987

By Grafton Thrasher

For the proper discussion of this subject it is necessary to incorporate in this paper the substance of part of an article published by rite in Metallurgical and Chemical Engineering for January, 1915. CAST-IRON TEST PLUG, SHOWING LOW MOTTLED AND MOTTLED FRACTURES. Several years ago, while I was thief chemist for a malleable-iron company, it occurred to me that the mere regulation of silicon was not sufficient to produce the desired degree of chill. But only after repeatedly encountering this fact in befit open-hearth and air-furnace, as well as cupola metal, was I led to regard variation in the total carbon as the principal cause of disturbance; and I resolved to determine the total carbon as well as the sill on ill every heat, and by a carefully prepared test piece to gauge the approximate degree of chill. The test piece selected was a round plug, 2 in. in diameter and 12 in. long, cast on end

Jan 10, 1915

By A. A. Ruitenberg, L. R. Fyffe

"This paper compares several distinct types of mineral deposits associated with different families of granitoid rocks in the New Brunswick Appalachians. Porphyry copper deposit s are associated with late-stage differentiates of Lower to Middle Devonian I-type igneous complexes. Contact metasomatic deposits were formed where these plutons intrude carbonate rocks and they gave rise to vein deposits in fracture zones near wrench faults. The I-type granitoids were emplaced mainly in areas of thin continental crust and locally along prominent faults in areas of thick continental crust.In contrast, tin-tungsten-molybdenum-bearing greisen deposits and skarns, and antimony-bearing quartz veins are associated with predominantly S-stype granitoid complexes ranging in age from Middle Devonian to early Carboniferous. The mineral deposits occur within or along the contacts of very fractionated (specialized) late phases of these intrusive complexes, which are characterized by high K2O/Na2O, Rb/Sr and Rb/Ba, and low Fe, Mg, Zr and Ti contents. These specialized granitoids are in a large wrench fault zone that cuts across thick continental crust in southwestern and central New Brunswick.IntroductionA great variety of igneous intrusions and subvolcanic stocks were emplaced in the New Brunswick Appalachians during the latter stages of and immediately after the Acadian Orogeny (late Lower to Middle Devonian) and during the subsequent Hercynian Orogeny (Carboniferous). The presence or absence and characteristics of mineral deposits associated with these intrusions reflect the level of intrusion, the composition of the associated igneous rocks and the composition of the invaded sequences.Nickel-copper sulphide deposits occur in mafic intrusions in the St. Stephen area of the southwestern Magaguadavic - St. Croix Zone and in the Goodwin Lake area of the northeastern Mirarnichi Zone. Contact metasomatic and vein-type copper-rich base metal sulphide deposits and porphyry copper deposits with or without molybdenum are related mainly to high-level granitoid stocks of intermediate composition in the Matapedia-Tobique and northwest Miramichi zones. Tintungsten - molybdenum deposits with or without base metal sulphide minerals and antimony-uranium deposits are mainly associated with Upper Devonian and Lower Carboniferous biotite-muscovite granites and related 'subvolcanic intrusions that occur in an arc-shaped belt extending from the southwestern Magagaudavic - St. Croix Zone into the central Mirarnichi Zone."

Jan 1, 1982

By A. Bamber

Canadian leadership in a global mining context will depend not only on entrepreneurship and best practice but also on technological innovation. This paper argues for more ambition and commitment to R&D for technological innovation in Canadian mining. It focuses on underground hardrock mining, where past R&D initiatives have simply not stood the test of time, and it is important to examine why. Concerns arise because industry’s commitment to R&D has not been sustained over time. Innovation through exploration, processing, and environmental technologies has been more significant. Meanwhile, R&D capacity and synergies in government institutions and universities have not been exploited. There is a need for more commitment, coordination, and collaboration by industry, governments, and universities. This paper examines some corporate models that have achieved sustainable innovation, along with some that have not. A strategy for innovation is discussed that relates to culture, commitment, coordination, and collaboration.

Jan 1, 2005

By J. P. Gouvea

Back-analysis of two mining-induced tremors in 2011 was used to determine a modelling criterion for the entire Klerksdorp Goldfield (i.e., Vaal Reefs region). At that time, most mining operations in the region were owned by AngloGold Ashanti (AGA) and shared many geotechnical similarities. By 2018 AGA had sold off all its Klerksdorp operations to different mining companies, which continued applying the 2011 modelling criterion. As mining activities became more remote, scattered, and isolated, the extraction of isolated blocks of ground and remnants became increasingly necessary. However, the inherited criterion allowed only minimal or no mining activities at these areas. Keeping in mind that safety is the overriding consideration, an innovative numerical modelling approach, which includes the application of peak particle velocity designs, was developed to provide practitioners in the Klerksdorp Goldfield with a suitable criterion to justifiably and safely mine isolated blocks of ground and remnants. This would not always be possible if a conformist approach was used.

Mar 14, 2024

By Schlanger H. P

A theoretical model for gas outbursts in underground coal mines is as follows. An outburst is the structural failure ofcoal due to excess stress resulting from body forces caused by gas pressure gradients. These body forces influence the stability of a mine face in the same manner that gravitational body forces affect the stability of the roof of a mine. The magnitude ofthese body forces can be appreciated when it is realized that for an average density coal, the gravitational body force is equal in magnitude to the force from a gas flow with a pressure gradient of 14 kPa m-I. Gas pressure gradients and the resultant stresses within a seam can be calculated with numerical methods. Thus, providing the necessary parameters can be measured or estimated, in principle the theory can be applied to compare the outburst risk of various mining arrangements.

Jan 1, 1985

By M. E. Wilson, A. C. Lee

"The property owned by Senator-Rouyn Mines, Limited, is in Rouyn township about 17'2 miles southwest of the town of Rouyn. It adjoins the Chadbourne claims of Noranda Mines, Limited, on the south and the Bagamac property on the ·west. It includes seven claims-block 44, blocks 80 to 83 and blocks 96 and 97; the mine is wholly in blocks 44 and 82.Late in 1936 gold was discovered in an outcrop of rusty weathering carbonate rock near the north end of block 44, and the following year the present Company was organized to proceed with the development of the property. During 1937-38, 17,000 feet of diamond drill core were bored to determine the extent of the ore deposit at depth. From October 15th, 1940, to April 15th, 1941, the ore was hauled to the mill at the Arntfield mine for treatment. The mill on the Senator-Rouyn property started on April 25th, 1941, and has been in practically continuous operation since than time. To the end of 1946, 574,874 tons of ore, from which gold having a value of $3,836,450 was recovered, were treated in the mill.GEOLOGYThe rocks exposed at the Senator-Rouyn mine, except in the southern part of the property, are almost wholly quartz diorite, part of an irregular mass that extends west from the town of Rouyn along the north shore of Noranda lake and thence southwest across the Senator-Rouyn claims. In the northern part of the propertyt inclusions of rhyolite occur here and there in the diorite. In the southern part the predominant rock is dacite and in the east-central part of block 44 claim andesite. Dykes of andesite, quartz syenite, and later diabase also occur on the property.The andesite of the Abitibi volcanics is not exposed on the property, but has been intersected in three diamond drill holes, one on the eastern boundary of block 44 and two farther west within the block. This andesite is probably the western end of a band of pillowed andesite well exposed in the Larose claim to the east."

Jan 1, 1954

By Michael D. Balen

During the years 1987 through 1989, the Bureau of Mines Alaska Field Operations Center (Bureau) in cooperation with the Western Field Operations Center and the Alaska Division of Geological and Geophysical Surveys (ADGGS), conducted mining, geological, and geochemical investigations in the 5.7 million-acre Valdez Creek Mining District (VCMD). This investigation was conducted as part of the Bureau's continuing Mineral Land Assessment (MLA) mining district studies program. The Bureau's MLA program is designed to provide reliable and comprehensive mineral resource information that supports mineral resource policy and land use decisions made by Congress and Federal land management agencies. The information also provides the basis for decisions that would expand the domestic supply of important mineral resources, primarily strategic and critical minerals. Much of the MLA work is done jointly with cooperating State or U.S. geological surveys.

Jan 1, 1992

By Paul Guliov

Preliminary investigations of stone resources were conducted in the La Range, Johnson Lake-Pelican Narrows-Deschambault Lake and Creighton-Amisk Lake regions of Saskatchewan. The work identified a rich variety of accessible, attractive and technically promising stone resources. Ordovician dolomites in various combinations of red, buff, yellow, grey and purple are very dense and take a very good polish. These are classified as marbles in the industry and some rival the famous marbles of Verona, Italy. A wide variety of attractive granites have been identified. Among these is a jade green stone (charnockite) and ornamental banded granites (gneisses). A dark greenish to black stone (amphibolite) with white and red veining resembles the well-known Verde Antique variety of Vermont and Italy and surpasses it aesthetically and in engineering properties. Some of these stones have been displayed at Canadian and United States expositions where they received an enthusiastic response from the international stone industry. More detailed evaluation and test quarrying of promising deposits are required. Such work could be rewarding to the industry as some stone varieties in the province have the potential for gaining international markets.

Jan 1, 2001

By M Ogle

"Booster fans are relatively rare in Australian coal mines. However, as mines become progressivelydeeper it is likely that such fans will be increasingly adopted as a method to sustain or improve the ventilation of underground workings. The reasons why booster fans may be an att ractive alternative include: increased cost of sinking additional ventilation shafts with greater seam depths; environmental objections to shaft sinking projects; and increasing urbanisation and surface constraints limiting availability of potential ventilation shaft sites. As Tahmoor Colliery movedinto its northern lease the ventilation constraints became the limiting factor on production. Thelimitations of the old workings meant that the existing ventilation system would be inadequateto sustain the required production. Extensive ventilation modelling was carried out to evaluatevarious potential solutions and the recommended option was the installation of a booster fanor fans, to gain underground access to an already approved shaft site in the northern lease.Proposals were sought from recognised fan manufacturers and various alternative arrangements were tendered. Ultimately the choice was between one large centrifugal fan and a set (three or four) of smaller æauxiliary-likeÆ fans in parallel. The successful tender was for a single centrifugal, an arrangement very similar to the booster fans that have been operating eff ectively at Westcliff Colliery for a number of years. This paper describes the current ventilation network, evaluation of the ventilation options, the fan selection process, and the project status to date."

Jun 1, 2012

By Jr. Frank Parrish

This report describes the performance of 17 selected water-injection projects producing from Pennsylvanian-and Permian-age reservoirs. Illustrations depict reservoir structure and thickness, and production and injection history. A selected bibliography of publications pertaining to area oil recovery and geology is included. Tabulations of field and reservoir data reveal marked differences in the projects. Increased oil recovery resulted from injecting water in most cases; however, seven projects recovered less oil than the operators anticipated. Oil recovery by water injection ranged from 0.2 to 262 bbl per acre ft, or 0.1 to 22.5 pct of the initial stock-tank oil in place. Major reasons suggested for poor performance include: (1) Adverse directional horizontal permeability, (2) channeling of injected water through fractures or zones of high permeability, and (3) lack of containment of injected water. One 330-foot-deep project is among the first successful shallow water-floods in north Texas. Another project is the first successful Canyon sand-stone waterflood reported in the area. Previous gas injection in two Cisco sandstone projects did not prevent the reservoirs from responding favorably to waterflooding.

Jan 1, 1965

By C. L. Kosmoski

The mining industry faces many workplace hazards that are a threat to human health and safety. The Bureau of Labor Statistics has found that employees in coal mining are more likely to be killed or sustain an injury or illness than workers in private industry. These injuries are also likely to be more severe (Bureau of Labor Statistics, 2007). In recent years, coal mining injuries have attained national attention due to highly publicized disasters. Despite these threats to worker safety and health, the U.S. relies on the mining of coal to meet its need for electrical power, with42% of electricity in the U.S. generated through the burning of coal (U.S. Energy Information Administration, 2012b; United Mine Workers of America, n.d.). Furthermore, the production of coal continues to increase and reach record levels every year(National Mining Association, 2012; U.S. Energy Information Administration, 2012a). For this reason, the coal mining industry must continue to find ways to protect its workers while maintaining productivity. One potential approach to protecting workers while maintaining productivity is through improving the safety culture at coal mines. In order to achieve this culture, operators, employees, the inspectorate, etc. must share a fundamental commitment to safety as a value. This type of culture is known in other industries as a ?safety culture? and can be defined as the characteristics of the work environment, such as the norms, rules, and common understandings that influence facility personnel?s perceptions of the importance that the organization places on safety. Fundamental to improving safety culture within an organization is understanding the existing safety culture; improvements cannot be made without first elucidating areas that require improvement. This manuscript details the process undertaken by researchers at the National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) to assess the safety culture at five underground coal mines across the United States. The purpose of this manuscript is to introduce the mining industry to a multi-methodological approach to safety culture assessments. Further, it is the goal of this manuscript to highlight the value of including both quantitative and qualitative methods into safety culture assessments in order to obtain the most comprehensive view of an organization?s safety culture. Because this manuscript focuses solely on the methodology implemented, data and results obtained during the five safety culture assessments will not be presented in this manuscript, but will appear in a future publication.

Feb 27, 2013

By Y Xie, L O’Connor, S C. Dominy

"Sheeted vein gold deposits are characterised by multiple subparallel veins and free milling gold. In situ heterogeneity of mineralisation results in grade and process parameter variability, which will increase project risk. Measured variability is often enhanced by poorly designed sampling and test work protocols. Protocols that are optimised within the framework of the theory of sampling to suit the ore type, together with quality assurance/quality control systems, will reduce variability and provide fit-for-purpose results. The geometallurgical approach requires spatially distributed samples within a deposit to support variability modelling. Diverse attributes from core logging, mineralogical/textural determination and small-scale tests are used to measure variability. This contribution emphasises early stage geometallurgical intervention during project development. It presents a discussion of representative sampling in the context of the theory of sampling. A case study presents a protocol that exemplifies how data can be gained from a well-designed and planned program to support a resource estimate and prefeasibility study.CITATION:Dominy, S C, O’Connor, L and Xie, Y, 2016. Sampling and Test Work Protocol Development for Geometallurgical Characterisation of a Sheeted Vein Gold Deposit, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 97–112 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016