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By Harry Asche

Tunnels are frequently specified by owners to be designed to a structural code, often a bridge code. In the USA, AASHTO have created a tunnel code, based on structural principles, the AASHTO LRFD Tunnel Design Specification. The Load Resistance Factor Design method (LRFD) described in the AASHTO title is an approximation to the probabilistic design of structures, based on the independence of load and resistance. This methodology is well known to be problematic in geotechnical design, but it is widely used. The paper considers the difficulties of this approach and describes alternative approaches that would result in more appropriate designs for tunnels.

Jun 13, 2021

By W. C. Painter

In 30 years of experience in Western Mines as Master Mechanic, Chief Electrician and Field Service Representative of Joy Manufacturing Company, I have seen a steady rise in the acceptance of A-C powered equipment for underground use in coal mines. This is also true for potash, gypsum and trona mines where coal mine type equipment and methods are used. This paper covers a large section of actual western mining practice with no theoretical calculations or predictions.

Jan 1, 1959

By Young C. Kim

Because of the tremendous technological advances achieved in recent years in microcomputers, it is not only technically feasible but also economically viable to develop an automatic truck dispatching system using a microcomputer. Such an effort was initiated by the Department of mining and Geological Engineering, University of Arizona in the summer of 1983. Up to date results and experiences prove that today's microcomputers can be economically employed for such a system to be used at small to medium scale open-pit mines. An IBM/XT microcomputer with 10 MB harddisk storage, together with automatic sensing capability of truck movements at several key locations in the pit, formed the core of this system. System software is written primarily in MICROSOFT FORTRAN with supporting subroutines in MACRO assembly language. The software is designed to automatically monitor truck movement throughout the pit, to make heuristic assignments based on expected shovel availability and truck travel times, and to record production statistics. It is currently dimensioned to handle 50 trucks, 10 shovels, 10 dump sites and 3 material types. Due to the lack of funds to purchase the necessary communications hardware, the work related to the automatic sensing of truck movements has not been performed to date. Otherwise, the automatic truck dispatching-system is fully operational on a realtime mode.

Jan 1, 1984

By John T. Cumberlidge

The Groveland deposit, in the Upper Peninsula of Michigan, consists of an E -W trending overturned syncline of Middle Precambrian Vulcan iron formation. At Groveland, the Vulcan formation can be divided into four units or facies. The total succession may be more than 550 feet thick, and consists of a basal unit composed of a lean chemical quartzite with traces of magnetite; a non-banded, partly clastic unit characterized by the preponderance of hematite over magnetite; a transition unit of well-banded magnetite-bearing iron formation interbedded with non-banded oolitic hematite; and a well-banded magnetite-quartz silicate unit at the top of the exposed sequence. The present magnetite-hematite ratios of different units within the orebody are considered to be a primary (post-diagenetic) feature of the original sediment. Subsequent regional metamorphism has increased the grain size of the original iron oxide minerals, but did not appreciably alter the oxidation state of the original sediment.

Jan 1, 1964

By Burton H. Boyum

The paper generally reviews the iron ore occurrences and regional geology of Western Australia, but features in particular the mesa deposits of PJasic Materials - Cliffs International. Initial production is planned from a aeries of mesa deposits of Eocene-Oligocene age. The ore is oölitic to pisolitic goethite and hematite. Source of the iron in the mesa deposits is thought to be from the Precambrian iron-formations. The geology and occurrences of the mesa iron ore deposits are summarized and illustrated.

Jan 1, 1964

By William Gleason

"Sometimes it’s the smallest things that make the biggest difference. In the world of mining, erosion can lead to small cracks, which can then lead to bigger problems that, over time, can eventually lead to a catastrophic event. However, when managed correctly, as in the case of the Manefey Slide at the Bingham Canyon Mine in Utah, the damage can be minimized.Numerous industry conferences, technical papers, studies and resources are dedicated to these issues each year, but what is sometimes overlooked is how the erosion of personal ethics can also have life-changing effects.At the 2019 SME Minnesota Conference, April 15-17 in Duluth, MN, two inmates serving their respective prison sentences at the U.S. Federal Prison Camp in Duluth spoke to the conference about how small cracks in their ethical foundations grew over time, eventually leading each man to his new address at the minimum-security facility.The men’s full names were not released and they were introduced as Jeff and Tony. Other than the matching green uniforms, both middle-aged men could have fit in with the rest of the crowd. They are well-educated and articulate whose career paths eroded thanks to greed and careless decisions.Tony, a licensed professional engineer, enjoyed a successful career working in contract oversight for the U.S. Department of Defense. Jeff is a former senior vice president of investments who ran a well-respected investment management team. Both spoke openly about the mistakes they made and emphasized that their crimes were not flagrant violations of the black and white rules but grew from ethical violations that live in the gray area between black and white, and right and wrong.Working in contract oversight for the U.S. Department of Defense (DOD), Tony said he was befriended by a wealthy man who was generous with his money. As Tony told it, a few meals with this man led to a few trips to casinos and eventually to gifts of money. The donor did not ask for anything in return, and at the time, Tony said he did not think that he was doing anything wrong. He admits now that the perception of a high-ranking officer in the DOD accepting gifts is not a good one, as it could be construed as the donor might have been trying to gain favor for future contracts; which is how it was presented in court by the prosecution team."

Jun 1, 2019

By William Gleason

"The Colorado School of Mines has used the Edgar Mine in Idaho Springs as an experimental mine to teach students since 1921. Since the school acquired the former gold, silver, lead and zinc mine, countless students have received hands-on engineering lessons on their way to earning mining engineering degrees. On Dec. 14, the House Subcommittee on Energy and Mineral Resources held a historic field hearing about the future of mining education in the United States in a classroom about 300 m (1,000 ft) inside the Edgar Mine. Representatives Doug Lamborn (R-CO), Rob Bishop (R-UT), Cresent Hardy (R-NV) and Ed Perlmutter (D-CO) were on hand for the first ever congressional hearing held in a mine where they heard testimony supporting the Mining School Enhancement Act, which was introduced to Congress by Hardy and Perlmutter on Oct. 9, 2015. The act, which is part of a larger mining development and reclamation reform package, seeks to address the absence of a viable pipeline necessary to replenish current faculty vacancies in United States Mining Schools. “What better place to hold a hearing to discuss the need for future mining engineering experts,” Subcommittee Chair Lamborn said in his opening statement. “It is a need felt by industry, states, the federal government as well as nonprofits.” The Mining School Enhancement Act would redirect millions of dollars in fees that are being collected from active mining operations to fund the research and educational programs at engineering schools with mining programs. Those fees now are being used in the form of grants awarded by the Surface Mining Control and Reclamation Act of 1977 (SMRCA)."

Jan 1, 2015

By Paul H. Rylund

Substantial priming was a considered necessity for proper initiation of ammonium nitrate-fuel oil mixes as ANFO began to carve its niche in the mining industry in the latter fifties. Heavy priming accompanied the introduction of prills and oil to many blasting operations, large charges of high explosives were commonly used at the bottom, top and frequent intervals through-out the column. As the quality of ammonium nitrate improved and operators became more experienced, primer costs began to diminish. Increased experimentation continued with reduced primer costs a main objective. Cast primers were introduced and became accepted as an excellent companion for ANFO. Although the trend toward larger diameter boreholes became increasingly popular, emphasis on lower and lower priming costs continued. A primer was simply required to produce any type of initiation within the ANFO column to be considered adequate. Suddenly ANFO priming had digressed from excessive to marginal. Early experimental data developed at "test site" and laboratory locations indicated that ANFO had a tendency to react inefficiently in the initiation region of the column unless substantially primed. This was evidenced by the presence of unstable reaction rates detected with newly developed detonation velocity measuring equipment. These 10" order or "transient" velocities were believed to originate because of inadequate primer strength or a primer diameter to column diameter mismatch. How-

Jan 1, 1972

By John D. Morgan

The U.S. economy annually needs over 4 billion tons of new mineral supplies. The value of domestically produced energy and processed materials of mineral origin exceeds $175 billion annually, but domestic production of both raw and processed minerals is not keeping pace with demand.

Jan 1, 1974

By C. J. Weiss

"A commercially available Through-the-Earth (TTE) communications system was evaluated at an underground coal mine in eastern Kentucky. This field study was conducted as part of a larger multi-site evaluation of available TTE systems to determine their operational sensitivity. Field testing is being performed along with simulation techniques developed for geophysical surveys. The results of the field test will additionally be used to determine the applicability of these simulation techniques to TTE communications. The mine detailed in this paper was idled at the time of the study, which provided the nearest practical representation of a post-event mine shutdown. For this study, the three following communication modes were tested: surface-to-underground, underground-to-surface and surface-to-surface. Standard deployments of the TTE system using the manufacturer’s recommended procedures were able to achieve clear communications between underground and surface locations. Other arrangements of the units yielded intriguing results, some of which were predicted by computer simulations, others were unexpected. Future experimentation is planned to further evaluate the observed phenomena. INTRODUCTION The ability to establish effective communication between surface and underground personnel after a mine event is essential for both mine evacuation and mine rescue efforts. Current communication technology is reliant on physical infrastructure, such as antennas, cables, and repeaters, located throughout the mine. Such systems are easily disabled during a mine event because of their vulnerability to physical damage. A true emergency communications system would have the ability to function regardless of a mine’s physical state. Through-the-Earth (TTE) wireless communications technology has the potential to provide such a tool. Wireless TTE communications are exceptionally challenging because electromagnetic (EM), or radio, signals are subject to drastic attenuation as they travel through solid strata. In addition to attenuation, EM wave propagation is directly affected by the physical and petrographic characteristics, mineral compositions, metamorphic properties, and the degree of water infiltrations in the strata [1-5]. These strata characteristics are unique to each mine thus making the design of an effective, universally deployable, and reliable TTE communications system very difficult. At present, TTE technology is in the preliminary stages of practical deployment with only a few permissible TTE systems commercially available."

Jan 1, 2015

By James E. Lonergan

To determine the best materials handling system for surface mined materials, one must develop a mine plan for each candidate system based on the most efficient use of that system. This is essential for a fair, unbiased economic compari¬son of the candidate systems. This paper will present two case studies where an integrated mine planning /systems engineering approach has been utilized at different levels of detail in the analysis of an in-pit crushing/conveying system vs. total truck haulage at 2 open-pit copper mines.

Jan 1, 1985

By R. W. Utley

The purpose of this study was to seek and evaluate possible relationships between the composition of coal refuse, as expressed by washability data, and factors affecting the product ion of a lightweight aggregate from refuse by bloating. The study was related to an intense program in the Department of Mineral Preparation at the Pennsylvania State University to study the possible elimination of air pollution from coal refuse fires by producing a low- carbon secondary refuse. Another phase of this program is considering possible uses of such a secondary refuse. Thus one study was to determine if a lightweight aggregate could be produced from this new refuse material and what effect the nature of refuse beneficiation would have upon the characteristics of a commercial aggregate product.

Jan 1, 1965

By M. A. Giralico

A new generation of hydraulic efficient pumper and auxiliary impeller designs is the result of an extensive research program focused on improving the overall performance of optimized SX/EW plants. Combined with the proper scale-up, these optimized designs will greatly reduce aqueous and organic entrainment losses, reduce or eliminate air entrainment and crud formation, enhance mass-transfer and maximize the overall copper yield. Currently, these new pumper and auxiliary impellers are installed full-scale in numerous plants ranging in flow rates from 90 to 15000 G.P.M. and developed heads up to 51 inches. Operational results reported by the independent metallurgist at each processing plant are reporting the lowest entrainment results in the industry. Further R&D has just been completed on a new mixing configuration that separates the systems mixing and pumping requirements. Results from the system pilot test document further improvements in reduction of both chemical entrainment and crud formation, while keeping mass transfer stage efficiencies.

Jan 1, 1998

By Alcides Freitas

The great importance of aggregates as a basic building and maintenance material for both public and private projects makes the identification and availability of this valuable resource imperative for our economic and social well being. This was one of the main reasons that led the California Legislature to enact the Surface Mining and Reclamation Act of 1975 (SMARA). The Act requires the State Geologist to classify mineral areas in the state and the State Mining and Geology Board to designate mineral deposits of regional or statewide significance. What is the "Classification and Designation" process and how is it working?

Jan 1, 1984

By Joseph W. Mullan

The today status of air pollution control legislation and regulations can best be described as an exaggerated state of environmental limbo. The '70's began but one and one-half months ago yet it already has been very appropriately named "the decade of the environment." This certainly will be the decade for new legislation - new regulations and hopefully "Clean Air." Already Washington is faced with legislators playing "pollution politics" to the crowds. Students have redirected their efforts from Vietnam to the cleansing of the environment and everyone including the man on the street has become an environ¬mental expert. This is the decade we all face, but where are we today? Pollution is not a new problem. It has been with us for centuries and while much is left to be done, much has already been accomplished. I will try to make some comparisons of what I believe to be the good and bad points in the national air pollution control picture and hopefully will generate within each of you sufficient concern as to which comparisons are sound.

Jan 1, 1970

By L. R. Hossner

Chemical and physical properties of surface soils and overburden materials must be evaluated prior to strip mining activities. This information can be used to assess whether subsurface overburden can be equal in quality to the existing surface soils, especially when these soils are classed as prime farm lands. In Texas, materials from the Carrizo, Calvert Bluff, Simsboro, and Hooper Formations overlie the lignite. The Carrizo Formation consists of thick clean sands with poor water and nutrient retention capabilities. These materials are least suited for placement of the surface of reclaimed land. The oxidized, medium textured overburden from the Calvert Bluff and Simsboro Formations possess adequate water and nutrient properties and are better suited for sustained plant growth. Non-oxidized Calvert Bluff and Hooper sediments generally have acceptable properties for reclamation. However, caution must be exercised in vegetating these materials since they may contain acid forming sulfide minerals.

Jan 1, 1982

By Donald J. Donahue

Ladies and Gentlemen: As we begin these three crowded days of technical and economic discussion of problems faced by mining and metallurgical engineers, it seems appropriate at this Keynote Session to consider the future of this industry from which we derive our livelihood, It is also appropriate at this international meeting to view our industry on a world-wide basis. First, let us assess the world's future needs for minerals - the needs which it is our industry's task to meet. Next, let us look at what supplies of minerals may be available to meet those needs. I will speak of this first in terms of the physical availabilities of minerals. Finally, we can consider some of the social or institutional factors which will condition the world's mining industry as it goes about its task of discovering, developing, producing, and delivering the minerals needed to meet the world's demands. Let me give you a foretaste of my conclusions. First, future world demands upon our industry will be enormous, eclipsing anything that we have known up to this point. Second, there is strong evidence that our earth's crust contains a sufficient physical quantity and variety of minerals to meet forthcoming needs for as long a period ahead as one can envisage.

Jan 1, 1974

By P. R. Taylor

Three refractory gold concentrates have been tested to evaluate the effect of roasting with hydrated lime followed by cyanidation. The results indicate that it may be possible to roast in such a manner as to contain nearly all of the sulfur, arsenic and antimony in the roaster calcine. Cyanidation results indicate that the gold recoveries are greater than 80% for all three concentrates.

Jan 1, 1993

By James J. Scott

In the fall of 1976 the author started test work with Friction Rock Stabilizers in uranium mines of the West, principally in the Ambrosia Lake and Churchrock districts of New Mexico. Tests were also conducted in other uranium mines in the Rocky Mountains area. These mines are plagues with problems in ground control due to the weak formations in which mineralization occurs, mudstones, siltstones, weak sand, etc. For this reason, it is extremely difficult to obtain good anchorage for long periods of time with conventional mechanical roof bolts. Resin bolts give good anchorage but are expensive and, because of hole erosion and difficulties in installation due to inadequate equipment for mixing the resin and placing the rebar, they are not widely used. Field testing was also carried out in trona, limestones and hard and soft shale formations. The mechanism of the Friction Rock Stabi1izer support is discussed and pull test data presented for various rock types.

Jan 1, 1977

By K. L. Woodruff

Shredding is the usual first step in processing municipal solid waste (MSW) for resource recovery. This unit process requires high capital cost and, usually, considerable maintenance cost. In addition, some shredders at times will render certain components of the MSW in a form difficult to recover. This is particularly true in the way metal cans are distorted and the way glass is pulverized. A trommel screen was proposed (1) to pre-process packer truck refuse prior to shredding. Part of the logic for this step is that the portion of raw refuse already within the specified shredder output particle size range would bypass the primary shredder and proceed directly to further processing, such as to an air classifier or secondary shredder. This would reduce the throughput of the primary shredder and allow certain recoverable materials, such as glass, to remain in larger piece sizes, important for recovery. In this way, operating costs for the shredder would be reduced and the recoverability of materials, and hence the revenue, increased.

Jan 1, 1975