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This report describes the activities and publications of the Bureau of Mines Health and Safety Research and Testing Center, Pittsburgh, Pa., for the fiscal years 1960-65. It includes a discussion or work being conducted on roof control, dust explosions, ventilation, health, coal mine fire control, and electrical-mechanical testing, and an abstract of each paper published during the report period.

Jan 1, 1966

By J. F. Childs

Montana consists of an Archean crystalline basement overlain by Proterozoic through Cenozoic sedimentary rocks. Igneous rocks range in age from Archean to Pleistocene; the most voluminous magmatism and volcanism occurred during the Late Cretaceous and early Tertiary. The state can be divided into three tectonic provinces whose deformational styles are a function of different bedrock responses to Late Cretaceous-early Eocene compressional tectonism. Several long-lived structural zones have been periodically reactivated since the Precambrian, and were the sites of recurrent magmatism. Regional gold distributions are strongly influenced by the tectonic provinces and structural zones. Lode gold systems in Montana occur in diverse geologic settings resulting from a complex interaction between structure, magmatism, and sedimentary depositional processes. Reserves or resources are known for 19 significant lode gold systems, and additional unannounced discoveries have been made recently. Mineralization ranges in age from Archean to Tertiary. The influence of long-lived structures is apparent at both the regional and deposit scale, and in some cases multiple mineralizing events have been superimposed upon one another. Most Montana gold systems have a direct spatial and genetic association with Late Cretaceous through Oligocene igneous rocks. However, the importance of sedimentary rocks and associated depositional processes should not be underestimated.

Jan 1, 1993

By T. D. Hackett

Multislice mining methods were analyzed by the U.S. Bureau of Mines to determine their application to western United States thick coal seams; ground control, geology, and costs were considered. Multislice mining is used in widely varying seam conditions worldwide, including flat seams too thick to mine in a single pass, pitching thick seams, and seams containing a rock parting. Longwall multislice methods predominate, but room-and-pillar variants also exist. The initial use of the method in western seams is planned at a deep Colorado mine where a rock parting will be used to separate two slices mined by longwall. Ground control and spontaneous combustion are major hazards associated with multislice mining. A well-consolidated upper slice gob can reduce ground control problems and provide a seal against spontaneous combustion. Geologic analysis indicates that the consolidation of the gob depends on the composition of the upper slice roof, the presence of water, and sufficient overburden pressure. A geologically competent intermediate rock parting can also reduce ground control problems and seal against spontaneous combustion. To compete in western coal markets, the cost of multislice mining must be within the range of normal longwall costs. Analysis indicates that multislice operating costs should be within this range, and that multislice mining costs decrease as panel width increases. Relatively wide (600 to 800 ft) panels also provide increased coal recovery.

Jan 1, 1990

By Frederick W. Horton

With large deposits of low-grade molybdenum ore and a latent market for molybdenum, which with development might perhaps equal that for tungsten, the United States has for years made no pro- duction of molybdenum ore worthy of mention. In fact, during the decade previous to 1914, there was no output of molybdenum ore in this country except in 1905, 1906, and 1907, when a few small lots of molybdenite and wulfenite were marketed." To ascertain why this possible source of economic wealth should remain undeveloped, the United States Bureau of Mines undertook an investigation in 1914, with a view of assisting the establishment of a molybdenum industry in this country. A preliminary review of the situation showed the following conditions: Briefly there was a lack of any considerable demand for molyb- denum for the one known use that might consume any large tonnage of it, that is, for the manufacture to certain alloy steels to which molybdenum imparts properties roughly similar to those produced by tungsten. It was at once evident that the market for molybdenum in alloy steels must be developed, or that extensive new uses for the metal must be created, before the demand would be sufficient to war- rant any extensive mining of molybdenum ore. Investigation showed that one of the chief factors in retarding the development of any demand for molybdenum by the alloy-steel trade was that manufacturers who might use, or might investigate the possibilities of using, the metal were kept out of the market by the fear of not being able to obtain steady supplies. On the other hand, those who might be interested in the development of some of the extensive low-grade molybdenite or wulfenite deposits in this country were prevented from doing so by the small visible demand and the fear that any large production would glut the market. Owing to these conditions the mining of molybdenum has in the past been confined almost entirely to small-scale operations on high-grade streaks of molybdenite ore, and the methods of recovery have been limited largely to cobbing and hand picking.

Jan 1, 1916

By C. E. Gregory

In terms of a Research Proposals supported by a Grant Agreement dated 30 June 1973, the author was commissioned to prepare an annotated bibliography of mine fires. The main objective was to conduct a comprehensive program of library research and search of official files to prepare a list of articles dealing with actual occurrences of mine fires. This bibliography as now completed includes an annotated reference from each article or report cited, underlining the cause, extent, methods used, procedural errors made, results achieved, ventilation effects, and lessons learned from the operation of subduing the particular fire.

Jan 1, 1974

By Peter J. Nicholson

The methods of reinforcement to be discussed in this paper are all insitu methods, ones that can be used on the soil structure as it exists in the ground, and do not rely on excavation and replacement of the soil. Current practice in the United States, as well as new ideas and methods, will be discussed as they relate to slope stability, retaining walls, and to other uses such as control of mine or cavity related subsidence and to liquefaction control under existing structures. The method is based on the concept of "nailing" or reinforcing the soil in place, and thereby causing a mass of soil to act as a coherent unit. When performed properly, a true gravity structure can be constructed, one that will remain intact under both horizontal and vertical loadings and that will also resist vibrational and seismic loadings.

Jan 1, 1991

Greater mining productivity requires a more efficient cutting process. The cutting force available from today?s mining machines has been optimized with respect to machine size and weight. Researchers have shown that when employing water-jet-assisted cutting, bit forces and drum torques can be reduced significantly, which may allow mining machines to become lighter and more efficient. The Bureau of Mines has initiated a program to develop a water- jet-assisted rotary cutting system using the conventional bit assisted by a directed water jet operating at moderate pressures (3,000 to 10,000 psi). This water-jet-assisted cutting system has the potential to improve cutting efficiency without increasing machine horsepower or water usage (beyond what is presently used for dust control) or requiring fundamental changes in mining practice. IR addition to improvements in productivity, other anticipated benefits of water-jet cutting include reduced generation of respirable dust, elimination of frictional ignitions, increased bit life, reduced fines, and fewer machine vibrations. The papers presented at this open industry meeting discuss the development of water-jet-assisted cutting technology and future application of this technology to a variety of mining techniques including roof drilling and longwall mining.

Jan 1, 1985

It had been more than a decade since this many booths were occupied at an SME Annual Meeting, but at the 2010 meeting in Phoenix, AZ 630 booths were sold to 470 vendors from the entire spectrum of the mining and minerals industry. Exhibitors such as Metso, FLSmidth, West-Tech, ABB, NIOSH, Eriez and Resource West took their usual prominent places on the exhibit floor and were joined by newcomers such as tunnel boring machine manufacturer Herrenknecht AG, Frontier Kemper, the International Society of Explosive Engineers and more than 100 other first-time exhibitors. On the floor, one could find everything from a new pair of boots to a new career in the recruitment pavilion where some of the biggest companies in mining (Barrick Gold, Freeport-McMoRan, Newmont Mining, etc..) set up shop. The following is a look at some of the companies and products that were on display at the 2010 meeting. For information about displaying at the 2011 annual meeting in Denver, CO, Feb. 27 to March 2, contact exhibits@smenet.org.

May 1, 2010

By Jianping Li, Ernesto Villaescusa, Kelly Fleetwood

During blasting, stress waves propagate through a rock mass, inducing stress and strain changes. This applied deformation affects intact rock, existing discontinuities, mine excavations, and engineered structures in the proximity of the blast. Traditionally in blasting, stress waves are quantified in terms of peak particle velocity (PPV) or peak particle acceleration (PPA), based on the method of measurement and the specified allowable tolerances. During analysis, the peak particle motion is coupled with an explosive source through various scaling laws to develop rock-specific attenuation relationships. Some studies have expanded this practice to the development of damage threshold values based on measured or predicted peak particle velocities. PPV-related thresholds are generally based on empirical models, where observation of overbreak, cracking, or fall-off are used to quantify damage. This method is often paired with the application of elastic plane wave equations to calculate the blast induced strain or the PPV threshold for tensile rock failure. Other factors that must be viewed critically in such models are the methods used to collect and analyse blast vibration data and the application of inappropriate vibration attenuation relationships.

Jan 1, 2009

By W. E. Crandall

The Star-Morning mine is a. 1000-ton-per-day lead-zinc producer located in the easterly part of the Coeur d'Alene Mining District of North Idaho. The property includes both the Star and Morning mines which are located on the westerly and easterly portions of the same complex of veins. The mine is 70% owned by the Bunker Hill Company (Gulf Resources, Inc.) of Kellogg, Idaho, 30% owned by Hecla Mining Company, and operated by Hecla Mining Company with head-quarters in Wallace, Idaho. One of the characteristics of mines in the Coeur d'Alene District is that many of the ore bodies extend to very great depths. The Star is no exception, but rather a leading example. The complex of near vertical veins and ore shoots extend some 7000 feet below the surface at present, with a maximum strike length of about 4000 feet. Ore has been mined on 20 separate veins and ore structures. More than 50 miles of headings have been driven and nearly 23 million tons of ore mined since the Morning mine started in.189S. The problems of mining at such depths are formidable temperature on the bottom level is 1100 F and high humidity problem. Pressure from the sheer weight of rock is as high foot. This paper will deal with providing a new access to the deeper levels of the mine and the installation of a hoist and related items to service these levels. By the time development had reached the 7100 level (Figure 1), it became apparent that a different 'hoisting system was going to be necessary if we were going to continue to mine at a profit. The main shaft extended to the 4000 level at which point a ?:3100"'foot winze shaft provided access to the 7100 level. The two hoists were limited to handling 3-ton payloads at 1200 to 1500 feet per minute. Some ores are still produced from above the 4000 level but as these ore reserves become depleted the hoisting of the desired tonnage (1000+/day-) from the lower levels of the mine would exceed the capacity of the existing hoisting system. A decision was made to sink a new vertical shaft at a point well in the south wall of the ore bodies where strong rocks and a minimum of faulting was expected and to purchase and install a new hoist capable of hoisting over 7000 feet. This new' shaft, designated as the No. 4 Shaft, was planned to reach 2000 feet below the 7100 level which was the deepest level at that time. The hoist would be in-stalled on the ,main 2000 Adit level which is used as an access and haulage level to the concentrator and surface plant in Burke.

Jan 1, 1971

By B. P. Watson, D. Hoffmann, D. P. Roberts

Potholes on the Merensky and UG2 reefs in the Bushveld Complex occur as near-circular to elliptical depressions or slumps on the reef horizon, normally presenting as severe disruptions which prevent economic extraction. Within the pothole, the reef and other strata may either be attenuated, absent, or highly deformed, this being the result of the overlying hangingwall strata having slumped down. The hypotheses for pothole formation involve several mechanisms, including downward erosion, upward fluid movement, or synmagmatic deformation. When potholes are exposed in mine workings, significant fracturing is often observed. This fracturing is particularly evident in anorthosite rock types. Stress measurements were conducted in a pothole on the Merensky Reef to determine if the fracturing was due to high stress conditions. The paper describes the measurement results and numerical modelling that was done to determine the influence of depth and mining on the stress condition at the site. The results show that high stresses do exist in at least some potholes, and that current formation theories do not adequately explain the measured stresses. In support of understanding the high local stress associated with the pothole, the study explored several rock engineering modelling processes to validate the conditions of the study site and enclosing excavations. A better understanding of the stress conditions in potholes with additional data could lead to more appropriate support design and avoidance of potential rockbursts in these structures.

Jan 1, 2021

By Ken McIntyre, Trodel Wolf-Dieter

"Sirius Minerals is a UK based fertilizer development company focused on advancing into operation its polyhalite project in North Yorkshire, England. The operation is known as the Woodsmith Mine which has an estimated 2.7 Billion Tonnes of reserves and is currently in the construction phase. DMC Mining Services was selected to carry out the construction of four shafts for the project, a production shaft of 6.75m diameter to a depth of 1594 m, a ventilation shaft of 6.75 m diameter to a depth of 1565 m, and two additional shafts to support the construction of the material transport system (the MTS and Lockwood Beck intermediate) to 360m in depth for servicing the underground conveyor network for transport of product from the mine site to the costal port facilities located at Teasside. This paper will review the status of the project to date and the innovative approaches that DMC is utilizing to ensure a safe and successful shaft sinking project. INTRODUCTION The Woodsmith Mine in North Yorkshire is a Sirius Minerals-owned deep potash and polyhalite mine located near to the hamlet of Sneatonthorpe, Whitby in North Yorkshire, England, approximately 75 km east of York. The area of interest is more than 700 km2. The £3.2 billion project is to develop the Woodsmith Mine to extract polyhalite, and a tunnel system to transport it to a materials handling facility and harbour at Teesside. The site is the world's largest and highest-grade deposit of polyhalite and is expected to produce 20 million tonnes of polyhalite, potash and POLY4 per annum, as well as create over 1,000 direct jobs and many more indirectly. It has the potential to generate over £2 billion of annual exports for the UK. As the project will require mining to be undertaken in the North York Moors National Park, many objections were raised about the mine. Sirius Minerals has gone to great lengths to ensure that the project is sensitive to the local landscape, including: mineshaft head frames that will be positioned below ground to reduce their visual impact; surface buildings will be kept to a minimum; and the entire site will be landscaped and screened by existing woodland to blend in with the surrounding area. The project will also abide by strict environmental limits which govern our activity during the construction phase."

Jan 1, 2019

By John H. Hild

"INTRODUCTION Alunite occurs within a radius of 10 miles of Marysvale, Piute County, Utah, in veins and as replacements of igneous rocks. A number of each type of deposit was explored by the Bureau of Mines, in cooperation with the Geological Survey, under the Strategic Minerals program during 1942. The exploratory work comprised geologic and topographic mapping, diamond drilling,,bulldozer and hand trenching, sinking test pits, rehabilitation of old workings, sampling alunite exposures, and constructing and repairing roads.ACKNOWLEDGNENTSIn its program of exploration of mineral deposits; the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches-are under the supervision of Dr. R. S. Dean, assistant director.With particular reference to this publication, acknowledgment is given to Richard E. Mieritz and William E. Young, who assisted on the project at various times; P. T. Allsman, chief. Salt Lake Division, Mining Branch, who advised on exploratory problems and gave valuable assistance in preparing the report and illustrations; A. P. T. Schumann, for preparing the illustrations; and to Gordon L. Bell, Max Willard, and Eugene Callaghan, of the Geological Survey, who cooperated as representatives of that agency."

Nov 1, 1946

By Brent K. Nelson, D. Lee Petersen, Charles R. Nelson

INTRODUCTION Tunnels are commonly constructed in the very weak St. Peter sandstone in the Twin Cities area of Minnesota. Historically, core recovery in this weak sandstone was very small in the critical weaker strata resulting in little preconstruction information on the ground conditions. Improved core recovery techniques have been utilized for recent projects, allowing rock quality rating methods to be developed for the recovered core. Down-the-hole tests, and the use of combination ratings between different types of core data provide for more detailed characterization of ground conditions. THE ST. PETER SANDSTONE The 45 m thick St. Peter is an unusually pure quartz sandstone. It underlies all the Twin Cities area, except where it has been eroded by the present day Mississippi River or by pre-glacial rivers. It forms conspicuous steep bluffs along the Mississippi River where the upper Platteville limestone formation protects it from erosion. Where the Platteville formation is missing, the sandstone slopes are often more gentle. Natural case hardening of the exposed sandstone bluffs often forms a resistant crust and reduces sloughing. This case-hardened surface is not representative of the sandstone back from the bluff.

Jan 1, 1987

By Daniel J. Brunner

The U. S. Department of Energy (D.O.E.) requires that the prospective nuclear waste repository in Basalt at Hanford, Washington, comply with State of California mine and tunnel safety orders. These regulations require that all main fans be installed in such a manner as to permit prompt reversal of airflow. This paper evaluates the requirement of air reversal and the appropriateness of imposing such regulations on the proposed nuclear waste repository in Basalt.

Jan 1, 1988

By R J. Wood

Raise drilling (or raise boring) is not a new technology or methodology. The first raise drilling machine was developed by The Robbins Company (TRC) of the USA in 1962. TRC manufactured the first tunnel boring machine (TBM) in 1952 and Jim Robbins, the founder of the company wanted to ‘turn the TBM concept on its head’ so to speak.Many improvements have ensued in the 50 years since the first machine. Such improvements include advances in the drill rod and thread design, cutters and reaming heads. Raise boring would not have been possible without the development of the tungsten carbide insert cutters and there have been big advances in both the carbide technology and in the mechanical design of the cutters.Over time mines have developed deeper with a greater use of diesel equipment resulting in greater ventilation requirements. This in turn means larger and deeper ventilation shafts. There have also been improvements in directional drilling techniques. This all combines with the need and ability to construct larger shafts using the safe method of raise drilling. With suitable geotechnical conditions the RBR900VF is capable of drilling shafts to a diameter and depth of greater than 8 m and 2000 m respectively. Greater diameters are possible over shorter lengths with suitable ground conditions.The RBR900VF was designed and manufactured to specifications developed by Macmahon. This machine has the greatest thrust and torque capability of any machine in the world. It enables cutters to be more heavily loaded in the larger diameter heads and this is essential for efficient rock excavation. Additional features of the new machine include minimal manual handling to provide a safer working environment and higher strength steel for the drill rods providing additional safety margin.CITATION:Wood, R J, 2014. A revolution in raise boring – the development of the RBR900VF, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 171–178 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

This publication contains eight papers presented at a Bureau of Mines Technology Transfer Symposium in Charleston, W, on June 22, 1983, Five of the papers describe the results of Bureau-sponsored research on cabs and canopies for low-coal underground mining equipment. The other papers describe the efforts of three underground coal mining equipment manufacturers (FMC, Joy, and Lee-Norse) in the area of cab and canopy design.

Jan 1, 1985

By Erik S. Bernard

"INTRODUCTION Conventional steel bar reinforcement is used in many tunnel linings to provide high flexural and tensile load resistance. These Reinforced Concrete (RC) tunnel linings may suffer flexural cracking during service or, in the case of precast concrete segments, during production, handling, or installation. Cracks can lead to corrosion of steel reinforcement, so limits are placed on maximum acceptable crack widths to reduce the likelihood of corrosion during the intended design life (AFTES, 2013; MC2010, 2012). However, the relatively light level of reinforcement used in many applications can result in quite wide in-service crack widths, so either additional steel bar reinforcement is required to limit maximum crack widths, or fibers can be included to control crack widths. Numerous investigations have been undertaken into the efficacy of including steel fibers to reduce crack widths in conventionally reinforced members (Stang and Aarre, 1992; Abrishami and Mitchell, 1997; Bischoff, 2003; Dupont and Vandevalle, 2003; and Jansson et al, 2010), but steel fibers suffer the problem that they are at least as sensitive to corrosion at cracks as steel bars and therefore have similarly tight limits placed on acceptable crack widths (AFTES, 2013). An alternative means of maintaining narrow crack limits in RC members has therefore been sought. The current investigation was instigated following an observation that theories promoted as an explanation for the ability of steel fibers to reduce crack widths in reinforced concrete flexural members (Deluce et al, 2014) do not depend on the material composition of the fibers used but instead depend primarily on the tensile stress generated by the fibers across cracks. Since it is known that macro-synthetic fibers are capable of equaling the post-crack tensile capacity of steel fibers, it has been hypothesized that macro-synthetic fibers are also capable of reducing crack widths in reinforced concrete flexural members but with the added advantage that macro-synthetic fibers are completely immune to the effects of corrosion. Use of macro-synthetic fibers to reduce maximum crack widths in reinforced concrete flexural members subject to aggressive environmental exposure is more rational than use of steel fibers because steel fibers are very sensitive to the corrosive effects of environmental exposure at cracks. The current investigation was therefore undertaken to explore the potential use of macro-synthetic fibers to reduce maximum crack widths in reinforced concrete members subject to flexure. Barchip BC54 fibers were selected as they are one of the most widely used and competitive high performance macro-synthetic fibers currently available."

Jan 1, 2016

By William M. (Bill) Shaver

"The author will review the early history of shaft sinking as well as focus on the improvements made in shaft design and construction over the last fifty years (1970 to 2019) to predict how shaft sinking will change over the next fifty years and describe what the shaft sinking world might look like in 2070. INTRODUCTION It is a great honour to be one of your keynote speakers for the Fourth International Conference on Shaft Design and Construction being held in Toronto in November 2019. This is one of the opportunities we have to thank the Mining Companies of the world as well as the industries and companies we serve for their support of the mining contracting and shaft sinking business of Canada and the world at large. Many of these companies are represented here today. Without your support many of the innovations we will talk about today would not be possible. We would also like to thank all the companies that work with us in our business including all the contractors and suppliers who provide the various services we require. These include equipment manufacturers, engineering companies, project management companies and suppliers large and small who cater to our every need as quickly as possible. Without all these partners we would not be as good as we are. Many of these companies are our sponsors this week. Thank you from all of us! This is also an appropriate time to pause and think about those Shaft Sinkers we have lost and those who have been injured on our projects around the world. Please bow your head and remember the Shaft Sinkers you have worked with, who did not return home or those who returned home injured. Think about how we can continue the work of making shafts safer every day as we go forward with our projects so everyone goes home to their families safe and sound. Pause for a minute and thank you. The subject matter we have chosen to discuss today is “Shaft Sinking in the Next Five Decades”. How will the work be done, how fast will it be done, what will it cost, and why we think this may occur? It is appropriate to consider this over the next few days with this auspicious group we have assembled. Today, we will look back at all the advances that have been made over the last many years and look ahead to the future to attempt to predict what shaft sinking will look like in 2070. When I look around the room I recognize that many of us will not be around then so we need not worry about being wrong. Suffice it to say that the next 50 years will be very interesting and exciting for the shaft sinking business."

Jan 1, 2019

By R. R. Givler

Since the 1860's the good ole days, oil has been nozzle fed to burners under pressure atomizing the oil into droplets -- 1960's has produced vaporized oil that burns oil with the flame color and consistancy of gas -- If you can tell the difference by looking at the flame, gas or oil I?ll buy the lunch. First, we must ask, "Why all the excitement about Blue Flame?" This question is best answered by you after you have studied the principle of operation and see the result. I will attempt to explain both of these so that you can draw your own conclusions.

Jan 1, 1975