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By S. S. Jenkins Jr.

While the method is seldom used anymore, coyote blasting is an historically interesting way to blast large quantities of rock. It was used extensively in the days before modern fast drills were available and can be very effective in some formations that have a natural breakage pattern. This paper will cover the general principles, some blast design factors and point out several actual blasts including some very large ones.

Jan 1, 2005

By Singer RP

The Latrobe Valley brown coal deposits are one of Australia's major energy resources with measured and indicated reserves amounting to some 162 billion tonnes. Economically recoverable reserves are estimated at some 65 billion tonnes, 47 billion tonnes of which are classified as available for mining (VBCC (1983)). These deposits contain one of the lowest grade fuels used anywhere in the world. Typical Net Wet Specific Energy values range from 6 to 9 MJ/kg. Despite the low energy value of the raw coal, the Latrobe Valley deposits represent approximately 90% of Victoria's indigenous non-renewable energy resources. Utilisation of this vast primary energy resource has been a key factor in the economic development of Victoria.

Jan 1, 1990

By R. C. Bates

Uranium mine workers? daily exposure to radon daughters was estimated by two methods of sampling, detailed and spot-check. Both methods involve time- weighting measured exposure levels to arrive at an average exposure figure. Random sampling, or sampling without regard for the duration of exposure, has proved inadequate for estimating average exposure levels. During the first phase of the study, the breathing zones of eight workmen in three underground uranium mines were sampled for an entire shift; 20 to 36 radon-daughter samples were collected per man-shift, Analysis of these data indicated that a suitably accurate estimate of the full-shift exposure could be made by time weighting a considerable lesser number of representative radon-daughter samples. This analysis led to the spot-check method of estimating full-shift exposures to radon daughters. Additional detailed studies were made in seven mines to Learn more about the full-shift radon-daughter exposures and to test the spot-check method, In all, 617 radon-daughter samples were taken in 10 underground uranium mines during 26 man-shifts, and the spot-check method was tested 35 times.

Jan 1, 1962

By J. M. Mutmansky, L. Xu

"This paper outlines the results obtained when sampling twenty underground coal mine sections, each in a different mine. The sampling effort was oriented toward a detailed characterization of coal mine dusts and thus eight-stage Anderson Model 298 impactors were used as the primary collection instrument. This instrument allowed a rather detailed size distribution for each of the particulates sampled. Because four of the mines used diesel outby equipment and/or diesel shuttle cars at the face, it is possible to make some comparisons on the particulate distributions in diesel versus non-diesel mines.One of the more interesting results is the pattern that exists in mines that contain only diesels used for outby utility haulage. Particulate in these mines seem to be consistently heavy in the fine size ranges, perhaps being of significant concern to the industry. While no definite conclusions can be achieved from the limited data collected in this study, the data indicates that more detaile~ study of particulates in diesel mines is needed so that some idea of the particulate loadings in diesel mines can be achieved."

Jan 1, 1988

By Richard Klimpel

A common problem in mineral processing and chemical engineering is the need to estimate flow rates and/or weight ratios involved with engineering operations for which it is inherently difficult to directly measure stream weights. Simple examples of this situation include stream separators (a classifier operating on a particle flow) and stream mixers (the mixing of new feed and circulating load in a ball mill circuit). Often in these types of operations, it is possible to sample the streams involved to get approximate component analyses (e.g. size distributions of solid streams, chemical composition of chemical streams). In this paper various formulae are developed which can be used to estimate stream flow rates or weight ratios given information on the stream components. The type and level of experimental error present in the stream component analyses does have an important bearing on the numerical values (and reliability) of the weight ratios calculated by the various formulae. A simple but theoretically sound method is shown for selecting appropriate estimation formulae for any given engineering operation. The derived formulae are applied to sets of experimental classification data for illustration purposes.

Jan 1, 1979

By McHenry Moiser

"SUMMARY This mine, which was discovered in 1846, was active in the 1850's, in the 1870's, and again in 1883. Since this last date, it has been idle. Two parallel bed-veins in lower Silurian limestone, about 50 feet apart, strike N. 70° E. and dip 70° NW. The north vein had an average width of 12 feet to a depth of 50 feet, where it was barren. The south vein had an average width of 16 feet to a depth of 75 feet; on the 110-foot level, although well-defined it carried little or no values. The zinc content of the ore was as high as 12 percent, and some lead and silver were associated with it. A reduction plant for production of spelter and zinc oxide was constructed at the mine. The only available record of production is for 1873 to 1876, inclusive, when 357 tons of smelter was shipped. The mine is caved and inaccessible, and nothing now remains of the treatment plant.Four holes totaling 1,046 feet wore diamond-drilled to probe for extensions of the ore in depth. Core recovery was about 85 percent. No samples were taken for analysis.INTRODUCTION AND ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. The policy of the Bureau is to publish the facts devel¬oped by each project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, does the actual investigative work, and prepares the final report. The Metallurgical Branch, Oliver C. Ralston, chief, analyzes samples and makes beneficiation tests.The deposit was examined in 1944 by C. B. White, mining engineer of the Bureau of Minos. Diamond-drilling was under the immediate supervision of McHenry Mosier. 2/ The diamond-drill cores were logged by Arnold Brokaw, geologist, Federal Geological Survey, and 'wore filed in the core library of the Bureau of Mines, Mount Weather, Va."

Jun 1, 1948

By Sadao Maruyama

INTRODUCTION Since the big discovery of Kuroko deposits in Kosaka mine, Akita Pref., northeastern Japan in 1959, major Japanese mining companies have been engaged in extensive exploration for the deposits expending large amounts of money. Above all their exploration activities have been particularly fruitful in discovering new deposits in northern Akita Pref. It is estimated that the total ore reserves newly found in the area are at least 50 million tons. Kuroko deposits are the most important ore source of copper, lead and zinc in Japan and have been mined since last century in the said area. Kuroko (black ore) is fine, compact aggregates with sphalerite , glena and barite as principal constituents and chalco- pyrite, pyrite and tetrahedrite as subsequent constituents. The name Kuroko comes from its appearance. It is not rare that total grade of copper, lead and zinc reaches 20 - 30% and the gold and silver content is also fairly good. Accordingly the unit value of the ore is much higher than the ore from other types of deposits. Besides the Kuroko ore, the Kuroko deposits consists of Ohko (yellow ore, massive cupriferous pyritic ore), Keikoh (silicious ore, cupriferous network ore) and gypsum ore. This type of deposit is considered to be not only an important source of base metal but also a source of gypsum and barite. Although the importance of this type of deposit had been commonly recognized, sub-surface nature of the occurrence hampered exploration work. In recent years the improved exploration techniques and increased knowledge of the Kuroko deposits have met with remarkable success in the location of new deposits. This outburst of exploration and dis-

Jan 1, 1970

By Peter N. Calder, Alan Bauer

INTRODUCTION One of the most important decisions involved in the design of an open pit mine is the selection of a slope angle. Despite this fact, engineering procedures have developed slowly in this field. Only recently have the instruments and know-how become available to undertake a design based on sound engineering principles. The effect of blasting on open pit slope stability is one aspect in which the state of the art has not developed fully. These effects include: a) the effects of the ground motion associated with blast waves on slope stability, and b) the fracturing of rock in the vicinity of slopes caused by blast waves. Natural rock jointing plays an important role in both of these. SUMMARY OF BLASTING EFFECTS In recent years there has been a trend to larger sizes of blast holes in open pits to the extent that today 9% in. and 12% in. diam. holes are the most common. The reasons for this have been economic. Larger machines are more efficient and produce at a lower overall cost per ton. As the size of blast holes have increased, so have the other factors associated with blasting. Bench heights have increased, the tons/ft. of hole yield has risen significantly and the explosive load per hole has increased. Quite naturally the rupture radius for a single blast hole has increased along with the vibration level produced per blast hole. Open pit blasting operations can result in two types of unwanted damage: 1. Damage to structures, such as buildings, dams and slopes by ground vibrations initiated by the blast. 2. Fracturing of ground beyond the planned excavation limits. Let us first consider item one. Vibration effects are determined by the type of blast which is fired and the type of medium through which the blast wave is being transmitted. They are strongly influenced by the weight of charge per hole, the number of holes per delay, the distance from the shot point, the mode of initiation, the point of interest relative to the blast, etc.

Jan 1, 1971

By William Glenn

The Ritchie vein, of Ritchie county, W. Va.,* was a straight fissure, about 3600 feet in length, which cut vertically downward across the horizontal beds of shale and of sandstone to a depth not ascertained. It might be described as lying in a. Vertical plane, bearing 12 degrees north of west. The geological horizon is that of the " upper barren coal measures'" of the Appalachian coal-field, being a part of the strata lying above the Pittsburgh bed. The vein matter was declared by Prof.

Jan 1, 1896

By Ligon Johnson

ONLY the acute phase of the smelter fume problem is new. The problem itself is older than the Christian era. While both lead and copper were mined and crudely smelted ; on: 3,000 years ago, it was not until the Roman occupation of the Iberian Peninsula and the British Isles, which occurred but shortly before the beginning of the Christian era, that there was any evidence of smelting operations on a scale sufficiently large to permit a fume problem. Around Huelva, Spain, are found more than 30 million tons of slag from lead smelting conducted there by the Romans. Pliny tells us that more than 20,000 slaves were employed in the Iberian mines. Extensive mining and smelting by the Romans in England and Wales were coincident with the Iberian proceedings. These metallurgical operations were upon a sufficiently large scale to produce marked results both upon the surrounding country and the smelter workers, but, as they were those of a conqueror upon conquered soil, conducted by slaves, imperial Rome failed to recognize that such a thing as a smoke problem did or could arise, and whatever fume question there may have been at that .time remained a question only to those who had no chance to answer any phase of it. The smelting operations of the Romans extended over about 400 years, and little is "recorded of lead and copper smelting from that time until the 16th century. From the revival beginning at this period up to the present century, the growth of smelting has been comparatively gradual. In Great Britain, smelting was conducted almost wholly in localities where metallurgical operations were of paramount importance, and the communities that grew up in smelter localities were due to and dependent upon the mines and smelters. This fact had much to do with the comparative freedom of British smelting from burdensome fume litigation and legislation. To a lesser degree these conditions applied to the German operations which, when coupled with the further fact that most of the early German operations were to a greater or less degree fiscal workings of Prussia, Saxony and Brunswick-Hanover; accounts for

Jan 5, 1917

By John C. Didlinger, John L. Didlinger

As we begin the pre-blast survey we need to decide on the number of holes needed for production and a detailed highwall inspection. The survey consists of checking the highwall and placement of barrier cones. At the Elmhurst Chicago Stone Company, Barbers Corner Plant, we use 18-24" orange highway type safety cones. These cones are easily noticed because of their high visibility color in all weather conditions and are placed approximately 20-25 feet from the face and approximately 50 feet apart along the highwall, then the area is checked for back break, under cut, over hang, surface filled area and clay area. This deposit is unique because of the number of clay filled areas and slip seams that meanders through the deposit plus a fault that runs North-Northwest and South-Southeast. This particular limestone deposit is overlaid with glacial sand and gravel and the top weathered stone wanders plus or minus 10 feet in 1400 feet.

Jan 1, 1996

Commodities statistics and other information are available through the following three systems: Internet Access: To access the USBM Gopher server on Internet, connect to: gopher.usbm.gov port 70, using gopher client software. Or contact the Systems Administrator for technical questions: Matt Klevemann, 412-892-6499 (klevemmc@miner.usbm.gov) These USBM materials are available on Internet, with more to come in the future: Publications and other research findings, including this bimonthly publications list, newsletters, tech transfer updates, environmental technology research, health and safety information. USBM software products Media materials and speeches. Mines Data: Computer bulletin board. Log on via modem through 202/501-0373, or call 202/501-0406 for technical assistance. Mines FaxBack Return fax service. 1. Use the touch-tone handset attached to your fax machine's telephone jack. (ISDN [digital] telephones cannot be used with fax machines.) 2. Dial 202/219-3644. 3. Listen to the menu options and punch in the number of your selection, using the touch-tone telephone. 4. After completing your selection, press the start button on your fax machine.

Jan 1, 1995

By Thomas O. Llewellyn

This U.S. Bureau of Mines (US8M) report presents a concise review on sources, processes, supply, and historical use patterns of domestic cadmium. It also covers a preliminary estimated cadmium material balance for the year 1989.

Jan 1, 1992

By Douglas Ragland

Two subjects certain to incite interest among a few practicing engineers and almost all engineering educators are professional recognition and decline in engineering enrollments. It is not surprising that this interest on the part of the educators is universal; it is only regrettable that such an interest on the part of the practitioners is not more widespread. In fact, it is probably the hope of the profession that some of the more penetrating searches now being made into the nature of engineering will generate sufficient cause for perplexity that members of the profession will assume a significant degree of personal concern toward purely professional matters.

Jan 1, 1963

The Beaconsfield gold mine processing plant is a complex operation and utilises crushing, grinding, gravity gold concentration, sulfide flotation, bacterial oxidation, cyanidation and zinc cementation to recover gold from the partially refractory ore. This paper discusses the challenges, developments and advancements throughout the processing plant since start up, which have culminated in a 25 per cent increase in the mill throughput over the nameplate design and a concomitant gold recovery increase from 75 to 92 per cent. The improvements have been attained via advancements in mechanical integrity, metallurgical review, process control and operator training, resulting in the current operation producing over 630 000 ounces of gold to date.

Jan 1, 2007

By Hanes J

More than 200 bursts in coal occurred at Leichhardt Colliery prior to December 1978 during mine development in the 6 m thick Gemini seam at depths approximating 400 m. Three large bursts each displaced more than 300 tonnes of coal and stone. Two of these which occurred in continuous miner developments, are described and compared. Geological settings, mining strains including induced cleavage and roof failures associated with bursts are described. A shotfiring technique replaced mechanised mining following a major incident at the colliery. Present mining procedures, the apparent improvement in stability of workings and ongoing geotechnical monitoring programme are discussed.

Jan 1, 1980

By G. W. Grove, H. R. Burdelsky, F. E. Griffith

"INTRODUCTION The work of using a system of air locks in unsealing a mine in Ohio following a fire probably was one of the outstanding jobs of its kind in a medium-thick coal bed.The fire in this mine, thought to have been of electrical origin, was discovered at about 1:30 a.m. on December 11, 1941. Forty-four men were working in the affected section at the time; 5 escaped unassisted, and 37, who had barricaded themselves, were rescued. The bodies of two men, who had succumbed after breathing fumes given off by the fire, were brought part way out of the mine before it became necessary to seal the mine.Direct attempts to extinguish the fire with water were abandoned when hazardous amounts of 'carbon monoxide, methane, and other inflammable gases were detected in return air passing through the main haulageway and escape-way of the mine.The mine was completely sealed on the surface at about 8 p.m. on December 12, 1941, with the two bodies remaining in the mine. Sixteen days after the mine had been sealed, the two bodies were recovered. This was accomplished by air-locking through a partitioned-off stairs compartment of a ventilation shaft. This work was done under adverse barometric and atmospheric conditions.A method for collecting representative air samples from the immediate fire area was used successfully by utilizing a vacuum pump on about 10,000 feet of existing water line that had been broken near the fire area.The immediate fire region was sealed, and confined to a relatively small area; the remainder of the mine was recovered, and operations were resumed February 9, 1942, or 59, days from the time of sealing the mine on the surface. This recovery was made by air-locking the main entries inby from the shaft and No. 2 right-face entries.The distance between air locks averaged about 500 feet, and as each new set of seal stoppings and air locks was completed, the old or outby seals were taken out and the area between was ventilated. In ventilating this area, it was often necessary to use line curtains to direct the air into dead-end places."

Oct 1, 1947

By Sandin E. Phillipson

"On April 5, 2010 a massive dust-fueled explosion at a longwall mine in southern West Virginia claimed the lives of 29 miners. The mine had experienced large gas inrushes from the floor on two known previous occasions, and natural gas was found emanating from floor fractures behind the longwall shields after the explosion, indicating a likely fuel source for the initial ignition. In succeeding months, another longwall mine operating in the same seam 15 miles away encountered smaller inflows of natural gas that halted production from two different longwall faces. Production was halted at a third longwall mine, 30 miles south of the first, in May 2011, when explosive levels of methane were detected inby the longwall face on the headgate. The same mine was evacuated on March 20, 2014 when a series of floor gas feeders were encountered on the longwall face. A literature review indicated that there has been little documentation or description of these events, and that their size and frequency are unknown. The most significant floor gas inrushes in the United States are believed to have been associated with longwall mining in the Pocahontas No. 3 Seam of western Virginia, in which an estimated 5.8 x 107 ft3 of natural gas was expended from a floor feeder on the longwall face over a two-week period (Aul, pers. comm.).A variety of mechanisms and circumstances are associated with methane emanations from underground mines. Hyman (1987) defined an outburst as a violent, simultaneous release of gas and comminuted rock material into a working face or the interior of a borehole, and indicated that certain soft or fractured coals have a propensity for outburst based on gas desorption rates. In this mechanism, reservoirs of autogenic gas hosted in pockets of soft, crushed coal surrounded by harder coal are released suddenly as confining stress is removed by mining. Hyman (1987) also suggested that highly stressed, relatively gassy coal that is penetrated by mining-induced fractures could be outburst-prone. Clayton et al. (1993) and Ulery (2008) recognized the importance of faults as potential conduits for gas from adjacent strata into coal mines, and suggested that biogenic gas trapped in adjacent strata could migrate into mined coal seams due to a pressure differential. Ulery (2008) distinguished between an outburst and a blower, the latter defined as an event expending a large amount of gas over an extended time period, most often emanating from underlying strata, but without expulsion of coal or rock. Methane feeders are further defined as a subset of blowers that continually expend gas over a long period of time but at a lower rate. Many of the mechanisms discussed by Ulery (2008) relate to geologic features that can impound gas within the seam, releasing a voluminous amount when mining breaches the elastic dike, fault gouge, or other geologic structure that had restricted and compartmentalized coalbed methane migration. Thus, the events discussed in this paper can be described as blowers and feeders. However, detailed geological observations of the three longwall mines discussed in this paper appear to indicate a mechanism that is different from those described by Hyman (1987) or Ulery (2008), in that they did not involve coalbed-sourced gas, and the reservoirs were not hosted by coal seams."

Jan 1, 2016

By P. C. Good

The Bureau of Mines conducted a laboratory investigation of a sinter-leach method to recover aluminum and fluorine from waste carbon potlining residues from secondary cryolite recovery operations in aluminum reduction plants. After removal of carbon by burning, the residue was sintered at 900° to 1,100° C with silica and N2CO3, then crushed and leached with dilute NaOH solution, dilute Na2C03 solution, water, or water containing residual Na2O which remained in the sinter after reaction and decomposition of Na2CO3. Over 90 percent of the contained aluminum and up to 87 percent of the contained fluorine were extracted from this waste product in the form of a mixed alkaline solution. Treatment of the alkaline solution with CO2 yielded a white precipitate containing 89 percent of the original aluminum and 61 percent of the original fluorine as a mixture of synthetic cryolite and alumina, together with a variable excess of soda.

Jan 1, 1969

By Carl R. Peterson

The Rapidex continuous drill and blast tunneling concept utilizes a unique spiral blasting pattern that permits efficient performance with relatively small single shots, while at the same time directing major blast fragments at right angles to the tunnel axis. The concept's self-shielding geometry permits the design of a lightly shielded machine that can stay at the tunnel face firing frequent small blasts to provide rapid, virtually continuous advance. This paper describes Phase III of the development program (supported under Bureau of Mines contract H0252047) in which the "front end" of the machine?drilling loading, and shooting components, together with the shield--was fabricated and field tested underground at the White Pine Copper mine, Michigan. One of the major accomplishments of the Phase III effort was to develop a fully remote controlled loading and initiation system in which explosive slurry is pushed, through a hose into the blasthole by a small water-driven piston carrying the blasting cap. The cap is ignited via an induction coil just prior to entry into the borehole, after which a delay permits complete -withdrawal and shielding of the loading hose. The ultimate objective of the present Bureau-sponsored program is to evaluate the feasibility of mechanizing hard rock mining operations, such as development to a point where drilling, loading, shooting, and mucking can proceed simultaneously and result in increased productivity.

Jan 1, 1977