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By S. B. Bealko

Mining haul trucks comprise the majority of the equipment used in underground limestone mining operations and are known to emit high levels of noise. A previous study conducted by the National Institute for Occupational Safety and Health (NIOSH) indicates that 70-90 percent of all miners have a noise-induced hearing loss (NIHL) great enough to be classified as a hearing disability by retirement age. These results demonstrate the public health need to protect the hearing of workers in the mining industry, including haul truck drivers. ng of workers in the mining industry, including haul truck drivers. Cab enclosures present an opportunity to isolate the haul truck operator from both truck and other noise in the mining environment. A total of twenty-five haul truck cabs were studied which were divided into three style (treatment) categories determined by soundproofing features and technology for noise reduction: old-, new-, and retrofitted-style. This study examines the contribution of cab acoustics, operator performance, and maintenance to noise reduction for each cab style. Dosimeters were used to measure 8-hr time weighted average sound pressure levels (TWA8 SPLs) inside and outside the cabs to determine if different acoustical treatments affect cab attenuation. Adherence to the Mine Safety and Health Administration (MSHA) Permissible Exposure Limit (PEL) of 90 dB TWA8 (with a 90 dB threshold) was used as the main indicator of overall noise reduction achieved. Dosimetery results indicate only 2% of the samples exceeded the PEL, but samples could still be reduced much further. Descriptive and comparative statistics indicate that noise levels inside the new-style cabs are significantly lower than the other two cab styles. Also, data suggest that there is no difference in noise exposures when comparing the old-style to retrofitted cab styles. Operator influence (opening doors and windows) was a significant factor for increasing noise exposure. This paper demonstrates that properly designed cabs can achieve major noise reductions, but noise levels could still be reduced much further below the MSHA PEL. New-style cabs, equipped with modern noise-reduction treatments, exhibit much lower noise exposures than the other two cabs styles, and the effectiveness of the current noise-reduction treatments for retrofitted cabs is questionable. Haul truck driver observations indicate that improved noise exposure reduction training is needed. Finally, specific targets for future noise reduction research are suggested that will further contribute to the prevention of hearing loss for haul truck operators.

Jan 1, 2008

By R. Timothy McCrum

It is not often that the Interior Department's Bureau of Land Management, Office of the Solicitor, and Interior Board of Land Appeals (IBLA) jointly act to do the mining industry a good turn. That happened, however, in the recent decision, Schlosser v. Pierce, 92 IBLA 109 (1986). It was ruled that the theorized "independent mine requirement" was not a part of the discovery standard for mining claim validity under the 1872 Mining Law. The phrase "independent mine requirement" would require the mineral reserves within the boundaries of each individual mining claim in a claim group to support an independent economic mining operation. This, without regard to the fact that reserves on adjacent claims could be mined in a group operation, resulting in greatly reduced mining and marketing costs per ton of ore. Such a rule would render invalid under the 1872 Mining Law mining claims for almost all low-grade, high-tonnage, commercially valuable mineral deposits. Until the Schlosser case, no judicial or administrative decision had addressed the issue of the independent mine requirement. Nonetheless, a series of Interior decisions in the 1970s implied such a rule. Even the Rocky Mountain Mineral Law Foundation reluctantly concluded in 1984 that, "each claim to be valid must be capable of being operated at a profit independently of any other claim," the Foundation did criticize the rule as "excessively stringent" and urged the adoption of a "more realistic rule." Fortunately, the IBLA did just that in Schlosser when it ruled that the "application of a requirement that each claim be independently capable of being mined and marketed at a profit is rejected," 92 IBLA at 134. Now, a year after the 1986 decision, there remains some unwarranted confusion over the issue resolved in, and the meaning of, the Schlosser decision. There is no need for this confusion. The Interior Department's decision is a clear and legally sound victory for the mining industry. Grazing rights vs. mining claims The Schlosser case was an unusual mining claim contest. A private contest was brought before the Interior Department. Schlosser was a federal grazing lessee and surface owner. He filed against Pierce, the locator of a group of mining claims for bentonite over the same lands. At a hearing before interior's administrative law judge (alj), Schlosser's counsel began laying the foundation for the independent mine requirement. Counsel asked the mining claimant's expert whether he would go through the permitting procedure, road building, and reclamation just to mine the amount of bentonite on any one claim in the group. Schlosser's counsel proceeded with this line of questioning for each of the 16 claims in the group. Pierce's mining expert testified that the tonnages of mineral on any individual claim could not be mined, processed, and marketed at a profit if only one individual claim was considered. However, if the claims in the group were operated jointly, all the mineral could be mined, processed, and marketed at a profit.

Jan 8, 1987

By Cong Zhang, Huaying Wang, Yixin Wei

"Water inrush is a serious geological accident in underground coal mines. This paper focuses on the method of the bow tie analysis based on fuzzy reliability to assess the risk of water inrush in coal mines. First, post failure probability and repair probability of initiating events are divided into 5 levels. Then triangular fuzzy numbers are adopted to quantify experts’ language and to acquire the reliability rate which close to the actual values by defuzzification and calculation. According to dynamic bow-tie analysis model, using the method of moments to fit the reliability time of events by Weibull distribution and offering the random sampling rule of failure and repair time for illustrating the feasibility of fuzzy reliability evaluation. To demonstrate the effectiveness of the proposed assessment approach, bow tie analysis model of water inrush in coal mines is taken as an example.Introduction Dynamic bow tie (DBT) analysis is composed of dynamic fault tree and dynamic event tree analysis, and considers the impact of the time factor upon risk assessment of a system. There are many algorithms applied to calculation of the probabilities of node accident and accident consequence of dynamic bow tie analysis: Hidden Markov Model, Bayesian Network (Khakzad et al 2013), Integral Algorithm (Amari et al 2003) and Monte Carlo Simulation (Kim et al 2016). In terms of simulated time and practicability, the Monte Carlo Simulation has an advantage over other methods. DBT requires mass data in quantitative analysis, including the failure rates and the repair rates of the basic events of the Fault Tree (FT) and the subsequent events of the Event Tree (ET) at different time points, i.e., the distribution of failure time and repair time. In practical analysis, it is hard to obtain a large amount of exact historical statistical data, which is a major problem of risk assessment. Due to the difficulty of obtaining the exact data and historical failure data of the basic events and the subsequent events, the FT and ET analysis is stuck with the study of minimal cut sets, minimal diameter sets, structural importance and qualitative analysis (Liu and Zhang 2010, Yan et al 2012, Wang et al 2009, Li and Wang 2011). This paper will use fuzzy numbers and the defuzzification method to transform the experts’ language into the failure rates and repair rates of basic events and subsequent events, solving the problem that it is difficult to obtain a large amount of historical statistical data, and will use the method of moment to conduct Weibull fitting of the reliability time to provide the random sampling criteria of event failure and repair time in Monte Carlo simulation."

Jan 1, 2017

By Jim Oehler

The US minerals industry, as well we know, has been hit hard by the recent recession and is faced with what is projected to be a slow recovery. Even so, there was an underlying feeling of optimism at American Mining Congress' International Mining Show in Las Vegas, NV, Oct 11-14. More than 25,000 people attended during a particularly rough financial year, dispelling fears that attendance would dip sharply below 1978's 30,000 plus tally. The equipment expositionheld every four years-was the largest show of its kind this year in the Western Hemisphere in terms of exhibit space, providing an extensive view of mining-related equipment. In addition to the nearly 700 exhibits occupying more than 445 hm2 (11 acres), 20 technical sessions were held covering topics ranging from minerals availability and the state of the mining industries to communications, computers, and accounting. Government officials were well represented, with six US senators and five US representatives participating in various convention functions. Sen. Paul Laxalt (R-NV) was the keynote speaker at the welcoming luncheon. Other senators involved in the show included Howard W. Cannon (D-NV), Pete V. Domenici (R-NM), James A. McClure (R-ID), Frank H. Murkowski (R-AK), and Steven D. Symms (R-ID). Representatives on the program were Joseph M. Gaydos (D-PA), Guy Vander Jagt (R-MI), Don Young (R-AK), Jim Santini (D-NV), and Ceil Heftel (D-HI). There were also many international vistors at the show, including exhibitors from Australia, Austria, Canada, England, Finland, Sweden, South Africa, and West Germany. Equipment Highlights Equipment and services featured at the exposition ranged from aerial mapping to wire rope. Aisle space alone between exhibits exceeded 8 km (5 miles). And the companies represented ranged from small businesses to large corporations. Some of the company products described here are representative of the many exhibitors in attendance. Atlas Copco's extensive display of rock drilling and tunnel and shaft boring equipment featured its Boomer H-201, the newest addition to its line of underground drifting rigs; the ROC 306, a new track-mounted, high pressure down-the-hole drill rig; a new hydraulic surface crawler drill, the ROC 712H, designed for small and medium-size holes in quarries and small open-pit mines; a computerized analysis system, CARE (see page 1570), designed to project productivity and operating costs for various mining operations; several electro-hydraulic loaders, including the new rail bound LM E60 and LM E80, and two Hagg-loaders-the 7HR and 10HR-that use two digging arms to rake and guide muck; a mechanized blasthole charging system; rock bolting equipment and its new Swellex roof bolting method; Sandvik Coromant drill steel and bits; and its new Jarva R200 raise boring machine.

Jan 11, 1982

By Richard B. Muter

In determining the layout or combination of unit operations to be utilized in a modem preparation plant, several factors must be taken into account. Among these are the washability data, size consist data, the particular market or markets for the coal, the mining method used, the degree to which the coal must be prepared, expected fluctuations in raw coal and markets, and the overall economics of the process. In addition, there are the health and safety aspects of coal utilization and preparation. Chapter 1 of this book discusses the characteristics of coal and coal markets, while Chapter 2 deals with the design of preparation plants. Once the unit operations for a particular plant have been decided upon, these arrangement may be depicted by using a flowsheet. A coal preparation plant flowsheet is a two-dimensional graphical representation of the sequence of operations, the arrangement of machinery, and the flow of materials for a particular coal cleaning operation. The flowsheet is usually qualitative in nature, becoming more quantitative as material balances, water balances, numbers and sizes of various pieces of equipment, etc. are added. The usual convention in preparing a flowsheet is to show the feed flowing from left to right, starting at the top left and working down as in an all-gravity process. Various symbols are used for each unit operation as depicted on a flowsheet, and Fig. 14-37 is a compilation of the commonly accepted international standard symbols for each unit operation. Fig. 14-38 through Fig. 14-40 are flowsheets of various coal cleaning processes as published in the January 1976 issue of Coal Age. Each process has its own unique features which, among others, depend upon the coal being cleaned, the coal market, and the mining operation. Fig. 14-38, for example, is a flow diagram for a jig plant preparing steam coal from two strip mines located a few miles apart. In addition to the jig washer, cyclones are used to treat the finer size coal. Fig. 14-39 is a flowsheet of a heavy media plant using a heavy media washer for + %-in. (+6.3-mm) coal, froth flotation for -28 Tyler mesh (-0.6 mm) material, and dewatering phase units (dwp) for Y, in. x 28 Tyler mesh (6.3 x 0.6-mm) cleaning of steam coal. In addition, thermal drying, centrifuge drying, and the use of vacuum disk filters and thickeners for dewatering are depicted. Fig. 14-40 is a flowsheet of a plant producing metallurgical coal. In addition to the heavy media and froth flotation circuits, a tabling circuit is also employed. These flowsheets are intended to give the reader an example of how the various unit operations for coal cleaning may be linked together. Figs. 14-41 and 14-42 illustrate the conversion of block diagrams into an IS0 prescribed set of symbols.

Jan 1, 1991

By Sandy Clamage

"Seeing the elephant" was a term often heard from 1849 to 1859, the period of the great California Gold Rush. The phrase was used by those who dreamed of instant wealth that was believed could be found in California's virgin earth and mighty rivers. When news of fabulous gold strikes throughout the Mother Lode reached far away places, thousands of gold seekers left home and family to join in this incredible adventure. The barren, placid state of California soon became one of the most bustling, populous areas in the West. Before the Rush Before 1848, Mexico ruled California. It was then a remote region, isolated from the urbane world of the East by 2900 km (1800 miles) of scorching desert and impassible mountains. By sea, it was 29 000 km (18,000 miles) via Cape Horn. Spaniards and Mexicans settled the coastal lands on tracts donated to them by the Mexican government. The inland area was the domain of Indians and a few settlers who also had been granted estates by the government. Among those settlers was Captain John Sutter. He had been fortunate enough to obtain about 11 leagues of land (spanning 100 km or 60 miles in length) from Governor Alvarado of Mexico. Sutter was somewhat of a visionary and possessed a gifted tongue. He managed to receive most of what he desired with minimal trouble. Enchanted with Sutter's personality, Alvarado promised him Mexican citizenship. Alvarado also commissioned him to become "representative of the government and officer of justice on the Northern frontier." With uncanny foresight, Sutter began building a fortress on his land in the Sacramento Valley. It later became known as Sutter's Fort. It was more than just a fort, however. It also became a stopping place and home for many foreigners and Americans who traveled to California, and it eventually became the mecca for overland pilgrims. Sutter engaged in many projects. These included a cattle ranch, fur trade and trapping, and the construction of an irrigation system. With the influx of immigrants over the years, the community around the fort grew rapidly. Lumber was much in demand and Captain Sutter agreed to supply the necessary capital for a community sawmill. The site chosen was some 72 km (45 miles) northeast of the fort on the south fork of the American River in the town of Coloma. During the course of its construction, Sutter's carpenter, James Marshall, discovered a problem with the tailrace on the mill. First Strike Early in the morning on Jan. 24, 1848, Marshall was checking the tailrace. He noticed an object shining in a foot of water at the bottom of a ditch. He reached down and picked it up. His heart began to thump wildly as he realized he was holding a gold nugget. Sutter planned to keep the find a secret for as long as possible. He knew very well that he could become an extremely wealthy man. The ever loyal Marshall remained faithful to his employer and the pair did their best to obtain more

Jan 3, 1985

By M. Pawlik

Canadian sylvinites contain over 90% of KCl and NaCl and a few percent of water-insoluble minerals. Cationic flotation is used to produce KCl concentrates. Since water-insoluble minerals appear in the pulp as slimes, and since long-chain primary amines are utilized as a collector, desliming is essential. The potash industry utilizes different desliming methods. This may involve selective flocculation of the slimes with polyacrylamide and removal of the flocculated product by flotation, or mechanical desliming with the use of classifying cyclones. Whichever method is applied, desliming is never complete; the flotation feed after desliming still contains about one percent of the slimes which heavily affect collector consumption and flotation selectivity. Therefore, the remaining slimes have to be rendered inactive by “blinding” them with polymers such as carboxymethyl cellulose or guar gum. The commercial blinders used by the potash industry include natural and synthetic polysaccharides. The most common is the use of carboxymethyl cellulose (CMC) and guar gum (GG). These are quite different polymers, while CMC is anionic, GG is non-ionic; while the applied CMCs are of relatively low molecular weight (about 300,000) GGs have much higher molecular weight. Guar gums are also heavily used as the depressants of naturally floatable gangue in the processing of platinum-bearing ores, and according to Harris et al. (1999) quite a large variety of modified guar gums are available in South Africa for this application. Cheng et al. (2002) claim that natural guar gum’s molecular weight is 1.935 • 106. Robinson et al. (1982) found that the molecular weights of five grades of commercial guar gums ranged from 4.4 • 105 to 16.5 • 105. The highest molecular weight sample is then very close to the natural guar gum studied by Cheng et al. (2002). According to the manufacturer, the Rantec KP4000 guar gum which is used by the Canadian potash industry has a molecular weight of about 1.5 x 106. Since both KCl and NaCl are soluble in water, the flotation process is carried out in saturated brine. At 20 oC, 1450 kg of NaCl-KCl-H2O saturated solution contains about 0.300 kg of NaCl, 0.150 kg of KCl, and 1 kg of water (Gaska et al., 1965). Thus, in the saturated NaCl-KCl brine there are about 5.1 kmole of NaCl and 2 kmole KCl per 55.5 kmole of water. This gives 3.9 molecules of water per each ion assuming complete dissociation of NaCl and KCl. Thus, it is obvious that all water molecules in the saturated brine must be bound in the hydration shells around the hydrated ions. The surface tension of the NaCl-KCl saturated brine was recently measured to be 85 mN/m (Laskowski et al., 2003).

Jan 1, 2004

By W. A. Crosby, A. Bauer

The recent increase in size of open-pit mining operations has resulted in major improvements in efficiency that are beneficial to the mining industry. Higher bench heights, larger diameter blast-holes, and more powerful explosives have played an important part in reducing mining costs. These measures have, however, resulted in increased energy concentrations in the blast area, which can result in severe backbreak problems for final pit walls. If backbreak is not controlled, a decrease in the overall pit slope angle will ultimately be necessary, and consequences, such as decreased recoverable ore reserves and increased waste-to-ore ratios, will result. Greater amounts of loose face rock will be produced, and planned safety berms will be less effective or nonexistent. Hazardous working conditions can also result. Remedial measures, such as scaling large areas and using wire mesh or other artificial support, are very expensive and difficult to implement. There must be a trade-off between the money saved by using larger blasts, and the time spent to maintain pit wall quality. The best approach is to control blasting effects so the inherent strength of pit walls is not destroyed. Presplit and trim blasting are two control blasting techniques used to accomplish this. Both techniques are designed to create a low explosive energy concentration per unit of wall area at the perimeter of the pit. Energy concentration of the main production blast must also be controlled to avoid damaging the final pit wall. A low-energy concentration at the final wall can be obtained by decoupling charges, decking charges, using less powerful explosives, decreasing blasthole diameters, and changing the burden and spacing. Rock properties-fragmentation and the final state of the pit wall-influence the success of a blast. The most important properties to consider are: in situ rock strength, and the nature, frequency, and orientation of structural features. Since these variables cannot be controlled, they must be evaluated by suitable field tests, and then a control blast can be designed using controllable variables, such as spacing, burden, and hole diameter, so the blast will be successful for appropriate rock conditions. One main thrust of this article is to show how control blasts can be successfully designed for larger hole sizes, up to 381-mm-diam. While efforts to produce a good control blast in shovel/truck pits have been ongoing for some time, recent use of a modified presplit technique in dragline operations has helped reduce water problems, improve safety, and increase dragline productivity in a number of surface coal mines. This article presents examples on designing and using presplit and trim blasting for large hole operations in both shovel/truck and dragline mines. Presplit Blasting As introduction to presplit blasting, Fig. 1 illustrates a typical presplit blast layout using 102 mm-diam presplit holes for 381¬mm-diam production holes. For this type of blast, presplit holes would normally be drilled first, ahead of main production holes. The choice can then be made between loading and firing the presplit line or infilling the main blast. In the latter case, the presplit line would be fired instantaneously 100-150 milliseconds before the main blast. As shown in the figure, the presplit line is formed ahead of the main

Jan 2, 1982

By William J. Miles, Raymond E. Blair

The oil and gas drilling industry is the largest user of "functional" industrial minerals for well drilling and completion. (Functional industrial minerals can be defined as those used for performance characteristics rather than composition.) This industry's use of industrial minerals involves complex mining, processing, and distribution of products. The cost of these products at the well site reflects the complexity of distribution to typically remote locations and the cost of service. Table 1 illustrates the use of functional industrial minerals by the drilling industry. The total tonnage shown is almost 2 1/2 times larger than the 3.3 Mt (3.6 million st) of kaolin used by the paper industry for filling and coating, another major use for functional industrial minerals. Drilling fluids are an indispensible part of a drilling operation. These fluids perform several functions simultaneously. They cool and lubricate the drill bit, remove formation cuttings, increase the specific gravity of the fluid to counteract formation fluid pressures, provide a filter cake on the wall of the drill hole to prevent drilling fluid loss to the formation, protect the porosity of producing zones, and prevent reaction of the formation or formation fluids with the drilling mud. When porosity of a formation exceeds the ability of the drilling fluid to form a wall cake, it is referred to as lost circulation. Because these fluids are being constantly formulated for changing formation conditions, they require a skilled technician or drilling mud engineer on the site at all times. Drilling fluids are composed of oil or water as the liquid phase, and industrial mineral products and chemicals to control chemical and physical properties. The basic function of viscosity and suspension result from the use of gelling clays and chemical and mineral dispersants; specific gravity of the mud is adjusted with mineral weighting agents; filtration control is maintained by clays and various natural and synthetic polymers; platey minerals and scrap products are used for controlling lost circulation in porous or fractured zones; salts are added to the mud to inhibit shale and clay swelling; chemicals are added for pH adjustment, prevention of corrosion, and as scavengers for formation fluid components. Because of the clay component, drilling muds have rheological properties different from conventional fluids, behaving as Bingham plastic fluids as opposed to the Newtonian behavior of water and oil. Newtonian fluids will begin to flow with the application of any force, however small. Bingham plastic fluids require a finite force or shear stress (yield value) before flow begins. Thixotropy is another property of clay-based drilling fluids. At rest they form a gel structure that suspends the weighting agents and rock cuttings. These gels break down when a finite force is applied and circulation is restored. At the bit where shear rates are the greatest, the viscosity or resistance to flow decreases, so hydraulic pressures and pumping costs are minimized. A drilling rig provides a means of rotating a hollow pipe attached to a cutting bit. A mud pit or tank is used for mixing the drilling mud and its components. A centrifugal pump delivers this fluid to the drill ripe and down to the bit

Jan 10, 1983

By Gordon M. Pugh, David G. Rasmussen

INTRODUCTION This method is a variation of cut-and-fill mining where either the wall rock or the vein is too unconsolidated to permit safe mining by conventional cut-and-fill methods. Basic development consists of driving a 2.4 x 2.7-m (8 x 9-ft) haulage heading laterally in the footwall side of the vein. Crosscuts are driven over to the vein at 91-m (300-ft) intervals. Then the vein, at each inter¬section, is mined out to a distance of about 9 m (30 ft ) above the track level. After the installation of an ore chute, scrams or intermediate drifts are driven in both directions along the vein. Mining then starts imme¬diately below the level bounding the upper limit of the stope. A cut varying between 3 and 4.2 m (10 and 14 ft) in depth and mined for a distance of 45.7 m (150 ft )along the strike is taken from the orepass in each direction (Fig. 1). In this mined-out void, the floor of the cut is equipped with 203 x 203-mm (8 x 8-in.) caps hitched into the wall with steel saddle hitches installed on 1.5-m (5-ft) centers. Double wood stringers, 152.4 x 152.4 mm (6 x 6 in.), are then installed on 1.2-m (4-ft) centers longitudinally down the length of the stope. Reinforc¬ing wire mesh is also placed, overlying each mat of timber. Directly above the stringers, stulls are installed from hanging wall to footwall to hold the timber in place during the sand-filling operation. Then a cement¬sand mixture in a ratio of about 1:10 weight is poured to a depth of about 2.4 m (8 ft). The entire cycle is then repeated down to the scram drift. Another variation of timbering is illustrated in Fig. 2. There is a vein width of approximately 5.5 m (18 ft) with the same unconsolidated ground conditions. The primary difference between handling this situation and the previously described undercut-and-fill method is that standard timbered sets are installed in each excavated stoping void rather than stulls. Once again the basic method is to work down the ore block from an upper timbered drift to a lower timbered drift. Cuts are taken from a timbered raise with a chute on the stope side. Each piece of ground excavated is essentially two sets high, 5.5 m (18 ft), by two sets wide, 5.5 m (18 ft), by the length of the cut along the strike of the vein. The timbered sets are 2.4 x 2.4 x 2.4 m (8 x 8 x 8 ft). The net result is, therefore, two sets of timber on a top floor separated by doubled-up 76-mm (3-in.) lagging from

Jan 1, 1982

By Ramon S. Pizarro, W. Joseph Schlitt

Introduction Trying to synthesize innovations occurring in gold processing is not simple. At present, this technology is exploding, brought about by the high price of gold. This price has compelled the mining industry, as a matter of survival, to produce gold. The frantic search for gold deposits continues, from glacial areas to tropical jungles. The search has been fruitful. New exploration techniques have helped to locate deposits. Some are amenable to conventional processing techniques. Others are in unusual settings that challenge the ingenuity of extractive metallurgists. Ore deposits containing traces of invisible gold, refractory mineralization, and impurities and deleterious materials that previously defied treatment are now being profitably processed. Metallurgists have developed various processing methods and equipment for gold ore treatment that reflect differences in ore characteristics, grade, mineralogy, reserves, topography, climate, and location. These processes can be categorized as: • For nonrefractory or readily leachable gold ores - vat leaching, heap leaching, and agitation leaching. • For ores containing free gold - gravity concentration methods, followed by mercury amalgamation, and • For refractory gold ores - flotation, roasting, pressure oxidation, followed by cyanidation leaching. In actual practice, a combination of these processes may be required. This is because gold mineralization, although usually simple, may be associated with other mineral species or with clays that make the ore difficult to treat. Furthermore, after the gold has been solubilized to form a cyanide complex, one of two important processes must be applied to recover the gold. These ore zinc cementation (Merrill-Crow process) and Carbon adsorption, desorption, and electrowinning. New techniques for leaching and recovery are also advancing. These will become the bases for the next generation of gold processing plants. Nonrefractory Gold Ores Nonrefractory ores with readily leachable gold are among the .easiest to treat. Even so, non-refractory ores from epithermal deposits are likely to contain too much clay. When these ores are damp, they may clog the screens and cone crushers. Depending on the type of process, scrubbing the crushed ore is very effective in overcoming clay problems. After dewatering, the slimes enter the cyanidation process and the thickener overflow is stripped of gold values and recycled. Semiautogenous (SAG) mills are also gaining popularity due to lower capital costs and ability to treat wet, sticky ores. If properly sized, the secondary crushing and screening plants, together with a secondary ball mill, can be eliminated. When the ore is of such a low grade that it can not support fine grinding, vat or heap 'teaching may be applicable. These systems are being actively applied in the US and elsewhere. Rapid construction and low capital costs are important features of these plants. Vat leaching is ideally suited for fast leaching ores and small tonnage deposits located in areas with harsh winters or wet tropical climates. For effective vat leaching, the ore is crushed to less than 25 mm (1 in.), agglomerated with lime or cement to control fines, and leached with sodium cyanide solution (upflow or downflow). The degree of size reduction is a tradeoff between increased costs of comminution and improved gold recovery from smaller particles. However, the size of material

Jan 11, 1984

By H. B. Weaver

The development of a method to manufacture diamonds has been rated as one of the out- standing scientific achievements of our time. The story is both interesting and significant. This paper will quickly review history of diamond and manufactured diamond. Next, it will discuss manufactured diamond as a product -- how good is it -- and what is the significance of this scientific achievement. And finally, present a few thoughts about the future of this technology and this product. For centuries, diamond was found only in alluvial deposits, primarily in the Golconda fields of India. As a result, man knew nothing of the process by which the stones were formed. In 1860, diamonds were found in South Africa under completely different conditions. Here, for the first time, they were found in volcanic pipe -- their mother ground. These volcanic pipes are roughly cylindrical columns of rock which go deep within the earth. The theory as to the formation of diamond was presented by the geologists in that era. The theory states that molten rock was thrust up through a layer of carbonaceous shale where it picked up the carbon necessary for diamond formation. It was generally agreed that diamond was formed approximately 240 miles below the surface of the earth, thus indicating that extremely high temperatures and pressures were involved.

Jan 1, 1964

By Michael L. Cramer, Kunsoo Kim

INTRODUCTION The Columbia River Basalt beneath the Hanford Site is one of several rock types being considered by the U.S. Department of Energy for the first commercial high-level nuclear waste repository. The Basalt Waste Isolation Project (BWIP) has been carrying out a comprehensive investigation to assess the feasibility of constructing a repository in basalt and to develop technology required for repository engineering and site characterization. Development of a nuclear waste repository requires a number of design considerations not usually necessary in the planning of conventional underground structures. Principal among these is the thermally induced stress field resulting from waste emplacement. This thermal stress, super- imposed on the preexisting in situ- and excavation- induced stress fields, needs to be evaluated in the design process due to the sensitivity of waste emplacement density to this factor. The nature of this thermally induced stress field is dependent on several factors, including the temperature distribution around the repository openings, the thermal properties of the rock mass, and the deformability of the rock mass. Re1iable performance of the repository structure is largely determined by the ability to under- stand the above rock mass characteristics and predict the underground opening response to waste emplacement based on this understanding. To gain an understanding of this rock mass behavior in a repository condition, the BWIP has conducted a large-scale heated block test in basalt at the Near-Surf ace Test Facility (NSTF) on the Hanford Site. This paper presents the results from the elevated temperature phase of the block test in which the thermal, mechanical, and thermo- mechanical response of the closely jointed basalt rock mass was evaluated as a function of stress and loading orientation at varying temperatures up to 200 oC. SITE GEOLOGY The NSTF test areas, including the block test site, are located in the entablature zone of the Pomona basalt f low. The Pomona flow entablature is structurally typical of most flows in the Columbia River Basalt Group in that it is characterized by long, undulating, polygonal columns up to 2.4 m in length. Columns vary from 15 to 30 cm in diameter, averaging about 20 cm. Over their length, columns can vary in dip by 150 to 200. The column structures are dissected by subhorizontal cross joints that are generally discontinuous and seldom cross columnar joint boundaries. Spacing of the cross joints also averages about 20 cm. A representative joint pattern taken from mapping of the tunnel wall near the block test site is shown in figure 1. Application of the Rock Mass Rating System (Bieniawski, l979) to the block test site yielded an overall value of 62. The corresponding value from application of the Q-system (Barton et al., 1974) is 8.7 (Cramer and Kim,1985). The NSTF is approximately 50 m below the surf ace. However, this depth is sti1l above the water table and conditions are generally dry. Interstitial water exists as the result of percolation of meteoric water from the surface.

Jan 1, 1986

By W. M. Kidd, P. J. Duport

INTRODUCTION The enquiry of the Royal Commission on Health and Safety of Workers in Mines of 1976, known as the Ham Commission after its chairman, Dr. J. Ham , now president of the University of Toronto, was one of the activities surrounding the upturn in the fortunes of the Canadian uranium industry and its markets in the mid-seventies. Although the regulation and licensing of Canada's ten major mine/mill facilities employing six thousand or more uranium mines is a federal concern under the Atomic Energy Control Act, this Commission, which paid particular attention to health and safety in uranium mines, was appointed by the Province of Ontario. Further provincial enquiries in British Columbia, Saskatchewan and Newfoundland have been aimed at quantifying, reducing or eliminating the environmental and health impact of uranium production. This work has created a mosaic of provincial regulation in what is essentially a field of federal jurisdiction. Various organizations of the federal government related to its regulatory function in the uranium industry are outlined in Figure 1 showing the matrices of regulatory, advisory and research activities associated with the exploitation of Canadian uranium resources. A more detailed examination [ ] of the governmental (federal and provincial) activities, commissions, etc., in the Canadian uranium industry indicates a definite parallelism of effort, if not of scale between the two levels of government in the execution of their roles in occupational and environmental health and safety and is presented here to explain the complex stage onto which the Canadian Institute for Radiation Safety has just entered. The development of the Institute and its precursors together with current and planned research activities are described. BACKGROUND Traditionally and constitutionally, natural resource exploitation and its regulation is under provincial jurisdiction; however, the uranium industry has been under federal control since the Second World War when security measures necessitated the creation of the Atomic Energy Control Board (AECB). Health and safety aspects, in terms of inspection, compliance and environmental monitoring are performed on behalf of the AECB by provincial labour inspectors (Saskatchewan and Ontario) and Ministries of Environment. Non-radiation health and safety matters are also enforced under the federal Canada Labour Code by provincial inspectors. In support of licensing and standard-setting functions, major research programs have been initiated and expanded at both the AECB and the Canada Centre for Mineral and Energy Technology (CANMET), formerly the Mines Branch of the Federal Department of Energy, Mines and Resources). CANMET established a Mining Research Laboratory at Elliot Lake, Ontario in 1965 to conduct research and development aimed at improving production capability, providing information on the security of uranium supply and investigating the hazards of mining and their implications for the health and safety of the miners. The provincial route in assessing the costs and benefits of uranium production has attempted to be far more conclusive in nature. While some on-going studies are funded, periodic inquiries by Royal Commission have become the accepted practice. Six such inquiries have been conducted in four provinces and widely differing policies have resulted from their findings and recommendations. For example, while the government of British Columbia in the Fall of 1980 declared a seven-year moratorium on(2) uranium mining and exploration in the province, the province of Ontario's crown utility "Ontario Hydro" financed the rehabilitation of a mine/mill complex at Elliot Lake. The latter instance is not surprising considering that the final report of Ontario's "Royal Commission on Electric Power Planning",(3) concluded that nuclear energy has a continuing role to play in the expansion of Ontario Hydro.

Jan 1, 1981

By J. W. Carson

Introduction Many bulk solids such as coal, limestone, and fine moist ores often flow unpredictably out of bins, hoppers, and boreholes. Vast amounts of time and money are spent-with or without success-on flow promoting devices. In addition, many solids segregate in storage, feed erratically, flood, arch, rathole, and stick to bin walls reducing the live capacity. This article discusses bulk solids flow properties and provides guidelines for designing storage bins, hoppers, and feeders to provide reliable flow. Bulk Solids A bulk solid is a granular material consisting of discrete solid particles-submicron to several inches in size-that is handled in bulk form (for example, in a bin or silo). The gas filling the voids is generally insufficient to fluidize the material and the liquid (usually water) content is assumed to be less than saturation. Types of Flow Problems To design an efficient storage system, an engineer must be aware of problems that can arise during storage and flow of bulk solids: • No flow. A stable arch or pipe (rathole) develops within the solid, stopping flow. • Erratic flow. Momentary arches form within the solid, (ratholes), partly or completely empty out, and then collapse. • Flushing. Powders become fluidized, aerate, and flush uncontrollably through the bin outlet. • Lack of design capacity. A large part of the stored material remains stable around a rathole. Manual prodding, severe vibration, and even explosives may be used to restore flow. • Segregation. Smaller particles tend to sift through the voids between larger particles causing accumulations of fines and coarse in various areas of the bin. • Product degradation. Some materials spoil, cake, or oxidize if they remain in a bin too long. This is usually caused by a first-in-last-out flow sequence. • Level control. Measuring the volume of material left in a bin is difficult if a rathole develops. In one portion of the bin the level control device may indicate the bin is full; in another portion it may indicate it is empty. Eliminating Flow Problems All flow problems can be minimized or prevented by suitable design of the bin/feeder unit. This involves knowing the flow properties of the solid, then choosing the appropriate type of bin and feeder to establish the desired flow pattern. There are three types of flow patterns that may occur in a bin: funnel flow, mass flow, and expanded flow. Funnel flow occurs when some of the material in the bin is stationary while the rest is in motion. Funnel flow bins, shown in Fig. 1, are characterized by: • Low head room. A flat bottom or shallow hopper bin has large storage capacity with minimum height. Unfortunately, all this storage capacity may not be usable ("live"). • First-in-last-out flow sequence. The first material put into a funnel flow bin is the last material withdrawn because the flowing material is concentrated in the region directly above the outlet. • Ratholes. Because of the flow channel that forms, a stable rathole develops if the material has sufficient cohesive strength. • Erratic flow. Once a rathole becomes partially or completely empty, it may collapse creating a stable arch and erratic flow. • Flushing. Collapsing ratholes cause flushing and flooding of fine material. • Segregation. If a bulk solid has a tendency to segregate, this tendency will be accentuated as the material is discharged from a funnel flow bin. Funnel flow bins are suitable for coarse, free flowing, nondegrading solids, when segregation is not important. Mass flow occurs when all the material in a bin is in motion whenever any is withdrawn. Char-

Jan 3, 1983

By Kenneth A. Rogers, Richard F. Hill

Introduction A number of processes for deriving more convenient liquid and gaseous fuels from coal are commercially available or in final stages of development. Generally, synfuels from coal processes have efficiencies ranging from 50 to 70%. Considerable engineering design and development work are necessary to bring forth commercial plants using the various technologies-but technological breakthroughs are not expected or needed. Gasification While a variety of solids handling, gas contacting, and gas quality upgrading techniques may be employed in the various gasification processes, the primary goal is the same-to convert a sulfur-containing solid to an essentially sulfur-free gaseous product. The gaseous product may be a mixture of hydrogen and carbon monoxide with nitrogen. Definitions are not rigorous, but high-Btu gas is generally over 900 Btu/scf(33 534 kJ/m3) and low-Btu gas is generally below 350 Btu/scf(13 041 kJ/m3). Medium or intermediate gas falls between these values. High-Btu production is more difficult, as it requires additional upgrading of a low- or intermediate-Btu gas stream to produce a commercially acceptable product. The carbon/ hydrogen ratio is adjusted either by rejecting a portion of the carbon, increasing the hydrogen, or a combination of both. The chemical processing steps include production processing gas containing carbon oxides and hydrogen by the reaction of carbon and steam (gasification); reaction of hydrogen and coal to form methane (a hydrogasification process); reaction of hydrogen and carbon monoxide to produce methane (methanation); and the removal of impurities. The gasification processes share a number of common techniques. The coal received at the plant site must be further cleaned and crushed or ground before it can enter the gasifier. Conventional cleaning methods are used to remove extraneous materials such as metal, rocks, etc. For some processes the coal must be finely ground so it may be fluidized or entrained in a flowing gas stream. For other processes crushing and sizing only are required. Agglomerating coals may be pretreated by heating, mild oxidation with air, or other procedures to assure smooth gasifier operation and to avoid reactor plugging. Nonagglomerating coals Such as lignite and subbituminous coal normally do not require pretreatment. Feeding a solid material such as coal to a higher pressure reactor is a difficult task. Dry feeders using a series of pressurized lock hoppers, or wet systems in which a slurry is pumped into the reactor, are used. The gasification step is the heart of the process. Here, the solid feed material is contacted with synthesis gas (carbon monoxide and hydrogen). The coal is devolatilized and a portion of the fixed carbon converted to methane. The gas-solids contacting methods used include fixed beds, fluidized beds, moving beds, entrained beds, and free-fall systems. The gasification process, overall, is endothermic and the heat required to maintain reaction rates is usually supplied by burning a portion of the coal feed. External heat sources such as electric resistance heating, molten salt or solid heat carriers, and the introduction of a hot hydrogen stream also have been tested. Following the gasification step the particulate materials and heavy hydrocarbons contained in the reactor effluent are removed by a water quench and solids separation system. If low-Btu gas or synthesis gas is the desired product, the raw gas is scrubbed to remove carbon dioxide and sulfur compounds and then is used directly. However, if high-Btu gas is desired, methanation is necessary. In most gasification processes, the hydrogen content of the gasifier

Jan 2, 1980

By Karl A. Smith, Roger T. Johnson, David W. Johnson

Conflicts are common in the mining industry. Engineers are accustomed to addressing issues such as land use, air and water pollution, and health and safety. Although conflicts of interest are important in the industry, they do not have the impact on organizational decision making that controversy does. Controversy is a type of conflict, probably the most important type, for effective decision making and competent problem solving. It exists when one person's ideas, information, preference, choices, conclusions, theories, opinions, or perspectives are incompatible with another's and the two seek to reach an agreement (Johnson and Johnson, 1979). Interpersonal and intergroup controversy is prevalent in the day-to-day functioning of organizations. If constructively managed, this type of controversy has important implications for effective decision making and problem solving. Too few organizational members accept controversy, and almost none attempt to stimulate it. This is because too few of them understand controversy well enough to accept and use it effectively. Most organizational personnel lack the interpersonal skills needed to stimulate controversy and manage it effectively. Discussion of conflicting ideas may not be common in problem solving situations due to the fear and anxiety most people feel in conflict situations. Traditionally, organizations suppressed conflict. They believed it was avoidable, caused by management errors. Optimal organizational performance required its removal. Conflict, though, is inevitable. And optimal organizational performance requires a moderate level of conflict. Management should manage the level of conflict and its resolution, for optimal performance. The current view stresses the importance of controversy for learning. Confronting a person with a different point of view stimulates that person to gather more information to elaborate, justify, or provide rationale for their position. Controversy: Process and Outcomes The decision making process begins with participants categorizing and organizing current information and experiences so that a conclusion is derived. When participants present their conclusions to another group and realize their conclusions are being challenged, a state of internal conceptual conflict or uncertainty ensues. This uncertainty motivates the challenged group to actively search for more information, experiences, and a more adequate cognitive perspective and reasoning process to resolve the uncertainty. Participants will adapt their cognitive perspective and reasoning through understanding the perspective and reasoning of others to derive a new or reorganized conclusion. This process may be repeated several times before a decision is reached. The active search for additional information on the alternatives is also promoted, along with greater mastery and retention of information and a more accurate understanding of opposing viewpoints (perspective taking). Of the many positive outcomes of the use of controversy, the effect on higher level cognitive reasoning and processing is especially important in engineering decision making. Research has been done on expert-novice difference in medical diagnoses, physics problem solving, and geological exploration. It shows that preparation for verbal interaction and the actual verbal interaction with peers with differing view-points promotes the development of expertise. Constructive Controversy Conditions Some controversies among decision makers concerning their preferred solutions to a problem can be beneficial. But sometimes they are not. As with all types of conflict, the potential for either constructive or destructive outcomes is present. Whether the consequences are positive or negative depends on the controversy and the way it is managed. The conditions and procedures of controversy management that determine the outcome include: the goal structure within which the controversy occurs; the degree of heterogeneity of decision makers; the amount of relevant information distributed among decision makers; the ability of decision makers to disagree with each other without creating defensiveness; and the perspectivetaking skills of the decision makers. Goal structure: Two possible contexts for controversy are cooperative and competitive. A

Jan 3, 1985

By A. T. Yu

Two major events highlight recent developments in US ore and coal ports: completion of the last series of modern taconite pellet transshipment facilities on the Great Lakes; and modernization and construction of coal ports, particularly on the East and Gulf Coasts. The New Taconite Transportation System To reduce raw material transportation costs, a fleet of new generation high-capacity 304-m (1,000-ft) self-unloading vessels were built to carry iron ore pellets from the Minnesota-Michigan iron ranges to the steel plants on the lower Great Lakes. Existing port facilities had to be modernized, revised, or completely rebuilt to accommodate these large vessels. Some of these were Burlington Northern's Allouez, WI, loading dock; Duluth, Missabe & Iron Range Railway Co.'s Two Harbors, MN, facility; Republic Steel's Lorain, OH, facility; and Chessie's Toledo, OH, dock. Allouez and Two Harbors receive taconite pellets from unit trains and load them onto large vessels either after dumping or via a large stockpile and reclaim system. The Lorain facility receives iron ore pellets from self-unloading vessels' discharge boom conveyor and reloads the pellets into rail cars or small vessels destined to inland steel mills. The Toledo facility receives Armco pellets from vessels, stockpiles them through the winter, and reloads into unit trains destined for Armco's mills along Chessie's rail tracks. Burlington Northern's $75-million Allouez pellet dock, completed in June 1977, was built to receive pellets produced by Hibbing Taconite Co. and National Pellet Plant in Minnesota, stockpile them through the winter when the lakes are frozen, and load them into 304-m (1,000-ft) vessels in the shipping season. As much as 10 Mt (11 million st) of pellets may be stockpiled within the loop track. A 6-km (4-mile) long conveyor system connects the stockpile area and the dock. Thirty-six new concrete silos were built on the dock to house 2 kt (2,000 st) each of pellets before shiploading. The $35.5-million expansion of the Two Harbors transshipment facilities began shiploading in July 1978 after ground breaking in Aug. 1974. Particularly noteworthy is the first application of the Orboom system-a breakthrough in technology for the modernization of the century-old pocket docks on the Great Lakes to accommodate the new generation of super vessels. The pocket-type loading dock has been a standard on the lakes for nearly a hundred years. Bottom-dump rail cars fill the ore pockets on top of a finger pier. Gravity chutes matching standardized ore ship hatch spacings are lowered to fill the holds of a 20.3-kt (20,000-dwt) ship. The construction is simple and the loading swift. In spite of advances in technology elsewhere, most of these docks continue to serve the iron ore and coal trade in the same manner they did in the 19th century. Although performance of the pocket docks on small vessels remains outstanding, the new 304-m (1,000-ft) vessels are beyond the reach of the old docks. After extensive development, the Orboom system (Patent No. 4,065,002) for pocket docks was successfully developed. The heart of the Orboom system is the retractable shuttle loading arm which loads the wide beam vessels. The Orboom shuttles are fed by existing pockets of the dock that, in turn, are charged by a tripper conveyor along the length of the dock. The Two Harbors shiploading system is supported by a 0.9 Mt (1 million st) storage-reclaim network. Unit trains are bottom dumped. Taconite pellets are stacked and reclaimed by bucket wheel reclaiming systems. Lower Lakes New Ore Ports At the lower Great Lakes receiv-

Jan 10, 1982

By Alfred Weiss, Andrew E. Nevin, Thomas J. Neil, O&apos

As Edward E. Runyan, 1983 AIME President, in an interview excerpt in ME, June, p. 607, stated, "...the AIME Transition Committee has recom¬mended to the AIME Board that each Constituent Society be allowed the option of separate incorporation, whereby each could become its own separate legal entity." Background The American Institute of Mining Engineers (AIME) was formed in 1871 by 22 engineers in Wilkes-Barre, PA. Although originally a mining organization, it became a home for metallurgists, iron and steel industry people, and for the individuals in the expanding petroleum engineering profession. There are now four Constituent Societies: Society of Mining Engineers, located in Littleton, CO, 29,000 members; Society of Petroleum Engineers, located in Dallas, TX, 47,500 members; The Metallurgical Society, located in Warrendale, PA, 10,000 members; and Iron and Steel Society, located in Warrendale, PA, 6,500 members. Each of the four groups has grown and continues to serve the specific and/or diverse needs of its membership. As the needs and requirements of their industries and professions change, each of the Societies has perceived and initiated programs that serve their constituency rather than AIME as a whole. Therefore, each Society has recognized an increasing need for autonomy to better augment their own programs. An AIME Ad Hoc Transition Committee, with Robert Merrill, AIME Past President, as chairman, made a number of recommendations pertaining to AIME operations that were approved in October 1982 by the AIME Board of Directors. One of the recommendations was to endorse separate incorporation of the Constituent Societies on an individual-society-option basis. The AIME Board commissioned a task force of Constituent Society representatives to develop specific revisions to the AIME Certificate of Incorporation and the AIME Constitution and Bylaws. This was done to allow separate incorporation and to reflect the decentralized structure of the Institute. The SME-AIME Board of Directors subsequently approved the recommendation of SME Working Party #69 that SME pursue separate incorporation. Meanwhile, Working Party #69 continues to work with the other Constituent Societies and with the AIME Task Force on Reorganization to determine the form and substance of the separate incorporation. Why Incorporate? George Webster in The Law of Associations quoted Chief Justice Marshall's (1819) definition of corporation as: "A corporation is an artificial being, invisible, intangible, and existing only in contemplation of law. Being the mere creature of law, it possesses only those properties which the charter of its creation confers upon it, either expressly or as incidental to its very existence. These are such as are supposed best calculated to effect the object for which it was created." SME-AIME attorneys, Davis, Graham & Stubbs, have pointed out that the status of an organization operating as an unincorporated association is always unclear. At present, SME-AIME administers assets of almost $3.5 million (mainly property and inventory) but technical ownership and ability to enter into contractual relationships resides with AIME. However, the operation appears to outsiders (particularly those with whom SME-AIME does business) to be an independent operation which would be expected to be a legal entity in its own right. Advantages of Incorporation Liability. Because of legal ownership by AIME of all assets of the Constituent Societies, those assets are subject to the claims of any of the creditors of AIME or any of its constituent parts (i.e., the other societies). Liabilities can be those usually encountered in business but also encompass special risks, which could develop if there were a careless and erroneous publication of material that might be used in practice or if standards are improperly established. The recent US Supreme Court decision in American Society of Mechanical Engineers, Inc.,

Jan 10, 1983

Hoses provide a variety of critical functions in nearly every mining operation. Care must be taken when selecting, installing, and maintaining hoses to insure maximum hose life. This article provides some tips on selecting, installing, and maintaining hoses, and gives some background on hose construction and safety. In the mining industry, hoses are used for everything from hydraulic systems that power drills and hammers, to suction systems that carry away dust and debris. Hoses are used on such a large scale that a detailed discussion of specific applications would require many volumes. Dayco Corp. has, however, provided these basic and brief guidelines on how to select and maintain hoses for mining applications. Hose Construction Industrial hoses are classified as much by construction as they are by application. So, it is a good idea to start any discussion of hoses with a description of their basic construction. There are four basic components to hoses: the tube, reinforcement, cover, and couplings. The tube is the inner core or lining, and is usually made of smooth rubber or plastic. Rubber or plastic composition is scientifically determined to be compatible with the materials passing through it, such as fluids, chemicals, gases, or substances. Other considerations in compounding rubber or plastic for the tube are temperature ranges and stresses. In practice, the required compound can be precisely chosen from various charts listing them according to application. There are, however, applications where the compounding of tube rubber or plastic must be customized. The reinforcement hose layer immediately surrounds the tube. As its name implies, this layer gives the hose strength and provides protection for the tube component. Reinforcement must be able to contain the inner forces-pressure and shock-transmitted through the tube, and such external forces as twisting, bending, and crushing. So it is usually made of high tensile strength cord, fabric, or wire that is wrapped, wound, or braided around the tube. The cover is the outermost layer, so it may encounter oils, acids, water, dust, abrasion, and other potentially damaging influences depending, of course, on the application. An appropriate cover material must be selected, usually a rubber compound. Couplings, even though they are a hose attachment, are as vital as any other component and should be considered part of the hose. Couplings are usually made of carbon steel or malleable iron; however, bronze or stainless steel might be used if corrosive chemicals are involved and brass or aluminum might be used for flammable fluids. A coupling is usually in two parts: an insert that fits into the hose bore and contains the threaded male, female, or other type of connection, and the ferrule or collar that fits over the hose and secures the coupling in place. There are, however, some one-part couplings that fit securely into the hose without a ferrule. These are usually limited to low pressure applications and are secured to the hose by clamps or metal bands. Some fittings can also be permanently "built-in" as the hose is made. Couplings can be classified as reusable or permanent. The reusables can be removed when the old hose expires and used again on a new hose. The permanent types are crimped or swaged on at the factory or in the field (using special equipment) and must be discarded with the hose. Although couplings are most commonly thought of as having threaded fittings, there is another type called "quick connect." These either have a crow-foot or jaw-type design that permits a fast, "snap" connection. This can

Jan 6, 1982