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By J. A. Hafford, J. K. Kerver, J. G. Richardson, P. M. Blair, J. S. Osoba

This paper presents the results of laboratory measurements of relative permeabilities to oil and gas on small core samples of reservoir rock by five methods, and describes the influences of such factors as boundary effect, hysteresis, and rate upon these measurements. The five methods used were the "Penn State," the "single core dynamic," the "gas drive," the "stationary liquid," and the "Hassler" techniques. In those methods in which the results are subject to error hecause of the boundary effect, the error may be minimized hy the use of high rates of flow. In order to avoid complexities introduced by hysteresis, it is necessary to approach each saturation unidirectionally. Observed deviations of relative permeabilities with rate can be explained as a manifestation of the boundary effect, and disappear as the boundary effect vanishes. The results indicate that all five methods yield essentially the same relative permeabilities to gas. Of the four methods applicable to the determination of relative permeability to oil, three, the Penn State, single core dynamic, and gas drive, gave relative permeabilities to oil which were in close agreement. The Hassler method gave relative permeabilities to oil which were consistently lower than the results obtained by the other methods. INTRODUCTION The relationship between the effective permeability of a reservoir rock to each of the fluids flowing through it and the corresponding fluid saturation is an important characteristic of the reservoir rock. Knowledge of this characteristic is and gas reservoirs and of the ultimate recovery to be expected extremely important in the prediction of the behavior of oil under various operating conditions. These effective permeabilities are usually expressed as the "relative permeability" to a fluid phase, defined as the ratio of the effective permeability to the permeability of the rock to a single phase at 100 per cent saturation. Relative permeability-saturation relations are not the same for all kinds of reservoir rock, but may vary from formation to formation, and within the different portions of a heterogeneous formation. In studying the performance of a specific reservoir, it is necessary, then, that the relative permeability characteristics of the individual portions of the reservoir be measured. These measurements may be made in the laboratory on small core samples from the reservoir. Various techniques have been proposed for the measurement in the laboratory of relative permeability-saturation relations. In varying degree, difficulties attend the use of all of the methods which have been proposed. It is the purpose of this paper to discuss the factors which influence the measurement of relative permeability, the difficulties encountered in several methods, and to present comparative results obtained by the use of various techniques. FACTORS WHICH INFLUENCE THE MEASUREMENT OF RELATIVE PERMEABILITY It is necessary that the relative permeability data measured in the laboratory yield the same relative permeability-saturation relationships that would govern the flow of fluids through the sample if it were to occupy its original position in the reservoir. Since the core sample upon which the laboratory measurements are made is not surrounded by similar core material as it was in the reservoir, an error in measuring the relative permeabilities may arise from the "boundary effect" which results from a discontinuity in capillary properties of the system at the effluent end of the core. Again, the rates of

Jan 1, 1951

By J. K. Kerver, J. S. Osoba, J. G. Richardson, P. M. Blair, J. A. Hafford

This paper presents the results of laboratory measurements of relative permeabilities to oil and gas on small core samples of reservoir rock by five methods, and describes the influences of such factors as boundary effect, hysteresis, and rate upon these measurements. The five methods used were the "Penn State," the "single core dynamic," the "gas drive," the "stationary liquid," and the "Hassler" techniques. In those methods in which the results are subject to error hecause of the boundary effect, the error may be minimized hy the use of high rates of flow. In order to avoid complexities introduced by hysteresis, it is necessary to approach each saturation unidirectionally. Observed deviations of relative permeabilities with rate can be explained as a manifestation of the boundary effect, and disappear as the boundary effect vanishes. The results indicate that all five methods yield essentially the same relative permeabilities to gas. Of the four methods applicable to the determination of relative permeability to oil, three, the Penn State, single core dynamic, and gas drive, gave relative permeabilities to oil which were in close agreement. The Hassler method gave relative permeabilities to oil which were consistently lower than the results obtained by the other methods. INTRODUCTION The relationship between the effective permeability of a reservoir rock to each of the fluids flowing through it and the corresponding fluid saturation is an important characteristic of the reservoir rock. Knowledge of this characteristic is and gas reservoirs and of the ultimate recovery to be expected extremely important in the prediction of the behavior of oil under various operating conditions. These effective permeabilities are usually expressed as the "relative permeability" to a fluid phase, defined as the ratio of the effective permeability to the permeability of the rock to a single phase at 100 per cent saturation. Relative permeability-saturation relations are not the same for all kinds of reservoir rock, but may vary from formation to formation, and within the different portions of a heterogeneous formation. In studying the performance of a specific reservoir, it is necessary, then, that the relative permeability characteristics of the individual portions of the reservoir be measured. These measurements may be made in the laboratory on small core samples from the reservoir. Various techniques have been proposed for the measurement in the laboratory of relative permeability-saturation relations. In varying degree, difficulties attend the use of all of the methods which have been proposed. It is the purpose of this paper to discuss the factors which influence the measurement of relative permeability, the difficulties encountered in several methods, and to present comparative results obtained by the use of various techniques. FACTORS WHICH INFLUENCE THE MEASUREMENT OF RELATIVE PERMEABILITY It is necessary that the relative permeability data measured in the laboratory yield the same relative permeability-saturation relationships that would govern the flow of fluids through the sample if it were to occupy its original position in the reservoir. Since the core sample upon which the laboratory measurements are made is not surrounded by similar core material as it was in the reservoir, an error in measuring the relative permeabilities may arise from the "boundary effect" which results from a discontinuity in capillary properties of the system at the effluent end of the core. Again, the rates of

Jan 1, 1951

By N. R. Joshi, A. D. Agate

It is estimated that more than 80% of phosphate rock output in the world is used for fertilizer production. In India, there are only a few high-grade deposits of phosphate ores; therefore, most of the requirement for phosphatic fertilizers is satisfied with imported DAP (diamino phosphoric acid). Due to the drain on foreign exchange reserves, this import-dependent, essential commodity is in short supply in India and, therefore, is sparingly used by farmers. In addition, of the added phosphorus, normally 80% becomes unavailable to plants because phosphorus complexes are formed in soil, causing deleterious effects on plants. In our laboratory, this problem was tackled by using a bacterial consortium of phosphorus-solubilizing bacteria. It resulted in the speeding up of seed germination and increasing available phosphorus in the soil by 14%, over a period of 80 days. To use the low-grade deposits of phosphatic rocks available in India near Hirapur, Madhya Pradesh, India, which contain high amounts of iron, beneficiation through microbial means was used for phosphorus removal. Beneficiation was achieved partially through removal of extra iron by oxidizing ferrous iron from the ore by a Thiobacillus species after removal of impurities containing both silica and iron, instead of sieving and cleaning the ore using different techniques. This resulted in a cleaner ore, with nearly 70% of such impurities removed. The factors for beneficiation technique were standardized at the laboratory level and are being used for scaling up of the process. Thus, the beneficiation of phosphatic rock from Hirapur will be an important first step of phosphorus production in India.

Jan 1, 1999

By C. R. Hocott

The distribution and movement of fluids in oil reservoirs are influenced to a great extent by capillary forces, which depend upon the size and shape of the pores in the reservoir rock, the surface characteristics of the rock, and the interfacial tension between the fluid phases. This paper presents the results of an investigation of the interfacial tension between salt water and crude oil containing dissolved gas under reservoir conditions. Apparatus and Procedure In the preliminary phases of this investigation, it was found that a scum formed at the oil-water interface, which made measurement of interfacial tension by either the ring or capillary rise methods unreliable. Accordingly, the drop-weight method, in which a fresh interface is continuously formed, was selected. In this method, a tip through which drops of one fluid can be expelled is immersed in a second fluid. At the instant that the drop becomes large enough to fall, the gravitational force tending to pull away the drop exactly balances the interfacial force tending to hold it. From the size of the drop, the dimensions of the tip, and the density of the two fluid phases, the interfacial tension may be calculated. The apparatus consists of a circulating pump for bringing the oil to equilibrium with gas at the desired pressure, a displacement pump for forming the drops, an interfacial tension cell in which the drops are formed, and a density cell to determine the density of the oil. The density of the water is determined separately in another apparatus. A flow diagram of the assembled equipment is shown in Fig. 1. The interfacial tension cell contains a stainless-steel dropping tip suspended from the top and extending below the surface of the oil. The tip is a cylindrical rod with a small hole in the center through which the water was forced to form the drop on the lower face. The walls of the tip were highly polished, to prevent the water on the tip from creeping up the side and increasing the effective diameter. The face of the tip, how-

Jan 1, 1939

By C. R. Hocott

The distribution and movement of fluids in oil reservoirs are influenced to a great extent by capillary forces, which depend upon the size and shape of the pores in the reservoir rock, the surface characteristics of the rock, and the interfacial tension between the fluid phases. This paper presents the results of an investigation of the interfacial tension between salt water and crude oil containing dissolved gas under reservoir conditions. Apparatus and Procedure In the preliminary phases of this investigation, it was found that a scum formed at the oil-water interface, which made measurement of interfacial tension by either the ring or capillary rise methods unreliable. Accordingly, the drop-weight method, in which a fresh interface is continuously formed, was selected. In this method, a tip through which drops of one fluid can be expelled is immersed in a second fluid. At the instant that the drop becomes large enough to fall, the gravitational force tending to pull away the drop exactly balances the interfacial force tending to hold it. From the size of the drop, the dimensions of the tip, and the density of the two fluid phases, the interfacial tension may be calculated. The apparatus consists of a circulating pump for bringing the oil to equilibrium with gas at the desired pressure, a displacement pump for forming the drops, an interfacial tension cell in which the drops are formed, and a density cell to determine the density of the oil. The density of the water is determined separately in another apparatus. A flow diagram of the assembled equipment is shown in Fig. 1. The interfacial tension cell contains a stainless-steel dropping tip suspended from the top and extending below the surface of the oil. The tip is a cylindrical rod with a small hole in the center through which the water was forced to form the drop on the lower face. The walls of the tip were highly polished, to prevent the water on the tip from creeping up the side and increasing the effective diameter. The face of the tip, how-

Jan 1, 1939

By H. B. Pulsifer

The unprecedented high price of zinc ore prevailing through the early months of 1915 caused great activity in the Joplin district of Missouri. The Media mill is conspicuous as one of the first of the new "big mills" of the district. The mill was built over a mine previously worked but abandoned in 1912 because of the leanness of the ore and the large quantity of water encountered. The ore prices prevailing—$100 a ton in June, 1915, as against $50 in 1912-—favored the new undertaking. The mill was designed for good recovery so that it might operate in times of depression. In design and equipment, the mill is exclusively local in conception and construction. Former Exploitation The tract of land is a part of the large Guinn holdings; 70 acres are comprised in this particular lot, which is situated just a mile north of the center of Webb City on the Alba line of the Southwest Missouri Electric Railway. The ore lies 242 ft. below the surface at the top of the knoll which is surrounded by the well known properties: Black Cat, Ground Floor, Florence, Hurry-Up, Electrical, and Mercantile. Since the abandonment, in 1913, of the Yellow Dog a bit farther to the north, the Black Cat, Ground Floor, and Florence workings had been flooded. However, as there was no cut through from this side into the area it was proposed to exploit, it was thought that moderate pumping facilities would take care of the water. Three shafts had already been sunk to the ore horizon during the previous operations; the ground was connected by wide drifts and possibly 10 acres mined out, principally about the two southerly shafts which at surface are 8 and 13 ft. lower, respectively, than the collar of the shaft at which the new mill was built. The former mill on the lease was known as the Bohemian Girl. This mill, built in 1910, was removed after some 3 years' work. A head frame and hopper still existed at the middle shaft, sometimes known as the lower Hold Out shaft, but at the most northerly

Jan 1, 1918

By E. F. La Vigne

On Aug. 10, 1884, the Retsof Mining Co. began the sinking of an 18 by 12-ft. shaft at Retsof, N. Y. Rock salt was reached in 1885, in September, at 1008 ft. below the surface. The first salt was shipped in the fall of 1885. A timber breaker was built in 1886. In July, 1895, there was a consolidation of the Retsof Mining Co., the Greigsville Salt & Mining Co., the Livonia Salt Co., and the Lehigh Salt & Mining Co. These consolidated salt companies are now known as the Retsof Mining Co., a subsidiary of the International Salt Go. Eventually all of the mines were closed except the mine of the Retsof Mining Co., at Retsof, Livingston County, New York. On July 6, 1921, about 1/2 mile south of the original shaft arid plant of the Retsof Mining Co., a new 9 by 28-ft. concrete-liried shaft was started. The shaft is 1063 ft. deep from the top of the shaft collar to the bottom of the salt bed. At the same time a reinforced-concrete breaker and other buildings were erccted. This new plant began operations on Dee. 15, 1923. It was designed for a capacity of 3000 tons in 8 hours. Geology The workable rock-salt bed is 1063 ft. below the surface and 326 ft. below sea level, and varies in thickness from 9 to 10 ft. The total thickness is greater than that but is contaminated with shale above and below the pure mineral. The characteristics of the formation are shown in Tables 1 and 2. The bed dips uniformly 0.87 per cent to the south. Prospecting As the salt deposil in New York State is known, very little prospecting has been necessary. Before the sinking of the Retsof No. 1 shaft, a well was drilled to prove the existence of salt. No. 1 shaft was sunk where the well was located. The several salt wells drilled in Livingston Courlty proved generally the existence of salt throughout the county. (See U. S. Geol. Survey Bull. 669: Salt Resources of the U. S.)

Jan 1, 1938

By E. F. La Vigne

On Aug. 10, 1884, the Retsof Mining Co. began the sinking of an 18 by 12-ft. shaft at Retsof, N. Y. Rock salt was reached in 1885, in September, at 1008 ft. below the surface. The first salt was shipped in the fall of 1885. A timber breaker was built in 1886. In July, 1895, there was a consolidation of the Retsof Mining Co., the Greigsville Salt & Mining Co., the Livonia Salt Co., and the Lehigh Salt & Mining Co. These consolidated salt companies are now known as the Retsof Mining Co., a subsidiary of the International Salt Go. Eventually all of the mines were closed except the mine of the Retsof Mining Co., at Retsof, Livingston County, New York. On July 6, 1921, about 1/2 mile south of the original shaft arid plant of the Retsof Mining Co., a new 9 by 28-ft. concrete-liried shaft was started. The shaft is 1063 ft. deep from the top of the shaft collar to the bottom of the salt bed. At the same time a reinforced-concrete breaker and other buildings were erccted. This new plant began operations on Dee. 15, 1923. It was designed for a capacity of 3000 tons in 8 hours. Geology The workable rock-salt bed is 1063 ft. below the surface and 326 ft. below sea level, and varies in thickness from 9 to 10 ft. The total thickness is greater than that but is contaminated with shale above and below the pure mineral. The characteristics of the formation are shown in Tables 1 and 2. The bed dips uniformly 0.87 per cent to the south. Prospecting As the salt deposil in New York State is known, very little prospecting has been necessary. Before the sinking of the Retsof No. 1 shaft, a well was drilled to prove the existence of salt. No. 1 shaft was sunk where the well was located. The several salt wells drilled in Livingston Courlty proved generally the existence of salt throughout the county. (See U. S. Geol. Survey Bull. 669: Salt Resources of the U. S.)

Jan 1, 1938

By Charles A. Taschereau

Burkina Faso ? Formerly known as Upper Volta; Country is landlocked and dry (Sahel sub-Sahara zone); ? Among poorest countries in the World, according to the United Nations Human Development Index (in 2005, 178 out of 179 countries; in 2009 173 out of 179); ? Population 13,9 Millions; Life expectancy is 51.4 years; Fertility rate 6.47 children/woman; Average age is16 years; literacy rate 23.6% and GDP per capita $1,213; ? French is official language; Politically stable country; very low criminality rate; corruption level low. Multiparty elections since early 90s; Legal and political systembased on French civil law system; ? Country just opened a few years ago to International mining companies, with a new mining code and investment code; ? No experienced labour; ? All new codes and laws; no established practices; Very limited economic development, mining is already main product of exportation and the country will become with Essakane a mineral economy (over 50% of total exports from mineral sources);

May 1, 2010

By Qingzhu Li

The adsorption process of Pb2+ from aqueous solutions by spent grains modified with Imol/L NaCI solution was investigated. The effects of solution pH, contact time, adsorbent concentration, initial Pb2+ concentration, particle size on Pb2+removal were also studied. The initial adsorption process was rapid and 90.35% of Pb2+ adsorption occurred within 30 min. The absorption equilibrium was obtained at 4h. When pH was 5.5, Pb2+ concentration in aqueous solutions decreased from the initial content of 20 mg/L to 0.0 I mg/L after 5 hours by application of IOg/L adsorbent at 25?C, Pb2+ removal efficiency reached up to 99.95% and the Pb2+ remaining in aqueous solutions was under China Sanitary Standard for Drinking Water (GB5749-85). Adsorption data fitted well with Lanf+muir and Freundlich models. However,Langmuir isotherm model was better to descnbe Pb- adsorplion than Freundhch model, mdlcatmg that the applicability of monolayer coverage of Pb2+ on the surface of adsorbent.

Jan 1, 2008

By John M. Hartman

The high temperature of the blast of modern furnaces renders it desirable that the pipe conveying the blast into the furnace crucible shall transmit and radiate as little heat as possible. To accomplish this, the pipe shown in the accompanying sketch was devised and patented. It consists of a slide-valve, leg-pipe, and belly-pipe, which are held together and to the tuyere by a system of levers and links. The slide-valve is superior to the old throttle-valve. The legpipe is formed of two thicknesses of wrought-iron pipe, with a space of half an inch filled in with clay and brick. The belly-pipe is made in the same way as the leg-pipe, and terminates in a globe face to suit the tuyere. The quarter turn is made extra thick, of cast iron, and the cap on the end is lined with clay also. The catches, A, B, C, are merely for convenience in putting the pipe together. The joints D and E are globe faces, and allow the pipe to adjust itself to any angle. The eye-piece is made of violet glass, which cuts off the glare from the bright coals in the furnace and allows a close examination of the interior, so that any water dropping or vapor can be detected. The glass does not become coated with dirt, like mica. Since good running of furnaces is shown by a bright tuyere, it is necessary to have a good eye-piece to examine them. To detach the pipe, a man lifts the weights, the side rods are then slipped off the bell crank under the quarter turn, the link under the belly-pipe is unhooked, and the pipe carried away. The same process is reversed to put the pipe together. The nozzle is changed by taking off the cap, G, drawing the nozzle through the belly-pipe, and inserting another. In this way the change can be made quickly, without taking down the pipe. On the old tuyere pipe bolts with brass nuts were used, which burned up and gave trouble. In other cases key-bolts were used, making it difficult to adjust the pipe. Bolts make too rigid a joint, and there is no provision for movement from contraction or expansion. As the temperature of the blast increases there is more expansion, and where rigid joints are

Jan 1, 1879

By John M. Hartman

THE high temperature of the blast of modern furnaces renders it desirable that the pipe conveying the blast into the furnace crucible shall transmit and radiate as little heat as possible. To accomplish this, the pipe shown in the accompanying sketch was devised and patented. It consists of a slide-valve, leg-pipe, and belly-pipe, which are held together and to the tuyere by a system of levers and links. The slide-valve is superior to the old throttle-valve. The leg-pipe is formed of two thicknesses of wrought-iron pipe, with a space of half an inch filled in with clay and brick. The belly-pipe is made in the same way as the leg-pipe, and terminates in a globe face to suit the tuyere. The quarter turn is made extra thick, of cast iron, and the cap on the end is lined with clay also. The catches, A, B, C, are merely for convenience in putting the pipe together. The joints D and E are globe faces, and allow the pipe to adjust itself to any angle. The eye-piece is made of violet glass, which cuts off the glare from the bright coals in the furnace and allows a close examination of the interior, so that any water dropping or vapor can be detected. The glass does not become coated with dirt, like mica. Since good running of furnaces is shown by a bright tuyere, it is necessary to have a good eve-piece to examine then. To detach the pipe, a man lifts the weights, the side rods are then slipped off the bell crank under the quarter turn, the link under the belly-pipe is unhooked, and the pipe carried away. The same process is reversed to put the pipe together. The nozzle is changed by taking off the cap, G, drawing the nozzle through the belly-pipe, and inserting another. In this way the change can be made quickly, without taking down the pipe. On the old tuyere pipe bolts with brass nuts were used, which burned up and gave trouble. In other cases key-bolts were used, making it difficult to adjust the pipe. Bolts make too rigid a joint, and there is no provision for movement from contraction or expansion. As the temperature of the blast increases there is more expansion, and where rigid joints are

Jan 1, 1879

By David W. James

DURING a recent investigation of the transition from a planar to a nonplanar solid/liquid interface for the systems H20-NH4F and 0-AIR,' an apparatus was developed which enabled the morphology of the ice-water interface to be examined during the transition. The slightly curved interface was viewed at a glancing angle with a Bausch and Lomb X30 stereomicro-scope. The interface was obliquely illuminated by a polarized light source. It was thus possible to differentiate between small projections or depressions at the interface, both by a shadowing effect and by the way in which they distorted the colored interference fringes across a particular crystal surface. Many attempts were made to photograph the various stages of interface breakdown. Unfortunately, the limited depth of focus of the microscope rendered the system unsuitable for photographic recording. Visual examination, however, was facilitated by continuous adjustment of the microscope focus control. The following observations of the interface transition were recorded for dilute solutions of ammonium fluoride in water. They are compared with iller's postulated morphologies shown in Fig. 1. i) The initial departure from planarity was characterized by the appearance of a large number of small depressions or "pores" in the interface. ii) The pores were arranged in wavy rows all lying roughly in the same direction within a particular grain. iii) The pores did not appear to form near to grain boundaries. iv) The pores appeared in certain grains before others. v) The transition from the pore structure to the elongated cell structure, Fig. l(d), was difficult to follow. It occurred quite rapidly and no truly irregular cell structure, Fig. l(c), was noticed. vi) The elongated cells gradually became more uniform in size and shape, with straight cell boundaries. They remained elongated, however, and no regular hexagonal cells were observed, cf. Fig. l(e). Several conclusions may be drawn from these observations. Firstly, the appearance of a poxed or, more accurately, a pore structure can be used as a criterion for the onset of constitutional supercooling. Care should, of course, be taken to distinguish between the true pore structure and artifacts caused by splashed-back liquid, particles of oxide, or inefficient decantation of liquid retained between cell boundaries, as described by Spittle et al? Secondly, and contrary to the suggestions of Tiller el l., it seems that interfacial perturbations are characterized not by curved projections but by small depressions or pores. A recent independent investigation by Biloni, Bolling, and cole5 reported in this issue indicates that the depressions might be explained in terms of dislocations intersecting the solid/liquid interface. It is possible that the dislocation concentration is reduced in the vicinity of grain boundaries. This would then explain the grain boundary depleted areas noted in (iii) above. This work was partially supported by the Air Force Office of Scientific Research, Contract No. AF 49-(638)-1029.

Jan 1, 1967

By Robert L. P. Kleinmann

Mining has been a significant component of the Appalachian economy for about 200 years. The region continues to be adversely affected by the environmental degradation associated with these past activities. In addition, companies today are being denied permits at sites where acid generation appears likely. And air emission limitations at power plants now threaten the economic health of many moderate- to high-sulfur coal mines. Thus, when considering the environmental impacts of mining coal in Appalachia, it is important to consider abandoned and active mine issues. For example, abandoned mines generate acidic, iron-rich waters that adversely affect more than 6,400 km (4,000 miles) of rivers and streams in Appalachia. In contrast, operations that were active after the enactment of the 1977 Surface Mining Control and Reclamation Act (SMCRA) cause little water pollution. However, the costs of water treatment at such sites exceed $1 million a day. Even where water quality is not dimished, water supplies can be affected by mining. Subsidence-induced fractures can lower water table elevations or drain a surface stream dry. Subsidence can also cause damage to surface and subsurface structures.

Jan 1, 1995

By Abdallah Khair, Nathalie Risso, Arie Herrera, Victor Tenorio

This study introduces a machine learning strategy to optimize icy regolith extraction from the Shackleton-de Gerlache Ridge using autonomous mining equipment. The model incorporates key parameters—distance, road gradient, vehicle load, speed, recharge logistics, and regolith water content—into a cost framework for excavation, hauling, and dumping. Regression models estimate energy and time requirements; classification predicts terrain navigability; clustering groups craters for efficiency; and K-Nearest Neighbors (KNN) determines optimal routing and scheduling. The system adapts to a six-month daylight cycle to maximize productivity and minimize costs, enabling intelligent planning for sustained lunar resource extraction under extreme environmental and logistical constraints.

Feb 22, 2026

By Jozef S. Stachulak

INTRODUCTION Conveyor belt fires represent a serious hazard in underground mines. This fact is well understood in most mining countries. The statistical data for Ontario mines (1) indicates that the majority of the conveyor fires occurred at the head pulley of the conveyor belt. The main emphasis for fire prevention and detection should then be concentrated at the drive pulley of the conveyor designed to transport non-combustible material. In the case of conveyor belt fires, it is of utmost importance to detect the hazard at an early stage, when the overheating has not yet reached the ignition point. Thermal noise detection sensors were installed in 1987 at several conveyor sites at Inco mines. PRODUCTS OF COMBUSTION THERMAL DEGRADATION OF CONVEYOR BELT Various investigations on conveyor belt fire hazards have been made in the past (2, 3, 4, 5, 6, 7). Several belt samples (6, 7) were subjected to thermal oxidative degradation. The belts used in these tests were neoprene, polyvinyl chloride and styrene-butadiene rubber (6). About 70 different compounds were identified in the volatile thermooxidative products. As expected, hydrogen chloride was the major toxic product formed, accompanied by relatively low quantities of other toxic compounds such as carbon dioxide, carbon monoxide, sulfur dioxide, carbon disulfide, hydrogen sulfide, benzene, chloroprene, cresols, chloroethanol, formic acid and C8 hydrocarbons. The research investigation (8) performed by the USBM indicated that "smoldering combustibles generate a very low level of CO compared to the level of smoke produced". The cited publication (8), states that, "During smoldering combustion, typical mine combustibles produce about 2.5 times more smoke than CO. As fires develop to their flaming stages, the trend reverses and about eight times as much CO is produced as smoke." The reader is referred to several significant sources of additional information pertaining to emission products that can be found in references (8), (9), and (10). ANALYSIS OF FIRE HAZARDS U.S.A. AND ENGLAND Nearly 15 percent of all underground coal mine fires in the United States involved ignition of conveyor belts (7). In many cases, the fires propagated through thousands of feet of belt entry and created losses in the millions of dollars. Some of these fires consisted of rubber belts. Some involved polyvinyl chloride and neoprene belts that were classified "fire resistant". Typically, a belt fire begins after the conveyor is stopped. The fire is initiated by burning coal dust and grease accumulation around defective rollers or belt drives that have become heated by friction (7). An analysis of 113 conveyor fires (11) showed that 41 originated at the driving pulleys, 32 at the defective rollers, and 40 elsewhere on the conveyor system. The severity of the fire, which can spread along a conveyor road, has been emphasized by the disaster at Creswell Colliery, Derbyshire, on September 26, 1950, when 80 men were overcome and killed by toxic fumes from the fire (12). The fire started from smoldering caused by friction, and developed into a flaming combustion, propagating along the roadway containing the rubber belt at an estimated speed of 40.2 m/s (90 mph), and travelling a total of 650 m (2100 ft) THE INFLAMMATION OF CONVEYOR BELTS THE MECHANISM OF IGNITION Defective operation of a conveyor belt may start a fire in several ways: - Friction of the belt on the drive pulley. - Jamming of a guide roller, and others.

Jan 1, 1991

By Gordon King

This paper presents a case study of large diameter continuous flight auger (CFA) piles and drilled shafts utilized for foundation support of a series of heavily loaded cement plant structures at the Suwannee American Cement (SAC) Plant in Branford, Florida. The high loads and exacting total and differential settlement criteria when combined with a highly variable subsurface geology provided a challenging design scenario. Fully instrumented static pile load tests were performed to determine design parameters in the variable weathered limestone bedrock. Ultimate side friction values ranged from 2 to 8 tsf within the limestone, resulting in the requirement for CFA piles up to one meter (approximately 40 inches) in diameter and socket lengths of up to 40 feet. At several localized areas, the limestone bedrock was in excess of 60 feet below grade, requiring the use of cased drilled shafts to depths on the order of 80 to 90 feet. An integral part of the production pile installation was the use of instrumentation to monitor drilling and concreting parameters. Calibration of drill rates, torque and auger rotation with rock quality was performed to allow monitoring of the soil stratigraphy at each pile location. When combined with the results of the instrumented load testing, the monitoring of drilling parameters allowed confirmation that sufficient socket length was achieved within the quality of rock present at each and every pile location.

Jan 1, 2003

By K A. Broadhurst

Over the years International Standards have produced and are continuing to work on documents related to damage from blasting and human exposure to whole-body mechanical vibration and repeated shock.

Jan 1, 1988

By J. E. Lawver, G. L. Samsel

The success of many mineral dressing processes, including froth flotation and electrical concentration, depends largely on knowledge of physical and chemical structures of the mineral surfaces involved. As a general rule solids have surface layers, usually invisible by optical tests, that differ from the substratum. To the mineral engineer, therefore, a knowledge of the surface structures of minerals is of paramount importance. During the past decade one of the most powerful tools in the study of froth flotation mechanisms has been the use of radioactive tracers, but this technique usually cannot give definite information regarding the chemical changes that may or may not have occurred at the surface. The electron microscope and electron diffraction camera can be particularly useful instruments in surface studies.. An election microscope permits much closer examination of surfaces than can be obtained with a petrographic microscope. In certain cases, it is possible to identify trace quantities formed by chemical reaction between flotation agents and mineral surfaces by the use of a single-crystal, reflection electron diffraction camera. This article describes several instances in which these instruments have been valuable guides in mineral dressing research at International Minerals & Chemical Corp. One of the first applications of these techniques employed by International Minerals was in conjunction with the study of electrical concentration of potash ore. The first reasonably successful separation of potash ore was made by subjecting a sample of the ore to a methanol wash. Subsequent tests using tagged 6C14 methanol showed that only a minute quantity of radioactivity was detectable after the methanol-washed sample had been dried and heated to about 300°F. It was concluded that although some methanol had been held to the surface by adsorption, this could not account for the improved electrification because there was no evidence of methanol selectivity with respect to NaCl or KCl. Consequently there must have been some other change in the surface. Carbon replicas* of the mineral grains were made before and after the methanol wash. The replicas were separated from the minerals by dissolving in water. This extraction replica technique is particularly attractive because the specimen can first be used with the electron microscope to observe the general structure of the surface and can be re-used as a specimen for electron-diffraction studies to identify any solvent insoluble material present on the mineral surface." Fig. 1 shows the general

Jan 1, 1960

Objectives ? New deposits can be found in mature Mining CampsNew Camps ? Volcanogenic Massive Sulfide (VMS) deposits ? polymetallicpolymetallicexamples are desirable exploration targets examples ? Genetic and exploration models for VMS deposits are robustrobust ? subtle but important differences exist between deposits and districts ? sometimes ??neglectedneglected??in resource modeling and exploration efforts ? ReRe-evaluation of a prominent existing camp is rewarding ? update on the exploration strategies currently being applied on a practical level The Falconbridge-Alexis approach includes GoCAD modelling

May 1, 2006