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By Hajialilue Bonab M.

The soil-pile interaction under lateral impact loads is not yet completely well known. Many tests on single piles under static lateral loads in centrifuge have been performed and P-y curves have been determined at different levels of the pile in soil. Following these static tests on piles, a large program is undertaken with the same piles submitted to impact loads. The pile equipped with various pile caps has been impacted under variable amplitudes of shock. The behavior of the pile under different impacts was studied and dynamic parameters of the soil-pile system have been determined. Many cases of loading constituting various load histories have been analyzed. They are resulting from parametric centrifuge tests run out, on the one hand with constant and cumulative impacts and on the other hand, variable and cumulative ones. The Influence of each type of loading was studied. Using a finite element method, a non-linear pile-soil system was conceived and a transient dynamic analysis have been performed. The results of the non-linear analysis and experimental data were compared giving a good agreement.

Jan 1, 2002

By Gerrit V. R. Goodman, Fred N. Kissell, Charles D. Taylor

In This Chapter [Methane emission peaks Exhaust line curtain or duct The spray fan system Dust scrubbers with blowing ventilation Dust scrubbers with exhaust ventilation The ventilation of abnormally gassy faces Methane detection at continuous miner faces Ventilation and methane detection at bolter faces and Reducing frictional ignitions] This chapter gives guidelines for preventing methane gas explosions at continuous miner sections in coal mines, both at continuous miners and at roof bolters. The need to control peak methane emissions is particularly stressed. Emphasis is also placed on ventilation principles, monitoring for gas, and reducing frictional ignitions. METHANE EMISSION PEAKS Methane emission from the coal at continuous miner faces varies considerably. Plotted on a chart, methane emissions consist of a series of peaks and valleys corresponding to the cutting cycle of the mining machine, with the methane concentration spiking as the machine cuts into the coal (Figure 3–1) [Kissell et al. 1974]. These methane peaks can be substantial. For this reason, efforts to safely dilute the methane must focus on the level of the [ ]

Jan 6, 2006

By R. W. Nice

"For many decades the incidence of a highly active graphite-like ore has plagued the McIntyre mine. This ore acts as a precipitant of the gold complex immediately upon formation of this complex. The gold is subsequently discharged with the tailings.Many different methods have been devised by various researchers all of which proved inapplicable for the McIntyre problem.Recently, McIntyre personnel, through their own research, developed a flowsheet. This circuit should give an overall recovery of 36% which is below the 94% experienced in the mill at present. Therefore, less revenue would arise from treatment of these ores. On the other hand there exists a possibility of more efficient mining methods in some of this ore thus allowing more economic recovery.INTRODUCTION This paper has been prepared to serve two purposes:i) To propose a method of recoverying gold from a sizeable orebody at the McIntyre mine at Schumacher.ii) To summarize and present the many methods suggested to solve a very old but very real mineral dressing problem familiar to the industry as long as cyanidation itself."

Jan 1, 1971

By Paul Worsey, Dave McCool, Ryan Freeman, Chris Wolters, Rick Hines, John Bowles

Carroll Cave, located in Camden County, in south central Missouri, is one of the most significant caves in Missouri with over 12 miles of mapped passages and over 100 known but unmapped side passages. In the early 1990’s there was a breakdown of the originally excellent landowner/caver relations as the ownership of the only known entrance moved to a new generation and grottos squabbled for control. Subsequently the current owner of the natural cave entrance refused to grant anyone permission to enter.

Jan 1, 2003

'Gee Whiz', a nationwide schools' science and technology competition, is being screened on SATY1 on Friday evenings at 18:00. Twenty-seven schools from al over South Africa are taking part in the series, which will run for 13 weeks. The participating schools were selected on the basis of their performance in the National Youth Science Olympiad and in Mintek's Minsa science competition, which has been organized on an annual basis since 1988.

Jan 1, 1991

By K. J. McGrew, J. W. Murphy

Introduction Maximization of profit consistent with environmental protection is the principal goal of new applications development for any conventional or in situ mining technique. Efficient evaluation of all the parameters that contribute to mining costs and production hinges on proper design and evaluation of testing programs and data. The program discussed uses several field and laboratory procedures to estimate ore deposit characteristics and optimize lixiviant compositions. Ore characteristics and lixiviant compositions are then used in a long path leaching test (stream tube test). Stream tube test data are analyzed by mathematical models with computer assistance to predict such wellfield rate parameters as target metal production, lixiviant consumption, and restoration. When these predicted rates are combined with market values for target metals, capital expenditures, prices of lixiviant chemicals, and other economic variables (labor costs, power rates, and licensing fees), an assessment of the relative feasibility of various proposed mining plans is possible. The flowsheet in Fig. 1 illustrates this process. [ ] Field and Laboratory Procedures In general terms, the procedures followed in the evaluation of an in situ leaching application aim at accomplishing: •rapid leaching and maximum recovery of the target metal in a marketable form, •low consumption of lixiviant chemicals, •unquestionably satisfactory restoration of the mined aquifer, and •minimization of capital and operating costs for the above through development of an optimum mine plan. Keeping these goals in mind, the following minimum test program is generally recommended. Geology •Estimate of ore reserves and their variability. •Average disequilibrium value for uranium deposits. •Ore thickness, depth to ore, water level, degree of confinement, and consolidation. •Characterization of quality and quantity of other ore deposit constituents (e.g. sulfide minerals, ion exchange parameters). Hydrology •Single well pump and injectivity test. •Downhole vertical permeability test to compare flow rates of barren and mineralized formations. •Groundwater quality as it may affect licensing, hydro metallurgy, and restoration. Hydrometallurgy • Flask or autoclave tests for optimization of lixiviant parameters and determination of specific reaction rate constants. • Flask or autoclave tests for assessing amenability of lixiviant solutions with ore, consumption of lixiviant, stability of metal in solution contacting ore, and environmentally important species mobilized. • A long-path leach test for modeling the behavior of the lixiviant solution flowing through a long mineralized streamline (stream tube testing). •Metal recovery tests from lixiviant solutions (ion exchange, electrowinning, etc.). •Lixiviant regeneration tests. •Environmental restoration tests.

Jan 1, 1985

By H. K. Fredrickson

"Midwest Joint Venture (MJV) owns a high-grade uranium deposit in northern Saskatchewan. The deposit is located too deep below surface to be mined economically by open pit methods, and as a consequence, present plans are that it will be mined by underground methods. High-grade uranium ore of the type at MJV, encased in weak, highly altered ground and with radon-rich water inflows, has not before been mined by underground methods.The test mining phase of the project, completed in 1989, had three objectives: 1. to evaluate radiation protection requirements associated with the handling of large quantities of radon-rich water and mining highgrade uranium ore in an underground environment; 2. to investigate the quantity and quality of water inflows into the mine; and 3. to investigate ground conditions in and around the ore zone as an aid in determining the production mining method to be used.With information gained from the test mining project, a mining method for the production mine has been devised. Level plans have been drawn up, ventilation system designed, pumping arrangements made and methods of ore handling considered. All this is to be done in a manner that will be safe for those doing the work underground. Some of the mining methods planned are felt to be unique in that they are designed to cope with mining problems not known to have been encountered before. New problems underground have required new methods to handle them. Remote drilling, blasting, mucking and backfilling form the basis of the planned mining method."

Jan 1, 1992

By Jack Parker

There are some simple theoretical approaches to pillar design but they leave much to be desired. There are also more complex theoretical approaches, but at this time the most realistic approach is to go into the mines and observe and measure how real pillars are performing under real conditions; to allow the information thus gathered to ferment in our minds - then to project the behaviour of those pillars into our new designs and mining techniques, probably with no formulas at all. Examples, from half-a-dozen different mines, show how a simple- minded approach, through observation and measurement, led to changes in pillar design which often contradicted the textbook but made very significant contributions to mining safety, efficiency and costs. The good news is that we know a lot more about pillar design than we realize. We have, between us, looked at millions of pillars of all kinds, under all conditions, but we have overlooked what they are trying to tell us. We can take problem situations and turn them into opportunities and, in that way, become better stewards of the resources which have been given to us.

Jan 1, 1983

By T. E. Gray

This report describes the preparation characteristics of the significant coalbeds in Nicholas County, W. Va. It is one in a series describing coals suitable for producing metallurgical coke, either as mined or after beneficiation. Almost 5 million tons of coal were produced in Nicholas County, W. Va., in 1960, of which over 2.6 million tons were cleaned in eight preparation plants. It has been estimated that over 6 billion tons remained in the county as of December 31, 1960, in beds 12 inches and more thick.

Jan 1, 1962

Engineers and masters of enterprise are waking fast to the realization that there is something more in the relations of employer and employee than mechanical output, which can be measured mathematically, and that the human side of service must receive greater consideration for the future. So much has been said and written on this subject that it has passed into a truism. Should not the same element, long neglected, be considered as of even greater importance than questions of "administration and membership, in the plans of engineering societies? Should mutual service and interest end with mere technical output by members and the rendering of care and management by officers? The world is recognizing, as never before, obligations for service to fellowmen clue from all, high or low, in rank or wealth. Our technical societies, organized for professional protection and advancement, are, insensibly to themselves, almost without conscious intent, widening their field of service to members and dealing heartily with questions broader than technique. Those who are doing such service find unconsciously more and more satisfaction in work so rendered. The growth of knowledge that comes to subaltern engineers or veterans by converse and contact with their fellows, working along and versed in the same subjects, brings interest and friendship. In this way are built some of the warmest friendships of life, coming as incidental and pleasurable result of meetings undertaken for other purposes. Should not the friendly purpose, the desire for service one to another, and es-

Jan 1, 1919

By P Ormsby, T Hewitt

Ore in pillars constitutes a significant proportion of the ore reserve at PasmincoÆs Broken Hill Mine. Many of these pillars are narrow (5 -6 m) and high (16 û 35 m) vertical blocks. High-grade ore has been left between primary horizontal cut and fill stopes. These stopes were mined from the late-1960s until the early-1980s. Fill material is a variety of hydraulically stowed sand, sand-cement, and remnant timber support. Many pillar cut-throughs were made between the old stopes. In order to gain access for the current pillar recovery operations, it has been necessary to develop pillar drill drives through, and adjacent to, the hydraulic filled stopes. Whilst long hole recovery of vertical pillars is not new, some notable successes using innovative ideas have been achieved during 1997. These innovations include:The use of steel mesh reinforcing in shotcrete when mining through, or adjacent to, hydraulic fill. Construction of steel sets to support vent rises and haulage ways encountered in the cut-throughs. The use of ground movement monitoring equipment. Survey lasers with chain droppers and convergence monitors were installed in the 18 Pillar to detect any movement of the pillar block and decrease risk to personnel. The development of a three-dimensional computer model of primary stoping, using Vulcan software, to assist in the design of pillars. Maximisation of recovery using different drilling and firing practices.

Jan 1, 1998

By L. B. Slichter

After statement of the principles of similitude which apply to electromagnetic modeling, charts showing the inductive response of conducting spheres as dependent upon frequency, conductivity, and size are exhibited in this paper. The shape of the curve which relates intensity of response to frequency is significant in indicating the advisability of low frequencies in the exploration for conducting bodies, when consistent with the securing of a large percentage of the ideally possible response. Comparisons of theoretical response and that observed with models are shown, and relationships with the subject of applied electromagnetic prospecting are indicated. Maxwell Field Equations The Maxwell field equations summarize the physical laws that govern electrical field phenomena; they are the basis for the solution of electromagnetic problems. These concise equations, with adequately formulated boundary conditions, specify the complete electrical condition of continuous media, and the development of their solution amounts merely to a more convenient re-expression of phenomena already completely described. Thus, the immediate content of the field equations themselves is sufficient and sometimes convenient for the treating of certain questions (such as those relating to electromagnetic models) which are independent of the special factors of geometry, or the nature of an impressed field. The four Maxwell field equations are written below, in c.g.s. gaussian units: curl E = -B/c [21 div eE = 4pp [31 div B = 0 [41

Jan 1, 1932

By Ian Townsend

A prerequisite for good filter performance is that the total filter installation has been well designed. In this sense, the filtration testwork will provide scale-up data, and an insight into the relationship between operating parameters that may then be optimised, and used in the development of a control strategy. A good understanding of the filter’s operating principles will ensure correct selection and sizing of ancillaries, allowing in particular for the difference between instantaneous and average flow rates.

Sep 13, 2001

Interpreted geologic domains provide the geologic architecture of many current models used to estimate the potential economic resources in mineral deposits. The spatial extent of each domain is usually defined by a three-dimensional wireframe or triangulated surface.The set of geologic wireframes forming part of a resource model might generally be called a spatial interpretation of some set of geologic features coincident with the mineralisation, based primarily on logged and mapped properties of the samples and other exposures of the mineralisation. The interpreted spatial distribution of rock type, alteration and grade of drill hole samples above a particular grade threshold are commonly used criteria in constructing the geologic domain wireframes. Frequently, the grade threshold is closely related to the anticipated economic cut-off grade. The boundaries or spatial limits of different domains are most commonly defined as æhardÆ or æsoftÆ. A æhardÆ boundary usually means no dependent relationship of any kind is defined between the properties of samples inside a particular domain wireframe and those samples outside the wireframe. A æsoftÆ boundary commonly implies that some kind of dependent relationship does prevail between the properties of samples inside and outside the particular wireframe. Many ways are used to describe those relationships, few of which are based on spatial analysis of the continuity of sample attributes across the domain boundaries. In local estimation procedures such as ordinary block kriging, æhardÆ boundaries act as a total barrier to the influence of samples on either side of the boundary depending on the location of the block being estimated. In some instances, æsemi-permeableÆ boundaries are used in which the samples inside a domain wireframe are allowed to influence the estimates outside but not the reverse. This can lead to many undesirable effects in estimates of block grades.This paper discusses the value of this approach to geologic domaining from a viewpoint of model complexity, as well as in relation to the implications for both linear and non-linear estimation methods and contrasts it with alternatives. It also explores some important consequences of using æhardÆ and æsoftÆ geological boundaries with the commonly used modelling methods: excessive smoothing of estimates near domain boundaries and conditionally biased estimates of grade at the global and local scale.

Sep 26, 2011

The GDR has extensive lignite deposits at its disposal, which formed the basis for the development of an independent energy source after 1945 and which will retain their significance well beyond the year 2000 (see fig. 1). In 1946 lignite output was about 110 x 106 t. In 1985 312x 106 t was produced and in 1988 the planned output will be ca. 315 x 106 t. Thus, the domestic produc- tion of lignite covers ca. 75% of the GDR's primary energy requirements. More than 80% of the electrical energy is gener- ated by the use of lignite and about 12% by nuclear energy. In addition to this, about 18 x 106 t/a mineral oil and about 6 x 109, m3/a natural gas are imported, predominantly from the Soviet Union. The lignite deposits of the GDR are of Tertiary origin and are recovered exclusively by opencast mining. There are two large regions (fig. 2): - in the region east of the river Elbe (Cottbus/Senftenberg- "Niederlausitz") and - in the region west of the river Elbe (Halle/Leip- zig/Magdeburg). These deposits differ in geological age and conditions of depo- sition, consequently there are differences in their chemical and physical composition and, thus, in their uses. The younger Mio- cene coals of the main region in the East of the river Elbe belong to the epirogenetic type and have a low content of ash and sul- phur. Among other things, they are suitable for the production of brown coal high-temperature coke (Lauchhammer and Schwarze Pumpe). The older Oligocene coals of the Halle/Leip- zig region are bitumenous in certain areas. Therefore, they form the basis for production in low-temperature carbonizing and chemical plants. In the Halle-Magdeburg region, where the lig- nite is in contact with the underlying Zechstein subdivision, so- called "salt coals" are found.

Jan 1, 1989

By Ted T. Biddle

The world energy crisis has created a greatly expanded exploration program for energy fuels. The demand for materials required for drilling operations such as barite, which is the primary component of drilling fluids, has increased proportionally. As in the case of many other minerals, existing high grade barite mines are no longer capable of producing the required tonnage. Consequently, exploration and development of lower grade ore bodies has been increased. The need to produce a high quality product at maximum recovery rates, along with the ever changing economics affecting both selling price and production costs has triggered accelerated research programs toward more sophisticated and efficient beneficiation methods. Taking into account the specific gravity differential between barite (4.5) and the normal gangue minerals such as silica and calcite (2.7), gravity concentration methods are the prime consideration with flotation as a scavenging process. Greater emphasis on particle size liberation, size reduction and concentration is also indicated. In order to accomplish these objectives, it has been necessary to revert back to the old adage, "Recover your minerals as soon as they are free."

Jan 1, 1980

By Sarat C. Rubra

Geographically, British India includes India or Hindustan proper, Burma, and a part of Beluchistan. In ancient times India occupied a very important position anlong the producers of minerals and metals; in fact, as late as the middle of the seventeenth century, it contributed a very considerable quota of the mineral and metal supplies of the world. The branches of the industry worthy of special note are gold, silver, lead, antimony, copper, iron, diamonds and other precious stones. The famous " Damascus steel" was originally manufactured in India, Damascus being only a mart; and it is interesting to note that even at the present time this product is still made in India. Prior to the discovery of diamonds in Brazil in 1728, India was the sole producer of this important mineral; and while no diamond-mines are now systematically worked, fine specimens are occasionally reported to be found in river-beds and in alluvial diggings. For ages, nearly all of the minerals of present commercial value have been produced and worked in India, and many of the deposits may still play an important part in the world's mining and mineral history. Despite the patient work of the ancient Indians, the limited knowledge they possessed of pumping and ventilation precluded the possibility of attaining any great depth in mining. Under special conditions, shafts have been sunk to 600 ft., but the average depth was much less. As a result of this limitation, the ancient miners confinecl their work to the available ores in sight, leaving large bodies of ore intact, which can be profitably worked with modern methods of mining. As an evidence of this statement may be mentioned the mines of the Kolar gold-fields in Mysore, which have reached in some shafts a. depth exceeding 2,400 ft. Traces of ancient work in these

Jan 1, 1904

By Lucien Eaton

IN anticipation of a shortage of labor for hand-tram-ming at the Cliffs shaft mine of the Cleveland-Cliffs Iron Co. at Ishpeming, Mich., early in 1923 three 4-ton Goodman storage-battery locomotives, equipped with Edison batteries, were purchased. Storage-battery locomotives were chosen for this work because the expense and time required to put up trolley-wire and to bond the rails of the complicated system of tracks on the levels, where the locomotives were to be used, would not have been warranted by the amount of ,ore to be handled. The only changes in the tracks necessary for storage-battery locomotives were new switches and extra ties and braces on curves. The tracks were 24-in. gage, and were laid with 20-lb. rail. Edison batteries were chosen, because it was desired to charge the batteries from the trolley circuit already, in the mine, and this would have been impracticable with lead batteries. Each locomotive is equipped with 126 A-4 Edison cells, which are charged in series from the 240-volt trolley circuit while the trolley locomotives are running; and are discharged in parallel in two banks of 63 cells each. These locomotives were so successful that later 5 smaller locomotives, weighing 11/2 tons each, were pur-chased for use e with cars that are filled by hand and on levels where the amount of ore handled is small. These locomotives, built by the Geo. D. Whitcomb Co. of Rochelle, Ill., are equipped with batteries of 40 A-4 Edison cells each, the cells being the same as those, on the larger locomotives. They are charged from mer-curial-are rectifiers. These locomotives are operated by the trammers themselves, and have not special oper-ators like the larger machines. The trammers are all young men of American birth, and take quickly to the operation of machinery, and the simplicity of the con-trol on these locomotives has made special training unnecessary. A survey of the results was made by the A. C. Nielsen So., an excerpt from which follows: Eight Edison-equipped battery locomotives are now in use at an Ishpeming mine of the Cleveland-. Cliffs Iron Co. This equipment was installed to take the place of men who formerly pushed loaded cars by hand. Results have been very satisfactory and the de-pendable, trouble-free operation of the Edison batteries is considered to have been an important factor in the effectiveness of the new hauling method.

Jan 3, 1927

By W. G. Bearden, P. P. Scott, G. C. Howard

This paper concerns the rupture or breakdown of rock formations as related to drilling, completing, and stimulating production of wells, and comprises data compiled from a study of literature and records of treatment of oil and gas wells. and from tests conducted in bores drilled into rock cores and outcrops of rock. Results of the investigation indicate that the internal pressure to rupture cylinders of rock and to breakdown rock formations surrounding a bore in the earth is dependent upon the extent of intrusion of fluids. the position of bedding planes. the ratio of internal to external diameter, the tensile strength of rock, and magnitude of confining pressure, and is independent of the size of bore, degree of fluid saturation. and temperature of rock within practical limits. It is concluded that the mathematical relationship of pressure in bores and stresses in the surrounding rock must not be limited by the simplifying assumptions of homogeneity. isotropy, and impermeability; that the incidence of lost circulation of drilling fluids to induced fractures may be reduced by preventing intrusion of fluids into the small intrinsic fractures along weak bedding planes; and that the magnitude of the breakdown pressure of wells to be treated may be lowered by removal of mud cake. INTRODUCTION The purpose of this paper is to present and discuss the results of tests which may serve to broaden the understanding of the phenomena of rupture or breakdown of rock and thus contribute to the improvement of the techniques for drilling and completing wells. including such operations as preventing lost circulation, stimulating production, and placing cement. Since the early recognition of the possibility of rupturing rock adjacent to a well by fluid pressure, the distribution and magnitude of stresses around a well and the internal pressure to cause failure have been expressed mathematically by application of the principles defining the elastic and inelastic behavior of thick-walled cylinders of a homogeneous. isotropic, impermeable material. In either the elastic or plastic state, if the conditions of homogeneity. isotropy, and impermeability were the normal characteristics of rock. there would be no reason to question the validity of the above principles when applied to rock. However. since most rock formations are characteristically permeable to some degree, contain bedding planes and small intrinsic fractures. and are heterogeneous, rendering invalid the assumptions of homogeneity, isotropy, and impermeability, the application of the thick-walled cylinder theories to the behavior of rock formations penetrated by a bore appears illogical. Also the failure to consider the effect of the properties of the drilling fluids, which certainly intrude in various degrees into most rock formations. is further cause for questioning the application of these principles. Even in the case of cylinders of hardened chrome-nickel steel, which would he considered relatively homogeneous isotropic. and impermeable, as compared to rock, it has been observed that the internal pressure capable of being withstood by the cylinders varied with the sizes of molecules comprising the rupturing fluid used. Because of these apparent weaknesses in the theories of the behavior of thick-walled cylinders when applied to bores in rock, and the importance of knowing the true behavior of rock under the influence of fluid pressure when planning drilling and completing procedures for wells, tests were undertaken to determine by observation the actual rupturing pressure of cylinders of rock and the effects of such variables as environmental conditions and characteristics of rock formations, fluid properties, and bore dimensions. It was intended that by these tests the validity of the thick-walled cylinder theories when applied to rock would be determined and, if found invalid, mathematical expressions would be derived for predicting stress and rupturing pressure of rock formations under various conditions. Since the derivation of mathematical expressions has been only partially completed, all of the results of the latter phase are not included in this paper. PROCEDURE The investigation was initialed with a study of the theories pertaining to the rupturing of thick-walled cylinders of homogeneous. isotropic, impermeable material and a study of the

Jan 1, 1953

By Robert C. Bates

Background is given on the various equations used to describe diffusion and convective flow of radon in porous media. Bureau-developed equations for modeling diffusion and Darcy flow through multilayered porous media are described briefly, and examples of their use are given. Analysis results discussed include: The transient effect of pressure changes in different length models, time dependent flux changes in multi-layered models, and radon flux through pinholes in sealants

Jan 1, 1980