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By Oliver Bowles

The term" sandstone" is applied to a rock composed of mineral grains smaller than pebbles, cemented together more or less firmly. "Conglomerate" is the name given to a rock composed of pebbles, or pebbles and bowlders, of various sizes cemented together. If the pebbles are large and well rounded the rock is sometimes called " pudding stone." Although the term "sandstone" includes all varieties, certain specific terms are applied to types characterized by particular compositions, colors, or uses. "Quartzite" is a variety in which the individual grains are so firmly cemented together with quartz that the rock will fracture as easily through the grains as through the cement; "ferruginous sandstone" is one rich in iron as cementing material, or as grains, or both; "micaceous sandstone" is one in which mica is prominent; " arkose" is a feldspathic or granitic sandstone composed of angular grains; "calcareous sandstone" is one containing considerable calcium carbonate; and" argillaceous sandstone" is one containing considerable clay. The term "flagstone" is used for a rock that splits readily into sheets suitable for flagging; "freestone" for rock than can be cut or carved readily, and with equal ease in all directions; and" ganistel'," in the United States, for sandstone suitable for the manufacture of refractories. Others are named from their characteristic colors such as " bluestone," " redstone," or " brownstone."

Jan 1, 1917

By Jr. Boyle

This report analyzes the availability of chromium in the form of ferroalloy products (high-carbon and low-carbon ferrochromium and ferrochromium-silicon) and chromite products (metallurgical, chemical, refractory, and foundry sands) in market economy countries (MEC's). A total of 873.5 Mmt of in situ material, containing 202.5 Mmt of chromium, in 10 MEC countries was analyzed for availability as of the January 1989 study date. Extraction and beneficiation of this in situ material would result in 475.4 Mmt of marketable chromite products. As analyzed, 288.5 Mmt of these chromite products would be available for export or for internal chemical and refractory use and 186.9 Mmt would be smelted in-country to produce 74.3 Mmt of high-carbon ferrochromium, 3.9 Mmt of low-carbon ferrochromium, and 2.0 Mmt of ferrochromium-silicon, all available for export. A network flow model, which includes centrally planned economy countries (CPEC's), was also constructed to analyze world chromium supply and demand interactions for the period 1986 through 1994 and to address a hypothetical North American embargo on direct imports of all South African chromium products beginning in mid-1990. The model shows capacity constraints developing in the MEC high-carbon ferro chromium industry in 1987 and a possible subsequent overreaction by the industry in terms of new capacity additions. The results suggest that sufficient chromium is available to North America should an embargo on direct imports from South Africa be imposed by its governments. However, the effect on export revenues in South Africa is relatively small, and timely increases to world ferrochromium, chemical chromite, and foundry sand chromite capacities would be required.

Jan 1, 1993

By W. W. Adams

In mining coal, the Nation's principal mineral fuel, loss of life has been much lower recently than in earlier years when coal mining contributed so heavily to the industrial-accident death toll in the United States. Particularly notable has been the relatively small number of deaths during the past few years compared with the number that occurred 20 or 30 years ago. Reports received by the United States Bureau of Mines, covering all commercially operated mines that were active during all or any part of the calendar year 1935, showed that accidents during that year had resulted in the loss of 1,242 lives. This death toll, although regrettable, represents a material improvement over the industry's experience during most years prior to 1935, and especially over the industry's worst year, 1907, when 3,242 men were killed. Fewer lives were lost in 1933, when 1,064 men were killed at work, than during any year for which complete figures are available.

Jan 1, 1938

CONTENTSIntroductionGeneral GeologyCoral Reef-Volcanic Set'iesRock TypesMicaceous Sandstone and MudstoneLimestoneVolcanic RocksChertsDepositionDiatremesEarth MovementsRelation of Ore Bodies to StructureINTRODUCTIONThe author encountered the problems discussed in this paper in 1947 while surveying the mining centres of Mungana and Redcap for Broken Hill South Ltd. After his resignation from that company he made a semi-regional survey to investigate the regional problems raised by the preliminary study. Broken Hill South Ltd. continued its studies on the known ore bodies while the author's investigation was going on, and he is indebted to the staff of this company for assistance during his field work.The area mapped is part of a larger area mapped in reconnaissance by the Aerial, Geological and Geophysical Survey of Northern Australia by a party headed by Dr. H. I. Jensen...

Jan 1, 1952

By W. G. Diamond

Lightweight aggregates have become increasingly important to the construction industry. From 1953 to 1960, the quantity of the aggregates used in concrete block, precast and prestressed concrete, and monolithic structures increased about 92 percent. The present study was conducted in Bureau of Mines Area IV which encompasses the South-Central States of Arkansas, Kansas, Louisiana, Mississippi, Missouri, Oklahoma, and Texas. This is an administrative area and does not delimit a market area or imply an economic unit. Because of the increasing importance of metropolitan areas in evaluating economic growth, significant data showing relationships between growth of the metropolitan areas and the lightweight aggregate industry are included.

Jan 1, 1964

By Julián M. Ortiz

Uncertainty quantification of a spatially distributed variable at any scale can be handled through geostatistical simulation. Large computation time, storage, and post-processing of the realizations are required to obtain a final assessment of block uncertainty. Multi-Gaussian kriging is a flexible alternative to simulation. The idea is to compute the conditional distribution of uncertainty after normal score transformation of the original samples. Under the multi-Gaussian assumption, all marginal and conditional distributions are Gaussian, hence fully defined by their mean and variance. The parameters of the conditional distributions are obtained by simple kriging and can be back-transformed to the original units of the variable of interest. An estimate and any summary of uncertainty can be easily retrieved. The main disadvantage of performing multi-Gaussian kriging is that change of support is not straightforward, that is, calculating uncertainty of block grades. We propose a methodology to overcome this limitation by considering a matrix simulation to generate multiple probability fields. Each probability field is used to draw spatially correlated point values from the point-support conditional distributions, and multiple realizations of the average can be obtained. This permits the calculation of the average over the block and its uncertainty. These blocks may correspond to selective mining units or to volumes from longer production periods relevant for engineering decisions. They can even be disjoint blocks, such as when several faces are mined at the same time. POSTMG, a Fortran program to perform these calculations, is described and a case study is provided.

May 1, 2004

By JOHN W. KOSTER, JAMES R. FLEMING

The following report is made through the Bureau of Mines as a result of the work under the cooperative agreement with the State geological survey and the engineering experiment station of the University of Illinois. It deals with the use of permissible explosives in the coal mines of Illinois, and is intended primarily to present to mining men the possibility of assuring safer conditions in mining through the use of these explosives. Twenty coal mines in Illinois were using these relatively safe explosives at the time this report was prepared. Of these, seventeen were in Franklin County, two were in Saline County, and one in Montgomery County. In these various fields experience had shown that although black blasting powder was a useful agent in breaking down the coal at the working face, yet it had given such conclusive evidence of its danger to life and property in causing explosions and mine fires that a substitute was sought and has been found in permissible explosives. Each coal mine in Illinois in which permissible explosives are used was visited and a study made of the problems involved. The report deals briefly with the dangers of black blasting powder now in such common use in coal mining. It discusses the development of permissible explosives and their introduction into Illinois coal mines and points out the characteristic differences between permissible explosives and black blasting powder. The present system of blasting and the most approved methods of using permissible explosives are described. Data are given to show that not only has safety and efficiency in these mines been greatly improved, but that the cost of explosives to the miner per ton of coal has been reduced, and that sizes of coal produced from permissible explosives compare favorably with those previously obtained at the same mines with black blasting powder. The successful use of permissible explosives in these Illinois mines as well as in many other mines throughout the country should aid in their introduction into a larger number of mines and bring about that degree of freedom from explosions and fires which should be attained in mining.

Jan 1, 1917

By John D. VandeKraats

Yielding rock bolt support systems have been developed to accommodate ground movement in shifting ground such as in coal operations; in creeping ground such as salt, trona, and potash; and in swelling ground associated with some clays. These systems, designed to remain intact despite ground movement, should enhance mine safety and help contain costs in areas where rebolting of rigid non-yielding systems is typically required. Four such systems were tested in straight tensile pulls in the laboratory. They include the Slip Nut System from Dywidag Systems International USA, Inc., Ischebeck's bolt mounted Titan Load Indicator, Rocky Mountain Bolt Company's Yielding Cable Bolt, and a rock bolt installed variation of the yielding steel post developed by RE/SPEC Inc. The first two systems are currently marketed products and the latter two are prototype systems. Each system responds to load and displacement by yielding in a unique manner. All are designed to yield at predetermined loads. A description of each system and its yield function is provided. Each system was tested over its prescribed yield range in a test machine. At least five tests were performed on each system. Each system yielded and continued to provide support according to its design. Each shows promise for ground control use in shifting or creeping rock. This work helps to illustrate the comparative differences in performance between these specialized systems and the applications where they may be most useful.

Jan 1, 1996

By Y. H. Cheng, D. M. Lewis, V. Castranova, M. W. Barger, J. K. H. Ma, J. Y. C. Ma, W. F. Xin

Bis-basic ethers off fluorene and fluoren-9-substituted derivatives such as tilorone have been reported to inhibit silica-induced fibrosis in rats. The potential antifibrotic potency of 2,7-bis (diethylamino) ethixy fluorine fluorenone (F-9-H.H), fluorenoxime (F-9-one), and fluorenol (F-9-ol) was F-9-axime > F-9-one ~ F-9-H,H > F-9-ol. Since the release of reactive oxygen species and growth factors from alveolar macrophages (AM) in response to silica exposure has been linked to the development of pulmonary fibrosis, the present study was carried out to determine the inhibitory effects of these compounds on rat AM activity in vitro. The following parameters were monitored: (1) cellular viability; (2) zymosan-induced respiratory burst activity (superoxide and hydrogen peroxide release, chemiluminescence, and oxygen consumption) of AM; (3) drug binding to AM; and (4) lipopolysaccharide (LPS)-stimulated interleukin- I (IL-1) release from AM. The bis-basic ethers, at 40 did not affect cell viability when incubated with AM for 30 min, but significantly inhibited zymosan-induced macrophage respiratory burst activity. The inhibitory effect of these agents was F-9-oxime > F-9-one ~F-9-H,H > F-9-ol. Binding of these drugs to AM was time and dose dependent, and exhibited the following binding affinity: F-9-oxime > F-9-one > F-9-H,H > F-9-ol. F-9- oxime was shown to inhibit LPS-stimulated IL-I release by AM in a dose-dependent manner. This inhibition of IL-1 release by AM cannot be explained as a decrease in viability. In addition, these drugs were also shown to impair human fibroblast proliferation in response to serum stimuli without impairing cell viability. These results indicate a positive correlation between drug binding to AM or other cell types and their inhibitory effects on cellular activities including oxygen consumption, superoxide release, hydrogen peroxide secretion, chemiluminescence, IL-I release, and proliferation. The ability of-these bis-basic ethers to modify AM and fibroblast functions in vitro suggests that further investigation of their reported antifibrotic potency in vivo is warranted.

Dec 1, 1996

This consolidated index covers all publications of the Institute for the years 1926 through 1935. The following list indicates subjects of volumes and gives numbers or abbreviations used to designate them. TRANSACTIONS VOLUME *G26. Petroleum Development and Technology in 1925 (Published in 1926). *G26. Petroleum Development and Technology in 1926. *E27. Institute of Metals Proceedings. 73. Nonferrous Metallurgy, Milling and Concentration, Nonmetallic Minerals, Institute of Metals and Iron and Steel. [ ]

Jan 1, 1936

By Hal J. Kelly

A number of problems that developed in processing the halloysitic clays of eastern Washington and northern Idaho were investigated by the Bureau of Mines. The deflocculating effect of tetra sodium pyrophosphate is compared with several other compounds, and on the basis of current theory, the advantage of sodium pyrophosphate as a deflocculating agent is explained. The adsorption of the sodium ion by clay in a clay"-water system was established by a radioactive tracer technique, and the deflocculating action of sodium pyro- phosphate was postulated. The effective dispersion of the halloysitic clays was limited by the occurrence of tightly bound aggregates of small, individual crystals. Disaggregation of the agglomerates was investigated by liquid extrusion and ball milling of dilute slurries and by extrusion of the clay in a plastic state. The greatest increase in the production of small particles was by high? pressure liquid extrusion.

Jan 1, 1963

By Richard B. Stein

Section 25 has been assembled to give the geological, mining, or metallurgical engineer an overview of some of the important downstream operations that typically follow mining activities. This subject is obviously too broad and complex to be covered in detail within this Handbook. However, the engineer will be interested to learn about the basic fundamentals, and especially how they might affect the economics of the total project from prospecting and mining through to metals recovery and marketing. In this way, it is hoped that the engineer will have a better overall appreciation for the technical and commercial prospects of a mining and metal-producing project.

Jan 1, 2008

By J. H. Bain, D. C. Haigh, L. C. Parsons

Jan 1, 1964

By A. A. Paoli

The selection of a mining plant for carrying on development work presents many problems distinct in themselves, and affected by various local factors. In this paper, the writer proposes outlining and discussing in some detail the chief factors governing the economic selection of such plants. This will be followed by an enumeration of the underground and surface plant required for carrying on several hypothetical exploratory and mining operations. Where it is impossible or not convenient to obtain hydro-electric power, and where wood for fuel is scarce, we now find oil engines being used. A 100 h.p. oil engine, such as would be required to operate a three-drill air compressor, consumes approximately five Imperial gallons of fuel-oil per hour at full load. On the basis of a 60 per cent load factor, this gives, for eight hours' operation, a probable actual consumption of twenty-four Imperial gallons.

Jan 1, 1929

By B. P. Watson

The first crush pillars on the Bushveld platinum mines were introduced at Union Section in 1978. Before the introduction of crush pillars, serious problems were experienced when stoping advanced to a point 30 m to 40 m on both sides of the centre gully. At least three to four stopes were collapsing per month. The introduction of the pillars stopped the stope collapses in the mining area where they were introduced. The residual stresses of these pillars were never measured; however, the successful elimination of the ?back-break? problem suggests that the original pillars had a residual strength of at least 8 MPa. Apart from back analyses, very little work has been done to determine the residual strength of crush pillars and only very recently have any measurements been made. The lack of knowledge in this field has resulted in pillars being designed based on experience. Concerns about stope collapses, similar to the Coalbrook disaster, have led to larger pillars being cut in more recent times. If such pillars were cut in brittle quartzites they would always fail violently but the ductile nature of the Merensky Reef generally allows large pillars to fail without bursting. Occasionally, however, one would burst in a working area. Increased incidence of bursting has been reported on some mines at deeper levels but most of these bursts occur in the back areas. Nevertheless, the incidence of bursting increases the risk of falls of ground in already dangerous areas, and the larger pillars decrease the extraction ratio. This paper describes the evaluation of stress measurements conducted in two boreholes over a crush pillar with dimensions 2.5 m x4.0 m, and a height of 1.2 m. Boussinesq equations for vertical and shear stress were used to analyse the original measurements and provide a stress profile across the pillar as well as the residual strength of the pillar. The results showed an unexpectedly high peak stress of 280 MPa at the centre of the pillar and a residual strength of 48 MPa. The reason for the high residual strength is suspected to be the result of the stiff environment under which the pillar failed and the small height of the siding on the up-dip edge of the pillar. More measurements should be conducted on several mines to establish a range of residual strengths for narrow crush pillars.

Jan 1, 2008

By Pilon CG, Deakin RC

It is proposed that a waste rock dump be constructed on slopes consisting of soft colluvium and weathered Chim Formation mudstone at the Porgera Gold Mine, in Enga Province, Papua New Guinea (PNG). Geolog- ical, geomorphological and geophysical investigations were conducted in support of geotechnical studies to assess the physical character of the 6km2 site. Geomorphological studies focused on the extent and nature of colluvium cover and landslide activity. Detailed ground traverse mapping resulted in classification and delineation of eight terrains and seven material types. Seismic refraction and resistivity profiling, combined with drilling, provided subsurface data. Results were presented as standard profiles, coloured contoured sections and plans. Subsurface features, including deep colluvial channels, buried cliffs, slump blocks and buried alluvial channels, were identified. Results of the combined investigations allowed designers to model the colluvium/ bedrock surface and identify critical areas of deep, mobile colluvium and weak bedrock. A design approach was developed which accounted for the morphology of landslide systems and distribution of colluvium types.

Jan 1, 1991

By David K. Hylbert

This study investigated stratigraphic and structural causes of roof falls in room-and-pillar drift coal mines in nine mines in eastern Kentucky. A contract modification provided for remote sensing studies in the Dunkard Basin of West Virginia and Pennsylvania. Results of stratigraphic and structural studies of an earlier contract (H0133018) were applied to several new mines. It was found that similar rock sequences contributed to unstable roof conditions. Structure contour and isopach maps were found useful In projecting these trends together with fence diagrams. Using Landsat imagery, a direct relationship was found between lineament direction and the trends of rock jointing, roof fall zones, "snap top" zones and sandstone channels in the examples cited. It was found that, by analyzing lineament intersections, from 50 percent to 65 percent coincided with roof falls.

Jan 1, 1980

By Karl Oltay

A series of 15, stations beginning with Potsdam and Budapest and ending with Budapest and Potsdam were occupied inn the period August, 1908, to January, 1909. The intermediate stations were all at points which had been connected by Baron Eötvös with torsion-balance traverses. The observations were made with an invariable pendulum of the standard four-pendulum type of instrument of the Geodetic Institute, made by Stückrath at Berlin-Friedenau. The observations at each of the field stations lasted-one to three days with one exception; two or three time determinations were made; four to eight series of pendulum observations were made; the error of determination of the elevation of the instrument above mean sea level ranged from 0.30 meter to 1.10 meters, with the exception of the Arad and Baja stations, where the elevation was known more accurately and averaged about ± 0.8 m, which would cause an error of ± 0.25 x 10-3 dynes. No topographic correction was applied. The values for ?g were taken from Eötvös: Report on Geodetic Observations in Hungary, especially Observations with the Torsion Balance, Budapest, 1910. The differences in ?g as determined, by the torsion balance and by the unvariable pendulum were: Kuvin-Hidegkut 1.2 km. 0.001, Livada-Kuvin 9 km. 0.001, Pankota-Livada 13 km. 0.004, Kuvin-Arad 20 km. 0.000, Pankota-Arad via Kuvin 42 42 km.0.005, Pankota- Arad via Kurtics 50 km.0.000 dynes. Oltay concludes that if the stations are close enough together and if the terrane is rather flat, the measurement of ?g with the Eötvös torsion balance is as accurate as with the invariable pendulum. -- Donald C. Barton.

Jan 1, 1929

By James Wm. White

Today a large number of open pit mines use computer-based mine management systems to automatically assign haul trucks, track equipment, and manage information. Now advances in digital communications allow the use of these systems in underground operations. Underground mine management systems help maximize production by providing impressive gains in areas such as equipment and manpower utilization, draw point equalization in block caving operations, preventive maintenance, and safety. Current systems use allocated or "locked" train and LHD dispatching. While allocated dis-patching rarely optimizes open pit production, it offers an efficient mode of operation underground where options are more limited.

Jan 1, 1996

By AIME AIME

WHEN "Chief" Buehler in mid-September set out on his official 10,000 mile swing-around-the-circle visiting Local Sections he decided not to tell his audiences how to organize and operate a state geological survey. As the director for 28 years, of the Missouri Bureau of Geology and Mines (which, he concedes, is the best in existence) lie could have done this to good advantage; but he preferred to discuss affairs of the Institute. In 25 speeches made to member and student groups, he dwelt on sonic or all of the following phases of activities. He stressed the vital importance of the Local Sections in providing the opportunity for members to associate under pleasant auspices with others in their profession. The benefits of Institute membership he classified as tangible and intangible. Of the two lie felt that the latter were more important. A man's progress in his profession depends in large measure upon a broad acquaintance and friendship with others. The Institute is incomparably the best medium for meeting fellow engineers. The primary, function of the new enlarged Membership Committee is to obtain a comprehensive list of engineers eligible to be members, always hearing in mind that the standards of membership must not be lowered in any degree. These men are to be invited by individual letter to apply for membership. Whether they become members or not is of less importance; but it is vital that no qualified man should be outside the fold for the reason that membership had never been suggested to him. Dr. Buehler emphasized repeatedly his feeling that the younger man that had never had Institute membership brought specifically to his attention had been cheated:

Jan 1, 1935