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By R. Pakalnis, H. Miller, Madill. T.

"This paper describes a methodical approach to the estimation of the orientation and the magnitude of in-situ stresses. The study was performed at the Ruttan Mine, Sherritt Gordon Mines Ltd. , a 6,000 T.P.D. underground operation, located in northern Manitoba, Canada. It involves an initial estimate to be made based upon: structural interpretation • virgin stress measurements conducted in other areas (world wide, regional)The verification of the prevailing stress regime was made by conducting CSIRO hollow inclusion(1) overcoring measurements. The current cost for a virgin stress determination is about $7000 per measurement(2) and the difficulty encountered in attaining a good reading is high. This paper will describe the analytical procedures employed at Ruttan in evaluating the in-situ stress magnitude and orientation based on three overcore tests. It is proposed to perform an additional six measurements in order to verify the following results:Vertical stress = av (MPa) = 0.027 by depth (m)Major principal stress = o! """" 2.5 xav (340°/-20°)*Intermediate principal stress = a2 - 1.2xav (070°/0°)Minor principal stress = a3 """" o.8xov (160°/-70°)IntroductionThe Ruttan Mine of Sherritt Gordon Mines Ltd., a 6,000 T.P.D. underground operation, is located in northern Manitoba, Canada (Fig. I). The Ruttan copper-zinc orebody is a multi-lensed, steeply dipping (70 degrees) en-echelon deposit. Individual lenses have a maximum strike length of 350 m with widths varying from 7 m to 61 m. The mining method is o pen stoping with delayed backfilling and extends from surface to 860 m below surface."

Jan 1, 1985

By John H. Perry

The Bureau of Mines has developed several techniques for draining methane from coalbeds in advance of mining. Drilling long horizontal holes from an underground location is one such technique, which was successfully demonstrated in the Pittsburgh and Sunnyside Coalbeds. The same technique has now been applied in the Mary Lee Coal bed at Jim Walter Resources, Inc.'s No. 4 Mine, Brookwood, Ala., where two holes were drilled horizontally--one to a depth of 1,010 feet (308 m) and the other to 540 feet (165 m). The 1,010-foot (308-m) hole proved successful in degasifying a portion of the Mary Lee Coalbed. The hole drained methane for 1 year, during which time the initial gas flow of 200,000 ft3/d (5,663 m3/d) declined to 65,000 ft3/d (1,840 m3/d). Total gas production was 40 x 106 ft3 (1.1 x 106 m3). The gas was of commercial quality, with 98 pct methane and a heat rating of 990 Btu/ft3 (36.89 Mj/m3). The methane emissions from the faces of the mine section advancing into the degasified zone were reduced by 60 pet. The 540-foot (165-m) hole was terminated prematurely when it became impossible to maintain an open hole. Because of caving, very little gas was drained through this hole.

Jan 1, 1982

By A. L. Martikainen

In fluctuating airflow, continuous air velocity recording is the most reliable method of air velocity measurement. It allows for fast recognition of changes and the calculation of long-term averages. Also, it enables the mine operator to identify when the airflow has decreased to a point requiring action. Using ultrasonic anemometers provides an accurate option for continuous air velocity monitoring. This paper provides information about the effect of common obstructions in underground mining on air velocity readings. Stationary and moving obstructions are used to represent workers and equipment that would cause discrepancies in measured airflow. Also, it is important to know how large of a sample size is required to ensure reasonable accuracy of results. Statistical analysis is used to evaluate the required sample size. The sampling procedure is further studied by comparing two different sample rates. The results show that obstructions provide noticeable differences in air velocity measurements. Also, movement of obstructions can be recognized from changes in results. Surprisingly small sample sizes provide reliable air velocity information. Standard sample rates are found to be suitable for the underground environment.

Jan 1, 2011

By P. Roghanchi

The Rock Mass Rating (RMR) system is an internationally recognized classification system that can be used for preliminary ground control design. The RMR system assigns quantifiable values to predefined classified parameters of a rock mass. Assigning a single value rather than a range to each parameter is a source of uncertainty, however, assigning a single value can be useful for further studies related to RMR ratings. Fuzzy systems are being used in an increasing number of application areas where linguistic rules are used to describe the system. In past decades, fuzzy systems have been successfully used in geotechnical and mining engineering problems to cope with uncertain data as well as with vagueness. In such scenarios, linguistic rules and rating-based classification of rock masses have always been questionable. The objective of this study is to apply fuzzy set theory to the RMR classification system. The fuzzy system proposed in this study is specified for weak and very weak rock masses (RMR<50) based on data collected from Nevada gold mines where 68% of RMR data is in the ?poor? and ?very poor? classes. In this approach, a Mamdani fuzzy algorithm has been constructed to evaluate basic RMR89 rating for the ?wet condition.? Comparison between basic RMR89 and fuzzy RMR shows the fuzzy RMR system is valid to predict RMR from the discrete rating of each input parameter.

Feb 27, 2013

By W. G. Jewitt

THE Box mine, situated in Saskatchewan on the north shore of lake Athabasca, is unique in two respects. It is the first and, so far, the only gold mine in Saskatchewan, and it is the only gold mine in Canada to employ a large-scale forced caving system as the main mining method. Discovered in 1934 by Tom Box, an Edmonton prospector, its subsequent history, while breaking no records for speed, has been one of steady and more or less normal development. Camp and plant are situated close to the shore of Beaverlodge bay, sorne 50 miles east of the Saskatchewan-Alberta boundary and 35 miles south of the north boundary of the Province. The railhead at Waterways, Alberta, is about 220 miles to the southwest. Prince Albert lies some 450 miles to the south. The surrounding country presents a rather rugged variation of the usual Precambrian topography, with hills rising five to six hundred feet above lake Athabasca. The numerous lakes and islands, together with the wide expanse of lake Athabasca, compose an attractive scene, at least in the not over-long &apos;open water&apos; season. The winters are long but not extremely cold, judged by prairie standards. The small lakes break-up around May 20th and the &apos;freeze-up&apos; stops navigation early in October. Though apparently remote, the Box mine is fortunate in having reason-ably cheap transportation from Edmonton. The 300-mile railway from Edmonton to Waterways is the most expensive section, the rate for 1st class freight being $1.70 per hundred pounds and for 5th class freight $0.77 per hundred. Freight from Waterways to the mine, approximately 140 miles down the Athabasca river and 90 miles along lake Athabasca, is delivered by barges and tugs for 50 cents per hundred pounds. All freight is delivered during the &apos;open water&apos; shipping season, which lasts from about .Tune 7th to October 7th. In normal years, barges are loaded to 3 to 3 1/2feet draught up to September 1st. After that date, and earlier in dry years, shallow water at Waterways reduces the barge loads. Barges of 100 to 200 tons capacity handle all mining freight, including pieces up to 15 tons in weight, without undue difficulty.

Jan 1, 1940

By Ann Barron

“Hurry up” is the latest battle cry at explosives companies struggling to stay in compliance with the ever-growing onslaught of government regulations. The pressure continues to mount on industry professionals who face stiff penalties if their companies fail to comply with the law. Such penalties can range from monetary fines and revocation of blasting permits and licenses, to increased liability for civil claims or even criminal charges.

Jan 1, 2006

By Compiled by Staff

"INTRODUCTIONThe U.S. Bureau of Mines (USBM) was established in the public interest to conclude inquiries and scientific and technologic investigations on mining and the preparation, treatment, and utilization of mineral substances; to promote health and safety in the mineral industries; to conserve material resources and prevent their waste; to further economic development; to increaseee efficiency in the mining, metallurgical, quarrying, and other mineral industries; and to inquire into the economic conditions affecting those industries. The organic act of the Bureau, as amended by Congress and approved February 25, 1913, made it the province and duty of the U.S. Bureau of Mines to ""disseminate information concerning these subjects in such manner as will best carry out the purposes of this Act.""In accordance with this directive, USBM reports the findings of its research and investigations in its own series of publications and also in articles that: appear in scientific, technical, and trade journals; in "" proceedings of conventions and seminars; in' reference books; and in other non-USBM publications. The number of these reports, the wide range of subjects they cover, and the variety of mediums in which they appear make this kind of list both necessary and valuable.This edition describes reports and articles published during calendar years 1992 and 1993. It supplements the 50-year list of Bureau publications from July 1, 1910, to January 1, 196O 2; and these 5- year lists of publications and articles: from January 1, 1965, to December 31, 1969 4, from January 1, 1970,to December 31, 19745 , from January 1, 1975, to December 31, 1979 6 , from January 1, 1980, to December 31, 1984 7 , and from January 1, 1985, to December 31, 1989 8."

Jan 1, 1994

By George S. Rice, L. C. IlsLey

"A remarkable explosion of fire-damp caused by a discharge of lightning at the new shaft at the Sitalpur coal mine, has been reported by the Chief Inspector of Mines of India, who gave the following details:""The explosion occurred during a thunderstorm, and the evidence showed that a flash of lightning had, to all appearances, passed down the shaft caus¬ing disruptive discharges at certain points between the guides and the winding rope, rending the latter at two places situated respectively .228 .feet and 278 feet from the surface, The distance between the winding rope and the side of the shaft was 5 feet 4 inches, indicating a spark gap ;of this width, and an intensity of discharge which could not fail to ignite the explosive mixture of gas and air known to be present in the shaft.""The Compressed Air Magazine, January 1920 issue, which contained the above extract also goes on to state;""In 1915, M, Ferey described in a paper read before the Societe de l'Industrie Minerale phenomena of a similar character to the above. In a pit liable to sudden outbursts of gas, for the sake of safety, shot firing was carried out from the surface. During a storm, in the year 1905, shots went off in two places after the detonators had been connected to the conductors) we read in the Colliery Guardian, London. These shots were situated respectively 1,400 and 1,410 metres from the firing station, Realizing the possible danger from this cause, the precaution was taken to cut the conductors at the bottom of the shaft and to connect there just before firing, Even under these conditions a shot went off spontaneously, -.owing, it is believed, to lightning."""

Feb 1, 1920

By H. Oda, L. E. Fong, K. K. McBride, B. P. Weiss, F. J. Baudenbacher, A. Usui

Fine-scale dating is a key parameter in characterizing the growth history of hydrogenetic ferromanganese crusts. We once compared several dating methods, micropaleontological (calcareous nanofossil), radiometric (10/9Be), and paleomagnetic (step-wise measured inclination) methods on single samples, but these independent methods were not consistent with each other (Joshima & Usui, 1999). For example, a 4-cm thick crust was dated as 3Ma by the fossil-paleomagnetic combined method, while it dated older than 5.5 Ma by Be-10 dating. This discrepancy suggests a question if the Be-10 radiometric method can give us false ages or growth rates (Usui et al., 2002) because of post-depositional change, diffusion or other reasons. In order to answer the question, we conducted ultra-fine magnetostratigraphy with a SQUID microscope on the same hydrogenetic Mn crust sample. Rock magnetic measurements revealed that the main magnetic mineral is well dispersed single domain grains, which is typical to magnetite but not yet specified (Oda, 2005).

Aug 24, 2006

By S M. Denn

The Cawse nickel-cobalt operation is situated 50 km NW of Kalgoorlie in Western Australia, at latitude30o22&apos;30&apos;&apos; south and longitude 121o08&apos;30&apos;&apos; east on the Kalgoorlie 1:250 000 geological map sheet (SH 51-9) (see Figure 1). The project is owned and operated by Centaur Nickel Pty Ltd (CTR) and was the first in Australia to commercially produce nickel metal and cobalt sulphide through pressure acid leach (PAL) technology. Cawse has a total resource base (all categories of resources + reserves) of 213 million tonnes Mt at 0.7 per cent Ni and 0.04 per cent Co, comprising 127 Mt at Cawse Central which is 100 per cent owned by CTR and 86 Mt at Cawse Extended where CTR has a 80 per cent equity. Cawse Extended is located immediately to the northwest of the Cawse Central leases. All current reserves (proved and probable) of 30 Mt at 1.0 per cent nickel are contained within Cawse Central. In addition the Siberia project area 20 kilometres to the NW has a resource of 63 Mt at 0.7 per cent Ni. Cawse is a dry laterite deposit, with nickel and cobalt hosted by iron and manganese oxides. Cawse Central mineralisation extends over a ten kilometre strike length, with three pits currently being mined. The Bunyip pit has the premier nickel and cobalt grades within Cawse Central. There are seven dominant lithology types forming mappable units within current pit exposures. Four of these units are host to nickel and cobalt mineralisation. Ore types are defined as Upgrade, Grind and Non-upgrade, depending on their physical characteristics with respect to the treatment route. Mining commenced in February 1998. To the end of calender 1999 the operation has produced 2100 tonnes nickel plate and 470 tonnes of cobalt as a cobalt sulphide product. Future production will target 9000 tonnes per annum Ni metal and up to 2000 tonnes per annum Co, based on processing 500 000 tonnes of ore per annum.

Jan 1, 2000

By R. Fragoudakis

AISI 4130 steel is a medium carbon Cr-Mo steel used in automotive, aeronautic and other general-purpose industries. In this study, 4130 steel fatigue specimens were carburized at 927oC to enhance the carbon content in the steel, raising it from approximately 0.30% (non-carburized) to 0.90% (carburized, oil quenched and tempered). Rotating bending fatigue tests were performed on the R. R. Moore Rotating Beam Fatigue Testing System, in order to determine the high cycle fatigue (HCF) life of 4130 steel and plot the corresponding S-N diagrams. A comparison of the results of carburized and non-carburized specimens shows that carburizing of steel: a) increases the surface hardness and b) improves the fatigue strength of the steel by at least two orders of magnitude.

Jan 1, 2010

By Erik Westman

Coal bumps remain one of the industry?s most devastating but least understood phenomena. If changes to the internal conditions of the rock mass could be observed there is hope that bumps could be forecasted. Seismic tomography has been used over the past 25 years in an attempt to image these changing conditions in the vicinity of the longwall face. This paper describes the history and practical considerations of using seismic tomography in bump-prone coal mines. The implementation of seismic tomography at six different longwall mines will be described along with lessons learned. Early studies used mining independent sources of seismic energy, including explosives and sledgehammers. Subsequently more operator friendly sources, such as the mining equipment itself and mining-induced seismicity, were used. Seismic energy sensors have been placed in gateroads and on the surface above the mine. Each of these configurations has associated advantages and disadvantages. Although the results obtained have been encouraging, the application of seismic tomography to monitoring a bump-prone longwall face is still immature. The ultimate goal of clearly imaging changing stress conditions in the longwall panel in a manner that does not inhibit mining operation is still distant, yet drawing nearer. When this goal is achieved, the industry will have a capable tool for identifying locations where bumps are imminent.

Jan 1, 2008

By C. A. Snyders

This paper investigates the recovery of platinum group metals (PGMs) from a dilute cyanide leach solution containing base metals, in a manner similar to that used for gold extraction in a typical CIP process, and focuses on both the adsorption and elution stages. The carrier-phase extraction of precious metals using activated carbon offers significant advantages over other processes in terms of simplicity, the high pre-concentration factor, rapid phase separation, and relatively low capital and operating costs. As a sorbent, activated carbon is still by far the most important material because of its large surface area, high adsorption capacity, porous structure, negligible environmental toxicity, low cost, and high purity standards. Adsorption tests were performed on a pregnant alkaline leach solution (0.15 ppm Pt, 0.38 ppm Pd, 0.1 ppm Au) resulting from cyanide extraction performed in column leach tests. The initial adsorption rates of platinum, palladium, and gold were very fast and recoveries of these three metals were approximately 90 per cent after 2 hours and 100 per cent, 97.4 per cent, and 99.9 per cent respectively after 72 hours. The parameters that influence the extraction of PGMs and Au were examined to assess their relative importance during the adsorption process in order to provide the basis for process optimization. The concentration of thiocyanate was not identified as significant factor for PGMs adsorption, while nickel concentration was the most significant extraction process parameter. Base metal cyanide complexes adsorb and compete with the PGM complexes for sites on activated carbon, and while copper adsorption can be minimized by adjusting the residence time, nickel adsorbs at approximately the same rate as that of the PGMs, influencing the loading capacity and adsorption kinetics of the PGMs. The feasibility of eluting platinum and palladium cyanide complexes from activated carbon using an analogue of the AARL process was investigated. Platinum and palladium elute from activated carbon almost to completion in 4 to 5 bed volumes at 80°C, while the elution of gold at this temperature is slow, with a significant amount of gold still to be eluted after 16 bed volumes. Cyanide pre-treatment was found to have a significant influence on PGM elution. Higher cyanide concentration in the pre-treatment step results in more efficient elution up to a point, and experiments suggest the possibility of an optimum cyanide concentration, beyond which elution efficiency starts decreasing.

Jan 1, 2012

By Chi Zhang, Junyi Wu

"The use of permanent stainless steel cathodes for electrorefining and electrowinning of cathode copper had been introduced to the market long time ago and now is a well-accepted technology worldwide. During the last decades, the Chinese copper refinery industry had been growing rapidly and many large scaled production plants had been built. In the modern refineries, permanent stainless steel cathodes are introduced and used instead of traditional starter sheets. The most common steel grade used is austenitic stainless steel S31603 (316L/1.4404), while both S30403 (304L/1.4404) and N08904 (904L/1.4539) have been used depending on the actual working conditions, especially with regarding corrosion environment. While 316L permanent cathode functions well in many plants, different kind of problems, such corrosion and deformation, have been reported. There is therefore an increased need for more suitable material. New stainless steels, such as duplex stainless steels, with better properties have been tried and introduced into the application of permanent stainless steel cathode with satisfied results. The article introduces first the Chinese copper refinery industry and properties of duplex stainless steel in general, and then describes the development of using permanent duplex stainless steel cathode, including the actual working conditions, production of cathode sheets as well as the experiences of application in details. After more than one year’s usage, the advantages of permanent duplex stainless steel cathodes are clear seen.INTRODUCTIONChina has become a major player in the international copper market, accounting for around 40 percent of global refined copper demand. Despite the slowdown of the Chinese economy, the consumption of copper products will still increase, but with a medium and/or low growth which will be the new situation for the coming years. The average growth rate is expected to be around 5 percent per annual. In the coming Five-Year plan for National Economic and Social Development a number of initiatives will be finalized which will require massive amounts of copper. In 2015, the expected consumption of copper products will be over 9 million metric tons. The main driver of the consumption is the electric power industry which accounts nearly the half of the total consumption; followed by cooling application with 15% and transportation with nearly 10%, see figure 1."

Jan 1, 2016

By Edie Trimmer

Utah statute defines sovereign lands as "those lands lying below the ordinary high water mark of navigable bodies of water at the date of statehood, and owned by the state by virtue of its sovereignty." The lands within the bed of Great Salt Lake (GSL) are, by this definition, sovereign lands, acquired at statehood in 1896 in accordance with the "equal footing" doctrine, granting each state control and ownership of navigable waters and the lands underneath those waters within its borders. Under public trust doctrine, the state, as trustee for the people, bears responsibility for preserving and protecting the right of the public to use of the waters for navigation, commerce, fishing, recreation, and wildlife habitat. Also by statute, sovereign lands are defined as "state lands," to be managed by "multiple use sustained-yield principles." The Division of Forestry, Fire and State Lands is given management authority for sovereign lands and, as manager, has responsibility to prepare comprehensive plans, initiate studies of the lake and its resources, implement comprehensive plans through state and local entities, and coordinate the activities of various divisions within the Department of Natural Resources (DNR). The Division of Forestry, Fire and State Lands also has responsibility for management of mineral leasing on sovereign lands. The many resources on the lake--water, minerals, wildlife, recreation, archeological and historical values--are managed by as many state agencies which occasionally creates conflicts. The brines of GSL contain several ions that crystalize into valuable minerals during evaporation. The major ions in the lake are, in order of relative abundance, chloride, sodium, sulfate, magnesium, and potassium. Mineral products which are currently extracted from lake brines are sodium chloride, magnesium chloride brine which can be sold as flake magnesium chloride or further processed into magnesium and chlorine gas, and potassium sulfate. Mineral products which have potential for extraction include gypsum, sodium sulfate, and trace amounts of lithium, boron, and bromine. The GSL contained an estimated 4.3 billion short tons (st) (3.9 billion metric tons [mt]) of dissolved salts in 1998. Utah Geological Survey (UGS) estimates of the dissolved salt content in GSL have fluctuated from 4.0 to 5.5 billion st (3.6 to 5.0 billion mt) due to the dynamic conditions in the lake as salts are precipitated and redissolved, and due to the diversion of brines from GSL, such as the West Desert Pumping Project. The lake has four areas of varying salinity, separated by dikes or other man-made structures: north arm and Stansbury Bay brines at near saturation (25 to 27 percent total dissolved solids [TDS]); the main body of the south arm with concentrations ranging from 7 to 15 percent TDS as lake elevations fluctuate; the waters in Farmington Bay at approximately 3 to 5 percent TDS; and Bear River Bay at <1 to 7 percent TDS. The percent TDS in Bear River Bay fluctuates with lake level, and changes in Bear River inflow. The transfer of salts from the south arm to the north arm has raised questions about the viability of the mineral and brine shrimp industries. The UGS and the U.S. Geological Survey (USGS) continue to monitor salinities at designated sites on the lake to document changing lake salinity. A recurrent theme is that placement of dikes and diversions can have significant and rapid impacts on various conditions in the lake. Hydrocarbon resources on the lake are significant, but presently undeveloped. The hydrocarbons are low gravity (4 to 9 degree API) and tar-like, contain high nitrogen concentrations, and up to 12 percent sulfur. The unusual characteristics of the oil have been the subject of studies by chemists at Weber State University and University Louis Pasteur de Strasbourg. However, these resources are difficult, and at present, uneconomic to extract using current technology because of the nature of the hydrocarbons, and production in "an offshore, highly saline environment." Oolitic sand deposits make up many of the beaches and shorelines around the lake. Because of their high calcium carbonate content, oolites have been used by Magnesium Corporation of America (MagCorp) and its predecessors for acid neutralization and dike construction. Oolites are also used in very minor amounts in flower drying. The Utah Division of Oil, Gas and Mining reports up to 130,000 st (118,000 mt) mined annually by MagCorp from U.S. Bureau of Land Management (BLM) lands adjacent to GSL. Currently, there are twelve producing mineral leases which generated slightly more than $1,000,000 in royalties during calendar year 1998. IMC Kalium Ogden Corp. (IMC Kalium) produces potassium sulfate and magnesium chloride from brines concentrated through solar evaporation in Bear River Bay and Clyman Bay. By-product sodium chloride is transferred to IMC Salt, which packages and sells the salt. MagCorp produces magnesium metal from brines concentrated in Stansbury Bay. Cargill Salt produces sodium chloride from brines provided by MagCorp under a lease agreement. Morton Salt produces salt at the southeast end of Stansbury Island. Lastly, North Shore Limited produces cocentrated brines for use in dietary and mineral/vitamin supplements near Spring Bay in the north arm of the lake. Producers of magnesium, potash, and salt from GSL contribute significantly to the value of metals and industrial minerals in Utah. Together these companies contribute approximately $240 million in gross value, or 18 percent of the value of the state&apos;s nonfuel mineral production. Most of this production is exported.

Jan 1, 2001

By John Latilla

Exxaro Mining?s Matla Coal situated in Mpumalanga, South Africa operates two shortwall faces on the No 4 and No 2 seam while the No 5 seam has also been longwalled in the past. Severe strata loading events have lead to a number of serious roof falls on the wall face (facebreaks) resulting in safety threats as well as considerable production losses. In 2002 the No 4 seam shortwall suffered a facebreak restricted mainly to the tailgate side of the mining panel due to a thick, near surface dolerite sill not breaking properly. This was partly due to the premature suspension of longwalling in the overlying No 5 seam. The resultant overloading lead to severe pillar damage and subsequent bord collapse. Surface pre-split blasting was successfully used to relieve the pressure as well as to pre-condition the dolerite above the following two panels. The shortwall on the No 2 seam has experienced mid-face loading due to No 4 seam chain pillars lying over this area and creating a secondary cantilever effect. Pre-split blasting of the solid rock above the No 4 seam pillars has resulted in a significant reduction in the number of facebreaks. The panel layout of the No 2 seam was subsequently changed so that the chain pillars on both the No 4 and No 2 seam are superimposed whereas previously they were offset.

Jan 1, 2007

By Keith Schaeffer

This paper presents a history of the planning, engineering and construction completed for the railroad tunnel crossing part of the West Elizabeth Avenue Storm Drainage Project, undertaken to relieve flooding within the West Elizabeth Avenue area in Linden, NJ. The Railroad Crossing Contract is part of the larger Linden Drainage Improvements Project consisting of a new gravity storm sewer system. The improvements are required to provide additional storm drainage for the City of Linden and the Merck Pharmaceuticals manufacturing facilities in the City of Linden.

Jan 1, 2008

By A. T. Harris

Ground quartzite, known in the industry as amorphous silica, is produced from a quartzite deposit near Honey Brook, Pa., by George F. Pettinos, Inc., of Bala-Cynwyd, Pa. The quartzite is mined by the open pit method and processed in a mill at the mine. The operation regularly produces five standard grades of sand and one grade of crushed stone; however, the company accepts special orders and will produce material to meet the customer&apos;s specifications. Beneficiation (chiefly crushing and screening) is controlled by laboratory screen tests on samples taken during preparation of the sand. The chief uses of the sand are for foundry operations, furnace lining, concrete aggregate, and Other specialized uses. The quartzite in this deposit is of uniform composition and does not require control by chemical analysis. However, for special purposes, analysis will be furnished.

Jan 1, 1965

By K. K. Kelley, W. W. Weller

The heat capacities of four crystalline silicates of barium ( BaSiO3 , BaSiO4 , Ba Si¸0 , and BaSi₂0 ) and two crystalline silicates of strontium (SrSio and Sr₂Sio ) were measured over the temperature range from 51 ° to 298° K. The results were used to evaluate the entropies at 298.15 ° K. The entropy values were joined with known heats of formation to obtain the free energies of formation of the silicates with respect to their constituent oxides at 298.15 ° K.

Jan 1, 1964

By Gary L. Seider, Dana A. Wesolek, Fred C. Schmednecht

"A new condominium project, The Atelier, developed by Pickus Companies located at the corner of Bryn Mawr and Sheridan in Chicago, IL required an earth retention system to protect the surrounding roads, alley, and existing neighboring apartment bui lding during its construction. Slurry Systems, Inc. (SSI) and Ground Engineering Consultants, Inc. designed the earth retention system using cantilevered sheet piling for three of the four sides: two sides bordering major streets and one side bordering an alley. For the fourth side, which borders an existing occupied brick building, a combination of sheet pil ing and AB. CHANCE® helical screw piers were used. SSI was actively involved in the review process of its earth retention system with the City of Chicago and quickly learned that there was no specific code for hel ical piers/anchors. (It appears that this is the case with most metropolitan cities throughout the United States). Consequently, the approval of underpinning for this project became the critical path, as much testing, calculations, meetings, and other details were required prior to its approval.SSI and AB. CHANCE® recognized that this process for underpinning approval must be seen by other contractors/suppliers who wish to use helical piers/anchors in the City of Chicago. Consequently, this project served as an opportunity to work with the City of Chicago and the City's Building Code Committee in furthering the development of the Helical Piers/Anchors Code, Section 1814. INTRODUCTION - HELICAL PIERSDefinition. A helical pier or anchor consists of one or more helix-shaped steel bearing plate(s) attached to a central steel stem (solid bar or pipe), which is installed by rotating or ""torquing"" into the ground. Each helix is attached near the tip, is circular in plan , and is formed into a screw thread with a defined pitch. Helical piers/anchors are pre-fabricated and can derive their load-carrying capacity through both end bearing and skin friction. The helical piers/anchors can be augmented with grout."

Jan 1, 2005