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ON July 2 the Krupp plant in Essen was occupied by the French. The City of Frankfurt, on the edge of the Mayence Bridgehead was surrounded by the French. French infantry and cavalry occupied some more towns in the Ruhr. These moves were apparently in the way of reprisals. The Bank of England on July 5 raised its discount rate from three per cent. to four, per, cent., the lower rate having previously prevailed for almost exactly a year.. The advance appears to have been inspired by the reserve ratio, but especially owing to the fact that the low rate in the London market had led to the out-flow of funds from there to other markets. Philip Snowden brought up again in the British .Parliament his motion in favor of the condemnation of the capitalistic system and the substitution of socialism. The motion was put to vote and was defeated by large majority, only the members of the Labor party voting for it. The Allies and the Turks finally came to an agree-ment at Lausanne, the Turks getting about all for which they asked. It would be tiresome to record the details. The main fact is that the Turks, after having been ejected from Europe in 1918, are now going to return. Russia agreed to the settlement respecting the Straits. The Soviet Government of Russia formulated and adopted, subject to ratification, a constitution for the United States of Russia, which appears to be patterned after the constitution of the United States of America and the unwritten constitution of Great Britain. The important thing about this seems to be that it definitely reunites the constituent parts of the old Empire, the semi-independence of the Ukraine being surrendered.

Jan 7, 1923

Raymond Weir Smyth, born Nov. 3, 1888, was the son of Herbert Weir Smyth, professor of Greek Literature at Harvard University. He graduated (A. B.) from Harvard in 1909 and later pursued advanced studies there in chemistry and in metallurgy. He held the position of metallurgist for the American Steel and Wire Co. at Worcester, Mass., and also for the Steel and Tube Co. at Youngstomn, Ohio. For a time he was inspector of munitions for the British Government and stationed at the Railway Steel and Spring Co. at Latrobe, Pa. For a short time, in 1917, he was Inspector of Ordnance for the U. S. Government, and the following year, having entered the U. S. Naval Reserve Force, he was ordered in a similar capacity to the Midvale Steel Co. In September, he removed to the Navy Yard, League Island, Philadelphia, to train for the obligatory minimum of six months' sea duty. There he contracted influenza, which was followed by pneumonia, from which he died, September 27, at the Navy Yard Hospital. Captain Braxton Bigelow* Captain Braxton Bigelow was the son of Major John B. Bigelow, U. S. A., retired, and grandson of the late John Bigelow, author, and Minister to France under President Grant. Captain Bigelow graduated

Jan 1, 1920

By Tetsuo Yamazaki

Natural cold seepages are characterized as rapid upward transports of methane from deeper parts of geological structures to the seafloor. Thermogenic and/or biogenic methane generated in deep sediments moves up to seafloor, and major part of methane is consumed in anaerobic oxidation of methane (AOM) and hydrogen sulfide is created in anaerobic sulfate reduction by consortium of microorganisms. Then the hydrogen sulfide is utilized by chemosynthetic communities near the seafloor, such as Acharax, Calyptogena, Bathymodiolus, and the mat-forming bacteria Beggiatoa (Fig. 1). When the supply of methane is large or rapid, remaining methane escapes from seafloor, and it is aerobically oxidized in seawater. A mass balance ecosystem model of chemosynthetic community around natural cold seepages in sediment layer and on seafloor has been created and improved by the authors (Yamazaki et al., 2005; Takeuchi et al., 2007). The model is constructed from 3 main processes as schematically shown in Fig. 2: (1) Methane supply process; (2) Ecosystem process; (3) Water column process. The part of chemosynthetic communities is in the ecosystem process. A numerical model CANDI (Carbon And Nutrient Diagenesis) was developed by Boudreau (1996) to simulate the biogeochemical processes such as organic matter, oxidant, nutrient, bi-product, and pH diagenesis in aquatic surface sediments. Then, the improved version named C. CANDI was developed (Luff and Wallmann, 2003; Luff et al., 2004). The authors created the same type carbon and nutrient diagenesis process model with calcium carbonate formation like C. CANDI (Yamazaki et al., 2005), and have added the sulfur oxidizing and immobilization processes (Takeuchi et al., 2007). The sulfur oxidizing and immobilization processes are connected with the carbon and nutrient diagenesis process model.

Jan 1, 2008

By Hugo E. Camargo

In an effort to reduce Noise Induced Hearing Loss (NIHL) in the mining industry, the National Institute for Occupational Safety and Health (NIOSH) is conducting research to develop noise controls for mining equipment whose operators exceed the Permissible Exposure Level (PEL). The process involves three steps: 1) Noise source identification (NSI), 2) development of noise controls, and 3) evaluation of the developed noise controls. For the first and third steps, microphone phased array measurements are typically conducted and data are processed using the conventional beamforming (CB) algorithm. However, due to the size and complexity of the machines, this task is not straight forward. Furthermore, because of the low frequency range of interest, i.e., 200 Hz to 1000 Hz, results obtained using CB may show poor resolution issues which result in inaccuracy in the noise source location. To overcome this resolution issue, two alternative approaches are explored in this paper, namely the CLEAN-SC algorithm and a variarion of an adaptive beamforming algorithm known as Robust Capon Beamformer (RCB). These algorithms were used along with the CB algorithm to process data collected from a horizontal Vibrating Screen (VS) machine used in coal preparation plants. Results with the array in the overhead position showed that despite the use of a large array, i.e., 3.5-meter diameter, the acoustic maps obtained using CB showed "hot spots" that covered various components, i.e., the screen deck, the side walls, the I-beam, the eccentric mechanisms, and the electric motor. Thus, it was not possible to identify which component was the dominant contributor to the sound radiated by the machine. The acoustic maps obtained using the RCB algorithm showed smaller "hot" spots that in general covered only one or two components. Nevertheless, the most dramatic reduction in "hot" spot size was obtained using the CLEAN-SC algorithm. This algorithm yielded acoustic maps with small and well localized "hot" spots that pinpointed dominant noise sources. However, because the CLEAN-SC algorithm yields small and localized "hot" spots, extra care needs to be used when aligning the acoustic maps with the actual pictures of the machine. In conclusion, use of the RCB and the CLEAN-SC algorithms in the low frequency range of interest helped pinpoint dominant noise sources which otherwise would be very hard to identify.

Jan 1, 2009

By C. F. Lee, Bezalel C. Haimson

A 300 m deep test hole at Ontario Hydro's Darlington nuclear plant site, 65 km east of Toronto, was used to determine the state of stress in the Paleozoic limestones (O-22O m depth) and the Precambrian granitic gneiss (220-300 m). The results of the hydrofracturing measurements indicated a state of high horizontal stress along the depth of boring and a consistent orientation of principal stresses in each geologic unit. These results were confirmed by a borehole TV camera survey, and by overcoring tests. The magnitudes and orientations of the measured in situ stresses were used in a feasibility study of siting an underground nuclear plant, and in particular in the geotechnical design of proposed reactor caverns in Precambrian rocks. Their implications on cavern stability under operational and accident conditions were analytically studied, taking into consideration the potential superposition of thermomechanical stresses under loss-of-coolant condition, and the possibility of thermal spalling in the host rock.

Jan 1, 1979

The meeting was called to order in the Albany hotel, with the President, John B. Marks, in the chair. At the request of the Secretary, the chairman brought before the Institute the question of a reorganization of the finances and system of conducting the Institute, explaining that, although the Institute is in good financial shape and the meetings are of great interest and are attended by a large and serious minded membership, the Institute is getting so large and of such value to the operators that it should be taken over by the operators, conducted by some man elected by and from the operators, and its financing put on a definite basis. At present, it was explained, the Secretary, not a coal operator nor interested in operating, arranges and conducts all meetings and finances the Institute from three sources: the very low dues, the advertisements published in the Proceedings, and by direct solicitation of contributions among the supply and machinery houses. Mr. James Dalrymple spoke vigorously on the need of having the Institute entirely free from any taint of commercialism. Upon motion by W. D. Brennan, seconded, a committee of four, one to represent each State, was voted. Appointment of this Committee was deferred temporarily. The reading of the minutes of the previous meeting was then called for, but upon statement of the Secretary, that the minutes were published in Volume 2 of the 1925 Proceedings, they were dispensed with. The Secretary-Treasurer's report was made informally inasmuch as the last report had not yet been audited. In brief, the Secretary reported on a cost of approximately $1,600.00 a year to publish and send out the Proceedings, an expense of approximately $1,800.00 to care for the Denver meeting, and an expense of approximately $1,200.00 to care for the summer meeting. The Secretary's salary of $25.00 a month has not been collected, but a certain portion of this has been used for stenographic expense. The Secretary asked for expression from the floor regarding the advisability of continuing the publication on the present elaborate plan. Mr. Gibson, Mr. Marks, Mr. Whiteside, Mr. Littlejohn, Mr. Dick and others spoke positively on the value of the present form of the Proceedings, and urged that no changes be attempted in this. Upon motion of Holbrook Mahn, it was moved, seconded and carried that E. H. Weitzel and W. F. Murray be made life members of the Institute in recognition of their services in the organization of the Institute, placing them with Floyd W. Parsons as the original organizers of the Institute. Mr. Murray spoke briefly in acknowledgment of the courtesy. Mr. Weitzel's words are included in the discussion A letter was read from George B. Pryde relative to the present emblem of the Institute. Upon motion by Mr. C. W. Sinclair, seconded by Mr. Dalrymple, it was moved that the consideration of a new emblem be

Jan 1, 1926

By K. B. Culver

"This paper provides background information on the expansion programs of Rio Algom Limited at Elliot Lake. Included are details on the Quirke expansion program, the Panel mine rehabilitation program, including the selection procedure for the tailings containment area, the Stanleigh mine rehabilitation program, housing, government regulations and the Environmental Assessment Board hearings. Introduction After 2Y2 years of public hearings, 4 years of arbritrating differences of opinion between our engineers and government licencing authorities, interspersed with research into radium removal and development of the LAMIX process and carrying out the work associated with some 24 control orders issued to us by the MOE, it is very difficult to compress all of the experiences and frustrations into a single paper. The highlights, as they relate to the expansion programs of Rio Algorn Limited and its affiliate, Preston Mines Limited, will be covered. Denison Mines Limited, of course, is the other uranium producer in Elliot Lake. They are currently in the process of expanding from 7,000 to 11,000 TPD by the second half of 1980 and then to 15,000 TPD by the mid 1980's. In giving this overview, the following seven items will be discussed: • The basis for Rio Algom's and Preston's expansion plans. • The Quirke Expansion. • The Panel Rehabilitation. • The Stanleigh Rehabilitation. • Housing Programs. • Government Licencing Requirements. • Environmental Assessment Board Hearings."

Jan 1, 1980

By Dale Preece

In the late 1970’s and early 1980’s substantial resources were devoted to research focused on producing oil from the vast oil shale reserves in the western United States. Since the oil is solidified in the pore space of the shale, extracting it in production level quantities presented monumental technical challenges. Major advances were made in the methods used to extract oil from the shale in large quantities. Extraction methods evolved to culminate in the underground in-situ retorting process. In-situ retorting relied on explosive blasting of the shale to fragment the rock and induce sufficient porosity and permeability for a burn front to propagate through the oil shale. That burn front consumes some of the oil and liberates a substantial portion of it (~30%) for collection and further processing. Oil shale retorting is a blasting intensive process where the entire retort is rubblized in one very large, delay timed blast. Retort 7 in Western Colorado consumed 540,857 lb of slurry explosive to rubblized 348,940 tons of oil shale. Current rock blasting fragmentation predictive capabilities have evolved substantially since these retorts were designed and tested. It is the purpose of this study to simulate the explosively induced fragmentation of oil shale using state-of-the-art computer codes and material models and to infer retort design implications for future development.

Jan 1, 2007

By Alexander Bowie

Of the following problems, some have been suggested by recent articles in technical journals, which have led me to believe that the mathematical discussion here submitted may be of use to mining engineers. Problem I. To Find the Grade or Angle of Inclination upon which the Power Required to Move a Loaded Car Down-hill Will Haul an Empty One Up-hill. Let a be the desired angle of inclination; C, the coefficient of' friction; W and w, the weight in pounds of the loaded and of the empty car, respectively.

Jan 1, 1902

By Hsun Hu, B. B. Ruth

The rates of migration of high-angle boundaries in zone-refined aluminum crystals rolled 20 to 70 pct in the (110)[i12/ orientation were studied. Following a recovery anneal at an appropriate temperature to stabilize the polygonized structure, boundary migration rates of artificially nucleated grains were measwed isothermally at several temperatures. Results indicate that the rate of boundary migration depends strongly on the amount of deformation and on the cell size of the polygonized matrix, and is related to the driving free energy by a power function. The degree of anisotropy in growth 0.f the re crystallized grains nn&apos;th preferred mientation is independent of deformation; the migration rates of the fast-moving and the slow-moping boundary segments of a gowing grain differ by as much as one order of magnitude. The actir\ation energy fm a grain boundary migration, although nearly the same for both the fast-moving and the slow-moving boundaries for a given deformalion, decreases from 45 to 30 kcal per mole with an increase in deformation from 20 to 70 pct reduction. Re crstallization by the growth of the artificially nucleated grains results in preferred orientation. The Percentuge of&apos; grains favorably oriented for growth increases with increasing deformation. None of these grains corresponds to the ideal Kronberg-Wilson orientation relationship. The observed growth aniso-tropy is discussed in terms of boundary structure. The boundary velocity as a function of the cell inter -facial area, or the driving free energy, is discussed in the light of current theories of boundary migration. It is well established that recrystallization with re-orientation occurs by the migration of high-angle boundaries of strain-free grains. The driving force for this process is provided by the free energy stored in the metal during deformation. A quantitative study of the effect of varying driving force on grain boundary migration in deformed metals has not been possible heretofore, primarily because of: 1) concurrent recovery steadily decreasing the available driving free energy for boundary migration, &apos;-3 and 2) in-homogeneity of strain in the deformed metal.4 Aust and Rutter3 studied grain boundary migration in striated single crystals of zone-refined lead. Although the driving free energy in such crystals remains unaltered during annealing, this method does not provide a range of driving free energies over which measurements of grain boundary migration can be made. In the present investigation, the rates of migration of high-angle boundaries in deformed aluminum zone- refined single crystals were studied at various temperatures, after deformation ranging from 20 to 70 pct reduction by rolling at -78°C in the (ll0)[i12] orientation. The boundary migration rates along different crystallographic directions were determined under steady-state conditions, i.e., in the absence of competing recovery processes or impingement of recrystallized grains growing into the deformed single crystal matrix. Simultaneous recovery was eliminated by suitable anneals prior to the boundary migration measurements. The recrystallized grains, which grew a ni so tropically into the homogeneously polygonized matrix, developed flat boundary segments during early stages of growth. These boundary segments subsequently migrated along a direction approximately normal to the boundary plane into the matrix rystal. Increasing deformation over the range employed was estimated to increase the driving free energy for boundary migration by about five times. The kinetics of the boundary migration process, examined under these conditions, indicate that the boundary velocity is greatly affected by a small change of the driving free energy in the matrix crystals. These results were examined in the light of the current theories of grain boundary migration. EXPERIMENTAL PROCEDURES Single crystal strips (9 by 1 by 0.125 in.) of zone-refined aluminum, were seed-grown by the Bridgman method in a high-purity graphite mold (<lo ppm ash) at 1 in. per hr. Precautions were taken to minimize contamination of the metal during crystal preparation and subsequent handling. Spectrographic analysis of the metallic impurities in the grown crystals is Qven in Table I. The crystals were rolled in the (110)[112] orientation at -78°C to various reductions in thickness, ranging from 20 to 70 pct, in 10 pct increments. The desired reduction was achieved by many rolling passes, each being no more than 0.002 in. To minimize surface friction, the crystal was rolled between two thin layers of teflon. For those crystals rolled more than 40 pct, it was necessary to remove the disturbed surface layers by electropolishing at -5" to -10°C at an intermediate stage of rolling. The edges of deformed crystals were removed by a jeweler&apos;s saw while submerged in alcohol at -78° C to obtain samples of about ? by i in. The distorted metal at the cut edges and the surface layers were then removed by electropolishing, with removal of a minimum of 0.004 in. from each surface. The thickness of the crystals prior to rolling was chosen so that the final thickness was 0.025 in. for all samples. These deformed single crystals were each prean-nealed for 1 hr at an appropriate temperature in the range of 130" to 280°C, depending upon the amount of deformation. The purpose of this preannealing was to

Jan 1, 1970

Kinetics of bubble-particle interaction, surface hydrophobicity and interfacial phenomena in sulfide mineral flotation are discussed in this paper. Results of the measurements of a bubble and mineral induction time (IT) and detachment force (DF), vacuum of bubble evolution (VE) and mineral floatability are discussed for pyrite, galena, chalcocite and chalcopyrite. Natural wetting and wetting induced by xanthates with different lengths of alkyl chains are examined. Experiments show the existence of several maxima of hydrophobicity on dependences of pH and electrochemical potential. These maxima are attributed as the reflection of mineral surface heterogeneity due to xanthate adsorption and the presence of cationic and anionic centres with uncompensated positive and negative charges. These charges can be neutralised by both regulation pH and applied potential. The aim of this paper is to evaluate a thickness of the rupturing film and to estimate how long the bubble-mineral interactions are according to the experimental values of IT, in order to develop a procedure for comparing of the results of DF and atomic force measurements in the same dimensionality, and to compare the results of the experimental studies on the wettability of sulfides with those predicted by the models of physics of capillarity.

Jan 1, 2005

By Persifor Frazer

Comparative columns expressing the series of rocks of the lower half of the Mesozoic age in this country and in Europe are not yet definitely established. The following represents a co-ordination of the beds in England and Germany,* with a list of materials to be worked in from this country .†

The kinetics of desorption of nitrogen from molten iron were investigated using the electromagnetic levitation technique. The respective influences of gas flow rate and surface active element (S) were examined. A second order behaviour with respect to the nitrogen concentration in the melt prevailed at all experimental conditions. Sulphur had a marked inhibiting effect on the desorption rate. The experimental results on the rates of nitrogen desorption have been interpreted with the aid of a reaction mechanism consisting of a sequence of elementary steps.

Jan 1, 1991

By J Edmund Hay, T S. Bajpayee

The Bureau of Mines is developing a test to determine the initiating strength of commercial detonators. Various tests of "detonator strength" are in use, but many of them do not correlate well with each other, and so far, there is little evidence that any of them correlates well with the ability of detonators to initiate detonation in an explosive. Therefore, the Bureau decided to attempt a measurement of the ability of detonators to initiate detonation. To this end, an explosive mixture of adjustable sensitivity was developed. This mixture was nitromethane sensitized with ethylene diamine, the sensitivity being "fine-tuned" by the addition of nitropropane.

Jan 1, 1992

By Roger L. Beals, George A. Tweedy

The results of the cyanide-operations, given in detail in the following paper, show the progress that is being made at the Minas del Tajo. The old pan-amalgamation process, in operation up to and including 1905, while paying a profit on high-grade ores, was no longer able to treat profitably the ores in sight at that time; hence an alteration in the process was imperative. The success of this alteration is eloquently expressed by the following data : Pan-Amalgamation. Cyanidation. 1905. 1905. " 1908. Tons treated,.... 51,387 58,983 69,200 Value per ton (U. S. currency),. $ 10.78 $8.39 $8.28 Extraction, per cent.,.. 65.00 88.56 87.45 Extraction, per ton,.. $7.00 $7.43 $7.24 Total cost, per ton treated, . 6.50 4.36 4.01 Profit, per ton treated,.. 0.50 3.07 3.23

Jan 1, 1911

By E. T. Turkdogan, P. Grieveson

Experimental results are given for the rate 0.f solution of nitrogen in y iron in the temperature range 1000° to 1200°C. It is shown that, when purified reacting gas is used, the rate-controlling process is the diffusion of nitrogen into the iron. The difhsiuity of nitrogen in y iron is calculated from the results and the equation logD = —(8800/T) — 0.04 is recommended to represent the temperature dependence of the diffusivity. In some experiments using unpurified nitrogen, solution rates are found to be slower than those attributable to a solely solid-state diffusion process. Indications are that in the presence of impurities in the gas, e.g., H,O, chemisorption of nitrogen at the surface is hindered and becomes a rate-controlling process for the transfer of nitrogen across the gas -metal interface. ALTHOUGH the solubility of nitrogen in y iron at known nitrogen activities has been well-established,&apos;-a the kinetics of the solution of nitrogen in iron are not known. The work of Darken, Smith, and Filer&apos; indicates that at temperatures below about 1300°C the rate of solution of nitrogen in y iron is controlled by a chemical reaction at the metal surface, while at temperatures above about 1300°C the rate-controlling process is the diffusion of nitrogen in the metal. Fast and verrijps studied the denitro-genization of y iron using wet hydrogen at 950°C and their results clearly indicate that the rate of nitrogen removal is controlled by diffusion of nitrogen in the metal. In Part I of this series of papers, the kinetics of the solution of nitrogen in y iron are discussed in the light of the present experimental work. EXPERIMENTAL Apparatus. The reaction chamber consisted of a platinum wire-wound resistance furnace with a re-crystallized alumina reaction tube. The temoerature of the furnace, which was automatically controlled to approximately 1°C, was measured with a Pt/Pt-13 pct Rh thermocouple and a potentiometer. The temperature distribution in the working zone of the furnace was determined using a calibrated Pt/Pt-13 pct Rh thermocouple and the hot zone was found to be approximately 3 in. long with a temperature variation of * 3°C. A series of experiments was also carried out at 1000°C and pressures above atmospheric using a pressure vessel which was similar in construction to that described elsewhere.1° Materials. Ferrovac E grade iron used in all ex-

Jan 1, 1964

Underground mechanized excavation in New Zealand has become more commonplace in civil and mining applications during the last three years. At one stage up to seven Dosco Road- header machines were being used on different projects around the country. The Huntly West Mine Drifts inclined at one in four were by far the most severe grade conditions that the machines were subjected to; however, other operations posed their own particular problems for the machines. Two major interrelated factors became evident as soon as the machines commenced at Huntly. These were traction problems on the grade and control of water, particularly on the invert.

Jan 1, 1978

By E. Chin

The countries of Asia and the Pacific have large resources of diverse minerals. Australia and China have extensive mineralization that are commercially being exploited. The major minerals in Australia with known reserves adequate for both domestic demand and export markets include bauxite, clays, copper, diamond, gold, iron ore, lead, manganese, mineral sands (titanium minerals), nickel, salt, silver, tin, uranium, and zinc. China is the world leader in proven reserves of antimony, barite, magnesite, molybdenum, rare earths, titanium (ilmenite), tungsten, and vanadium. It also has about 55 billion tons of iron ore, albeit with an average grade of only 30 % to 35 % elemental iron content. With the exception of chromium and copper, China has significant resources of a wide array of minerals and metals, based on its production and/or export capability for these commodities. Additionally, India has significant resources of bauxite and mineral sands; Indonesia, bauxite, copper, nickel, and tin; Malaysia, tin and associated titanium; Mongolia, copper, fluorspar, and lead-zinc; New Caledonia, nickel; New Zealand, gold and iron sand; North Korea, magnesite; Papua New Guinea, copper, gold and mineral sands; Philippines, copper, chromite, and gold; and Sri Lanka, gemstones. Moreover, there appears to be extensive mineralization III Burma (Myanmar), Cambodia, Laos, Thailand, and Vietnam, but they have yet to be definitively delineated.

Jan 1, 1994

By M. King Hubbert

DuRing the past summer the writer was asked by the Illinois State Geological Survey to make a study of some of its economic geological problems with regard to the applicability of geophysical methods of prospecting to their solution. The following four problems were suggested for investigation: (1) the fluorspar area of Southern Illinois, (2) oil structures in the south central part of the state, (3) the lead and zinc-bearing area of northwestern Illinois, and (4) the water supply and gravel deposits of the glacial drift. The prime requirements were to find a means of obtaining a maximum of useful information with a fairly modest outlay of expenditure for technical staff and equipment. The method of procedure adopted was that of making a preliminary study of each of the problems named by means of available office data and published reports with supplementary field reconnaissance where necessary. Preliminary Studies Fluorspar.—The fluorspar deposits of southern Illinois as shown by Weller,1 Bastin2 and others are of two main types: (1) vein deposits along steeply dipping normal fault planes, and (2) "blanket" deposits occurring practically horizontally along a certain sedimentary horizon. The vein deposits are composed mostly of calcite and fluorspar in sheetlike veins of thicknesses, where mined, ranging from about 2 to 12 ft. The surrounding topography is in a mature state of development with a relief of about 100 ft. or more. Any geophysical prospecting for this ore would have to depend either upon the physical properties of the ore and associated minerals or upon the properties of the geologic structure containing them. Fluorspar has a density of 3.18, which is somewhat greater than 2.7, that of calcite. Its

Jan 1, 1934

By R. A. Paul

The requirements for water inflow control for the Chicago Intercepting Sewer System are stringent. This posed special problems in grouting the bored and conventionally mined tunnels, shafts and chambers of the system. In adapting conventional grouting techniques to the specific problems encountered in the system&apos;s pilot project, numerous field procedures were developed. Careful preand post-grout testing and evaluation identified the most efficient and economical of these procedures. As an example of some of the conclusions reached during the project it was found that the mineralized groundwater in the Chicago area tended to reduce the efficiency of the grout holes, thus limiting their useful life. Pressure washing to remove natural fillings was a critical factor in achieving a permanent grout seal. The value of relatively thin lubricating grout mixes was definitely established. Although not an ideal situation, satisfactory results could be obtained by manifold grouting several grout holes simultaneously if done within specific limits of hole groutability, location and numbers. Caulking proved to be a primary controlling factor in achieving acceptable results. To achieve such a high degree of water inflow control requires close supervision by experienced personnel. "Temporary grouting as a construction expedient" produces seepage conditions which are extremely difficult to treat.

Jan 1, 1974