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By P. T. Brooks

Semipilot scale tests were made to demonstrate a newly developed electrorefining process which could be extrapolated to commercial scale in producing high-purity nickel and cobalt from crude nickel metal and high-grade ferronickel. The new process comprises application of solvent extraction techniques to remove and separate cobalt and iron from nickel and the electrodeposition in diaphragm cells of pure nickel and cobalt from chloride-based purified electrolyte. Using water insoluble organic amines, the solvent extraction operations enabled production of commercial-sized nickel and cobalt cathodes of higher purity than that of commercial electrolytic metals. The solvent extraction operation for separation of cobalt from nickel was made simpler than the conventional method. Furthermore, the solvent. extraction operation for iron removal made possible the electrorefining of ferronickel without the prohibitive loss of nickel resulting from the method ordinarily used for iron removal.

Jan 1, 1970

By R. J. Heemstra

A method was developed for calibrating photographic emulsions and retrieving working curves for emission spectrography. The values obtained from a digital readout or a recorder chart of a comparator-microphotometer are converted to light intensity values using an emulsion characteristic curve derived from a quartic polynomial preliminary curve. The characteristic curve, consisting of Seidel transform versus the logarithm of intensity, is split into two cubic polynomials at the zero value of the transform, resulting in eight emulsion calibration coefficients. These methods allow use of the calibration curves even at very small and very high intensities, thus extending the range of analysis. Use of a small computer allows rapid calculations. A computer program was written to formulate, code, and file each working curve along with its statistical error. Proper coding of the input data permits the direct printout of the concentration of the elements under investigation.

Jan 1, 1970

By Clarence O. Babcock

In this report, the Bureau of Mines presents a method for reducing the complexity of designing room-and-pillar mining systems by treating them as anisotropic soft inclusions in the surrounding ore or host rock. Theoretical models were derived for the calculation of the effective Young's moduli for these systems. The predicted behavior of the plate-type elements used in these models agreed well with test results from 21 plates each with 49 holes spaced on a 7 X 7 Cartesian grid. The plates behaved as anisotropic solids, the effective Young's moduli of which could be predicted from the scaled hole size and spacing. Actual hole shape was insignificant. The effective Young's moduli for simple mining systems are calculated in sample problems. This approach should provide information about field stress in the mining region and the stress distribution in the surrounding ore or host rock when the actual mining configuration is replaced by an anisotropic inclusion in a finite element analysis. The field stress within the inclusion can then be applied to the actual opening shape to determine the stress distribution within the mining region.

Jan 1, 1970

By Fred Leighton, Wilson Blake

The microseismic method of detecting instability and high-stress zones in underground mines was developed by the U.S. Bureau of Mines (USBM) in the early 1940's.l,2 For about 25 years this method has been used throughout the world by mining and construction companies in assessing the stability of underground and surface excavations. Rock noises are the release of small amounts of stored strain energy propagating outward from their source as a seismic wave that can be detected with special geophysical equipment. This release of strain energy is caused by a rock mass undergoing load changes resulting in small-scale displacement adjustments such as microcracking, shearing, sliding, and crushing of crystal grains, some even as small as the elastic displacements themselves. No detailed field studies of any of these mechanisms have been made, and knowledge about the origin of rock noises is relatively incomplete. Laboratory tests have shown that when rocks are stressed in a testing machine, the rock noise rate-the number of rock noises generated per unit of time increases with increasing applied stress.3 This increase is most pronounced as the ultimate strength of the rock is approached. The standard field procedure has been to monitor a rock structure at intervals and plot rock noise rates vs. time, thus gaining a semiquantitative estimate of the behavior and stability of the structure. The success of such monitoring, however, has depended almost entirely on the experience and knowledge of the operator, his interpretation of the data, and his equipment. Very little study has been devoted to the basic properties of the vibration record of a rock noise. USBM decided that the microseismic method was being used sufficiently by various mining and construction companies

Jan 1, 1970

By E. F. Ferrell

Electrowon molybdenum powders and a commercial hydrogen-reduced powder, all with different minor impurities, were investigated by the Bureau of Mines with respect to inherent properties, to fabrication techniques, and to proper-ties of the fabricated sheet. Compared with the commercial hydrogen-reduced powder, the electrowon powders had a larger particle size, a greater flow rate, a higher apparent density, and a lower oxygen content. Sheet materials prepared from the two types of powders showed similar mechanical properties, under the same conditions of heat treatments, except for low-temperature ductility. Yield strengths varied with carbon content, heat treatment, and test temperature.

Jan 1, 1970

By John L. Hatton

The author will introduce and describe the nature of Fiberglas-Reinforced Plastics. Successful applications of corrosion-resistant structures will be shown and described, including pipe, ducts, tanks and other equipment. These structures are generally designed to handle corrosive liquids and gases and have proved both satisfactory and economical in service in various industries in Canada. The specification of structures will be discussed in relation to materials, construction and workmanship, physical properties and methods of testing.

Jan 1, 1970

By J. C. Bradbury

The Illinois State Geological Survey's program in industrial minerals is twofold-the gathering of information on mineral raw materials and the generation of data on the use of these materials. The first function is carried out by the Industrial Minerals Section and the Clay Resources and Clay Mineral Technology Section of the Geological Group, and the second is the responsibility of the Chemical Engineering Section of the Chemical Group. Gathering in formation on raw materials includes both mapping of resources and fundamental geological research. Recent and current research projects include studies relating lithologies of limestones to their physical properties, investigation of sulfur dioxide reactivity of various types of limestone, lithostratigraphic studies of limestones of Mississippian age, investigations of heavy minerals in Cretaceous, Tertiary, and Pleistocene sands, studies of the environments of clay deposition, electron microscope studies of clays and limestones, and investigation of long-term expansion in ceramic products. A relatively recent development that relates more to dissemination of information than to research is environmental geology. This affects the Survey's industrial minerals program chiefly by stimulating the study of rock and mineral resources in metropolitan areas and reporting the results for the land- use planner as well as the engineer or mineral producer. The Survey's program of research on the use of industrial minerals was expanded and diversified in 1966. Incorporating a minerals beneficiation lab, the program is designed to develop new uses for existing mineral resources and to assist producers in implementing these ideas: Projects of the minerals engineering program have included the separation of a feldspar concentrate from certain glacial outwash and river sands, recovery of kaolinite from the waste from silica sand operations, development of the use of an Illinois clay as a binder for pellets, and investigations into the use of fly ash and fluorspar mine tailings.

Jan 1, 1970

By D. A. Keefe, O&apos

The electrowinning of beryllium from beryllium oxide (BeO) using a molten-salt electrolyte composed of 56 LiF-37 BeF2-7 BeO (mole-percent) was investigated. Anodes made of porous carbon were found to be superior in current-carrying capacity and gave a lower cell voltage than other types of anode material tested. When porous carbon anodes were used) the resultant increase in anode area prevented anode passivation. The cell voltage was 3.3 volts) and electrode current efficiencies of 50 to 70 percent were obtained. The electrodeposited beryllium was recovered as beryllium powder or was coalesced to metal beads by heating to 1,300° C.

Jan 1, 1970

By Leslie G. McMillion

A field project to develop and demonstrate a method for alleviating problems of highly-mineralized ground water where they occur as isolated zones or pockets in fresh-water aquifers is being conducted in the Ogallala Aquifer of eastern New Mexico by the Robert S. Kerr Water Research Center. Removal of contaminated water is by a large-capacity well and the pumped poor-quality water is used locally for secondary recovery of oil, Benefits of the operation are threefold in that the aquifer is being reclaimed for future fresh water production, contaminated water is being used beneficially, and fresh water which otherwise would have been used for waterflooding is available for other purposes. Ground-water quality in the site has improved markedly after 21 months of operation. Water quality in 15 specially-drilled monitoring wells has returned to the original quality level of the aquifer, and chloride concen¬trations in the pumping well have dropped to half the maximum level recorded thus far. Project results are very favorable and provide guidelines for initiation of similar undertakings in localities where needed.

Jan 1, 1970

By D. H. Hileman

Economic investigations indicate that bituminous coal can be mined underground in the Uinta region and marketed at a cost competitive with that of other energy sources in the West. A selling price of $3.90 per ton of coal was calculated from a cost analysis of a projected coal mine in the Emery coal- field of Utah. Although mines in some of the coalfields have extremely difficult mining conditions and cannot compete in the energy market at this price level, at least two other coalfields in the Uinta region contain coal reserves that could be mined and sold at a price of approximately $3.90 per ton. Projections by power companies and other coal-consuming industries indicate a strong future market for the large coal reserves in the Uinta region.

Jan 1, 1970

By R. Taggart, R. H. Ericksen, D. H. Polonis

Transmission electron microscopy techniques hare been used to study the spontaneous marfensite phase that forms during the thinning of Ti-Cr alloys. The structure of this phase has been found to differ. from the hcp martensite and has been identified as a clisforted fcc lattice. The spordaneous marlensile in this system is interpreted as a metastable isomorph of the equilibriunz TiCr, phase. WHEN thin-foil specimens for transmission electron microscopy were prepared from metastable alloys of the Ti-Cr system, a spontaneous transformation occurred' when the foils contained the untrans-formed 0 phase or two-phase mixtures of the 0 and w phases. The purpose of this paper is to examine the relationship that exists between the crystal structure of the spontaneous product and that of the matrix. The differences between the martensite transformation that occurs in the bulk material and the spontaneous reaction that occurs during the preparation of thin foils are compared with the observations that have been reported for similar phenomena in a commercial titanium alloy.' A spontaneous reaction that exhibits characteristics similar to a martensite transformation has been reported to occur in thin foils prepared from the retained metastable structures of several alloy systems.1'3"7 ~ull~ observed such a spontaneous reaction in 0 brass and attributed the apparent increase in the martensite transformation temperature to a decrease in the non-chemical free energy associated with bulk strain energy. He also showed that the spontaneous product did not have a specific habit plane, but that its orientation relationships to the parent matrix were dependen on the thickness of the transforming region. It has also been pointed out by Breedis6 that in thin films the absence of the constraints imposed by a bulk matrix can cause different requirements for the martensite plate interface and lattice distortion which is reflected bv a dependence of the transformation mechanism on the specimen geometry. In the case of the spontaneous reaction reported for Au-Zn alloys7 a definite habit plane was determined and shown to correspond with the habit plane calculated on the basis of the Bowles and Mackenzie crystallographic theory of the martensite transformation.'- lo EXPERIMENTAL PROCEDURE A series of titanium alloys containing 5.5, 5.9, 6.4: 7.6, 8.0, 11.3, and 18.7 at. pct Cr were prepared from high-purity (iochrome) chromium and iodide-grade titanium by levitation melting. The experimental procedure used for sectioning the alloys and for thin-foil preparation has been reported in an earlier paper.' X-ray diffraction patterns were obtained using a 114-mm Debye-Scherrer camera and Cu-Ka radiation. In order to minimize fluorescent radiation from the specimen, a strip of aluminum foil 0.002 in. thick was placed in contact with the X-ray film. After a specimen was removed from the camera: an additional X-ray experiment was performed, to insure that no spurious lines were obtained due to the presence of the aluminum foil. The interstitial impurity analysis for the alloys used in this study was as follows: oxygen, 100 ppm: hydrogen, 30 ppm: nitrogen, 28 ppm. EXPERIMENTAL RESULTS Electron diffraction patterns were obtained from several individual crystals of the spontaneous marten-

Jan 1, 1970

By D. S. Burgess

An investigation of the hazard of spillage of liquefied natural gas (LNG) onto water is described. About 2,000 gallons of LNG were consumed in various tests. The initial vaporization rate of LNG following spillage was found to be 0.037 lb/ft2 sec; when the spill was confined, this vaporization rate was moderated after about 20 seconds by the growth of an ice layer on the water surface; when the spill was unconfined, a coherent ice floe was not observed and the vaporization rate was essentially time independent. The maximum diameter (in feet) of the spreading LNG pool was found to be given by 6.25 Wo 1/3, where Wo is the weight of LNG in pounds, Downwind of a natural gas source, time-averaged methane concentrations were given in good approximation by standard air pollution equations. However, peak concentrations were as much as twentyfold higher than average, adding an additional factor to the assessment of hazard. The effect of layering by the cold vaporized natural gas was similar to the effect of a temperature inversion on normal gases in the atmosphere. Small-scale explosions were observed on pouring LNG onto a water surface; no single explanation seems pertinent to all of the incidents observed.

Jan 1, 1970

By F. J. Cservenyak

The Bureau of Mines Solid Waste Program is directed toward three main areas of research: (1) Extraction of mineral, metal, and energy values from urban refuse; (2) recovery of mineral and metal values from wastes generated in the industrial extraction, processing, and utilization of raw materials and mineral-base products; and (3) upgrading and utilization of automotive scrap. The Bureau also has a contract and grant program which supplements the in-house research and aids in the training of personnel in the proper management of mineral- and metal-based solid wastes.

Jan 1, 1970

By B. Ladanyi, G. Archambault

It is generally recognized to date that a rational stability analysis of slopes and foundations in rock masses is a desirable but still rather remote goal of rock mechanics.1 In principle, a slope analysis is possible provided the original state of effective stress in the ground is known and the shear strength of the earth material can be clearly defined. In a macroscopically continuous earth medium such as soil, the two basic ingredients of the stability analysis in most cases can be assessed with sufficient approximation. A much less favorable situation exists when the slope is composed of a macroscopically discontinuous medium such as rock mass containing one or more sets of geological planar structures. In such a case, both the original effective stresses and the overall shear strength of the mass are much more difficult to determine. As for the former, it is only recently that certain calculation methods and solutions concerning the stress distribution2 and the seepage forces3 in a discontinuous medium have been proposed. As the strength behavior of the rock mass is concerned, much valuable effort has been made in recent years toward reaching a proper understanding of the phenomenon of rock mass failure under stress. Probably one of the most complete investigations of the problem to date has recently been made at the University of Illinois. The study resulted in establishing a first useful working hypothesis of the shear behavior of a regularly jointed rock mass, proposed by Patton in 1966.4 The main purpose of the work described in this chapter is to establish a more general framework for the shear behavior of rock mass, one that would be directly related to some basic rock parameters and would also

Jan 1, 1970

By R. D. Nelson, F. E. Bowman

Evidence has been found for a (010)a?(111)B[102]a /,11[341]/B crystallographic relationship between the monoclinic a and B phases of plutonium during the a?B transformation. The results of an X-ray diffraction study, where [010] fiber textured a samples were used in the absence of suitable single crystals indicate that the (OIO)a planes become (111)B planes upon transformation under near-equilibrium conditions. The transformation strain along the fiber axis, which was the [010] direction, was measured dila-tomekically; the measured 8.5 pct expansion compares favorably with the 8.44 pct expansion in the in-terplanar spacing represented by the (010)a?(111)B relationship. From plots of the atom positions in each of the related planes, a correspondence was deduced between the [102]a, direction and the [341]B direction. Further analysis of the two lattice structures in the light of this relationship revealed a rotation about the [102] direction of 1 deg 43 min and a slight shearing in this same direction of about 30 min. THIS paper discusses the (B crystal structure of plutonium and the orientation relationship existing between the monoclinic a and B phases during the a?ß transformation. The kinetics of the a?ß and (3 — a transformations have received extensive consideration, and because of the crystallographic complexity of these phases, the question of the mechanisms by which these transformations occur is especially intriguing. Nelson and Shyne1 evaluated the existing experimental evidence and concluded, from the indirect evidence available, that both the ß ? a and a ? ß transformations occur by a martensitic process. Their data reveal the anisotropic nature of these transformations which suggests the existence of specific crystallographic relationships between the parent and product phases. In this paper, we are concerned with the confirmation of the existence of such a relationship resulting from the a ? ß transformation and the derivation of the crystallographic details necessary to specify it. EXPERIMENTAL RESULTS X-ray diffraction and dilatometric data were obtained from samples of a plutonium having a [010] fiber texture. These cylindrical specimens, approximately 1 cm in diam, were prepared by transforming the ß phase to a under the influence of a uniaxially applied compressive load.' The [0l0] direction is parallel to the direction of applied stress; it is also perpendicular to the (010) planes. This correspondence between the plane normal and the direction having the same indices is, in the monoclinic a plutonium structure, restricted solely to this (010)[010] combination. Such a specimen was mounted in an evacuated, elevated temperature specimen holder on an X-ray dif-fractometer so that the diffracting surface was perpendicular to the fiber axis. The a diffraction pattern, Fig. 1, taken at about 115ºC, revealed the predominance of the (020) reflection. This monoclinic, P 21/rn space group yields no (0k0) reflections when k is odd. The temperature was raised slowly to 160°C to effect the complete transformation to the phase; then it was lowered to 120°C so that a diffraction pattern of the ß could be obtained near the a = ß equilibrium temperature for direct comparison with the a at the same temperature. The (3 diffraction pattern, Fig. 2, obtained under these conditions showed a (222) reflection relatively much more intense than in the random pattern. The other reflections appearing with sig-

Jan 1, 1970

By H. C. Fiedler

Heats of high purity iron containing 3.1 pct Si and be -tween 0.0003 and 0.0295 pct N were prepared by vacuum melting ad then pouring while in a nitrogen atmosphere with the pressure between 0 and 90 psi. Strip from a heat with 0.0184 pct N underwent complete secondary recrystallization during the final anneal. Heats with less nitrogen had too few Si3N4 particles to restrain normal grain growth, and the heat with higher nitrogen had too many particles to allow complete secondary recrystallization. In the hot-rolled structure, Si3N4 precipitates only at the grain boundaries, with the consequence that annealing after hot-rolling diminishes the ability to subsequently undergo secondary recrystallization. In contrast to this behavior, ALNprecipitates uniformly in the hot-rolled structure. Under 1 atm of nitrogen, Si3N, in 3.1 pct Si-Fe dissociates between 900" and 950°C; the solubility of nitrogen increases from 0.0010 pct at 900" to 0.0030 pct at 1200°C. The solubility of nitrogen in Si-Fe has been the subject of many investigations. Corney and Turkdogan1 heated a 2.83 pct Si alloy in nitrogen and found the solubility, under 1 atrn of nitrogen, to be 0.0019 pct at 900°C. They claimed that Si3N4 did not form in the alloy above 705°C in 1 atrn of nitrogen. Fryxell et al.2 heated samples of 3.25 pct Si-Fe containing 0.0025 pct N over a range of temperatures and then analyzed for total nitrogen by vacuum fusion and for nitrogen in solution by a modified Kjeldahl technique. At 900°C, they reported the solubility of nitrogen in equilibrium with Si3N4 to be 0.0011 pct. pearce9 found the solubility of nitrogen at 900°C under 0.95 atrn of nitrogen to be 0.0017 pct in a 3.06 pct Si alloy. He reported that Si3N4 does not form above 770°C in 1 atrn of nitrogen. Although internal friction measurements have given somewhat higher values for the solubility,4-6 if the solubility of nitrogen is as low as has been reported by most investigators, and if Si3N4 is stable up to at least 945°C at 1 atrn pressure of nitrogen as reported by Seybolt,7 a small amount of nitrogen in properly processed Si-Fe should be effective in promoting secondary recrystallization. The requirement is that in the final heat treatment there be enough small, well-dispersed particles of Si3N4 to restrain normal grain growth. Fast8 has obtained secondary recrystallization by nitriding high-purity 3 pct Si-Fe after hot-rolling to a thickness of 0.118 in., followed by processing to 0.012 in., and annealing. A large amount of nitrogen, 0.076 pct. was introduced during the nitriding heat treatment, but he has since reported9 that "a few hundredths of a percent" is sufficient. Small amounts of aluminum10 or vanadium" nitride are capable of promoting secondary recrystallization. Heats containing as little as 0.010 pct A1 or 0.042 pct V and from 0.006 to 0.009 pct N underwent complete secondary recrystallization at final gage, whereas heats with lesser amounts of aluminum or vanadium did not.l2 To be reported is the behavior of nitrogen in high-purity 3.1 pct Si-Fe, and the relation of this behavior to the ability to undergo secondary recrystallization. PROCEDURE Ingots weighing 1 lb were made by vacuum melting high-purity electrolytic iron (A104, Glidden Co.) and high-purity silicon (Monsanto Co.). The latter was used in preference to ferrosilicon to insure a low aluminum content. The design of the melting furnace permitted pouring with the furnace atmosphere either below or above atmospheric pressure. Accordingly, at the completion of melting, nitrogen was admitted to the desired pressure and the heat then immediately poured. The ingots were sound, with no indication of porosity. In Table I are listed the heats investigated, the nitrogen pressure at pour, and the nitrogen and oxygen contents as determined by vacuum fusion with a platinum bath at 1850°C, a procedure which insures measurement of the total nitrogen.13 In addition, all heats contained 3.1 pct Si and not more than 0.002 pct C, 0.003 pct S or 0.005 pct Al. It was subsequently found that the quantity of nitrogen contained in the heats in Table I does not necessarily represent that obtained under equilibrium conditions. For example, the ingot poured immediately after 1 atrn of nitrogen was admitted to the chamber contained 0.0093 pct N, whereas an ingot poured 3 min after the nitrogen was admitted contained 0.021 pct N and another poured after a 6-min delay contained 0.029 pct N. While some bleeding of the hot top occurred in the latter instance, the ingot when examined in cross section appeared sound. The ingots were heated to 1325°C in hydrogen and rapidly rolled to 0.080 in. in 3 passes. The roll speed of the final pass was reduced so as to increase the quenching effect of the rolls. The hot-rolled pieces were processed both as-hot-rolled and after heating for 3 min at 900°C in hydrogen. After cold-rolling to 0.026 in., the strips were heated for 2 min at 900°C in hydrogen, then cold-rolled to the final gage of 0.012 in. The loss of nitrogen in going from the ingot to cold-rolled strip was no more than 10 pct. The final heat treatment, which was for the purpose of develop-

Jan 1, 1970

By Peter Silveston, Earl Shannon

Process-oriented experiments on the use of coal as an adsorbent for certain soluble components of sewage are described. The capacity of Canadian coals for these components was less than 0.1 per cent by weight for the highest concentration at which these components could be expected to be found in domestic sewage. This is much less than values reported in the past. A pronounced selectivity between components was observed. Experiments on bacteria removal in beds of coal, regeneration of spent coal to restore adsorption capacity and COD contributions of coal are reported in the paper. The simple application of coal as an adsorbent does not seem promising.

Jan 1, 1970

By W. A. McKinney

The U.S. Bureau of Mines, Kennecott Copper Corp., and New Mexico Institute of Mining and Technology are cooperating on a research project to improve extraction of copper from previously leached waste dumps that are in part compacted and impervious to leach solutions. The field work is being done at the "J" leach dump, Chino Mines Division, Kennecott Copper Corp., Santa Rita, N. Mex. The laboratory percolation leaching tests were made at the U.S. Bureau of Mines Salt Lake City Metallurgy Research Center on drill core samples from the "J" dump to determine how much copper might be leached if permeability could be restored by explosive heaving or other means. The core samples from nine drill holes on "J" dump contained from 0.06 to 0.14 percent copper. Copper extractions ranging from 15 to 3 percent were obtained in 75 days by percolation leaching of minus-1-inch material with dilute sulfuric acid. The tests results indicate that about 2'7 percent of the copper remaining in the "J" dump could be extracted under ideal leaching conditions.

Jan 1, 1970

By Harry J. Fitzgerald

During World War II mining machinery manufacturers were limited in the development of their product improvement programs. Following the war, however, the ideas and intentions of both the users and manufacturers of mining equipment became evident. The Coal Industry launched a series of events which indicated their determination to rise to the economic challenge of developing profitable machines which would eliminate the out-dated and back-breaking methods of mining previously used. Two major technological advances were developed as a result of the ambitious goals forecast by the Coal Industry: 1. Coal mining was going "off-track" and concentrated mining operations were to follow in rapid succession. 2. Carbide tools provided the remaining missing contribution to another technological breakthrough....Continuous Mining. Little did the inventors realize the significance of the misnomer they created because twenty-five years later the industry is still striving to secure the results implied by the meaning of the word...."Continuous". Nevertheless, all major manufacturers embarked on programs in an attempt to compete for recognition in this new mechanized-mining endeavor Eventually in 1950 there were three types of boring machines and two types of ripping machines being manufactured. Mining Speed was the desired goal.

Jan 1, 1970

By T. P. Meloy

In the last decade increased and prolonged interest has been displayed in the use: of tunneling or rapid excavation to solve many of the urban and industrial problems confronting our society. There has been talk and action on the interurban rapid transit systems for major cities, and even preliminary designs for a Boston to Washington interurban transit system. Much of this interest stems from the search to the solution of our increasingly complex urban problems, where the surface area must be given over more and more to the inhabitants, and the subsurface for transit, utility and other services. While tunneling is not a panacea to urban ills it holds a real solution to many existing problems. There is also, among the tunneling experts, a growing confidence that technical problems of rapid tunneling can be solved. To solve these problems, R & D money must be invested. If it is to be money invested either by private industry or governments, there must be significant returns on the investment to justify the research and development need to bring about the breakthrough that will make tunneling a major contribution to the solution of urban problems. To make these economic studies more extensive and more accurate tunneling demand figures were needed. To this end, the Organization of Economic Cooperation & Development - OCED - included in its Conference on Tunneling a section on tunneling demand. As a result of the conference the organization for Economic Cooperation and Development issued a report entitled "The Advisory Conference on Tunneling - Report on Tunneling Demand 1960-1980. " This report was presented at the OCED Conference on Rapid Excavation, held at Washington, D.C. To obtain the data in the Report, questionnaires were sent to the OCED countries and 18 replies were received from Australia, Austria, Belgium, Canada, Denmark, France, Germany, Ireland, Italy, Japan, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom, and the United States. While it is true, that data were missing, that sometimes the definitions were confused, and that several countries provided no cost estimates at all, in general, this report contains the most comprehensive gathering of data that ever existed in the field. All data in the OECD report is expressed in terms of meters or cubic meters, and costs are in U.S. dollars.

Jan 1, 1970