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By Fei-chiu Huang

A 17-acre landslide occurred in February 2001, on a slope below Via Bellota in the City of San Clemente, California. Three homes were destroyed and many others placed in jeopardy. The landslide, involving portions of five separate developments, continued to move significantly in the years following. Litigation ensued among the affected parties, and investigations continued through 2007. A mediated repair resolution was ultimately reached among the parties. The agreed upon repair consists of a multi-million dollar stabilization program that included grading, drainage, and structural systems. Part of the construction cost was offset by creating 4 new ocean view custom lots and 20 new mobile home lots. The landslide repair and slope stabilization design involved removal and replacement of portions of the landslide debris and construction of buttress and stabilization fills as well as installation of 74 shear pins in two rows. The shear pins were designed as 4-foot diameter by 50 feet in length and incorporated continuous W30x211 wide flange steel. The shear pins were designed to be installed 25 feet above the slide plane and 25 feet below the slide plane at each location. Construction of the 74 shear pins was initiated in 2008 and completed in 2009. Four-foot diameter holes were drilled by utilizing a truck-mounted, flight-auger-style drilling rig with a 4-foot diameter solid-flight auger. Prior to the installation of the shear pins, an engineering geologist downhole logged strategically selected holes to further evaluate the actual slide plane elevations. The wide flange steel shear pins were then lowered to the desired elevations and encased within 4,500 psi, Type V, 0.45 maximum water/cement ratio concrete. Inclinometers installed within four pin shafts and behind the pin rows indicated performance in accordance with the design. Slight to non-perceivable shear displacement was measured which mobilized the intended capacity at the monitored shear pins. No excessive slope movement was detected at any of the inclinometer locations during or after the construction period. Actual shear displacement of the steel wide flange elements was less than the movement anticipated before shear pin installation.

Jan 1, 2010

By Charles P. Lazzara, Charles D. Litton, Frank J. Perzak

This U.S. Bureau of Mines report details the results of a series of large-scale experiments where small coal fires were used to ignite the conveyor belt at air velocities ranging from 0.76 to 6.1 m/s. In the tests, electrical strip heaters imbedded within a pile of coal were used to heat the coal to a point of flaming ignition. The flaming coal subsequently ignited the conveyor belt located approximately 5 to 10 cm above the coal pile. During the tests, temperature, CO, and smoke levels were continuously measured in order to determine both alarm time and level as the fire intensity progressed through the stages of smoldering coal, flaming coal, and flaming coal plus flaming belt. Analysis of the data leads to certain conditions of air velocity and sensor alarm levels that are required for early detection of conveyor belt entry fires. Two nomographs are presented, which define sensor alarm levels and sensor spacings as a function of belt entry cross-sectional area and belt entry air velocity.

Jan 1, 1991

By M. W. Davies, P. N. Smith

The activity of MnO has been measured in the system CaF2-MnO at 1773 and 1873 K and in the system CaF2-CaO-MnO at 1773 K by the method of equilibration with platinum. Large positive deviations from ideal solution laws have been found, but these became less as the lime content rose. The loss of a volatile component made activity measurements impossible in the CaF2-AI203-MnO system, but the boundaries of a two-liquid region have been measured at 1773 K.

Dec 1, 1971

By G S. Anderson, N W. McDonald

"The IsaMill™ was originally developed to address liberation issues at Mount Isa Mines (now Glencore) operations, McArthur River and Mount Isa in the early 1990s. Following on from the industrial success at those operations, the IsaMill™ was commercialised. In the year 2000, Kalgoorlie Consolidated Gold Mines (KCGM) became the first external user of the technology with a 1.1 MW M3000 IsaMill™ installed to supplement the roaster capacity at its Gidji Processing Plant. The IsaMill™ was used to ultra-fine grind about 10 t/h of pyrite flotation concentrate to 10–12 µm prior to gold cyanide leaching. Based on the success of the Gidji installation, another was installed at the processing plant at KCGM’s Fimiston operation in 2002 in a similar duty.In 2014, a 3 MW M10 000 IsaMill™ was selected to replace the roasters at Gidji as part of the A$98 M emissions reduction project. The mill was commissioned in April 2015 at the design 30 t/h, allowing the immediate shutdown of the two roasters. Replacement of roasting with ultra-fine grinding completely eliminated air emissions at Gidji while maintaining overall plant production rates.This paper details the history of the IsaMill™ at KCGM from the original M3000 to the latest M10 000. It covers the basis of the process selection, circuit design, operating and maintenance data.Citation:Anderson, G S and McDonald, N W, 2016. IsaMill™ at Kalgoorlie Consolidated Gold Mines - from the M3000 to the M10 000 and Replacement of the Roasters at Gidji Processing Plant, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 29–38 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By Roswell H. Johnson

The principle of sliding or graduation in royalties is accomplished either by the block, period, cumulative, or class method. The block method calls for a very low royalty rate on all oil produced up to a certain amount. This amount would normally be that which is believed to suffice to repay the cost of the well. A higher rate would be charged after the well is making a profit. This method, common in many industries, is peculiarly inadaptable to any industry such as this where the productivity per day of the units gradually and inevitably decreases. This, for reasons given later, is because it forces an early abandonment of the well and so offends against conservation. In the period method, the royalty rate is changed by some definite amount when the well produces less than a specified quantity per day or other given unit of time. While simple to explain, it operates badly because a great deal is made to depend upon a small reduction in production, whereas the reduction as a matter of fact declines rather erratically owing to the exigency of lease management, connecting of tankage, and vagaries of the gaugers. These disadvantages are obviated by the cumulative method. In this method, all the production less than a certain amount per week has one rate of royalty, or none at all, and the oil produced in excess of that amount pays an additional rate of royalty. In the long run the calculation is probably no greater than with the period method, for simple tables will be published and printed in the oil papers that can be cut out, enabling quick readings to be made. Even without the table the calculation is easy with the few royalty rates, two or three, which would be used. In this method, the amount paid in royalty declines gradually, rather than suddenly as in the period method. The following reasons might be advanced for the adoption oi cumulative royalties: 1. To distribute the burden in accordance with the capacity to pay. This principle is a unique one in business, although familiar in taxation. This is because it does not distribute reward in proportion to efficiency.

Jan 1, 1916

By M. Dhainaut

This paper presents computations of the electric field inside a furnace. We first look at the effect of contact between two coke particles from an electrical point of view. We give values for the amount of contact resistance in the total resistance of the system formed by the two coke particles. We show that the effect of contact resistance decreases rapidly with increasing contact area. We then look at the complete electric field inside a full scale furnace. The aim is to evaluate the amount of current that short-cuts the metal bath for different vertical positions of the electrodes. We show that electrodes high above the metal bath are undesirable since they offer a larger surface of conductive charge materials where current can flow through. On the other hand, deeper electrodes force the current to go the whole way down to the metal bath. Ohmic heating along this path ensures a high temperature of coke and slag that are beneficial for metal recovery.

Jan 1, 2004

By Antonio Nieto, Jesus Castillo

Research and Development (R&D) departments in the mining sector are essential for creating new solutions on productivity, safety, and sustainability. Nevertheless, the selection of R&D projects is complex, often influenced by subjective judgments and uncertainties. This paper explores the application of the Multicriteria Decision Analysis (MCDA) as a structured approach to evaluate and prioritize innovation projects based on various criteria such as safety, cost, environmental impact, and social acceptability. By assigning weights and quantifying criteria, MCDA enhances decision-making transparency and objectivity. This study aims to show a method that facilitates strategic thinking, resource optimization, and stakeholder engagement, ensuring that selected innovations align with the company’s long-term objectives and commitment to responsible mining practices.

Feb 1, 2025

By B. Seymour

The National Institute for Occupational Safety and Health (NIOSH) is conducting research to develop safe practices for the use of shotcrete as ground support in underground mines, particularly mines operating in weak host rock. As part of this research, tests were conducted with a commercial poly-fiber reinforced shotcrete mix to develop a practical means of measuring shotcrete adhesion strength. Full-scale tests were conducted in a test frame equipped with concrete panels having three distinct surface roughness profiles. Adhesion test fixtures either embedded or epoxied in the shotcrete were overcored into the underlying concrete, and direct tensile tests were conducted to determine the bond strength of the shotcrete cores to the substrate after a selected shotcrete curing interval (1, 3, 7, 14, 28, or 90 days). Measured adhesion strengths typically ranged from 0.5 to 2.0 MPa depending on the curing age of the shotcrete samples. This paper presents the results of these tests, describes the portable test system components, and addresses some of the design issues encountered in the development of a rugged and reliable method for determining shotcrete adhesion strength in underground mines.

Jan 1, 2010

By Michael J. Beus, Jan G. Patricio

INTRODUCTION The U.S. Bureau of Mines, Spokane Mining Research Center, has been conducting and documenting rock mechanics research in the Coeur d’Alene mining district for the past ten years (1, 2, 3, 4, 14, 15). A current project combines the information gathered from rock mechanics instrumentation, geologic structure, and analytic techniques to improve shaft and support design for the deep mines of the district (3). This project required knowledge of the anticipated loads and the physical properties of the rock mass to provide accurate input data for computer design models. Several techniques have been utilized to determine the physical parameters including the USGS (U.S. Geological Survey) solid inclusion probe, the CSIR (Council for Scientific and Industrial Research) biaxial and triaxial strain cells, and the CSM (Colorado School of Mines) dilatometer. This paper describes the determination of the in situ modulus of deformation in three mines over a period of three years and the evaluation of these results as they applied to this project. The need for in-situ rock mass properties such as the modulus of deformation has stimulated research and development of a large number of instrumentation techniques. One area of continuing interest involves various methods of radial borehole dilation. This concept was pursued by Menard (9) with an apparatus known as the pressure meter, which is used frequently in soil mechanics. Other developments in rock mechanics include the CPC (cylindrical pressure cell) by Panek (11) and the dilatometer by Rocha et.al. (13) in Portugal. The CSM dilatometer, which also utilizes this technique, was chosen for this project because it required a small amount of background study, was inexpensive, and could easily be combined with other experiments being planned for the test locations. Although no previous field applications to hard rock (compressive strengths greater than 20,000 psi) has been documented, the instrument was selected since good results have been achieved in granite, oil shale, and several coal measure rocks (11, 12).

Jan 1, 1977

The Steering Committee for Minerals and Mining Policy convened two workshops during March 1996 to address the following topics: Business Environment- National and Provincial Powers, Administration and Regulation, Mineral Marketing, Beneficiation, Research and Development, Environmental Issues, Mining Impact on Surface Usage, Southern Africa Regional Issues. Human Resources: Elementary Residual Racism, Housing, Downscaling, Migrant Labour and Human Resource Development. Mineral Tenure: Mineral Rights, System of Access to Mineral Rights, Access to Exploration information, optimal Exploration, Trust Lands. Small-scale Mining. Development of Small-scale Mining, Artisanal Mining.

Jan 1, 1996

"Standing 92 stories high and just over 1,362 ft tall, Chicago’s Trump International Hotel and Tower is perfectly positioned at the center of one of the world’s most impressive skylines.The Tower serves as a link between its famous predecessors, Willis Tower (formerly, the Sears Tower) to the south and the John Hancock Building to the north. Originally planned to be the world’s tallest building, the project was scaled back when the developers started questioning the need for super-tall buildings after the September 11, 2001 terrorist attacks. In its River North neighborhood, Trump Tower dominates the skyline as a symbol of Chicago’s last great building boom, standing triumphantly over other high-profile projects that have been postponed due to current economic realities.It is often said that the three most important factors in real estate are location, location and location. This maxim was not forgotten by The Trump Organization when the site was selected for the International Hotel and Tower. Located two blocks west of Michigan Avenue and Chicago’s famed Magnificent Mile, the site is bound by the historic Wrigley Building to the east, Wabash Avenue to the north and west, and the Chicago River to the south. The building’s position along a bend in the Chicago River allows visitors and residents unobstructed views to the mouth of the Chicago River and Lake Michigan. Site ChallengesUnderneath the site there are approximately 10 to 20 ft of sand and urban fill underlain by soft Chicago blue clay. At 75 ft in depth, the soft clay transitions into Chicago hardpan, a very hard till that was consolidated by the glaciers over 10,000 years ago. Below the hardpan, the till turns granular with cobbles, boulders and water under pressure. Bedrock is about 100 ft below existing grade and has a weathered surface with fractures and clay seams. Unweathered limestone bedrock is sound and hard with unconfined compressive strengths of 10,000 to 20,000 psi."

Jan 1, 2009

By D. P. Caplice

On behalf of the Ontario Water Resources Commission, I would like to express my sincere appreciation to your Institute for presenting us with this opportunity to outline the regulatory control programme as it relates to the mining industry in the Province of Ontario. In Canada, and particularly in Ontario, we are blessed with an abundance of natural resources. Fresh water in the form of lakes and rivers covers nearly 17 per cent of the area of the Province. (Total area of the Province of Ontario is 412,582 square miles.) The mining industry, which had its beginning in the early 1800's with a small iron ore plant, has progressed with the major discoveries of nickel and copper in 1883, silver in 1903, gold in 1908, iron in 1939 and uranium in 1953, to the point where, in 1966, almost one billion dollars in mineral wealth was mined in Ontario. Water, in spite of its great abundance and with due respects that it may become a natural resource worthy of export in the foreseeable future, has become increasingly precious in Ontario, particularly in the more urban areas in the southern part of the Province.

Jan 1, 1968

By Faruk Oksuz, Dave Schiemann, Miguel Sanchez, Patrick Jensen

"The McCook Main Tunnel connects Chicago’s Tunnel and Reservoir Plan (TARP) Mainstream Tunnel to the McCook Reservoir. The tunnel system consists of a 10 m (33 ft) finished diameter and 490-m (1,600-ft) long hard-rock tunnel constructed from a 27.5-m (90-ft) diameter and 92 m (300 ft) deep main gate shaft. The gate shaft houses six high-head 4.4 x 9 m (14.5 x 29.5 ft) wheel gates installed in the bifurcated and steel-lined section of the tunnel. The tunnel also includes portal and energy dissipation structures as it daylights into the reservoir. Construction of the McCook Main Tunnel in live flow conditions was a challenging task for the McCook Main Tunnel Project participants, the project owner U.S. Army Corps of Engineers (USACE), local sponsor Metropolitan Water Reclamation District (MWRD) of Greater Chicago, designer Black & Veatch and contractor Kiewit Infrastructure Co. (Kiewit). Once completed in two stages in 2017 and 2029, the McCook Reservoir will hold 38 billion L (10 billion gal) of combined sewer overflows (CSO) and flood waters from the city of Chicago and 36 surrounding communities in Cook County, IL The construction of the tunnel system was divided into two contracts. The first contract for the gate and construction access shaft was completed in August 2011. The second contract included tunnel excavation and concrete and steel lining that was completed in September 2014; installation of gates and hydraulic cylinders that was completed in June 2017; and the last major construction activity was the removal of a temporary concrete plug (bulkhead) and lining that tunnel section to bring the overall tunnel and gates system online before Dec. 31, 2017.This article focuses on the installation, testing and commissioning of the high head wheel gates. Live tunnel connection details to TARP Mainstream Tunnel were addressed in a previous paper submitted at the World Tunneling Conference in 2016."

Mar 1, 2019

By Neal P. Cochran

It is always a pleasure for me to address a group of mining engineers. I am doubly grateful when I am allotted sufficient time to describe the total Office of Coal Research program. My remarks are directed to our total program but I trust you will all understand my emphasis of the utilization aspect of our activities since that is my portion of the program. From its inception, the Office of Coal Research has sought out creative ideas for improving our national use of coal by developing new uses, improved mining procedures, lower costs, and appropriate studies with respect to the resource itself. Quite early in the game, our Economics and Marketing Division contracted for studies with respect to New England export market, Western coal, and similar items. Our Mining and Preparation Division has successfully developed a packaged coal-fired boiler and has partially developed a packaged fluid-bed type boiler as well. Our Mining and Preparation Division is working in such diverse fields as treatment of sewage with coal and the separation of coal into distinct-petrographic constituents so that all fractions of the coal can be put to the best possible use. We would like to be doing more work on improved mining methods, better preparation techniques, and any other mining improvement that will benefit the industry and our program. The synthetic fuel plants I will describe later will operate seven days per week, 24 hours per day. We would like the mine to operate on this same sort of cycle and are prepared to support research that will lead to this.

Jan 1, 1970

By David Griffiths

I am' not an orator and have never said a word in public during my thirty years' experience in the coal mines of Colorado; but, being requested to speak by our worthy chairman, and as I am deeply interested in the future welfare of this organization, I will make an effort to say a few words in behalf of the Rocky Mountain Coal- Mining Institute, which we are about to organize. As I understand it, it is the object and intent of this organization not merely to assemble occasionally for the purpose of discussing various problems in coal-mining, and thus to obtain the best possible results in economic operations, but its especial duty will be to devise ways and means whereby accidents in coal mines will be minimized. Figuratively speaking, we are about to plant a tree in the State House of Colorado, and desire its roots and branches to extend over Wyoming on the north, New Mexico on the south, and Utah on the west. So we expect this tree to bear fruit over a vast area. .We must remember that the planting of a tree, even in good soil, is useless unless we cultivate, prune, and nurture its development. If we will not do so, the tree will not bear the desired fruit. So, in order to make the Rocky Mountain Institute a success, we must not only start it off in good shape, but we must keep on adding to its strength in various ways, so that it will become a known factor and a recognized power over this broad teritory. In other coal-mining states and countries of the world much has been accomplished through similar organizations to reduce loss of life among, men engaged in the production of coal, and there is no reason why our institute in the West should not be equally useful and attain the same results. There are many ways by which this organization can be made beneficial to the men engaged, in various capacities, in handling the "dusky diamond.' I will endeavor to confine my brief remarks to the necessity of a crusade of an educational nature among three classes of men that are directly and indirectly connected with coal mines. First-We need to educate ourselves. It is amazing how few of our number, holding positions of trust, and having charge of men in and around coal mines, are conversant with our brief mining laws and cognizant of our duties in enforcing them. Going down the line to our company men and miners, I think I can safely say that not over 5 per cent of them are in any way familiar with the statutes

Jan 1, 1913

By DONALD H. McLAUGHLlN

Few factors have had more influence in maintaining the strength and stability of the United States than our persistent habit of providing .checks and balances to the dynamic powers of free enterprise on the one hand and to the controls and guidance exercised by the State on the other. .Indeed, it is this same concern for matching forces against each other that has given our republic its ability -to preserve a democratic basis of life for its citizens, and yet maintain a ,government that is able to protect the rights of all and to resist and minimize the danger of excessive concentration of authority. Our current efforts to clarify the nation's mineral policies and to define more clearly the role that the governmental agencies should play in conjunction with the functions of private -enterprise again reveal the desirability and advantages of maintaining our traditional controls. At times, the equilibrium has been temporarily disturbed by too great enthusiasm for one or the other of these basic concepts. Sooner or later, however, the balance has been restored by the healthy opposition that is always created by excesses of one sort. At the current stage in our history, the swing toward undue enlargement of the powers of the State seems to have gone dangerously far and we would be untrue 'to our traditional behavior if the group that must demonstrate the virtues of free enterprise did not rally to its support with the utmost earnestness.

Jan 1, 1949

By Kidd, Robert L.

INASMUCH as galena and sphalerite flotation concentrates are being produced that contain over 95 per cent galena or sphalerite, it is not unreasonable to believe that a flotation concentrate assaying at least 80 per cent of native gold can he secured provided the gold is free. As yet, little if any fundamental information has been published concerning the flotation of free gold either alone or in the presence of sulfides. So far, we are unable to make as complete a separation of gold from sulfide minerals by flotation as is possible in, the separation of one sulfide from another by this method. An introductory study of the flotation of several free gold ores has been made in our Utah laboratories. For this study three general types of gold ores were chosen, namely: (1) Quartzite containing 0.26 oz. gold per ton in which no base metals are present; (2) sulfide ore (2.04 oz. Au; 1.31 oz. AO containing pyrite as the only sulfide present and the gold free; and (3) oxidized ore (1.10 oz. Au; 0.70 oz. Ag) from an oxidized zone of the vein from which sulfide ore (No. 2) was taken; little sulfide iron was present.

Jan 1, 1932

By Gerhard Lang

"Slurry Microtunneling is a well-established technology building on over 20 years of experience in successful tunnel installations under all kinds of soil conditions across the U.S. and Canada. Recent microtunnel installations prove that initial hesitation, e.g. curved drives, is fading and long-distance pipe jacking projects as well as lake outfalls are being considered. One of the younger technologies is Direct Pipe®, which combines the benefits of HDD and Slurry Microtunneling. It fits exactly into the area where HDD is not feasible or too risky to apply. The paper points out the benefits of the Direct Pipe® technology for owners, engineers and contractors and discusses the latest developments of Slurry Microtunneling for long-distance, curved drives and sea/lake outfalls with wet recovery of the equipment such as on the ‘Keswick Outfall Project’ in Ontario. The first Direct Pipe® installation in the US was executed in August 2010. Since then, another 22 crossings have been carried out amongst a total of more than 60 Direct Pipe® crossings worldwide. INTRODUCTION Pipelines installed underground are indispensable for supplying the growing world population with water, oil, gas and electricity, for removing wastewater and for providing functioning telephone and communications networks. During recent years the limits of trenchless applications have been permanently shifted, leading to higher and more stringent project requirements and consequently new technologies, either as further development of existing methods, or through the development of new methods by incorporating elements of proven technologies. MICROTUNNELING TRENDS IN NORTH AMERICA Slurry Microtunneling has a wider geological application range in comparison to EPB and hard rock Microtunneling. The Slurry MTBM can be equipped with specific cutting wheels to cope with different soil conditions. The most flexible and most often employed type is the mixed soil cutting wheel, which contains a mixture of disc cutters as well as scrapers for varying soil conditions from cohesive soils (clay, silts) to highly permeable soils including sands, gravels and cobbles and even hard ground formations such as rock and boulders. A detailed geotechnical report provides the appropriate data to configure the MTBM and its features to the ground conditions expected. Mixshield or hydroshield (AVN/AVND) MTBMs in particular, can be safely operated with little overburden (~ 3-5 x machine diameter) and minimum risk of frac-out or settlement on the surface. This is especially beneficial in urban areas with sensitive buildings or for river crossings with protected fish habitats."

Jan 1, 2016

By L. W. Burger

The need to establish and harmonise methodologies to quantify air emissions, atmospheric dispersion and the consequences of air pollutants (especially hexavalent chromium) from the ferrochrome industry became important aspects with the increasing demands for comprehensive impact assessments. The paper includes a synthesis of current knowledge on the following aspects: ? Locally and internationally accepted methodologies for the quantification of chromium emissions, including sampling methods and emission factors; ? A compilation of recognised and accepted air quality sampling and laboratory analysing techniques; and, ? Dispersion modelling and impact assessment tools. Depositing and removing materials from the chromium ore stockpile and wind erosion of exposed stockpiles result in mainly chromite emissions unlikely to contain significant amounts of hexavalent chromium. Pre-treatment processes such as drying, crushing and screening also produces chromium emissions, but mainly as trivalent chromium. The smelting of chromium is the major source of chromium emissions - open furnaces have the highest uncontrolled chromium emissions, followed by semi-closed and closed furnaces, respectively. Based on the current knowledge on emission rates, interim emission factors for particulate, total chromium and hexavalent chromium releases are provided. Ambient sampling and analytical methods to determine environmental exposure of the general public require that hexavalent chromium needs to be quantified in very low concentrations. Suggested sampling and analytical methods for both source characterisation and ambient monitoring are provided. The selection between dispersion models needs to be based on the size of the modelling domain and the complexity of the terrain. The discussion on dispersion models includes the US EPA?s Industrial Source Complex Model (Version 3), the AERMET/AERMOD suite of models and the CALMET/CALPUFF suite of models. Guidelines are also proposed for environmental exposure assessments including cancer and non-cancer health effects.

Jan 1, 2004

IN THE past, we have, perhaps, been somewhat careless in our furnace practice, in the use of high-grade material, lowering the production costs through demanding high-grade ores, increasing the size of units, and eliminating heat losses by collecting and returning unused heat to our furnaces. Further economies would seem to be possible through keeping out of the furnace those materials that appear to serve no useful purpose and carry with them heat that should be used in reduction operations. In the manufacture of pig iron, about three tons of inert nitrogen pass through the furnace for each ton of iron produced. This nitrogen serves no useful purpose in the chemical actions involved, but when discharged into the atmosphere it carries away a considerable quantity of heat. Can not this loss be eliminated, at least in part, through the use of more oxygen in the blast? Many metallurgical chemists, during the past 20 years, have stated that they thought it can and have urged that the plan be tried. Others have expressed doubt, not being able to visualize how more oxygen could be used in present practice; they have regarded it as impracticable, without trying to conceive of an entirely new practice based on a new reagent. That more experimental work has not been done is due to the fact that no cheap oxygen has been available, but the committee believes that there is strong reason to expect that, should a demand exist, 99 per cent. oxygen may be made at a cost not to exceed $3 per ton. The theoretical studies of the committee have indicated such marked economy by using oxygenated air in various operations that its members strongly recommend experimental work to verify the anticipated economies. The committee has developed plans for experimentally determining the effects of oxygen-enriched air on the operation of an iron, blast furnace. A furnace with a height of 30 ft. has been built and it is recommended that the plans be put in, effect as the first step in the research.

Jan 11, 1924