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By Robert M. St. Louis, Janet M. Edgecombe

The Mercur Mine's autoclave is an alkaline pressure oxidation system, operating at 220°(428°F) and 3061 kPa (444 psig) (total). Up to 725 metric tons (800 st) of ore, grading 2.02 g per mt (0.059 oz/st) Au and containing 1 to 2% sulfide sulfur, are treated daily in this circuit. A mineralogical and chemical investigation was initiated to locate the cause of lower than anticipated gold recoveries. Greater than 70 wt. % of reduced sulfur is oxidized; therefore, the autoclave is operating at specification. The low recoveries were attributed to increased concentrations of organic carbon in refractory ore. Activated carbon concentration in the attached CIL circuit was increased from 15 to 40 g per 1, leach temperature held below 21°C (70°F), and carbon flow changed to counterflow. These measures resulted in gold recovery improving from 75 to 82%.

Jan 1, 1990

By C. J. Badenhorst

Oxides of sulphur are corrosive and are produced when sulphur-containing fuels are burned. Sulphur dioxide (SO2) is a colourless gas with a characteristic, irritating, pungent odour. Exposure routes to the human body are mainly through inhalation and skin and/or eye contact. Symptoms of exposure to SO2 may include irritation of the eyes, nose, and throat; rhinorrhea (discharge of thin nasal mucous); choking; cough; and reflex bronchoconstriction. To protect employees against the ill health effects of SO2 exposure, they are often required to make use of respiratory protection whenever entering areas were the SO2 levels exceed the statutory limits. The use of respiratory protective equipment should always be a last resort and should be considered only after other control measures have failed to reduce occupational exposure levels to below the occupational exposure limit or whilst other control measures are being investigated or implemented. Whenever the use of respiratory protection equipment is considered, it should always be used as part of a comprehensive respiratory protection plan. It is also extremely important that all potentially exposed persons are adequately and comprehensively informed and trained.

Jan 1, 2007

By Henry S. Munroe

The plan of organizing a summer class of students of tha Bchool of Mines, for the practical study of mioing and miner's work, rewived at the outset the following cordial indorsement: ...." 1 have thonght over the plan proposed by you of taking the students to the mines during the summer, acd of having them actuaily ttrke part, under the direction of skilled worktnbn, in dl the various kinde of mining work; and of using them as a cerps of engineers to make inside and outside surreys, particularly with a view to the detailed study of the geology of the mine. I have no beitation in saying, that if the students have been previously instructed in the theoretical part of thrir studies, by lectitras and practice during the winter, the plan would be an admirable one. Of courae experience will suggest modiflcations of detail. Frorn the work you have done at our mines this spring, I feel sure that you would be perfectly competent to curry out your plan, and 1 shall gladly aid you in uny wny I can. " Yours, sincerely, The plan of the proposed summer school thus indorsed by Mr. Coxe was adopted by the trustees of Columbia College, and an appropriation of one thousand dollars, or so much thereof ss might be necessary, was voted for the experitneat. A volunteer class of thirteen students was formed, and the first summer school was held at Drifton, in July and August of that year (1877). The following extract, from an editorial notice in the iden of the organization of the school and the work required of the stiudens. "The students, on reporting to Professor Munroe, were divided into sqoade of two or three men each, and on Monday, July 2d, were aesigned to the qre of skilled miners, selected for the purpose by the mine boss, for instruction in gangway work. Half of the students worked in the morning and the other half in the atternoon, one squad at a time with each miner, The times of going and coming to and from work were so arranged that each student spent four to four and a half hours in the mine each day. While in the mine they assisted the miner to load his car, thereby learning readily to distinguish I slate ' and

Jan 1, 1881

By Pierre Filiatreault, Brian Straight, Stephanie Thibeault, Devin Castendyk, Londie Cameron

"Working on or near water at active, closed or abandoned mine sites is inherently dangerous. Between 1996 and 1999, the U.S. Mine Safety and Health Administration (MSHA) reported 17 fatalities involving drowning at U.S. metal, non metal and coal mines (MSHA, 2000). Openpit mines which fill with water following mine closure, called pit lakes, present numerous risks to environmental monitoring teams including: a) drowning, b) hypothermia, c) falls to the ground from the top of high walls, d) collapse of unstable access roads, e) rock falls and avalanches from pit walls, f) avalanchegenerated tsunamis traveling across the lake surface and g) rapid degassing events.Some pit lakes are simply not safely or easily accessible for ongoing monitoring. However, the routine collection of water samples from the entire water column on a regular basis is needed to monitor the evolution of water quality over time, verify the accuracy of numerical predictions and, ultimately, manage lake water chemistry and ecological risks. For pit lakes with surface water discharge, regular monitoring is used to appropriately design and adjust water treatment plants in order to produce acceptable site discharge water quality.As a product of these risks and the need for water samples, mining companies spend considerable expense on pit lake safety as part of monitoring programs. This includes training personnel for on water duties and hazards, purchasing or hiring specialized equipment and personnel (such as boats, boat operators, personal floatation devices and cold-water clothing called mustang suits), stabilizing pit walls and maintaining safe access roads to the lake surface and employing spotters who can directly communicate with emergency medical services to watch sampling activities because cell phones and radio signals can be blocked by pit walls. Some sites utilize redundancy to prepare for unexpected incidents and accidents. For example, one Canadian mining company requires two boats on the water during pit lake sampling events, with a third boat on the shoreline, gassed and ready to go. In addition, water samplers are required to hold Marine Emergency Duties training to ensure the entire boat crew is sufficient and competent for the safe operation of the vessel in the event of an accident."

Jan 7, 2017

By A. A. Smith, J. S. Smart

THE controlled amounts of phosphorus, arsenic, sulphur or selenium found in commercial coppers perform a variety of highly useful functions. Indeed, a large segment of modem copper technology is essentially dependent upon the presence of one or more of these elements. Consequently, the literature contains many references to their effects but the scope is broad and has been only partly covered. New data are presented herewith directed toward a better understanding of the basic behavior of these elements in copper, with particular emphasis on the composition range 0 to 0.05 per cent. These data are a part of a general program of research on the effects of impurities on the properties of oxygen-bearing and oxygen-free copper, other portions of which have been reported previously.1-2-3 Schematically, the behavior of individual elements is determined from measurements of conductivity and softening temperature,1, 2 and the binary alloys employed are synthesized from high-purity copper in order to eliminate interference from the effects of extraneous impurities. Alloys of selected composition were first prepared in the oxygen-free form by continuously casting the melts in the form of 3/8-in. diameter rod. Oxygen was added subsequently to portions of the alloys, either by remelting or by diffusion at 850°C. from a surface scale. Test wires were drawn one B. and S. number per pass, using four 30-min. 600°C. anneals at o.3125, 0.257, o.204 and o.162 in., and a final cold reduction of 95 per cent t0 0.081 in. Oxygen-bearing slugs made by remelting were hot-rolled to 5/16 in., drawn to 0.162 in., annealed for 30 min. at 600°C. and cold-drawn 95 per cent to 0.081inch. The alloys containing phosphorus, having been compounded very early in the program, were prepared in the form of 5/16-in. rod, and processed to wire with only the last three intermediate anneals listed above, all of these having been conducted in commercial nitrogen. In addition, the conductivity anneals on these alloys were also performed in the same atmosphere, and the small amount of oxygen present as an impurity in the gas resulted in some loss of accuracy at temperatures of 700° to 800°C., as will be shown later. Subsequently, the anneals for all oxygen-free alloys were conducted in hydrogen to prevent oxidation, and purified nitrogen was employed only for oxygen-bearing samples. All conductivity anneals were of one hour duration followed by a rapid quench in 10 per cent H2SO4. EFFECT OF PHOSPHORUS The widespread use of phosphorus as a deoxidant has resulted in universal appreci-

Jan 1, 1945

By James Westfield

Following is a brief resume of the Division's activities that have had a favorable effect on health, safety, and the reduction of injuries at coal mines: 1. The Federal Mine Safety Code for Bituminous Coal and Lignite Mines of the United States was issued originally by the Director of the Bureau of Mines on July 24, 1946, after consulting with management and labor representatives of the coal-mining industry. The code has been used by Federal coal-mine inspectors while inspecting bituminous-coal and lignite mines as a basis for determining the existence of unhealthful and unsafe conditions and practices in these mines. A revised code was issued by the Secretary of the Interior on October 8, 1953, after further consultations with representatives of management and mine workers and was incorporated by reference in the 1952 and subsequent bituminous-coal wage agreements. The agreement of May 29, 1946, between the Secretary of the Interior, acting as Coal Mines Administrator under authority of Executive Order 9728, and the United Mine Workers of America, covering bituminous-coal and lignite mines in Government possession, charged Federal coal-mine inspectors with the responsibility of making periodic investigations of the mines and reporting to the Coal Mines Administrator any violations of the Federal Mine Safety Code. Federal coal-mine inspectors also had temporary authority to close mines found to be imminently dangerous, but such authority under Executive Order 9728 was removed on June 30, 1947, when Government control of the mines was terminated.

Jan 1, 1961

The 118th, meeting of the Institute, which has been arranged primarily for the benefit of the Institute of Metals Division and of those members who are particularly interested in iron and steel, will be held in the Milwaukee Auditorium, Milwaukee, Wis., on Oct. 8 to 11, 1918. This date has been selected because at that time, and at the same place, the American Foundrymen's Association and the American Malleable Castings Association will hold meetings. A notable exhibit of metallurgical and mechanical processes and products, at which over 165 firms will be represented, has been arranged in Machinery Hall, of the Auditorium Building. Wherever practicable, the machinery will be in operation. The program of the Institute's sessions was published in Bulletin 141. A special announcement of the meeting, together with a program of the sessions of the American Foundrymen's Association, has been mailed to every member who was thought to be directly interested in the meeting. A report of the meeting-and of the discussion of papers will be printed in the December Bulletin.

Jan 10, 1918

By Randall E. Brown

Irrigation simulates a climate change so that crops can be grown that otherwise would not thrive. The abundant sunshine and warm weather of many arid regions induces a rate of growth in excess of that in cooler, moister regions. Hence, the arid part of eastern Washington, traversed by the Columbia River, is admirably suited to irrigation. The Pasco Basin lies in south-central Washington at the south end of the Columbia Basin Irrigation Project of the U.S. Bureau of Reclamation. The Basin, because it lies in the rain shadow of the Cascade Mountains, receives only 6 to 10 inches of precipitation a year with somewhat greater amounts, commonly as snow, on the higher hills. Recent extremes included 3 inches of precipitation from August 1967 to August 1968, and 12 inches in the succeeding "12 months. Most of the precipitation falls during winter. If it were to fall in summer or were evenly distributed throughout the year, evaporation rates probably would produce a true desert.

Jan 1, 1971

By H. Walqui, S. K. Kawatra, C. H. N. Jeltema, T. C. Eisele

"The literature contains many cases where the shape of hydrocyclone efficiency curves vary from the ideal “S” shape. These often appear as changes in slope, or inflections. These inflections can be divided into two categories: “coarse” inflections, which are caused by differences in the density of the minerals being separated, and “fine” inflections, for which there are a number of competing hypotheses concerning their cause. The existing literature addresses either the fine inflection or the coarse inflection, but no studies have reported both types of inflection occurring at once in a single hydrocyclone test. This paper presents hydrocyclone results from both in-plant studies and laboratory experiments that show both coarse and fine inflections. The industrial significance of both types of inflections is discussed. Hydrocyclone efficiency curves show the probability of any given particle reporting to the hydrocyclone underflow as a function of its size. Selectivity functions, S(d), are used to represent the fraction of the feed material in size fraction “d” that reports to the hydrocyclone underflow. Plotting this selectivity function against particle size leads to the standard S-shaped efficiency curve shown in Fig. 1. In the “uncorrected” curve, the tail of the curve does not go through 0%, because a portion of the solids are bypassing classification. This happens as a result of their being carried along by the water, and is most important for the finest particles. The curve can be “corrected” based on the fraction of the feed water that reports to the underflow, represented by the bypass fraction, Rf. The corrected curve then normally passes through 0%, as shown in Fig. 1.The act of correcting the curve shifts the value of the d50 size, which is the size that has an equal probability of reporting to either the overflow or to the underflow. Correcting the curve to account for the bypass fraction makes it easier to compare cyclone performance under conditions that cause the quantity of water in the underflow to change, but that do not alter the actual corrected cut size (d50c).The corrected efficiency curve can be expressed closely by equations such as Plitt (1976):"

Jan 1, 2015

By Klados. T.

MSC.Software assessed the performance of the drive end and non-drive end bearings on a ball mill using the finite element method. The assessment included the effect of mill and pedestal deformation on the performance of the bearings. Oil film thickness, oil pressure distribution and power requirement were of interest. A solution approach coupling a structural solver to a Reynolds equation solver was specifically developed for the project. Results showed that the deformation of the bearing surfaces had a significant influence on the performance of the bearings. For example, for the non-drive end bearing, the minimum oil film thickness computed for the deformable bearing surfaces was significantly lower than calculated for the non-deformable case. The results also showed that cavitation was likely in both the drive end and non-drive end bearings (severe negative pressures were obtained in both bearings). Other design variations were also assessed, e.g. a case with a modified radial clearance which improved the results.

Jan 1, 2006

By Gary F. Rajala, Bruce R. Greenwood

INTRODUCTION The Empire Mine is an iron ore mining, concentrating and pelletizing facility operated by The Cleveland-Cliffs Iron Company in the Upper Peninsula of Michigan. Owners of the mine are Inland Steel, LTV Steel, Wheeling-Pittsburgh Steel and Cleveland-Cliff s. The orebody is a fine-grained, low grade iron formation with magnetite as the primary constituent. Also present are iron carbonates, iron silicates, chert, hematite, goethite and quartz. The original six concentrating lines were started in late 1963. Successive expansions of ten lines in 1967, five lines in 1974 and 3 lines in 1979 have resulted in Empire reaching a present annual capacity of 8.0 million long tons of pellets. The Empire flowsheet was developed over several years of laboratory bench testing, pilot plant testing and testing of a full-scale primary autogenous grinding circuit. Since the original flowsheet was established, modifications have been made based on pilot plant and full-scale plant tests. The present flowsheet for three sections of the concentrator consists of one stage of crushing, two stages of closed circuit autogenous grinding, two stages of magnetic separation, one stage of hydraulic concentration and two stages of flotation (rougher and scavenger). The flowsheet for the fourth section of the concentrator (Empire 4) is the same as the first three sections, except a crusher has been added to crush excess pebbles. The Empire 4 flowsheet appears in the at- tached figure. PRIMARY GRINDING CIRCUIT FLOWSHEET Empire has a total of 24 individual grinding lines. However, at the present time, Line 1 is not being used for processing crude ore. The primary mill on Line 1 is now grinding flux stone for fluxed pellet production and the secondary mill is being used as a ball mill to grind rougher flotation tailings prior to a scavenger flotation circuit.

Jan 1, 1992

By Munro P. D

Eh-pH measurements were taken on an industrial zinc reverse flotation process at Brunswick Mining and Smelting Corporation Limited. Laboratory zinc reverse flotation testwork on samples of the feed to the industrial process produced Eh-pH data which were similar to the data from the industrial process.Later, the Eh-pH data from the industrial process were compared with data from a pilot plant scale zinc reverse flotation process at Mount Isa Mines Limited. After comparison with the data from Brunswick Mining and Smelting Corporation, deficiencies in the pilot plant Eh-pH data could be recognised and corrective actions were taken for the pilot plant. A robust pilot plant zinc reverse flotation process was obtained with consistent performance at the expected level.The implications of these findings for a range of processes are also discussed.

Jan 1, 1988

By Rong Fan, Andrea Gerson

"The small recovery of Ag, often in the order of 50%, by traditional flotation and leaching process strategies is closely related to the complicated and heterogeneous nature of Ag-bearing minerals with Ag typically being associated with numerous minerals within any given ore-body. Moreover, grain sizes may be extremely fine with micron-scale common. In order to design cost-effective Ag-bearing mineral flotation and leach recovery strategies it is firstly necessary to characterise the speciation of Ag and its correlation with other elements, e.g., Cu, As and Sb, within the ore matrix and process streams. The traditional QEM-SCAN analytical approach can prove problematic for some mineralogies due to difficulties in recognising degrees of crystallinity, polymorphs, complex solid solution series, high value trace element mineralogy, very fine grained materials; and the requirement for a comprehensive data base. Moreover, there is difficulty ‘seeing’ either surface films or surface contaminants which can both lead to poor flotation performance. There is therefore clearly a need to develop confirmatory and complementary approaches when these uncertainties arise. Synchrotron X-ray microprobe analysis provides a powerful tool for the mineralogical characterisation of finely segregated heterogeneous Ag-containing materials. These measurements enable comprehensive characterisation of the Ag-bearing components using synchrotron microprobe X-ray fluorescence mapping (µ-XFM), X-ray diffraction (µ-XRD) and X-ray absorption spectroscopy (µ-XAS). Further analytical strength is provided by principal component analysis of laboratory ToF-SIMS data which enables the statistical identification of correlated surface species enabling examination of surface chemical characteristics responsible for mis-reporting of Ag containing components within flotation streams. We describe the application of these techniques to a selected Ag-containing feed and tail and demonstrate how these compliment and extend traditional analytical methodologies."

Jan 1, 2014

By P M. Hancock, Associates

Lacustrine sediments, hydrothermal explosion breccias and spring precipitates deposited 5200 - 1800 years BP as a result of geothermal activity at Lake Rotokaua, contain New Zealand's largest known sulphur reserves. Current drill indicated reserves are 2 600 000 tonnes of elemental sulphur, assuming a ten per cent (dry basis) cut-off, contained in some 17 000 000 tonnes of ore with an average grade of 214.0 per cent (dry basis) sulphur. Additional inferred ore containing 500 000 - 900 000 tonnes of sulphur has yet to be prospected by drilling. Geological factors will be important in exploitation of the deposit, particularly the extent and disposition of the orebody, sulphur grades and distribution, physical characteristics of the ore, permeability and stability of the overburden and the nature and extent of geothermal activity in the area. Trials to date indicate that Frasch mining and possibly opencutting are unlikely to be successful mining methods. Further mining feasibility studies will be required to ascertain the most likely mining system for the deposit.

Jan 1, 1984

By Andrew Franklin

The eightieth regular meeting and convention was called to order by the President, John T. Atkins, at 9:15 a.m. Monday, June 25, 1984 in the Colorado Ballroom of the Marriott's Mark Resort in Vail, Colorado. President Atkins welcomed the members and their guests to the convention and noted that the annual business meeting would be held Tuesday afternoon at 2:00 p.m. in the same room. A convention update was made by the Conven¬tion Liaison Officer, Loren V. Linville. This was followed with a program report by the Program Chairman, Doug Ingram. The chair then called on Clifford Barrett, Upper Colorado Regional Director of the Bureau of Rec¬lamation of the United States Department of the Interior. He presented the Bureau's Citizen Award to RMCMI former president Ira E. McKeever for his outstanding contributions to the joint private/ Federal effort and the open planning process for AQUATRAIN. According to Barrett, "from 1981 to early 1984, McKeever led private industry work in the AQUATRAIN project, a proposal for a 1,400 mile long pipeline system. AQUATRAIN was conceived as a possible alternative to solve the government's problem of rising salinity levels in the Colorado river, as well as the private sector's need for a more economical coal transport method. The Citizen Award cites McKeever's efforts in developing a model for future cooperative ventures between government and industry that can benefit the nation." Following this presentation, the formal program of the 80th meeting and convention began with the president, John Atkins, introducing the convention kickoff speaker, Andrew Franklin, President of Nerco Mining Co., Inc., followed by the convention keynote speaker, Dr. Margaret N. Maxey of the University of Texas. These speeches are printed in this Proceedings together with those of all other convention speakers. I'm Andrew Franklin, President of Nerco Min¬ing Company, and I'm delighted to be here to kick off the annual convention of the Rocky Mountain Coal Mining Institute. This has always been a very special convention in my eyes and I'm sure this year's will be no exception. I am also here to share my thoughts on the western coal industry and how we're all affected - for good and bad - by public policy decisions. Although the title of my talk is "Western Coal: An Industry Under Siege," I believe a more accurate title might be "Western Coal: The Pit and The Pendulum," because of the wide swings in public policy and coal development in the past 15 years which have cut a zigzag path for growth over this period. As one of the nation's largest coal producers, Nerco is well aware of the problems facing western coal production. Nerco Mining Company is the western coal mining subsidiary of Nerco Inc. We have been "in coal" for more than 25 years through our parent company, Pacific Power & Light. To state my conclusion at the outset, I feel it's extremely important that consistency and common sense should guide our national policy for the development of valuable energy resources. In particu¬lar, we must reduce the wide swings in government policy and activities which have affected energy development. In short, we must decide what kind of game we're playing so that the "players" and the "referees" can keep their eyes on the "ball." Business today faces two main types of uncertainty market uncertainty and public policy uncertainty. As businessmen, we expect and are used to facing the familiar challenges and uncertainties of the market in which we operate. Over the past 10 years, the market has appeared to be bullish on coal. But the facts make our future less rosy. Last year, western coal producers faced over 50 million

Jan 1, 1984

By F. Sillers, R. T. C. Rasmussen

"INTRODUCTION This is the fourth report of investigations dealing with the cooperative tests between the Bureau of Mines and industry on the use of electrolytic manganese in steelmaking. The first report dealt with the use of electrolytic manganese in the manufacture of stainless steel 3/ the second with its use in acid electric steel practice, 4/ and the third with its use in low-carbon basic open-hearth steelmaking. 2/ A résumé of those investigations E7 appeared in the magazine STEEL. 5/ The present report deals with the use of electrolytic manganese in the manufacture of four types of stainless steel and the new Timken 16-25-6 alloy. The Bureau of Mines supplied The Timken Roller Bearing Co. with 62,000 pounds of electrolytic manganese for use in the tests.The electrolytic manganese was produced at the Bureau of Mines pilot plant, Boulder City, Nev., by the process developed by the Bureau and described in Bulletin 463, Operation of Electrolytic Manganese Pilot Plant, Boulder City, Nev., by J. H. Jacobs. J. W. Hunter, W. H. Yarroll, P. E. Churchward, R. G. Knickerbocker, R. W. Lewis, H.A. Heller, and J. H. Linck. The workcarried out under the direction of R. S. Dean, formerly assistant director, Bureau of Mines, and R. G. Knickerbocker, formerly chief, metallurgical branch, as part of a long-range program involving the development, manufacture, and use of manganese from domestic ores. Preliminary arrangements for the plant tests were made by the late A. A. Dow. 7/"

Jun 1, 1947

A study of drilling data at various stages of development of an orebody show that the semi-variogram, used for calculating the accuracy of block estimates can be ill-defined if too few data are available. The consequencesin this case are to have blocks supposedly more accurately known than is possible at the early drilling stage; such a result being potentially dangerous. However, as the amount of data increases the recalculated, semi-variograms approach the underlying semi-variogram of the deposit and the calculations made using them become more reliable and robust.

Jan 1, 1977

By R. M. Imhof, M. J. G. Battersby, J. V. Brown

There is a plethora of former industrial sites where coal mining operations have left large slurry impoundments. These contain raw washed fines, which have previously been too expensive to process to requisite grades for commercial use. New technology has been developed for fine material processing, namely the Imhoflot pneumatic flotation G-Cell. This froth flotation technique is a highly efficient means of concentrating coal and is particularly appropriate to the nature of materials encountered in tailings ponds. The high volumetric throughput resulting from the vastly reduced residence time in the cell allows for drastically reduced equipment sizes when compared to conventional flotation cells. This means the process, when combined with innovative pre treatment and filtration equipment can be developed as a mobile plant concept. This is seen as a minimum requirement when re-treating and rehabilitating fine coal ponds.

Jan 1, 2003

By B. H. Zhao

A low grade Pt-Pd ores, with 1g/t Pt and 0.13g/t Pd, and 8.70% Fe and 2.50% P2O5 is experimented to recover of Pt and Pd. The flowsheet is proposed which consists of Pt-Pd selective flotation, apatite flotation from tailings of Pt-Pd flotation, magnetic separation of magnetite from apatite flotation tailing. With butyl xanthate, N-ally group-O-isobuturyl-thioanimoformate and Sodium y-89 xanthate as collectors, sodium silicate as depressant, and sodium carbonate as pH regulator, a concentrate, assaying 324.52 g/t Pt and 45.62 g/t Pd, is obtained with recoveries of 87.23% Pt and 76.89% Pd from surface ore. A concentrate, assaying 1693.53 g/t Pt and 64.12 g/t Pd, is obtained with recoveries of 88.54% Pt and 83.78% Pd from primary ore. At same time, A iron concentrate assaying 64.12% Fe with a recovery of 24.94%, and a apatite concentrate assying 30.32% P2O5 with a recovery of 80.12% are obtained.

Jan 1, 2014

By Fabrice Mathieu

The Cutter Soil Mixing (CSM) provides a cost effective solution for the rapid construction of retaining and cut-off walls using new equipment developed from diaphragm wall cutter technology. CSM consists of cutting and mixing drums mounted on compact hydraulic motors. Soletanche Bachy CSM has been designed to leave the space above the tool free, thereby mixing the soil efficiently during all the phases of the wall construction, with high penetration rates. The precise positioning and verticality of the wall is achieved using a kelly bar and full monitoring. Soletanche Bachy CSM is a versatile equipment which can be mounted on various carriers: pile rigs, hydraulic crane, carrier equipped with telescopic mast. The major phases of Soletanche Bachy CSM development are presented, including the results of an extensive trial carried out in Le Havre (France). The soil consists of hydraulic fill with soft soil lenses overlying sandy deposits. 20m deep panels were constructed to support a rectangular shaft. During the construction, and after its completion, the shaft was subjected to an extensive series of tests followed by a partial excavation. The paper discusses also the future development of the technique and its potential applications.

Jan 1, 2006