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By M Costa, L Polizzi

Process optimisation and continuous improvement are usually acknowledged when making a process more effective, efficient and transparent. During the last few decades, thousands of companies around the world have used total quality concepts in order to establish a continuous improvement process in their companies. Typically these companies apply some kind of Kaizen-type tools and expect results in the short term; however, the great majority of companies are poorly implementing these continuous improvement programs.Usually the most common reasons for failure of the program are lack of commitment from leaders, lack of discipline and engagement from the team to follow process and lack of clear targets for the program. When the results do not come at the expected timeline, it is common to simply drop the current process and apply a different approach from another company or consulting firm.This paper will explore some successful cases of companies that have invested time and effort to establish a reliable and sustainable process of continuous improvement. The focus will be case studies of mines and smelters around the world that use the plan–do–check–act (PDCA) cycle to increase productivity with the best services and lowest costs. The main tools and processes used by these companies will be discussed, as well as results achieved.CITATION:Costa, M and Polizzi, L, 2014. Introducing and sustaining a continuous improvement program in mines and smelters, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 55–62 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By Kwitko G

Exploration for coal has been on-going in South Australia for the past 100 years. During this period substantial resources of low rank coal have been delineated throughout the State. These deposits are of variable quality often with high moisture, sodium, chlorine, sulphur and ash content and although generally regarded as suitable for use in conventional pulverised fuel boilers, many are difficult to utilise. The only operating coal mine in South Australia is at Leigh Creek where coal bearing shale was discovered by chance in 1888 during excavation of a railway dam near the township of Copley. Leigh Creek has had a very diverse mining history from the initial small scale underground mining through to open-cut mining utilising draglines and more recently large shovels and trucks.

Jan 1, 1992

By Sally Gillies

During the 14 years since the last update to National Instrument 43-101 (NI 43-101), there have been many discussions between Canadian regulators and mining companies about mining disclosure deficiencies that arise from regulatory reviews. These discussions are not made public, and as a result, there has been some drift in how NI 43-101 is interpreted by the regulators, which in turn creates uncertainty for the mining companies trying to comply with the instrument. To reduce uncertainty in mining disclosure requirements, the Canadian Securities Administrators (CSA) has issued a notice to update the current NI 43-101 with a streamlined instrument and form. Changes and benefits are listed in the “CSA Notice and Request for Comment — Proposed Repeal and Replacement of National Instrument 43-101 Standards of Disclosure for Mineral Projects,” which is available on the Ontario, Quebec, Alberta and British Columbia Securities Commission websites. The public has been invited to comment, with the comment period ending on Oct. 10, 2025. The 43-101 Companion Policy (43-101 CP) provides an update to the views of the regulators on how the CSA staff interpret and apply certain provisions of the instrument. Collectively, some of the changes to NI 43-101, the form and 43-101 CP are likely to increase the financial and other burdens on the mining companies responsible for the disclosure, and the qualified persons (QPs) who create the disclosure. In other instances, there are missed opportunities to reduce the burden on mining companies and QPs without impacting the markets.

Sep 1, 2025

By J. I. Gazzarri

A model of solid oxide fuel cell AC impedance behaviour has been developed and is used to simulate the frequency response of a single cell with and without mechanical damage. The results indicate that the presence of mechanically induced damage within the components of a solid oxide fuel cell can be detected by comparing the frequency response of the undamaged cell with that of a cell in which in-plane cracking or delamination has occurred. The presence of such defects manifests itself as a new semicircle in the Nyquist impedance diagram of the full cell. A parametric study reveals the resolution capabilities of the method in terms of the geometrical characteristics of the defects.

Jan 1, 2005

By Stephen Utter

Stresses induced by block-caving mining were estimated from in-place measurements of strain or deformation in rock and concrete around mine openings. The four types of gages used for measurements in the Climax Molybdenum mine during 1959-61 were Whittemore gage, Carlson strain meter,2 Valore strain cell, and Climax extensometer. Gage performance in the laboratory was evaluated by stressing instrumented rock and concrete specimens in a universal testing machine and by comparing measurements taken by the gages and a standard gage. Gage performance in the mine was evaluated by comparing measurements taken during an 18-month test. The Whittemore gage, Carlson strain meter, and the Climax extensometer proved suitable for the investigation; the Valore strain cell, effective in the laboratory tests, gave erratic measurements in the mine.

Jan 1, 1965

"The development of non-destructive testing (NDT) methods for deep foundations occurred in several parts of the world, gradually coming together into the present state of the art. The compilation of this brief NDT history is the best effort of several knowledgeable members of the Deep Foundations Institute (DFI) Drilled Shaft Committee, coupled with the recollections of several historically important contributors to the science. It is not intended to be exhaustive, but rather concentrates on the origins of the methods in common use and on which this manual focuses.Modern NDT methods, and the spread of knowledge about them, have expanded through application to real foundations projects by the original researchers, sometimes inspired by their own curiosity, sometimes to respond to the cost and time limitations imposed by static testing, and sometimes to address the questions raised on research projects funded by large government agencies such as the Federal Highway Administration (FHWA) in the USA, and various European transportation agencies. Initial attempts were primitive by today’s standards, and equipment limitations often restricted successful application to relatively simple cases. As electronics improved and confidence in them increased, the early researchers began commercial promotion of their methods, published their findings in professional journals, and shared experiences at conferences held by such groups as the DFI, the International Association of Foundation Drilling (ADSC), the International Conferences on the Application of Stress-Wave Theory to Piles and other venues such as ASCE and Transportation Research Board (TRB) conferences.NDT methods were developed to fill a need to assess the quality assurance of deep foundation elements. New pile types and higher design loads prompted engineers to verify the safety of their foundations via additional testing during construction. Static load testing was the traditional method to assess performance, and this method has been used for centuries and perhaps even millennia.Relatively recent alternatives to static load testing for determining the capacity of drilled shafts include the bottom load test method. This method uses a jack embedded in the lower portion of the pile (bottom load test) and was first reported to be used from Canada in the early 1970’s (Gibson& Devenny 1973). The concept immediately caught on in Israel, where it was used as a quality control measure for small-diameter piles drilled in rock (then a new technology). The method was later patented in the US by Jorj Osterberg, and offered as a commercially available service in thelate 1980s (Osterberg, 1989)"

Jan 1, 2004

By Benjamin W. Haynes

This research was conducted as part of the U.S. Department of the Interior, Bureau of Mines program to recover metals, glass, and a combustible fraction from municipal solid waste (MSW). The objective of this analytical study was to determine the concentration of antimony, arsenic, and mercury in samples taken from various sampling areas in the Bureau of Mines raw refuse recycling plant and to compare these values with those for coals used in the generation of electricity. To provide the necessary analytical data, sensitive reproducible ashing-chemical digestion-atomic absorption procedures were adapted from published procedures. It was determined that antimony and mercury concentrations in the combustible fraction of MSW are approximately an order of magnitude higher than those found in coals presently used for power generation;' the arsenic concentration is similar in both fuels.

Jan 1, 1978

By D. R. Cook, W. M. Shepard, H. T. Morris

The East Tintic district in central Utah has produced ores of gold, silver, copper, lead, and zinc valued at more than $120,000,000. All of this ore has been produced from blind ore bodies in Paleozoic sedimentary rocks that are concealed beneath hydrothermally altered volcanic rocks and cut by intrusive bodies of Eocene age. The Paleozoic rocks, which range in age from Early Cambrian to Mississippian form the core and limbs of a large, northtrending asymmetric anticline that is cut by low-angle thrust faults, high-angle transcurrent faults, mineralized fissures and faults, and normal faults that are both older and younger than the mineralized fissures. The ore bodies generally may be grouped into two classes: ( 1) massive replacement bodies that are rich in silver, lead, zinc and manganese and (2) fissure veins that are valuable primarily for their content of gold, copper, and silver. The replacement ore bodies are localized chiefly in the Middle Limestone Member of the Ophir Formation of Middle Cambrian age where it has been thrust-faulted against older or younger rocks and cut by northeast-trending mineralized fissure zones. The fissure veins primarily are productive only in the Lower Cambrian Tintic Quartzite. Extensive lowgrade deposits of lead-zinc-silver ore recently have been discovered in Devonian carbonate rocks in the Lower plate of the East Tintic thrust fault but as yet are unevaluated. The principal guides to ore include: ( 1) intersections of northeast-trending fissures and crossbreaking faults that brecciate the carbonate rocks; (2) zones of late-stage pyritic, calcitic, and sericitic alteration in the lavas; ( 3) primary geochemical anomalies in the altered rocks; and ( 4) mineral zoning patterns of the known ore bodies. The present development of the Burgin mine would seem to assure the continued productivity of the district for at least a decade.

Jan 1, 1968

By B. P. Watson, A. Carpede, W. O. Kekana, N. Fernandes, W. Theron, M. P. Mahlangu, G. Betz

The research described in this paper was done to confirm the Upper Group 2 (UG2) PlatMine peak pillar strength formula (Watson et al., 2007), which was determined from a back-analysis of failed and unfailed pillars. Underground measurements were made on a stable pillar that was loaded by firstly reducing it’s length and then by mining the surrounding pillars until pillar failure took place. The pillar was instrumented with suitably positioned strain cells and closure meters, which allowed both the average pillar stress and strain to be determined. The paper describes the methodology applied to identify a suitable position for the instrumentation, as well as the results. A stress/strain curve is presented for a UG2 pillar with a w/h ratio of 2.0, at Booysendal Platinum Mine. The measured pillar strength was similar to the predicted strength using the PlatMine pillar strength formula for UG2 pillars. The PlatMine formula has been successfully implemented on Booysendal Platinum Mine, and about 3 670 pillars have been cut without a single failure. An additional revenue of US$1.3 billion was calculated for the 25-year life of the mine as a direct result of the improved pillar design, given the January 2020 platinum group metals basket price. An extended life of mine and better mining efficiencies will also be realized.

Aug 1, 2021

By L. A. Ayres da Silva, J. P. G. Negri, A. L. M. Ayres da Silva

"Rock hardness is dependent on the type and quantity of the various mineral constituents of the rock and the bond strength that exists between the mineral grains. As the book “The Complete ISRM Suggested Methods For Rock Characterization, Testing and Monitoring:1974-2006” explains, hardness is a concept of material property. As such, the quantitative measure of hardness depends on the type of the test employed.Among the three types of tests that have been used to measure the hardness of rocks and minerals: 1) indentation tests; 2) dynamic and rebound tests; 3) scratch tests, the authors of this paper chose indentation tests, more specifically the Vickers test, and complementary verified the correlation between the results of the Schmidt sclerometer tests (rebound tests) and the Vickers microhardness tests in a set of the same 9 (nine) granite rocks.The objective of this research was to verif y the correlation of one created index, based on the Vickers test that can be able to represent the rock material hardness. We know that Vickers tests determine the microhardness of individual rock minerals. A pyramidal shaped diamond is applied to the surface with a specified force. The area of the permanent residual deformation divided by the applied force is a measure of the hardness. Using the relative participation of the mineral components of the rock, we established a hardness index denominated EVM (Equivalent Vickers Microhardness).The correlation of the EVM with others strength properties and application parameters like UCS (Uniaxial Compressive Strength) to study sawability of granite blocks have presented very good results. The association of equivalent microhardness with others strength parameters, allowed to find powerful algorithms for analyzes of the rock materials behavior under diversified circumstances, as the sawability of granite blocks, as we can see in Fig. 1.Other very interesting correlations were found as the EVM values and that were obtained by the use of the Schmidt impact hammer for the superficial hardness determination."

Jan 1, 2015

By R. Walker

This paper deals with the selection and design of a belt conveyor handling steam coal between a mine and a barge loading terminal, and extending for some 5 ¼ miles over some of the most rugged terrain in the state of West Virginia, U.S.A. After a thorough analysis by consulting engineers and the owner's engineers, a single-flight cablebelt conveyor was chosen as representing the alternative of greatest reliability and lowest over-all cost. The value analysis and design features of the system are covered in this paper along with an updated report on the performance of the system since its start-up in the spring of 1969.

Jan 1, 1971

By Frank B. Fulkerson

Mining began in Pend Oreille and Stevens Counties about 1885, Lead and zinc have been the principal products, and the area has supplied nearly all the output of these metals in the State. Fend Oreille County's output of lead and zinc from 1902 to 1956 was 110,700 and 229,600 tons, respectively. The Stevens County total was 54,100 tons of lead and 87,600 tons of zinc. Copper ore was produced mainly from the United Copper mine, Chewelah district, from 1912 to 1920; the principal gold mine was the First Thought, Orient district, which was active from 1904 to 1942. Approximately 225 mines and prospects produced; most of the ventures were on a small scale. The total value of gold, silver, copper, lead, and zinc produced from 1902 to 1956 was $75.2 million in Pend Oreille County and $39.4 million in Stevens County. INTRODUCTION In compiling the figures for this report, use was made of Bureau of Mines permanent records of nine production, the annual tabulations of producing mines, and the Minerals Yearbook. Requests to publish individual data, obtained from the annual production canvass, were made to the latest recorded operators of all mines in the area. Response to this request was good; therefore, it was possible to make the tables nearly complete. In a few instances the producer requested that the production data remain confidential, and in others it was not possible to reach the mine operator at his last known address. The district and county tables combine statistics for all mines, including those mines whose output could not be published separately.

Jan 1, 1958

A panel discussion on carbon-in-pulp processing of gold and silver ores was one of the highlights of the 1981 AIME Annual Meeting in Chicago. The session generated considerable interest and discussion among panelists and the audience. For those unable to attend the panel, the program was recorded and the discussion appears in this two-part report. The panel was co-chaired by Robert S. Shoemaker, vice president of San Francisco Mining Associates, and Laurence D. Hartzog, principal engineer with Bechtel Civil and Minerals Inc., San Francisco, CA. Panel members included: George Potter, consultant, Tucson, AZ; Kenneth B. Hall, metallurgical superintendent, Homestake Mining Co., Lead, SD; and Donald M. Duncan, resident manager, Pinson Mining Co., Winnemucca, NV. There have been several types of carbon-in-pulp adsorption vessels in use, such as the Dorr-type agitator, the simple propeller agitated tank, the Pachuca tank, and, lately, the draft tube-type of agitated tank. Which one of these is best and why? Potter: On the selection of the most appropriate adsorption vessel, there is a considerable difference of opinion that stems largely from the fact that every ore is different. The mesh of grind, the pulp solids, and the apparent viscosity of the pulp as caused by its clay content and chemical conditions all differ. The traditional Dorr agitator with the slow speed center sweep and either peripheral or center column air lifts has worked quite well on the finer grinds of all minus 65 and probably 70-80% minus 200 mesh. Pachuca tanks have also been successful and they may be capable of handling a coarser feed than the traditional Dorr tank. One uranium mill, for example, handles minus 28 mesh sandstone ore in a Pachuca. The most recent development and one that commands consideration is the draft tube agitator in which there is a turbine which closely fits inside a draft tube. Velocity in the tube is carefully calculated to avoid undue shear and thus abrasion of the carbon. The objective in all cases, of course, is to mix the granular carbon, which is typically 6 x 16 mesh, very gently but thoroughly in a slurry with minimum carbon abrasion. I do not know that there is one outstanding choice just yet and I have been unable so far to get information on C-I-P service for ore grinds as coarse as 35 mesh. Duncan: The major advantage of draft tube-type is the ease of startup. At the Pinson plant we installed draft tube-type agitators but it is too early to quote experience with them. We also haven't operated long enough to determine just what our carbon loss is. The advantage, of course, in the draft tube design is that it requires only about one-third the horsepower input of a conventional agitator. If it has no other advantages, it has that. Hall: The type of vessel most suitable for C-I-P adsorption depends on the type of ore treated and the prevailing operating conditions. In most cases, a deep tank with turbine-type mechanical agitator and low speed tip velocities would be satisfactory. Turbine-type impellers give a positive type of agitation which assures optimum ion contact and reduces short circuiting. Thorough aeration is possible with an air sparge properly located. A mechanical agitator can easily be started up after an outage, but it is usually necessary to drain and wash out a Dorr rake-type or Pachuca before restarting. The turbine-type impeller requires more power, but maintenance costs are negligible if rubber covered impellers are used. Carbon losses are minimal. In smaller plants, Pachuca type agitators provide adequate aeration and agitation. Bob Polak, Occidental Minerals (from the floor): Mr. Hall, you favor the mechanical-type agitator with the preface that the proper design is critical. Could you elaborate on this for us? Hall: The most important thing is low tip speed to prevent carbon attrition. I think the impeller should be sized so that you get a good sweeping action toward the bottom of the tank, across its bottom, up the sides, and back to the center. The advantage of the draft tube is that you get a more positive agitation and you probably get improved aeration too. Polak: Do you know of anyone using an upflow mechanical agitator rather than a downflow unit? Hall: I think that Bob Wilson at Custom Equipment has designed one where he has located the sparge directly beneath the impeller. The air bubbles are broken up by the impeller as the slurry passes through it. The slurry flows upward, outward, down the sides, and, again, back to the center of the tank. I don't know that any tanks of this design are in commercial use. Hans Von Michaelis, Randol International (from the floor): A question to any of the panelists on flat bottom versus conical bottom Pachucas. Hall: I would say the conical bottom would be most suitable in most cases. Some plants have experienced problems with flat bottom Pachucas in that they have a tendency to sand in on the sides of the tank so only the center of the tank is active. Duncan: With our draft tube tank we placed an inverted cone in the center of the tank bottom and blanked off the bottom comer around the circumference of the tank to facilitate movement of the pulp. Other than that, as far as conical bottom tanks are concerned, I'm generally opposed to them because of the cost and height differential. Larry Kramer, Kennecott Minerals Co. (from the floor): Mr. Duncan, you mentioned that the draft tube-type could be agitated with about one-third the horse-power applied to a conventional propellor agitated tank. I have trouble trying to pin down that kind of number. Could you give a bit of rationale as to why that mechanism has a lower horsepower requirement? Duncan: I think it has to do with the fact that below the propeller you have straightening vanes. The pulp, which is flowing vertically downward, is turned and flows upward again without any recirculation. You have an inherently less horse-power requirement in that type of tank. The one-third horsepower requirement is a number I obtained from Lightnin, which supplied us with details of the draft tube. There is probably much more recirculation with a conventional impeller type that is wasted motion. Potter: Last week I saw some agitators in South Africa with short draft tubes and actual turbine-type impellers. This plant was handling 200 kt of ore per month. The tanks were flat bottomed, and the agitation appeared to be quite satisfactory.

Jan 8, 1981

By E. H. Mohr

AT the McGill concentrator of the Nevada Consolidated Copper Co., all flotation operations have been carried out in Forrester cells since November, 1926. In respect to cost of operation, the new cell has proved to be superior to the Callow, which it supplanted, and its incorporation in the flow sheet has resulted in a marked improvement in the metallurgy. Before citing the advantages of the new machine over the old, it should be explained that the Forrester has not only replaced the Callow, but it has made possible the elimination of a number of tables as well. When Callow cells were in use, table concentration preceded flotation. The ball mill pulp was elevated, by means of air lifts, to roughing Wilfley tables situated two floors directly above the flotation floor. On an intermediate floor were additional tables which cleaned the concentrate from those above. The finished table concentrate constituted approximately 60 per cent. of the total mill production, and contained about 40 per cent. of the recovered copper. The table tailings were returned to the classifiers, the overflow from which went to the flotation cells and the oversize to the ball mills. As soon as the Forrester cells were installed, this tabling operation was discontinued. The ball mill pulp now discharges into the classifiers direct, without the intermediate tabling. It was impracticable to employ the present flow sheet when Callow cells were in use, for the reason that unless the greater part of the heavy mineral was first removed, it accumulated on the mats and adversely affected the flotation operation. By tabling ahead of flotation, it was practicable to maintain the concentrator at 10 to 20 per cent. greater capacity (depending up on the pyrite content of the ore) than was possible by flotation alone. This was due to the necessity for finer grinding in the latter case. Even though the table concentrates contained only 6 to 8 per cent. copper con- tent, the low smelting costs made it advantageous to operate at high mill capacity, at the cost of low grade of product. STANDARD SECTION EQUIPMENT With the old-flow sheet, a standard section consisted of four ball mills and classifiers, one air lift, 20 roughing tables, 10 cleaner tables, 12 primary

Jan 1, 1928

By IRVING H. WENTIVORTII

(New York Meeting, February, 1912.) THE little town of San Nicolás, Tamaulipas, Mexico, lies approximately 60 miles east of Linares, situated in the State of Nuevo Leon, and 150 miles SE. of Monterey, as shown in the sketch-map. Fig. 1. The place is reached from Monterey by the Tampico train as far as Linares, a distance of 92 miles, and then by coach the rest of the way. It is situated in a narrow valley between low hills, the houses forming one main street and a plaza. It is peopled by about 500 inhabitants. The climate is temperate, the thermometer ranging from 90° in summer to a few degrees below freezing-point in winter; but this severe weather only lasts a day or two at a time, when the " northers " blow. There are no streams in the vicinity, but water sufficient for the use of the people is obtained from wells. The rainfall is about the same as that in the rest of NE. Mexico. The rainy months are July, August, and September. The rest of the year is practically dry, with an occasional showery day or two during the winter, when a " norther " is blowing. Timber is abundant in many localities. There are two varieties of oak, besides mesquite, ebony, "maguira," "patol," and a number of other kinds of trees indigenous to this region. I. HISTORY. On the discovery of the silver-lead hearing veins occurring in this district, the mining-camp of San Nicolás was founded in 1767 by the Spaniards, and numerous mines were opened and worked for a distance of abort 3 miles east and 5 miles west of the town. At the western extremity and near the Carrolena mine, a small town called San Pedro was built. The ruined walls of the houses form a single street, and all is over-

Aug 1, 1912

By A. Perucho, J. P. Harrison, A. Bedi, L. Alejano, L. Lamas, A. Sofianos, A. M. Ferrero, R. Migliazza, R. Olsson, J-F. Mathier

"In 2010, the Eurocode for Geotechnical Design, EN-1997-1:2004 (CEN, 2004), informally known as Eurocode 7 or EC7, became the Reference Design Code (RDC) for geotechnical design – including rock engineering design – within the European Union (EU). EC7 is one standard within the comprehensive Structural Eurocode suite, which as a whole has been also adopted by a number of other countries beyond the EU. EC7 is thus becoming a key design standard for geotechnical engineering worldwide.As part of the Structural Eurocode suite, EC7 requires designs to adhere to the principles of Limit State Design. However, it is not clear that current rock engineering design practice can satisfy this requirement. In addition, evidence is accumulating that EC7 is currently difficult to apply to, and may even be inappropriate for, rock engineering design. These issues may be due to the fact that the development of EC7 to date took place without any formal input from the international rock mechanics and rock engineering community.In early 2011 under the auspices of CEN (Comité Européen de Normalisation / European Committee for Standardisation), EC7 entered a formal period of maintenance which was aimed at improving the applicability and ease-of-use of the Code. This maintenance cycle will conclude in 2020 with the publication of a revised version of EC7.This paper describes a number of critical aspects for rock engineering in the context of EC7, inparticular the following:– the history of the Structural Eurocodes and the concepts they embody;– the nature of Limit State Design and the challenges and opportunities it poses for rock engineering design;– the formal means by which the Structural Eurocode maintenance cycle proceeds;– the plans currently being developed for improving EC7 with regard to rock engineering design and construction;– the unique and vital opportunity for the entire international rock mechanics and rock engineering community to comment on the Code and make suggestions for its improvement."

Jan 1, 2015

By Loic Galisson

"Urban tunneling projects are usually extensively monitored. Most of the instruments used rely on benchmarks providing a sustainable datum throughout the life of the project. The monitoring program also is based on a predicted model of deformation induced by specific construction methods. Events can interfere with those assumptions and eventually alter the stability of these datum. In addition, the anticipated ground conditions and hence the theoretical deformation model often differ from reality. Satellite Radar Interferometry provides useful information to overcome the weakness of the hypothesis made before construction. It is also a powerful tool to ensure the continuity of the monitoring program throughout the life of the project, accurately describing the true effect of the project on the surrounding environment. This paper emphasizes the benefits and limitations of this technique for urban tunneling applications, illustrated by examples of major tunneling projects around the world. MONITORING URBAN TUNNEL PROJECTS Why Monitoring? Retrofitting existing tunnels or constructing new tunnels – including access and retrieval shafts, portals and cross passages – implies an alteration of the neighboring soil structure. Excavating, dewatering, grouting, loading tie backs, etc. artificially modifies the natural equilibrium of the pore-water pressure, of the water table level and of soil stability. In many cases, the effects are immediate: ground loss, deformation of utilities, settlements of buildings, and distortion of infrastructure are a few examples resulting from construction activity.Instrumentation and Monitoring Scope To control and mitigate the risks of damage associated with the above effects, tunnel projects usually include an instrumentation and monitoring program. Depending on the level of geotechnical, structural and environmental risk, the magnitude of this program varies. Projects with a low exposure to risk may restrain the program to conventional methods such as limited topographical surveys and intermittent manual readings of geotechnical instruments. On the other hand, iconic projects with high risk or with controversial history may implement complex and extensive instrumentation plans, involving highly technical solutions such as Automated Motorized Total Stations (AMTS – see opposite Picture 1), Multi-Point Borehole Extensometers (MPBX), In-Place Inclinometers (IPI) and a wide series of fully automated geotechnical, structural and environmental sensors. In this case, all the devices are usually connected to field data loggers collecting raw data around the clock at frequencies ranging from days to seconds, depending on the sensors."

Jan 1, 2016

By Y. Hayashi, A. Fuwa

To analyze zinc vaporization kinetics of zinc smelting slag in the ISP furnace, reduction reaction rate of zinc oxide from ZnO-FeOx-CaO-SiO2 slag system with CO-CO2-Ar gas mixtures has been measured by a therm o-gravim etric apparatus at various ZnO content, Pco, and temperature. The reduction rate was measured under a chemical reaction control in the initial three minutes where surface zinc content can be assumed constant. Through the reaction rate dependency analysis on ZnO contents, Pco and temperature, discussion has been made on its reaction mechanistic information in terms of rate coefficient, adsorption/desorption mechanism and activation energy.

Jan 1, 2008

By R. A. Elliott

This paper describes the development of an infra-red ore dryer at the Mines Branch. The dryer utilizes an infra-red heat source mounted over a stainless-steel belt to dry ores and concentrates of varying particle size and moisture content. It has been found to ?be successful in meeting Mines Branch requirements of minimum dusting loss and ease of cleaning to decrease ,contamination between various batches of dried products. It is described with the hope that it might .prove useful in other laboratories where there are similar problems. It might have an application in the drying of concentrates containing high values where dust losses would result in a considerable loss of revenue; also for small batches of material or an intermittent drying problem.

Jan 1, 1958

By J. P. Barkley

"The accompanying tabulation gives the results of a series of operating tests on two types of small stokers. One was an inclined, natural-draft, moving-grate, overfeed ""hand-stoker"" fired and manipulated by hand; the other was. a horizontal, forced-draft, stationary-grate, underfeed, mechanical unit-stoker operated by an electric motor. These were installed as shown by the accompanying sketches (figs. 1 and 2) under horizontal return tubular boilers of a nominal rating of 150 bl.h.p. each.The steam load carried by these boilers was a rather typical heating load. It was fairly constant and of about 30 bl.h.p. throughout the summer months, with small variation between day and night. During the winter months the daily variations were dependent upon the outside temperature. The boilers were banked a considerable part of the night.As noted in the table, two kinds of coal were used. The size of one kind was run-of-mine and the other 11/4 inch nut and clack. These coals from two different mines of the New River district both caked considerably during burning, the nut and slack more than the other. Analyses of the coal were as follows:"

Jun 1, 1929