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By K. Thuro, R. J. Plinninger

ABSTRACT: Determining tunnel stability is a key issue during preliminary site investigation. In contrast, problems of excavatability have been largely ignored. While the choice of an economic tunnelling method is admittedly a clear priority in the planning stage, special investigations focus-sing on rock fragmentation (e.g. drilling or cutting performance, rock mass blastability or tool wear) are rarely carried out. This paper explores possibilities to quantify key parameters for rock mass excavatability in drilling, blasting and cutting by TBMs and roadheaders. RÉSUMÉE: La détermination de la stabilité du tunnel est une question clé lors des études prélimi-naires. En revanche, les problèmes d'excavabilité sont souvent en grande partie ignorés. Tandis que le choix d'une méthode de percement économique est évidemment une priorité claire dans l'étape de planification, des investigations spéciales se concentrant sur la fragmentation de la roche (par exemple le comportement de la roche au forage, à l’excavation ou au dynamitage et l’usure des outil) sont rarement effectuées. Cet article explore les possibilités pour quantifier les paramè-tres clé de la roche lors d’excavation par forage, dynamitage, au tunnelier (TBMs) ou à l’excavatrice. ZUSAMMENFASSUNG: Beim Tunnelbau wir meist die Vorhersage der Stabilität des ausgebrochenen Hohlraums als Schlüsselfragestellung betrachtet. Im Gegensatz dazu werden Probleme der Gebirgslösung weitgehend ignoriert. Während der Wahl einer wirtschaftlichen Vortriebsmethode während der Planungsphase meist noch eine gewisse Priorität beigemessen wird, werden spezielle Untersuchungen zur Gebirgslösung (Bohr- oder Schneidbarkeit, Sprengbarkeit oder Werkzeugverbrauch) nur sehr selten durchgeführt. Diese Publikation zeigt Möglichkeiten der Quantifizierung von Schlüsselparametern für die Gebirgslösbarkeit auf, also der Bohr- und Sprengbarkeit, der Fräsbarkeit mit Teilschnittmaschinen und der Schneidbarkeit mit TBMs.

Jan 1, 2003

By Dae Young Kim, Sim Bo Kyung, Ebrahim Farrokh, Ki Chang Hyun

"TBM cutter life evaluation in abrasive granitic rocks is a very important issue, especially in pressurized face tunneling with mixshield TBM for which the planning of costly interventions becomes crucial. This paper presents an overview of methodologies for cutter life evaluation in rock. A comparative study is performed to indicate the predictability of cutter life evaluation methods based on detail data from the NS3 tunnel project in Singapore. A new model is developed based upon the cutter wear information of eight TBM tunnels from around the world. New methods are proposed to evaluate the optimum intervention interval length and the number of worn-out disc cutters for a tunnel project. Finally, two new laboratory tests in the evaluation of disc cutter abrasion, including a full-scale and a small-scale test, are introduced, and their test results are discussed. INTRODUCTION The issue of wear evaluation for hard rocks has been extensively studied in drilling and pavement industry. In this regard, several tests and evaluation methods have been proposed to estimate or evaluate the state of tool life (e.g. bit life for drilling). In the case of TBM tunneling, tool wear may depend on several factors such as mineral composition, strength, or type of cutting, but as the abrasion is usually the major mechanism for the tool wear in hard rock, the developed methods for cutter wear or cutter life evaluation are mostly based on the abrasion indices such as Cerchar Abrasivity Index (CAI). This paper attempts to review the major methodologies for disc cutter wear and life evaluation and to propose new methods to evaluate cutter life and intervention interval evaluation based on detail information of a mixshield tunnel project in Singapore as well as general information of some other projects from Iran, Italy, South Africa, and France. As the laboratory tests are crucial in the process of evaluation, two new lab tests are developed and used to inspect suitability of the new proposed model for disc cutter wear evaluation."

Jan 1, 2016

By M. A. Grossmann

THE hardenability of most steels can be predicted within 10 to 15 per cent provided the complete chemical composition is known, including "incidental" elements; and provided the as-quenched grain size is known; and provided, finally, that the composition and heating temperatures for hardening are such as to result in austenite free from carbide particles. In method proposed herein, the steel is considered as having a base hardenability due to its carbon content alone (the hardenability of a ''pure steel" of the given carbon content, without any other elements), and this base hardenability is multiplied by a multiplying factor for each chemical element present. After multiplying all these together, the final product is the hardenability. Grain sue may be taken into account either in the base hardenability or after the multiplication. Hardenability is stated in terms of "ideal critical diameter"; namely, the diameter of bar, in inches, that will just harden all the way through (absence of un- hardened core) in an "ideal" quench, and the calculation may also be related to the Jominy test. The data bring out certain features rather clearly. For example: I. It is quite useless to attempt to predict hardenability unless all elements, including "incidentals," are known; thus an "incidental" chromium content of 0.20 per cent increases the hardenability by about 50 per cent. 2. The relative effectiveness of different alloys is sometimes unexpected; thus molybde- num when calculated in this way appears to be of the same order of effectiveness as manganese, rather than much more powerful as wouldappear to be common experience; observe that an increase from no manganese to 0.20 per cent Mn provides a multiplying factor of 1.67, and an increase from no molybdenum to 0.20 per cent Mo provides a factor of 1.63, an increase of over 60 per cent in each case. However, if to a steel containing 0.50 per cent Mn there is added " 20 points of manganese," the factor is raised from 2.65 (for 0.50 per cent Mn) to 3.35 (for 0.70 per cent Mn), or an increase of only 26 per cent. Thus the first small addition of an element has a much more powerful percentage effect than an equal further addition when some is already present, and in most cases the effect of molybdenum is considered in relation to a steel in which molybdenum is absent. 3. If two elements are equally effective, a greater hardenability will be obtained by using, for example, 0.5 per cent of each than by using 1.0 per cent of either of them alone. 4. A knowledge of the as-quenched grain size is essential for precise work, since a difference of only one grain size number (say No. 7 instead of No. 6) makes a difference of almost lo per cent in hardenability (in these units); this, however, does not apply to certain steels of high hardenability. It should be emphasized that in chromium steels (over 0.30 per cent Cr) and chrome- molybdenum and chrome-vanadium steels, undissolved carbides are likely to be present in the steel as quenched, and that in such cases the charts can indicate only a maximum possible hardenability, whereas the extent of hardening actually obtained may be much less. Thus tests on a number of chrome-molybdenum steels have indicated a degree of hardening amounting to only 50 to 65 per cent of the maximum possible, and in chromium steels from full hardening (100 per cent) down to as low as 70 per cent. On the other hand, when the amount of such elements is small (Cr under 0.30 per cent, Mo up to 0.25 per cent in the absence of Cr, and V up to 0.04 per cent), the charts provide reasonable approximations. The precise figures on the charts are suggested as tentative, subject to some modification as more data accumulate, but the fundamental concept appears to be supported by tests made on a wide variety of steels, a few of the correlations being shown in Fig. I.

Jan 1, 1942

By M. A. Grossman

THE hardenability of most steels can be predicted within 10 to 15 per cent provided the complete chemical composition is known, including "incidental" elements; and provided the as quenched grain size is known; and provided, finally, that the composition and heating temperatures for hardening are such as to result in austenite free from carbide particles. In method proposed herein, the steel is considered as having a base hardenability due to its carbon content alone (the hardenability of a "pure steel" of the given carbon content, without any other elements), and this base hardenability is multiplied by a multiplying factor for each chemical element present. After multiplying all these together, the final product is the hardenability. Grain size may be taken into account either in the base hardenability or after the multiplication. Hardenability is stated in terms of "ideal critical diameter"; namely, the diameter of bar, in inches, that will just harden all the way through (absence of unhardened core) in an "ideal" quench, and the calculation may also be related to the Jominy test. The data bring out certain features rather clearly. For example: I. It is quite useless to attempt to predict hardenability unless all elements, including "incidentals," are known; thus an "incidental" chromium content of o.-2o per cent increases the hardenability by about 50 per cent. 2. The relative effectiveness of different alloys is sometimes unexpected; thus molybdenum when calculated in this way appears to be of the same order of effectiveness as manganese, rather than much more powerful as would appear to be common experience; observe that an increase from no manganese to 0.20 per cent Mn provides a multiplying factor of 1.67, and an increase from no molybdenum to 0.2o per cent Mo provides a factor of 1.63, an increase of over 6o per cent in each case. However, if to a steel containing 0.50 per cent Mn there is added "20 points of manganese," the factor is raised from 2.65 (for 0.50 per cent Mn) to 3.35 (for 0.70 per cent Mn), or an increase of only 26 per cent. Thus the first small addition of an element has a much more powerful percentage effect than an equal further addition when some is already present, and in most cases the effect of molybdenum is considered in relation to a steel in which molybdenum is absent. 3. If two elements are equally effective, a greater harden ability will be obtained by using, for example, o.5 per cent of each than by using 1.0 per cent of either of them alone. 4. A knowledge of the as-quenched grain size is essential for precise work, since a difference of only one grain size number (say No. 7 instead of No. 6) makes a difference of almost 10 per cent in hardenability (in these units); this, however, does not apply to certain steels of high hardenability. It should be emphasized that in chromium steels (over 0.30 per cent Cr) and chrome-molybdenum and chrome-vanadium steels, undissolved carbides are likely to be present in the steel as quenched, and that in such cases the charts can indicate only a maximum possible hardenability, whereas the extent of hardening actually obtained may be much less. Thus tests on a number of chrome-molybdenum steels have indicated a degree of hardening amounting to only 50 to 65 per cent of the maximum possible, and in chromium steels from full hardening (100 per cent) down to as low as 70 per cent. On the other hand, when the amount of such elements is small (Cr under 0.30 per cent, Mo up to 0.25 per cent in the absence of Cr, and V up to 0.04 per cent), the charts provide reasonable approximations. The precise figures on the charts are suggested as tentative, subject to some modification as more data accumulate, but the fundamental concept appears to be supported by tests made on a wide variety of steels, a few of the correlations being shown in Fig. I.

Jan 1, 1942

By Charles G. Kemsley

IN January, 1939, Dome Mines, Limited, purchased a few bars of an alloy drill-steel for the purpose of testing its fatigue resisting qualities as compared with those of a straight carbon-steel then in general use at the mine. A steel of the following analysis was selected: Carbon 1.00% Sulphur 0.022 Chromium 1.26 Silicon 0.17% Phosphorus 0.028 Vanadium 0.1 Manganese 0.32% Molybdenum 0.30 This steel has a tensile strength of 180,000 lb. per square inch and a Brinell hardness of 380, as compared with a tensile strength of 114,000 lb. per square inch and a Brinell hardness of 230 for the standard carbon drill steels, in the as rolled' condition. The result of this test showed that about five times as many runs could be obtained from the alloy steel before failure from fatigue. It was therefore decided to replace gradually the one-inch quarter-octagon carbon steel, then in use, with seven-eighths quarter-octagon alloy steel. In January, 1940, six machines was placed on the seven-eighths steel and this was gradually increased until now (March 15th, 1941) fifty per cent of the steel being used is alloy steel. An O'Donovan furnace is used at the Dome for heat-treating their carbon drill-steel. In this furnace, a magnet withdraws the steel when the critical temperature has been reached, and the operator then places the steel in the quenching tank. Not being able to use this furnace for the alloy steel, the management felt that some means should be developed to determine the quenching temperature without depending upon the operator's judgment of the correct 'colour'. With the assistance of the Canadian General Electric Company, a radiation-type vacuum thermocouple pyrometer was adapted to this purpose, with excellent results; in fact, with this instrument no previous experience in hardening is necessary and results are remarkably uniform.

Jan 1, 1941

By M. R. Pickus, I. W. Pickus

ORDINARILY age-hardening is thought of as being associated with a limited solubility of one metal in another. Much less has been written about the type of age-hardening that attends the formation of superstructures. Solid solutions generally have a disordered or random arrangement of atoms; that is to say, in a unit cell, such as that of the face-centered cubic lattice, there is no distinction between atomic sites. Atoms of a given metal may occupy cube corners or face centers. Under certain conditions, however, some alloys develop what is known as an ordered structure. In this case, cube corners would be occupied by only one type of atom and face centers by another type, Associated with this ordering process are many interesting changes in physical and electrical properties. Moreover, in many instances the alloys become susceptible to age-hardening. From the evidence now to be described, it appears that age-hardening in 14-carat gold alloys is due to the formation of both a super-structure and a precipitate. Alloys of the metals gold, silver and copper were known in antiquity. The available knowledge regarding their constitution has been ably summarized and extended by Sterner-Rainer,1 Janecke,2 Carter,3 Wise,4 and Coleman.5 Despite the long familiarity with these alloys and the numerous investigations of their properties that have been made, there is still much that remains unexplained. It has been known for a long time that the hardness of these alloys is closely related to the rate of cooling, Similar changes have been observed in the binary gold-copper system,6 one alloy of which corresponding to the formula Cu3Au, has been the subject of a careful and competent report by the English investigators, Sykes and Evans.7 They have established the fact that the shift of atoms from the ordered to the disordered condition takes place in some critical temperature range. At temperatures above the critical range the structure is random, and at temperatures below it the structure is ordered. No difference between these two structures is revealed by the microscope. Both have a face-centered cubic lattice and complete solubility, so that there is no evidence to suggest that the changes in properties are associated with a phase change, The more slowly the alloy is cooled, the higher is the degree to which the ordering process proceeds and the more marked is the increase in hardness. As experimental data were accumulated on 14-carat gold alloys, several contradictions arose. Certain observations tended to confirm the existence of a superstructure, while other observations seemed to be inconsistent with such a transformation. PRESENT INVESTIGATION As a focal point about which to develop this subject, it is expedient to consider first

Jan 1, 1943

By Jörg Fischer-Bühner

Conventional 22ct Au jewellery alloys are comparably soft in the as-cast and soft-annealed state and hardening by cold-working is the only way of giving strength to the jewellery. The paper first focuses on hardening of 22ct jewellery alloys by conventional means, i.e. solid solution hardening with base metals (aiming particularly at an increased as-cast hardness) as well as precipitation hardening by alloying with base metals beyond the solubility limits and subsequent age-hardening heat treatment. Co-additions of ~2% turned out to result in most pronounced solid solution hardening up to ~100 HV1 in an investment cast & quenched state. Subsequent heat treatments, consisting of solution annealing at 850°C for 1h followed by water quenching and ageing at 300°C ? 400°C for ~ 1h lead to pronounced age-hardening with a peak hardness of ~ 260 HV1. In contrast, 22ct Au alloyed with Ni, Fe or Sb display no age-hardening effect within the same range of heat treatment parameters. The 2nd part of the paper reports on some preliminary trials to enhance the hardening effect of the base metals by additions of suitable elements, which possess a strong tendency to phase formation with the added base metal during ageing treatments. It is shown, that the age-hardening behavior of 22ct and 990/995 Au alloyed with Co or Ni can be remarkably influenced by additions of Sb. A total of only 10wt%0 of CoSb or NiSb-additions lead to a peak hardness of ~ 150 HV1 for a 22ct Au and ~ 100-120 HV1 for 990 Au , which is obtained already after very short ageing times (20-40min) at 300-400°C after solution annealing at 700°C / 1h / water quenching. It is suggested that the age-hardening mechanism in these alloys consists in precipitation of intermetallic CoSb- and NiSb-phases.

Oct 1, 2003

By Robert Franke

(Butte Meeting, August, 1915.) IN view of the prominence which the conical mill has attained in the fine-crushing field within the few years since its introduction, the following comparison with its more mature forerunner, the Chilean mill, based on extensive tests, is submitted in the interest of the milling profession. Soon after designing the concentrating plant of the Miami Copper Co. in 1909, the Hardinge conical mill made its appearance in the milling forum. Its possibility as a suitable crushing device for the plant was well recognized, but in view of the lack of commercial demonstration, at the time, as to capacity, efficiency for desired product, and the still more uncertain factors of cost of maintenance and power consumption, it was deemed that the immediate adoption of this machine throughout the plant would be a hazardous undertaking. For these reasons it was decided to equip the majority of the imme diately required units of the plant with Chilean mills, the fine-crushing proficiencies of which were better known, and one section with Hardinge mills, to serve as a test unit for the guidance of future installations and replacements. Thereby, after 1.5 years' operation with both types of mills, a thorough test as to metallurgical efficiency and cost economy has been obtained. The conical mill used in these tests is the 8-ft. Hardinge pebble mill, having a cylinder 22 in. in length. The cylindrical portion of this mill is lined with cast-iron liner plates, and the conical extensions with silex bricks bound together by cement. Each liner plate carries a projecting lifter, the function of which is to increase the height of drop of the lifted material. Danish No. 5 pebbles, obtained from the coast deposits of Denmark, are used for the grinding charge. The Chilean mill used is a fast-running, 3-roller, 6-ft. Saturn mill, with screens of 0.037-in. opening. The feed to these mills is the oversize of Callow screens having 0.029-in. openings, which follow rolls crushing to 0.5 in.

Jan 7, 1913

By Leonardo Flores

"Minera Escondida operates two open pits on a porphyry copper district, southeast of Antofagasta, Chile. During 2005, ore will be delivered exclusively from one pit to two concentrators, while from 2006 both pits will provide ore to these plants. Annual testing programmes on drillhole samples, have allowed for the construction of hardness block models since 2000. These models have delivered two main hardness descriptors, the Bond work index and the SAG power index. These parameters and plant operational specifications have been used as input information to forecast, the expected throughput and ball mill product size (P80) for each block of ore. Two forecasting techniques have been used, an in house model, strongly dependant of bond work index and MinnovEx´s CEET2, dependant of Bond work index and Sag power index and other parameters. Model performance has been evaluated from reconciliating on a monthly basis, the forecasted throughputs against a recalculated plant throughput which accounts for losses in tonnage not caused by ore hardness but instead by unscheduled plant operation problems. The model performance for 2003 was ± 2% yearly and ± 5% quarterly, well within the expected ± 3% and ± 10%. INTRODUCTIONThe Escondida porphyry copper district is located 140 km SE of Antofagasta, Chile at 3150 m.a.s.l, at 24°16’ South latitude and 69°04’ West longitude (figure 1)."

Jan 1, 2005

By Frederick B. Kuhnow

Harmonic energetic delamination a building is being considered for demolition at a formerly known atomic power lab. The building is within a containment structure under a negative pressure, so that no radioactive material is leaked out to the environment. A new approach was developed to make this work possible.

Feb 1, 2020

By Trevor L. L. Orr

"AbstractThe background to the harmonization of geotechnical standards that has taken place in recent years in Europe has been the move to more economic and political integration following World War II that has led to the formation of the European Union. Prior to 2010 the standards used in the European countries for geotechnical design, investigation and testing and for the carrying out geotechnical work, such as the installation of piles, were the different national standards, which were not harmonized. The harmonization of geotechnical standards in Europe started in 1981 with work on a model Eurocode 7 for geotechnical design that led eventually to publication by CEN, the European Committee for Standardization, of the European Standard version of Eurocode 7 in 2004. In parallel with the work on Eurocode 7, a large number of associated harmonized standards have been, and are being, prepared by CEN and by the International Standards Organization (ISO) for geotechnical investigation and testing and for the execution of geotechnical works. Standards published by CEN must be adopted by the CEN member countries and all conflicting standards withdrawn. Hence all the CEN countries have adopted the same the harmonized text of Eurocode 7, but with National Annexes that allow national choice with regard to Design Approach and partial factor values. The adoption of Eurocode 7 and its associated geotechnical standards has removed the barriers to geotechnical activity in Europe due to the presence of different national standards. It has also enhanced the ability of EU firms to compete in the global market.Background to harmonization of geotechnical standards in EuropeThe initial moves towards the harmonization of geotechnical standards in Europe can be related to the economic and political developments that took place in the period immediately following World War II to revive the economies of Western Europe. Europe at that time was divided by a political and, in many places, a physical barrier, known as the Iron Curtain, into two very different and separate zones: communist in the east and non-communist in the west. In 1952 the European Coal and Steel Community (ECSC) was formed, linking 6 countries: Belgium, West Germany, France, Italy, Luxembourg and the Netherlands, and establishing a common market in coal and steel. The ECSC was the first international organization to be established on the basis of supranational principles whereby negotiated power is delegated to an authority by the governments of the member states. In 1957 the ECSC became the European Economic Community (EEC), also known as the Common Market in the English-speaking world, with the aim to bring about economic integration. With the addition of Denmark, Ireland and the UK in 1973 and Greece in 1981, followed by Portugal and Spain in 1986, this led to the formation of the European Union (EU) in 1993. East and West Germany were reunified in 1990, following the fall of the Iron Curtain in 1989. In 1995, Austria, Finland and Sweden joined the EU, and since then the numbers of countries in the EU has increased to 28, many of which are countries that were formerly behind the Iron Curtain."

Jan 1, 2014

By Silas C. Nichols

"Abstract Piling and deep foundations are a staple for transportation projects in the United States (US). Driven or bored piles have been used for everything from support of bridge foundations and retaining structures to support of culverts and embankments on soft ground. Deep foundations have been popular in the US transportation market to better handle large axial and lateral loads, extreme event loading, and to better control structure movement. However, there are challenges in the maintenance of design and construction codes in transportation for consistent and reliable structure foundation elements. A significant amount of effort continues in the US to maintain national codes and specifications at a level consistent with the state of practice, and identify and conduct research for providing safe and cost effective highway structures.IntroductionThe transportation sector in the United States has a hierarchy of design and construction codes that are used for the specification of piling and deep foundations. Any highway or bridge project on the National Highway System (NHS) must be designed and constructed in accordance with a national set of standards approved by the State Highway Departments, and that are acceptable to the Federal Highway Administration (FHWA). However, in any jurisdiction, exceptions are permitted with approval. Therefore, design may be governed by the national standard specification, a state standard specification and design manuals, special provisions, or guideline specifications. Any of these standards, or a combination, may be used depending on the needs of the owner agency.The FHWA and the American Association of Highway and Transportation Officials (AASHTO) have worked together in the development and maintenance of geotechnical design and construction guidance and codes that support the surface transportation community. General geotechnical engineering practice in the United States lacks a singular, national design and construction code that addresses all aspects of geotechnical engineering. As a result, the AASHTO specifications provide the most complete geotechnical specifications focusing on structure foundations, retaining walls, and buried structures for surface transportation applications. This includes piling and deep foundation types commonly used for support of bridges and transportation structures.The FHWA National Geotechnical Team has published several technical guidance documents that include guideline specifications for the design and construction of driven and bored deep foundations. Reference documents published by FHWA summarize the state of practice and provide recommended design and construction guidance. These reference documents have long served as a basis for provisions included in the AASHTO specifications. Maintenance of the design code and specification, and related guidance documents for consistent use on US transportation projects requires a collaborative effort between industry, FHWA, and the member state highway departments that make up AASHTO."

Jan 1, 2014

By Alyson Morley

The mining sector in Canada is facing significant challenges to develop a competent workforce, including increased technical and logistical operational demands, and the imperative to promote local content. There is an increasingly unpredictable labour pool which can be aging, or have skill shortages, or non-aligned skills. As globalisation continues, companies also require efficiencies during operation across various locations. AMEC has met these challenges in the global oil and gas sector by developing our Capability Development and Competence Assurance (CDCA) program. CDCA is applicable across all process industries, including mining. CDCA supports simultaneous consistency and flexibility by defining competence at task level, with corresponding best practice blended training programs, and evaluation criteria and processes. CDCA then defines role profiles mapped to local task definition. When combined with web-based technology, this granularity allows us to manage high volume workforces, while retaining individual learning plans and progression, aiding job satisfaction, and employee retention.

May 1, 2007

Jan 1, 1882

By Magnus Troilius

SINCE the discussion on steel rails in America has forcibly drawn attention to the value of chemical analysis, if not as a necessary stipulation, at least as a guide to control the usual mechanical tests, some doubt has been thrown upon the accuracy of the analytical results obtained by different chemists. To any one having the least acquaintance with chemistry, it is quite clear that if exactly similar results are to be obtained from the same borings of steel, exactly the same methods must be used by the different analysts. Hence the necessity (if complications are to be avoided) of establishing what I may call standard or normal methods, to be used both by the inspectors and by the chemists at the works. Remembering that the application of chemistry to steelrail inspection is yet in its infancy, it is of great importance to possess a perfect acquaintance with the best methods in use. Being myself a grateful pupil of Professor Eggertz, of the School of Mines in Sweden, it occurred to me, two years ago, that I could not do better than start a laboratory of my own, and engage one of his pupils, Mr. Troilius, for the purpose of analyzing the steel borings from mechanically-tested rails, so that I might thus obtain without delay thoroughly accurate determinations. Moreover, in order to carry on the operations in perfect accordance with the methods used at the steel works in England and Germany, where I had to control the manufacture, I deemed it desirable to allow Mr. Troilius to go through a course of training at these works; and I gladly seize this opportunity of expressing my grateful acknowledgments to several works in England and in Germany for affording every facility for such an exchange of information as mas found necessary in arriving at the best analytical methods to be used.

Jan 1, 1882

By S. H. Chauvenet

Jan 1, 1882

RACAL COMMITTEE OF ARRANGEMENTS Henry McCormick, Chairman; David Watts, Secretary; H. H. Campbell, A S. McCreath, S H. Chauvenet, C. E. Stafford, George S. Comstock, Jones Wister, E. C. Felton, F. W. Wood, Harvey Fisher. CITIZENS' RECEPTION COMMITTEE Governor H. M. Hoyt, Hon John C. Herman, Hon Simon Cameron, Hon. J. D. Cameron, W T. Hildrup, Charles L. Bailey, W. W. Jennings, Lane S. Hart, H. U. Carter, Gilliard Dock, T. T Wierman, Jr, James Boyd, D. L. Jauss, Dr. T J. Dunott, S. C. Gilbert. William J Rose, James Lynah, Dr. H. B Buehler, William N Lamberton, John Wister, G. M. McCauley, David Fleming, John Q. Donney, M. E. Olmsted, H. S Gross, Henry Gilbert. John B. McPherson, Lyman D. Gilbert, F. W. Forman, L. S. Bent, A. J. Dull, F. R. Leib, Dr. G. W. Belly, James McCormick. The opening session of the meeting was held in the hall. of the Young Men's Christian Association, on Tuesday evening, October 25th. Mr. Jones Wister, of the Local Committee of Arrangements, introduced the Hon. John C. Herman, mayor, who, in a brief address, extended to the members present a welcome to the city, of Harrisburg ; Lieutenant Governor Stone made an address of welcome on behalf of Governor Hoyt and the Commonwealth of Pennsylvania. President Metcalf responded, on behalf of the Institute, to the cordial addresses of the mayor and lieutenant-governor. The following persons proposed for members and associates of the Institute, and recommended by the Council, were unanimously elected :* MEMBERS. William F. Aldrich, - Montevallo, Shelby Co., Ala. George H Blake, - Steelton, Dauphin Co., Pa. L. Bertram Cady, - Salisbury, N. C. John B. Church, - Pottsville, Pa. Walter S. Church, - Pottsville, Pa, Frank L Clark, - Pittsburgh, Pa. * In the following list are included those elected at a subsequent session of this meeting.

Jan 1, 1882

By Dave Bigby

Hatworth Colliery, operated by RJB Mining (UK) Ltd, is successfully mining the Deep Soft Seam at a depth of 1000m using single face retreat longwalling. The seam is characterised by a weak roof generally comprising 4 to 6m of well bedded carbonaceous mudstones overlain by weak siltstones. The paper describes the layout and support design strategies which have enabled the colliery to adopt sole support by rock reinforcement techniques for its longwall gateroads. To achieve this success the colliery layout has had to be radically modified to take account of the in-situ horizontal stress field. The layout is also closely controlled by environmental considerations, the seam being one of the gassiest in the UK Economic support by strata reinforcement has been achieved using a combination of rockbolting of the roof and sides installed at the face of the heading, and systematic double birdcage cable bolting installed on drivage and supplemented ahead of the retreating panel. The layout and support strategies have been developed through a combination of detailed underground measurement of support and stress parameters backed up by numerical modelling using FLAC. The FLAC modelling has paid particular attention to careful representation of bedding properties and validation through underground stress measurement.

Jan 1, 1996

By C. M. Brinckerhoff

Much has been written in the mining technical magazines about the caving system. Many of these articles were published in the Transactions of the American Institute of Mining Engineers prior to World War II. In recent years little has been written on mining methods or on the detailed planning always required. Block caving had primarily been used to mine deep copper ores in Africa, the United States and in Chile, although other ores had been mined by this same system. Asbestos ore had been caved in Canada, tin ore in Bolivia, molybdenum ore in Colorado, iron ore in Wyoming and Sweden, and limestone in California.

Jan 1, 1984

By Robin J. Batterham

We still need to innovate, but it is getting harder. The real price of metals is declining, return on shareholder value is lower than other industries, and there is a shorter-term focus on staying viable in a capital-intensive industry where timeframes for implementation of new technologies can be long (+I5 years). In this environment, the levels of R&D spent by major minerals companies are remaining steady at around 0.2%-0.5% of revenue. This is not large and to remain viable in the future, we need to be smarter about the way in which we do R&D. The mining industry is a knowledge-based industry. Driving down the cost curve demands innovation, which demands knowledge. To be smarter and more effective in our approach to innovation, a new paradigm is required Generating, capturing and using knowledge has evolved from Mode 1 (discipline based and clear distinction between basic and applied research) to Mode 2 (multidisciplinary, team-based approached with flow between basic and applied activities). Mode 2 is now seen to be much more efficient and to deliver better appropriability (Tegart 2003). To survive, we need to innovate, and the best way to do this is collaboratively. Some examples and pointers for the future will be given in this paper. THE CURRENT SITUATION The Rand report and other recent studies have painted a grim outlook for the mining industry. The real price of metals continues to decline (Figure 1) and profit margins remain thin. This is reflected in shareholder returnwhich are well below other industries (Figure 2)-and current management strategies-which reflect something of a "survival mode." The current focus for most mining companies is on short-term, incremental gains

Jan 1, 2004