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By Y. C. Liu

THE existence of mechanical twins in bcc metals has long been known. With recent intensive interest in the mechanism of twin formation and its role in plasticity and crack initiation, a study of the general Characteristics of twin intersection appears pertinent. The scope of the present note will be limited to the crystallography of the twin intersections of (112) twins, without consideration of its mechanism, movement of atoms, crystal structure, or the strain energy involved at such an intersection. The twinning elements of (112) twins are considered to be K1 = {112}, n1 = (111) and K2 = {112}, n2 = (111) with a twin shear of 0.707. The crystallographic features of twin intersections have been worked out in detail by Cahn.1 The present work applies the general principles postulated by Cahn to the intersections of (112) twins. The basic conditions for the twin intersection are: 1) The trace of crossing (A) and the secondary (C) twins in the planes of the crossed twin (B) must be parallel. 2) The direction (n1) and magnitude (s) of shear must be identical in the crossing and secondary twins. Also the sense of shear must be the same. These two conditions have to be fulfilled in order to maintain geometrical continuity at the twin interfaces. Fig. 1 shows the perspective representation of how these two conditions are fulfilled at the intersection. This type of intersection will be named Type-I. It is the purpose of this note to point out the existence of another type of intersection, Type-II, as shown in Fig. 2. In this type of intersection, the crossing twin A remains straight and the crossed twin B has been bent. The two conditions laid down by Cahn must also be met. This leads to the following corollary conditions: 1) The interface between twins B and C must be parallel to the twin habit of crossing twin A. 2) n1c must be parallel to n1A. 3) The twin shear (s) of twin C must be exactly equal to and in the same sense as that of crossing twin A. Thus, in order for the Type-II intersection to take place, the twining elements of secondary twin C must fulfill the above three conditions with respect to crossing twin A. Let K1 of crossed twin B be (112). All indices of the matrix can therefore be converted into new in-

Jan 1, 1963

By A. Partos

It was decided to build a fourteen-storied office building over a six-storied garage and a four-storied office building. The high vertical and horizontal loads required foundations on rock approximately 18m below street level. Drilled piers (caissons) were selected. Eight caissons (1.98m diameter) were installed through the six-storied garage and four caissons from a temporary deck at the location of a former two-storied building. Excavations were done by the slurry method. Proof testing of rock was done before construction by test borings and during construction with a core barrel of small diameter. Quality control measures included telecommunications between ground crews and the equipment operator on the garage roof; records of field observations and testing of bentonite slurry and rock; and a continuous evaluation of all information. Instruments were installed in one caisson to monitor load distributions and curing of concrete.

Jan 1, 2010

By Edmond Chow

Shovel bucket blast fragmentation analysis is an alternate way to assess blast performance and its effects on downstream mining processes. A camera is installed on the boom of cable shovels, and the stick of hydraulic shovels. Images are captured automatically as the shovel digs, and are processed to acquire rock size information. The automatic data acquisition makes this method safe to use with minimal manual labour. It also allows for a large set of sample data to be captured from both the surface and the interior of a bench face. The system has been deployed in several mines to provide an objective assessment of blasting performance. Images are captured from their cable or hydraulic shovels. The images are grouped into sets based on the shovel location and time to match the fragmentation to specific blasts. Blast fragmentation reports are created for each blast after reviewing the results. Measuring blast fragmentation from the shovel bucket proves to be an effective alternative for blast performance assessment with unique advantages. The blast fragmentation information has been valuable to the mines, and the mines have begun adopting it into their operations.

May 1, 2011

The .subject of this paper is to briefly outline various methods of stockpiling and reclaiming, and the use of different types of bucketwheel re- claimers and stackers in these operations. The paper examines briefly the different types of bucketwheel equipment, their operations and relates them to different stockpile layouts, giving examples of their application in Australia.

Jan 1, 1973

By Byron S. Gottfried

This paper describes a comprehensive computer program, developed under the joint sponsorship of the U.S. Environmental Protection Agency and the U.S. Bureau of Mines, that simulates the performance of coal preparation plants. A typical plant configuration may include several different washers, crushers, and screens as well as stream blenders and stream splitters, interconnected in whatever manner the user may specify. The program will predict the mass and energy yields of each unit and the properties of each flowstream (weight, ash, pyritic sulfur, total sulfur, and energy distributions), provided the feed properties and appropriate values for various control parameters are given. The program is used to assess washability characteristics of different coals, to determine the effectiveness of different plant operating conditions, and to compare the performance of various plant configurations. A brief description is given of the methods used to carry out the calculations for each type of unit. Results of some calculations are also presented. These results illustrate the versatility of the program for analyzing both simple and complex plant configurations. The paper concludes with a description of other accomplishments and future plans.

Jan 1, 1977

By J. E. Strongman

This paper describes a system dynamics model of the international copper system. The development of the model is described regarding the questions it was designed to address, model boundary, major sectors and actors, the availability of data, the copper life cycle, and major supply and demand dynamics. A base forecast is presented describing future supply, demand, capacity, prices, trade flows, scrap flows and capital expenditures from 1976-1990 for the major producing and consuming market economy blocs.

Jan 1, 1977

By Jim Oehler

The US minerals industry, as well we know, has been hit hard by the recent recession and is faced with what is projected to be a slow recovery. Even so, there was an underlying feeling of optimism at American Mining Congress' International Mining Show in Las Vegas, NV, Oct 11-14. More than 25,000 people attended during a particularly rough financial year, dispelling fears that attendance would dip sharply below 1978's 30,000 plus tally. The equipment expositionheld every four years-was the largest show of its kind this year in the Western Hemisphere in terms of exhibit space, providing an extensive view of mining-related equipment. In addition to the nearly 700 exhibits occupying more than 445 hm2 (11 acres), 20 technical sessions were held covering topics ranging from minerals availability and the state of the mining industries to communications, computers, and accounting. Government officials were well represented, with six US senators and five US representatives participating in various convention functions. Sen. Paul Laxalt (R-NV) was the keynote speaker at the welcoming luncheon. Other senators involved in the show included Howard W. Cannon (D-NV), Pete V. Domenici (R-NM), James A. McClure (R-ID), Frank H. Murkowski (R-AK), and Steven D. Symms (R-ID). Representatives on the program were Joseph M. Gaydos (D-PA), Guy Vander Jagt (R-MI), Don Young (R-AK), Jim Santini (D-NV), and Ceil Heftel (D-HI). There were also many international vistors at the show, including exhibitors from Australia, Austria, Canada, England, Finland, Sweden, South Africa, and West Germany. Equipment Highlights Equipment and services featured at the exposition ranged from aerial mapping to wire rope. Aisle space alone between exhibits exceeded 8 km (5 miles). And the companies represented ranged from small businesses to large corporations. Some of the company products described here are representative of the many exhibitors in attendance. Atlas Copco's extensive display of rock drilling and tunnel and shaft boring equipment featured its Boomer H-201, the newest addition to its line of underground drifting rigs; the ROC 306, a new track-mounted, high pressure down-the-hole drill rig; a new hydraulic surface crawler drill, the ROC 712H, designed for small and medium-size holes in quarries and small open-pit mines; a computerized analysis system, CARE (see page 1570), designed to project productivity and operating costs for various mining operations; several electro-hydraulic loaders, including the new rail bound LM E60 and LM E80, and two Hagg-loaders-the 7HR and 10HR-that use two digging arms to rake and guide muck; a mechanized blasthole charging system; rock bolting equipment and its new Swellex roof bolting method; Sandvik Coromant drill steel and bits; and its new Jarva R200 raise boring machine.

Jan 11, 1982

By T. T. Read

A short time ago, one of the large steel companies courteously furnished the author with detailed records of the operations of a considerable number of iron blast furnaces over a period of two months. These will be made the basis of a subsequent study, but in beginning this study one of the first points requiring consideration was the probable error of the records, for what otherwise might be regarded as significant differences of performance under different conditions were perhaps really due to errors of observation, or failure to observe and record variations. If it is assumed, in blast-furnace records and calculations, that known quantities or factors are constant, .when as a matter of fact they are variable, the effects of these variations may erroneously be ascribed to some other cause. This is quite clearly expressed in the following quotation from E. Buckingham:l Theory always operates on an ideally simplified picture of reality because real phenomena are unmanageably complicated. The results obtained are not exactly true for any real phenomenon, though they may be for an ideal one; and the approxi-mation with which a theoretical equation, however obtained, represents the actual facts, always depends on the approximation in essentials between the ideal picture and its real prototype. The purpose of dimensional reasoning is to find out how some quantity which is involved in the phenomenon under consideration is related to certain others; or to find the relation connecting two or more quantities which vary, or may vary, simultaneously during the course of the phenomenon. Since we know that we must have a complete equation to start with, we begin by thinking the matter over, to see whether the quantities we have in mind are the only ones involved. Usually it is evident that they are not; so we next make a list of all the quantities we can think of which might under any circumstances be important. Upon considering this list, which is often a long one, it is usually evident that under the actual circumstances a number of these quantities may safely be ignored; so we cross them off the list and thus pass from our most general conception of the phenomenon to an ideal simpler one, in which these quantities are not involved at all.

Jan 1, 1926

By P Hanna

In an effort to improve returns to shareholders, the Australian Mining Industry has consolidated considerably over the past decade or so. Technical services at mines have been re-structured, whilst those at corporate offices have been all but eliminated. A recent study of the role of the geologist in BM Alliance Coal Operations Pty Ltd (BMA), showed the adverse impact on the companyÆs performance due to a lack of geologists. With an education campaign, to demonstrate the contribution of geologists to the æbottom lineÆ and in increasing the options available to the company, the value of the geology role became better understood. The implications of the loss of invaluable corporate knowledge, when long serving geologists left the company, also became clear. Steps have since been taken to increase the numbers of company geologists, particularly on mine sites. In common with other sectors of the mining industry, the Australian coal industry is experiencing a critical shortage of experienced coal geologists, as companies have found in recent recruitment efforts. This is further evidence that the recommendations from the recent study by World Competitive Practices, commissioned by The Australasian Institute of Mining and Metallurgy, æRising to the ChallengeÆ have not been adopted. People, and the mineral resource base, are the assets from which mining companies gain a sustainable competitive advantage. Geologists, as the nexus between the resource base and people, are in a unique position to enhance the profitability of their companies. To maximise their contribution to the industry, and ensure that they receive due recognition, geologists must adopt a more commercial approach in their work and take a front foot stance in promoting their value to management. Geology is a core competency for all mining companies. The tendency for companies to outsource this function, to the detriment of the company geologist role, is not sustainable in the longer term. TodayÆs geologists need to work closely with management, technical and human resource professionals, universities and schools to ensure their significant value is well understood, and that the industry can attract, train and retain new recruits through the implementation of graduate programs and company career paths.

Jan 1, 2003

By Eugene S. Perry

The most notable development in oil and gas operations in Montana during 1938 were extensions to the Kevin-Sunburst and Cut Bank fields. No new fields were discovered, although about 20 widely scattered wildcat wells were operated. Within or adjacent to proved fields about 100 wells were drilled, resulting in 81 oil wells and 14 gas wells. In general, production activities were below those of 1937, largely because of market conditions. Markets for crude were improved late in the year by construction of refinerirs at Pocatello, Idaho, Spokane, Washington and Cut Bank; and also by price concessions. However, demand was much

Jan 1, 1939

By Eugene S. Perry

The most notable development in oil and gas operations in Montana during 1938 were extensions to the Kevin-Sunburst and Cut Bank fields. No new fields were discovered, although about 20 widely scattered wildcat wells were operated. Within or adjacent to proved fields about 100 wells were drilled, resulting in 81 oil wells and 14 gas wells. In general, production activities were below those of 1937, largely because of market conditions. Markets for crude were improved late in the year by construction of refinerirs at Pocatello, Idaho, Spokane, Washington and Cut Bank; and also by price concessions. However, demand was much

Jan 1, 1939

By A. F. Daily

Free World consumption of diamonds of all types closely follows the fluctuations of the business cycles in the large industrialized countries, particularly the U.S. Sustained purchasing by this country for stockpiling purposes has been a major factor in Free World demand for crushing bort and industrial diamonds, and it has been for this reason that investments in larger plants have been made by all major diamond mining companies during the past few years. For the purposes of this study, the diamonds produced in the Congo and elsewhere in the Free World are divided into three types:

Jan 5, 1961

On Feb. 16, 1948, the Board of Directors of AIME authorized the publishing of "Technical Notes" in METALS TECHNOLOGY. The purpose is to provide prompt publication of very short items of the following general types: I. Results of short investigations which do not warrant a paper. 2. The conclusions of extensive investigations of insufficient general interest to justify a regular paper. 3. Conclusions arising in the course of an investigation, which, because of interest to others in the field, the author wishes to present prior to completion of the investigation. 4. Pertinent factual comment (not mere argument) on the subject matter of previous "Notes." Such Notes will be subject to the approval of the Auxiliary and AIME Publications Committees, but can be handled more promptly than regular papers because they need not be referred to readers. The recommended maximum length is 500 words; notes in excess of 1,000 words will not be considered for this type of publication. A graph or photograph may be included as part of the note when particularly illustrative. As with regular papers, contributions to the new section should be submitted to the Secretarv of the AIME. Please furnish two copies, each complete with illustrations.

Jan 1, 1948

On Feb. 16, 1948, the Board of Directors of AIME authorized the publishing of "Technical Notes" in METALS TECHNOLOGY. The purpose is to provide prompt publication of very short items of the following general types: I. Results of short investigations which do not warrant a paper. 2. The conclusions of extensive investigations of insufficient general interest to justify a regular paper. 3. Conclusions arising in the course of an investigation, which, because of interest to others in the field, the author wishes to present prior to completion of the investigation. 4. Pertinent factual comment (not mere argument) on the subject matter of previous "Notes." Such Notes will be subject to the approval of the Auxiliary and AIME Publications Committees, but can be handled more promptly than regular papers because they need not be referred to readers. The recommended maxi- mum length is 500 words; notes in excess of 1,000 words will not be considered for this type of publication. A graph or photograph may be included as part of the note when particularly illustrative. As with regular papers, contributions to the new section should be submitted to the Secretary of the AIME. Please furnish two copies each complete with illustrations.

Jan 1, 1948

On Feb. 16, 1948, the Board of Directors of AIME authorized the publishing of "Technical Notes" in METALS TECHNOLOGY. The purpose is to provide prompt publication of very shod items of the following general types: I. Results of short investigations which do not warrant a paper. 2. The conclusions of extensive investigations of insufficient general interest to justify a regular paper. 3. Conclusions arising in the course of an investigation, which, because of interest to others in the field, the author wishes to present prior to completion of the investigation. 4. Pertinent factual comment (not mere argument) on the subject matter of previous ''Notes." Such Notes will be subject to the approval of the Auxiliary and AIME Publications Committees, but can be handled more promptly than regular papers because they need not be referred to readers. 'The recommended maximum length is 500 words; notes in excess of 1,000 words will not be considered for this type of publication. A graph or photograph may be included as part of the note when particularly illustrative. As with regular papers, contributions to the new section should be submitted to the Secretary of the AIME. Please furnish two copies each complete with illustrations.

Jan 1, 1948

On Feb. 16, 1948, the Board of Directors of NME authorized the publishing of "Technical Notes" in METALS TECHNOLOGY. The purpose is to provide prompt publication of very short items of the following general types: I. Results of short investigations which do not warrant a paper. 2. The conclusions of extensive investigations of insufficient general interest to justify a regular paper. 3. Conclusions arising in the course of an investigation, which, because of interest to others in the field, the author wishes to present prior to completion of the investigation. 4. Pertinent factual comment (not mere argument) on the subject matter of previous "Notes." Such Notes will be subject to the approval of the Auxiliary and AIME Publications Committees, but can be handled more promptly than regular papers because they need not be referred to readers. The recommended maxi- mum length is 500 words; notes in excess of 1,000 words will not be considered for this type of publication. A graph or photograph may be included as part of the note when particularly illustrative. As with regular papers, contributions to the new section should be submitted to the Secretary of the AIME. Please furnish two copies each complete with illustrations.

Jan 1, 1948

Brigadier R. S. G. Stokes of Sherborne, Dorset, is the oldest surviving member of the South African Institute of Mining and Metallurgy. He joined in 1904 and has been a member for 77 years. Book review Sittig, M. Hand book of catalyst manufacture. Park Ridge (U.S.A.), Noyes Data Corporation, 1978. The detailed information in this book is based on patents issued in the U.S.A. that deal with catalysts and their commercial technology. Project management The South African Institute of Mining and Metallurgy is to hold a Colloquium on Project Management in the Metallurgical Industry in March 1980. Ingenieurs-in-opleiding in die weermag Op 'n onlangse vergadering van die Suid-Afrikaanse Raad vir Professionele Ingenieurs is daar besluit om kwytskelding van jaargeld aan geregistreerde ingenieursin- opleiding wat tans met hulle tweejaar nasionale diensplig besig is, te verleen met dien verstande dat.... Engineers-in-training in the army At a recent meeting of the South African Council for Professional Engineers it was resolved that a remission of annual fees would be granted to registered engineers in- training who are doing compulsory two-year national service, provided that.... Processing of fine particles The Society of Mining Engineers of AIME is organizing an International Symposium on Fine Particles Processing, which is to be held in Las Vegas from 24th to 28th February, 1980. Economics of precious metals International Precious Metals Institute announces a Special Course for all interested in economic aspects of today's precious metals.

Jan 1, 1979

By Richard H. T. Garnett

The first, profitable, marine placer mining started with tin 100 years ago but no major industry developed until the mid-20th. Century. Dredging at sea yielded cassiterite in both South Thailand and Indonesia, and remains an important state-run industry in the latter country. Malaysia and Russia have also contributed production, and the coastal waters of Tasmania and England have been explored. Marine placer deposits of gold have been examined in New Zealand, Chile, Argentina, Russia and West Africa. Philippino deposits were dredged during the 1930s. Fifty years later, at Nome in Alaska, gold was recovered by dredging from the offshore, and the technical/economic benefits of a seabed-deployed crawler were first demonstrated. Off the coast of Namibia placer diamonds were recovered by airlift mining during the 1960’s, but De Beers effectively started the existing marine diamond industry in 1989. The Wirth drill and a crawler continue to be used by the company, and plans recently have been announced for operations in South African waters. Other commodities such as mineral sands, platinum group minerals, and chromite have been investigated offshore in several worldwide localities.

Aug 24, 2006

This brief resume of the events transpiring in Mexico, culled from the daily New York newspapers since the last Bulletin went to press, does not show any degree of improvement in the situation. MEXICO SEEKS TO AVOID BLAME FOR BANDIT RAIDS All foreign passengers leaving Nogales for Mexico on the Southern Pacific or Mexico Railroad. whose business would take them through territory occupied by the Yaqui Indians or Mexican bandits were requested by Mexican Consul Emilio Tamez to sign a statement that they relieve the Mexican government of responsi-bility for anything which might happen to them while in that part of Mexico. The Mexican consul stated, says the N. Y. Tribune, that this was by order of Mexican Ambassador Ignacio Bon ill as, at Washington. When the State Department was advised of this activity Secretary Phillips, in a message to the consulate at Tampico, according to the N. Y. Tribune, asserted that "compliance with the waiver requirement will not interfere with the relation existing between the United States and its citizens and that Americans so complying will in no way lose the protection of this government."

Jan 11, 1919

Polyacrylamide flocculating agent has been used in the Leaching Division of the Risdon Works of the Electrolytic Zinc Co. of Australasia Ltd since October, 1960. Since the introduction, the.: number of thickeners in use in the continu-ous thickening stage has been reduced from eight to three; there has been an increase of 25% in throughput and a reduc-tion of solids in.:thickener overflow from 3-4 gòpòl . solids to 0.5 g.p.l. solids. Reagent addition has been at the rate of 0.25. lb SEPARAN, NP10 per ton solids.Additionally there has been a gain of 3% in current efficiency as the direct result of the addition of SEPARAN NP10 to purified cadmium sulphate solution prior to electrolysis for cadmium metal. A smoother deposit has resulted and it has been possible to increase deposition time between strip-pings from 47 to 71 hours. However, there has been a slight increase the lead content of the cadmium-metal produced.

Jan 1, 1963