Search Documents

The November General Meeting of the Branch was held in the St. Helena Club at 8.00 p.m. on the 17th November, 1970. Mr J. N. Saunders (Chairman) was in the chair. There were also present six fellows, N. A. Honnet, C. J. Isaac, J. G. Kirchner, (Committee Members), J. M. Meyer, S. L. S. Swart and J. W. Wilson; seven members, D. V. Baum, M. de Lange, A. H. Edwards, G. J. G. Emere, E. R. Penny, G. P. Rundle, C. G. J. Vermeulen; six graduates, N. Mayer, H. Miller, E. J. Shillaber, P. J. H. Short, M. H. Smith, T. R. Stromsoe; five associates, M. Andriesse, A. E. Hooper, A. Paschalides, R. L. Solms, W. M. Todd; one student, J. C. Simms and 14 visitors. Apologies for absence were received from Messrs L. O. W. Leimer and G. Y. Nisbet. MINUTES OF THE ANNUAL GENERALMEETING The Minutes of the Annual General Meeting held on the 27th August, 1970, were taken as read. Their adoption, which was proposed by Mr N. A. Honnet and seconded by Mr J. G. Kirchner, was carried unanimously. MINUTES OF THE JULY GENERALMEETING The minutes of the General Meeting held on the 8th July, 1970, were taken as read. Their adoption, which was proposed by Mr C. J. Isaac and seconded by Mr J. G. Kirchner, was carried unanimously. GENERAL BUSINESS Members were advised that no more applications could be entertained for the visit to Western Holdings; they could, however, still apply to visit Welkom Mine and Harmony. TALK The Chairman invited Mr A. Paschalides to deliver his talk on 'Controlled blasting in stopes and new explosives developments'. The presentation proved to be of great interest to the meeting and lively discussion followed the talk. Mr N. A. Honnet proposed a vote of thanks to Mr Paschalides on behalf of all members of the O.F.S. Branch. CLOSURE The Chairman thanked Mr Paschalides for his talk and all present for their attendance, and as this was the last meeting for 1970 he wished all members a Merry Christmas and a Happy New Year. He declared the meeting closed at 9.30 p.m.

By W. P. Blake

Forging under the hydraulic press, which was introduced by Haswell in the year 1861, at the machine shops of the Imperial State Railway Company of Austria, has since been greatly improved, so that at the present time there are very few parts of machines which cannot be produced in this way, and at no greater cost than iron castings. The process is now used at Vienna chiefly for such parts of locomotives as cross-heads, link-bars, axle-box frames, etc., especially where the form is intricate, and there are many angles and projections. These objects weigh from 50 to 150 lb. or more, and it is claimed for them that they are not only much cheaper than ordinary forgings, but are much more regular in form and stronger. The results which Mr. Haswell has attained, after years of patient experimenting, were well shown in the Austrian Department of the Vienna Exhibition by a collection of the pressed objects in iron and steel, just as they left the moulds, with some of them cut asunder longitudinally and the surfaces etched, so as to show the internal structure or direction of the grain. Through the courtesy of Mr. Haswell and his son I saw the hydraulic presses in full operation at the works, drawing down large Bessemer ingots, cutting them up into blocks of convenient size, and forming various park of locomotives. They have two large hydraulic presses in use; the largest, with a piston 24 inches diameter, gives 1200 tons pressure, and the second, with an 18-inch piston, gives 600 tons pressure. The pressure in the pumps is 600 atmospheres. The action is vertical; the piston descends upon the work, and for forging ingots is armed with a hammer-like head. An ingot of No. 7 soft Bessemer steel, which was forged in my presence, weighed 2030 lbs. One end being placed upon the anvil, the piston is brought slowly down and crowded into the mass as if it were putty or dough, forcing it each way, but chiefly in the direction of the length of the ingot, this being the narrowest section of the anvil and hammer. The piston is then raised and the ingot is moved forward for a second squeeze, and so on, until the first half of the ingot has been reduced in thickness, when it is turned on edge and the operation is repeated. The ingot is then turned end for end and forged until the whole length has been re-

By E. A. Domínguez

La Espingarda kaolin deposit was formed by ?in situ? alteration of volcaniclastic rhyolitic rocks belonging to Jurassic Marifil Formation. Three volcanic lithofacies were identified: porphyric biotitic ignimbrites (PBI), a coarse lithic ignimbrite (ILG), a fluidal intrusive rhyolite (RFI), all kaolinized in different degrees. The alteration covers an ellipsoidal area of ~20,000 m2, with its alteration decreasing downwards and disappearing at 8-12 m from the surface. The length to thickness ratio of alteration is 60:1. An erratic silicification was found as small zones (<3 m2) of quartz stockwork. The mineralogy is kaolinite + quartz + feldspars + Fe-oxyhydroxides ± halloysite ± illite and interstratified I/S, although the relative proportions change in each rock type. Due to coarse grain size and high quartz content, natural kaolin is unsuitable for slip cast ceramics, unless beneficiated. Washed ILG kaolin has the best rheological properties and behavior in casting and drying for its mineralogy, particle size distribution, thin texture and surface activity, as well as a certain fusibility and firing kinetics. PBI and RFI kaolins, due to finer texture, smaller grain size, lower surface activity, and higher halloysite amount, have worse slip viscosity and thixotropy that are due also to soluble salts. For the same reason, they have good casting and drying properties, but their purity brings about higher softening temperatures and water absorption. Several parameters are used to discriminate between hypogene or supergene kaolinite genesis. The hydrothermal genesis is mainly sustained by fluid inclusion temperature (150-180ºC) in quartz veinlets, while weathering is supported by deposit morphology, simple mineralogy, kaolinite stable isotopes (d18O ? 18, 13; dD ? ?59; ?85) and paleoclimatic record. It is concluded that a weathering process formed the main alteration with some participation of steam-heated meteoric waters. Neither the contents of Au, Ag, As, Sb, Hg, nor drill data support the existence of any epithermal gold mineralization at the kaolinite bottom.

Jan 1, 2010

By K. .. Sadayappan

The increasing cost of selenium made the conventional low lead alloys such as EnviroBrasses not economically viable. Efforts were made to develop newer alloys without selenium for plumbing applications. Recently a new copper alloy, C89836, was introduced. This paper discusses the properties of the new alloy including mechanical properties at ambient and elevated temperatures as well as corrosion behaviour.

Jan 1, 2007

By John Shirokoff, Ladan Khaksar

"Cyclic polarization technique and also potentiodynamic measurements were applied to study corrosion behavior of 13% chromium steels in chloride containing environment. Potentiodynamic measurements were performed at 25 and 75 °C with 0, 10 and 20 g/l NaCl in 0.01 M hydrochloric acid solution. At the same time, the significant pitting parameters such as corrosion potential (Ecorr), pitting potential (Epit), protection potential (Epro) and passive current (Ipass) of cyclic polarization curves with various NaCl concentration were analyzed and compared to describe the corrosion behavior of 13% chromium stainless steel. Surface measurement techniques such as SEM and EDS were used for morphology and analysis of corrosion products. The results showed that both temperature and Cl- concentration had significant effects on corrosion behavior of 13% chromium stainless steel in acidic solution.INTRODUCTION Of all the corrosion resistant alloys (CRA) used in oil and gas developments, martensitic stainless steels (MSS) are some of the most common ones these days. These steels not only have the advantages of normal steels: high strength, cost-effective, easy to manufacture, available in a wide variety of product forms, but they also have good CO2 corrosion resistance at higher temperatures as a result of their 11% minimum chromium content. One of the most common types of MSS used in the oil and gas industry is 13% chromium steel. NACE and API standards both reference several different varieties of 13% chromium steels for use in oil and gas projects(“Corrosion Resistant High Cr Steel for Oil and Gas Wells,” 2013). All types of 13% chromium steels have about 12 to 14% chromium and other minor alloying additions, and can be placed into two general groups: conventional and modified. Conventional 13% Cr steels (13Cr) are those most common in oil and gas, some of which are CA6NM (UNS J91150), AISI 410(UNS S41000), and AISI 420 (UNS S42000). These alloys have excellent corrosion resistance when compared to carbon steels up to about 300°F (150°C) and are used for a variety of wellhead, tubular, and downhole components however they have very limited resistance to cracking in H2S (Vallourec Group, 2015). Modified 13% Cr (M13Cr) steels came from the need for increased corrosion resistance at higher temperatures, increased H2S cracking resistance, and increased yield strength above 85 ksi (586 Mpa) primarily for tubular goods and other downhole equipment. These features were developed by taking a conventional 13Cr steel and adding nickel (Ni), molybdenum (Mo), copper (Cu), and other alloying elements. M13Cr provides better corrosion resistance than 13Cr up to about 350°F (177°C), yield strengths up to 110 ksi (758 Mpa), and also improved H2S cracking resistance(“Corrosion Resistant High Cr Steel for Oil and Gas Wells,” 2013)."

Jan 1, 2017

By George Meadows

Consultation and Accommodation Introductions Consultation -Best Practices The Role of Negotiations The HVC Experience Summary / Conclusions The Challenge Meeting legal and policy obligations to consult while adhering to project priorities, timelines and budgets Defining who needs to be consulted, by whom, and ?how much?? Accommodation ?who is responsible and what is the appropriate scope? Social License -establishing positive working relationships with First Nations involved in project review / approvals / implementation in a manner that advances the interests of all parties

May 1, 2010

By Scott Rosenthal, Logan Connolly

Butte, Montana holds a prestigious place in the history of mining, deemed “The Richest Hill on Earth,” containing a plethora of underground mines. The Orphan Boy/Orphan Girl underground mines, on the western side of Butte, operated from 1895-1956 producing zinc, lead, silver, and manganese. Today, the Orphan Boy mine is part of Montana Tech’s Underground Mine Education Center (UMEC) and the Orphan Girl mine houses the World Museum of Mining. Underground development in the Orphan Boy mine continues to progress as students from Montana Tech receive hands-on underground training; in addition, the UMEC is a multi-disciplinary research facility. Repeated underground blasting occurs in close proximity to old mine workings (wood supports installed circa 1950 or earlier). Research began to determine the impact of underground blasts on nearby pre-existing structures. Using the ISEE Field Practice Guidelines for Blasting Seismographs, one seismograph monitors the predominately-wooden structures to measure their response during each underground blast and one seismograph positioned on the surface to monitor surface structure response to the blast. This paper presents the findings of the research conducted to date for the project. The paper includes analysis of the research data, and conclusions determined from the research. Recommendations for the future work are included as well.

Jan 1, 2018

By R. J. Jones, L. D. Clark, R. C. Howell

This research provides an empirical approach toward further analysist10 of the variables in rock breakage under direct, hydroimpact (impacting on fluid) and explosive impulse loading. That the strain on the face of a block of rock, below an impact pin or explosive charge, is directly proportionate to the rupturing force F and inversely proportionate to the product of the burden W and the hole periphery S, is borne out in the laboratory using electrical resistance strain gages to measure a peak strain during rupture by small explosive charges detonated in boreholes. Furthermore, such findings established the validity of the expression F = Ss • Wy • R as a useful relationship from which, it is believed, can be derived practical applications in commercial rock blast design.

Jan 1, 1972

By Dale K. Fields

With today&apos;s technological advances in mineral processing equipment, there is an increasing demand for accurate system control. This can only come about through representative sampling. The purpose of this paper is to guide you in the selection of sampling equipment and outline design parameters for the cutters used in dry and wet sampling without adding redundant mathematical probability formulas to your files. Special attention will also be given to the equipment used in conjunction with samplers and sampling systems, such as feeders, crushers, chutes, launders, and controls.

Jan 1, 1979

J. L. CHRISTIE, Chairman T. S. FULLER, Past-chairman W. M. PEIRCE, Vice-chairman W. A. SCHEUCH, Vice-chairman E. M. WISE, Secretary International Nickel Co., Bayonne, N. J. W. M. CORSE, Treasurer Executive Committee H. A. BEDWORTH G. O. HIERS D. K. CRAMPTON R. H. LEACH E. H. DIX, JR. R. F. MEHL J. A. GANN J. WALTER SCOTT&apos; JEROME STRAUSS Finance Committee T. S. FULLER, Chairman W. M. CORSE H. S. RAWDON C. H. MATHEWSON SAM TOUR

Jan 1, 1934

By Thomas G. Murdock

ETHIOPIA, the first country to be liberated from Axis domination, has recovered remarkably from the ravages of occupation and war. Mineral production has contributed significantly towards this recovery, as it has provided a means of obtaining foreign exchange and has given employment to hundreds of workmen whose maintenance otherwise would have presented a problem. Although primarily an agricultural country, never with a large mineral production, Ethiopia has within its borders a variety of minerals, both precious metals and nonmetallics. Some of these are important to the country as a national asset and others contribute greatly to local economy and can be expected to do so even to a greater extent in the future1 (Fig I). PHYSIOGRAPHY AND GEOLOGY The Empire of Ethiopia is essentially a mountainous and volcanic country, in northeast Africa, situated principally between latitude 4° and I5°N and longitude 34° and 44°E. It is bounded on the north by Eritrea, on the northeast by French Somaliland, on the southeast by Italian Somaliland, on the south by Kenya Colony, and on the west by Anglo-Egyptian Sudan. These European possessions thus completely surround the country. Its access to the Red Sea is through Eritrea; to the Gulf of Aden, through French or British Somaliland; and, to the Indian Ocean, via Italian Somaliland. These routes range in length from 40 to 250 miles. Ethiopia has an area of approximately 350,000 square miles, with a width from north to south of 625 miles, and a maximum length from east to west, along latitude 8°N, of about 875 miles. Physiographically the country is characterized by two very extensive sub-tabular plateaus: the Ethiopian Plateau to the northwest and the Somaliland Plateau to the southeast, separated by a long tectonic graben-the Rift Valley of the Galla Lakes and Danakil. The Ethiopian Plateau, deeply cut and notched by the drainage, slopes in a general northwest direction toward the Sudanese Plains and the valley of the Nile; the Somaliland Plateau slopes to the southeast, toward the Indian Ocean. The valley of the Galla Lakes and its extension to the northeast-the Awash River Valley, separates the plateaus, from Lake Rudolph to Danakil. This depression which constitutes a continuation or ramification of the Great Rift Valley of Central Africa joins in turn the trough of the Gulf of Aden and the Danakil-Eritrean Rift, continuations of the Red Sea and the Jordan Valley. The general basement of Ethiopia is made up of very old rocks, usually considered as Archaen.2 These rocks are represented by the metamorphic crystallines, such as gneisses, different kinds of schists, included lenses of crystalline limestone, and massive intrusives such as granites, diorites, and syenites, all cut by

Jan 1, 1947

By L Smith, R Beckie

An intermediate scale (8 m + 8 m + 5 m high) constructed waste rock pile experiment was built upon a contiguous grid of 16 gravity drainage lysimeters to investigate the flow of water in unsaturated waste rock. Average net infiltration to the uncovered waste rock pile is 55 per cent of precipitation. Large rainfall events have net infiltration of 55 per cent to 85 per cent. Net infiltration estimates range from 23 to 120 per cent of precipitation between lysimeters. Small-scale lysimeters of less than 4 m2 area are shown to be poor predictors of net infiltration for uncovered waste rock. The appropriate size for lysimeters increases with increasing flow rate. The residence time distribution has an estimated median value of 3.0 to 3.9 years under average infiltration conditions. Water flows within the fine grained matrix, within larger pores (macropores), and in matrix free areas of the pile. In situ tracer concentrations vary between pore sizes, and between spatially distinct areas of the pile, indicating water geochemistry may also be variable. Water samples collected from in situ soil water samplers are dominated by the most mobile water fractions. In situ measurements of water content and matric suction are compared to the measured outflow. The data indicate the focusing of flow in spatially distinct areas can make in situ instrumentation a poor (non-conservative) predictor of volumetric water flow.

Jan 1, 2003

By William Newnam

WHEN Hugh Lee Pattinson discovered, in 1829, that the crystals formed during the slow cooling of molten lead were poorer, and the remaining liquid richer in silver, than the original lead, an important step was made in the metallurgy of this metal. Being the first process applicable to the desilverization of low-grade lead bullion, it soon found its way into all European countries having such a product to treat, thereby effecting the saving of many ounces of silver annually which previously had been thrown away. The old hand process was expensive, as viewed from the standpoint of more modern methods; the labor was great anti the tonnage was small, but on the other hand the results were fairly, satisfactory. This process flourished for some time after the introduction of the cheaper Parkes process in 1852 and it is still in use in a few European smelteries. Only one notable improvement was made on the original process, that of Luce and Roan at Marseilles, France. It consisted in the application of steam for stirring and the tapping of one-third of the liquid lead, through perforated plates covering the tap holes flush with the bottom of the kettle, thus leaving two-thirds in the form of crystals in the original kettle. This modification considerably lowered the operating costs as it permitted of much larger kettles, an increased tonnage and eliminated much of the slow, hard labor of the hand process.. The Luce and Rozan process has persisted in its original form to the present clay. Stephen Tredinnick, English born, spent most of his years around the Luce and Rozan plants at Marseilles and elsewhere in Europe, coming later to Eureka, Nev., in 1878, to operate the Luce and Rozan plant at that point. Mr. Tredinnick was a competent Luce and Rozan operator and being devoted to the process he firmly believed that with modifications the costs could be so lowered as eventually to supplant the Parkes process.

Jan 5, 1917

By A. K. Schellinger, R. D. Lalkaka

IF the ball mill is considered only from an energy standpoint, it can be thought of as a converter of kinetic energy into heat energy and surface energy. The law of the conservation of energy must apply to the ball mill as it does to any machine or process in nature. The heat energy output of the ball mill is apparent to any casual observer of the operating mill since the outflow pulp will be appreciably warmer than the inflow water and rock. The rock in the ball mill is crushed by shearing of its ionic bonding caused by some impact-induced stresses beyond the elastic limit. As the bonds holding the mineral crystal lattices together are ruptured, new surface area is created on each unit of which a definite number of unsaturated bonds exist. Such unsaturated energy of bonding may be termed the "surface energy," and is a potential energy figure. This created energy was withdrawn from the ball mill system and represents an absorption, or disappearance of heat. To reduce the size of the rock, surface area must be created and with it the at- tendant characteristic surface energies of the minerals concerned. Thus the creation of surface energy, from an energy viewpoint, is the creation of useful work by the ball mill. Because of the controversial nature of the energy efficiency figures for modern operating ball mills, it seemed worthwhile to approximate the ordinary magnitude of such efficiencies from the above viewpoint. This was done by an energy balance of the three aforementioned forms of energy, kinetic, heat, and surface energy, for two 9Y2x10-ft grate-type ball mills grinding cement raw materials. Kinetic energy input to the balls was approximated as closely as possible while the heat energy output was measured by means of a thermometer and water and rock flow rates. The assumption was made

Jan 1, 1952

By N. S. Dalal, X. Shi, P. M. Gannett

"Chromates are known to induce tumors (1, 2), mutations (3), and DNA damage (4-6). However, the underlying biochemical mechanism(s) is (are) not fully understood (6). Recent studies have indicated that hydroxyl (·OH) radical may play an important role (7-11). The mechanistic studies of Cr(Vl)-related ·OH radical generation in biochemical systems have shown the reaction of a Cr(V) species with hydrogen peroxide (H20 2 } through a Fenton-like mechanism to be one of the important steps (9-11): Cr(V) + H20 2 - Cr(VI) + ·OH + OH-. (1)In biological systems the Cr(V) species are generated via the reduction of Cr(VI) by a variety of components, such as microsomes (12), mitochondria (13), mitochondrial electron transfer complexes (14), and at least three flavoenzymes (glutathione reductase (GSSG-R),3 lipoyl dehydrogenase, and ferredoxin-NADP+ oxidoreductase) (9, 15, 16). In the case of flavoenzymes, Cr(V) formation is accompanied by the reduction of molecular oxygen ( 0 2 ) to H20 2 • The Cr(V) species then reduces H20 2 to generate •OH radicals and Cr(VI) (16).To understarid the mechanism by which Cr(V}-generated ·OH radicals cause cytotoxicity, Aiyar et al. (8) investigated the reaction of Cr(VI) and H20 2 to generate ·OH radical and its reaction with 2'-deoxyguanine (dG) to form 8-hydroxy-2'-deoxyguanine (8-0HdG}:"

Mar 1, 1992

By Birger Schmidt

The design of underground nuclear waste disposal facilities poses new problems related to the requirement of long term safety against radionuclide migration. The degree and effects of rock disturbance caused by construction and by the long term thermal effects from the hot waste must be predicted with confidence. Computer modeling can, to an extent, be verified by accelerated near-surface tests. Credible extrapolation to deep, long-term conditions requires successful near-surface modeling verification, proper characterization of near-surface and deep rocks, and successful determination of in-situ stresses. Excavation induced disturbance may be assessed primarily by empirical evidence.

Jan 1, 1981

There are presently no suitable underground mine production scheduling optimisation models available for application to sublevel stope mining. Scheduling underground production for maximum return is therefore still a manual process, which generally involves scheduling production from the next available highest cash flow stope within the operational constraints of the project. In most mining operations, the scheduling problem is too large and complex to guarantee truly optimal results through manual scheduling. This paper reviews some general optimisation studies that have been proposed for underground hard rock mining. Furthermore, an example of a mixed integer programming model is presented for a small conceptual sublevel stoping operation. Comparative results of a schedule generated by a mixed integer programming (MIP) production scheduling model and a manually generated model on a nine stope example is presented. Results indicate that the potential benefits of the MIP production scheduling model for the purpose of maximising NPV are significant. Finally, a new constraint was formulated to limit multiple exposures of fill masses for use in an existing MIP production scheduling model. Testing of the formulation took place on the central stope of the nine stope example, which showed that the formulation performed its task without breaking other operational constraints.

Jan 1, 2007

By H. L. O. Huyck

A microcomputer equipped with spreadsheet, data management, and FOR- TRAN programming software is used to update and quantify a model for ranking seventeen economically important metal commodities in terms of market potential (Huyck, 1982). Weighted factors are used for the ranking: (1) demand growth trends, (2) end-use substitution vulnerability, (3) recycling trends, (4) price trends, and (5) cumulative demand versus world reserves factor. Price trends are defined using (1) price-vs.-year slopes (with prices in 1967 constant dollars) and (2) standard deviations of slopes (to indicate price volatility). Substitution vulnerability is defined as the percent of end-use which is replace- able by other commodities, and a factor indicating the likelihood of such substitution. Factors are normalized and linearly combined to produce a ranking of the seventeen metals. Microcomputer software is essential for organizing data and calculating statistical parameters and linear combinations of factors.

Jan 1, 1986

By C. C. Harris

An analytical solution of the integro-differential equation of batch grinding is proposed as a first appoximation to the xYt surface. The size distribution equation (xY plane) is a three parameter equation previously suggested. Possible refinements are outlined. Comminution kinetics research is presently following several related courses. Some are equivalent, in that they represent different ways of viewing the same facet of the problem, though the entire endeavor cannot be described as being completely integrated. The purpose of this note is to propose and discuss a framework into which the various approaches might be fitted. This must clearly be founded upon an analysis of the xYt surface.&apos; (See also Fig. 1 of Reference 26.) The investigations referred to above comprise mainly researches into the following: (1) The kinetics of the creation of the finer sizes during relatively small grinding times. This is the Fahrenwald-Arbiter-Bhrany 2-3 approach which leads to equations equivalent to a special case of the charles4 relationship. It emerges that initial production of fines follow essentially zero order* kinetics. (2) Disappearance kinetics of the coarser fractions. This appears to be a first order relationship.5-6 (3) Prediction of the xYt surface via the selection and breakage functions utilizing computer-programmed or approximate solutions of the integro-differential equation of batch grinding.5,8-17 A recent discussion by Mika et al.5 references the relevant literature up to about 1966. In addition to these main-stream researches there is some work on the minor topic of extremely long grinding time considered as a limiting case.18-19 The field is supported by investigations into the size distribution of fragments produced by breakage processes, some of this work being most valuably statistical-mechanical in nature.20-25 Better fitting equations, however, are obtained by statistical and curve-fitting methods.26 This

Jan 1, 1969

By F. F. Peng

Fine Coal Cleaning Processes including froth flotation, aggregative flotation or oil agglomeration, depend upon the wettability of coal particles in the aqueous solution. The wettability of coals of various ranks, hydrocarbon oil treated coals and oil-agglomerates have been measured using film flotation, induction timer, and froth flotation. Various hydrocarbon collector dispersion techniques are used to alter the surface wettability of coal particles. Change in wettability behaviors, measured by flotation responses, due to various ranks with or without of hydrocarbon collector modification are explained in terms of surface chemistry modifications as analyzed by induction time, film flotation as well as DRIFT Spectroscopy. The relationship between the wettability of coals and collector treated coals, and floatability are discussed.

Jan 1, 1993