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By C J. Unger, A M. Lechner, A Walton, V Glenn, M Edraki, D R. Mulligan

In Australia, responsibility for abandoned mines can be unclear. With a few exceptions, state and territory governments have become responsible for abandoned mines on Crown land and private landholders are responsible for abandoned mines on freehold land. Abandoned mines pose risks and opportunities across the full suite of sustainability themes (environmental, human health and safety, socio-economic and community development) after mining ceases.Across Australia, there are more than 50 000 abandoned mines recorded, ranging in size from individual shafts to large polluting open cut mines. Addressing the safety and environmental impacts of these sites, as well as the socio-economic development opportunities of significant rehabilitation projects, requires the implementation of effective policies and programs. Qualitatively defined graded scales or ‘rubrics’ have been used for many years in student assessment and increasingly in the performance assessment of other sectors (Davidson, 2005). While risk-based maturity models have been used for safety prioritisation (Westrum, 1993; Hudson, 2007; DRET, 2008; Hancock, 2010) and evaluation of organisational development (Esteves et al, 2010), this paper is the first to adapt maturity models for the evaluation of abandoned mine rehabilitation programs in Australia.In this paper, we used indicators based on the national policy for abandoned mines to assess the maturity of abandoned mine programs. Fourteen elements of maturity were identified (Unger et al, 2012) under the five chapters of the national policy for abandoned mines (MCMPR and MCA, 2010). Jurisdictions were then evaluated and ranked on their maturity on the basis of information that was web-accessible. Information transparency of abandoned mines policies and programs is in itself one element of the maturity chart. Each jurisdiction in Australia was compared with one another and with a Canadian jurisdiction; the British Columbia (BC) Crown Contaminated Sites Program (CCSP), which represents leading practice (Unger, 2009; Unger et al, 2012).Our research found that in some jurisdictions in Australia there is little or no information on abandoned mine programs or individual abandoned mine sites on government websites, while other jurisdictions provided very detailed program information on planning, funding and implementation. Each jurisdiction in Australia, for which web-based information was available, had some elements where they were more mature than other Australian jurisdictions. For some elements, maturity ranked equivalent to the BC CCSP, but most Australian jurisdictions were less mature. There was only one element where a single Australian jurisdiction ranked higher than the BC program in maturity. Legacy mine policies, programs, priorities and funding information via departmental websites are easier to find in some jurisdictions, indicating progression toward greater transparency and more mature programs. A systematic approach to monitoring and evaluating abandoned mines programs is essential for accountability as it can demonstrate liability reduction over time and continual improvement. The maturity model approach can provide both a measure of progress over time as well as a tool to support the implementation of the national policy for abandoned mines (MCMPR and MCA, 2010).CITATION:Unger, C J, Lechner, A M, Walton, A, Glenn, V, Edraki, M and Mulligan, D R, 2014. Maturity of jurisdictional abandoned mine programs in Australia based on web-accessible information, in Proceedings Life-of-Mine 2014 , pp 467–480 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By Francis S. Kendorski

INTRODUCTION Drift design problems in caving operations are a re¬sult of the geologic factors contributing to the overall success of the system, of the engineering factors dictated by economic and technical considerations, and of ore production practices. Combining these factors, a rational underground sup¬port system of rock reinforcement, light steel channel section or welded wire fabric, and shotcrete can be de¬signed based on rock fracturing, rock load, abutment loadings, ground movement, expected repair and desired flexibility. The design concept uses the effect achieved by restraining, reinforcing, and maintaining some of the intrinsic strength of the fractured rock mass composed of interlocked blocks of intact rock and rock fractures. Three different examples of drift support design in hypo¬thetical mines using the caving system are given. Caving is a system of underground mining where ore is extracted by means of gravity after the ore body is allowed to fail by removing support from underneath. The rock mass of the ore body fractures and flows ver¬tically downward to let gravity do as much work as pos¬sible. Caving differs from many other mining systems in that blasting is used only to initiate the rock mass failure by removing the rock supporting the ore but not to break the ore itself. The initial movement of the rock mass dur¬ing failure and the consequent crushing and grinding during the continued movement serve to reduce the ore to particles of a manageable size, with only limited sec¬ondary blasting necessary. The broken ore is extracted from the bottom of the failed rock mass through funnels of some sort pre-excavated in the rock. Ore extraction must continue or the swell of the broken rock will even¬tually fill the cavity and stop further rock mass failure and movement. The excellent general discussion on block caving in the SME Mining Engineering Handbook (Julin and Tobie, 1973) adequately covers the principles and application of this type of underground mining. Many rock mechanics aspects of block caving have been covered by others (McMahon and Kendrick, 1969; Swaisgood, et al., 1972; Mahtab and Dixon, 1975; King, 1946) and will not be reviewed further. Maintaining the stability of production drifts is one of the most troublesome problems plaguing the mine manager in a caving operation. Many factors contrib¬ute to drift support problems, and identifying the causes of instability and producing a reasonable support design are two steps toward achieving stability consistent with the mine plan. This chapter sets forth a technique for the design of support systems for production drifts in caving opera¬tions. The basic support system elements employed are rock reinforcement, welded wire fabric, and shotcrete. Recognized as contributing to the design are the factors of rock load, additional load from mining activity, rock fracture characteristics, repair expected, and flexibility. It must be emphasized that the drift must first be stabilized as for a tunnel, and the additional strengthen¬ing for mining-induced loads cannot contribute to the initial premining stabilization, or the reserve of strength is used up. MINE PLANNING The efficient mine planning engineer not only must satisfy the economic, human, and environmental aspects of his task but must also consider the mechanical con¬sequences of his plan. The problems created for the mine by placing parallel drifts too close, by crossing drifts on different levels with inadequate, if any, separa¬tion, and by installing connections and crossovers in the haulage plan without regard for the effective spans cre¬ated, are only a few of the problems a mine planning engineer can create for himself and the mine. The effect on immediately adjacent mine areas when an area is caved is important to drift design because the removal of vertical support from a rock mass causes the weight of that rock mass to be shifted elsewhere. The adjacent rock mass will carry this load and reach a new equilibrium with the applied stress. The advancing front of stress increase that results from caving (and many other mining systems) is generally called the abutment load and is the increase in stress over the gravity or tec¬tonic stress that already exists, as shown in Fig. 1. In general, the abutment load will be similar in nature to the stress change found around an opening in rock and will be taken as causing an increase in the vertical prin¬cipal stress, due to an approaching caving boundary, so that

Jan 1, 1982

By Richard J. Mainiero

Traditional techniques for the experimental determination of toxic fumes produced by the detonation of high explosives are not applicable to blasting agents. To detonate properly, blasting agents require confinement, a significant booster, charge diameters of 3 inches (7.5 cm) or greater, and charge lengths greater than two-times the charge diameter. Without these conditions, blasting agents will not detonate at full order, leading to a misrepresentation of the gaseous products. A facility for detonating large, confined charges in a controlled volume has been constructed at the Pittsburgh Research Center’s Experimental Mine. The facility consists of a portion of mine entry (once used for full-scale mine explosion research and demonstrations) enclosed between two explosion proof bulkheads. Total volume of the chamber is 9,666 ft (274 m). The chamber is equipped with an air circulating system and is3 3vented using the mine's airflow. Up to 10-pound (4.5-kg) charges can be detonated in the chamber using a variety of confinements. For a typical test, the blasting agent is confined in a 4-inch (10-cm) schedule 80 steel pipe and initiated by a 3-inch (7.5-cm) diameter, 1-inch (2.5-cm) thick Pentolite booster. This combination of confinement and initiation yields a detonation velocity of about 4,000 m/sec for ANFO. This velocity is in line with that measured for blasting in the field. Twenty four 2-inch thick steel plates are suspended around the pipe bomb to stop shrapnel that would otherwise seriously damage the chamber. Following detonation of an explosive in the chamber, a circulating fan is run for about 10 minutes to uniformly mix the chamber atmosphere. Fumes samples are taken out of the chamber through 1/4-inch (0.6-cm) Teflon or polyethylene2tubes for analysis. The fumes are analyzed using bubblers or Vacutainers to collect samples for analysis by the analytical chemistry lab. The technique described here has been employed to determine the fumes produced by the detonation of a variety of ANFO formulations and commercial explosives. This technique may be developed as a standard test to measure fumes produced by blasting agents or may be used to provide data with which to develop a computer model that will reliably predict the expected fumes production based on chemical composition.

By G. V. Sullivan

This report summarizes the results of metallurgical investigations by the Federal Bureau of Mines of manganese oxide ore, averaging 23 to 25 percent manganese, stockpiled at the Butte-Philipsburg depot of General Services Administration (GSA). The oxide ores were stockpiled in two general classifications, straight oxide ore and mixed oxide-carbonate ore. Continuous-circuit flotation tests at the Albany (Oreg.) Metallurgy Research Center of the Bureau of Mines showed that each of these ore types could be concentrated by an oil-emulsion scheme to produce a concentrate that could be sintered to meet program specifications. About 88 percent of the manganese was recovered in the concentrate from the straight oxide sample, with the sintered concentrate containing 48 percent Mn. The sintered concentrate from the mixed oxide-carbonate sample contained 41 percent Mn with a recovery in the concentrate of 95 percent.

Jan 1, 1961

By John Loop, W. A. Gibbins, Donald D. Hogarth

"Introduction Background The Frobisher voyages of 1577 and 1578 were organized by the Cathay Company for the express purpose of finding and mining gold ore. Since publication of the Baffm expedition of Charles Francis Hallill, the location of Kodlunarn or Countess of Warwick Island, the headquarters of Frobisher's third (1578) voyage, and focal point of the largest Arctic voyage of all time, has been known to the world. Through Hall we also know the location of the Countess of Warwick Mine on Kodlunarn Island. However, the exact locations of the other mines are not known. Of the ""ore"" we know little. Pieces of the original ""black stone"", once as large as ""a half-penny loaf' have now disappeared altogether. Specimens collected at random from the repository of shipments in England and from loose rock on Kodlunarn Island were termed, respectively, ""hornblende pyroxenite"" and ""amphibolite"" and from a locale about 200 yards from Kodlunarn as (hornblende) ""pyroxenite""121. However, it is uncertain whether these specimens are representative of Kodlunarn or of the other mines, although Blackadar131 notes that, in the northern trench of Kodlunarn, biotite gneiss contains lenses and bands of amphibolite. The ""gold"" itself is even less well defined. It has long been accepted that gold was virtually absent in Frobisher's ore. The ""gold"" has been termed pyrite, biotite and both biotite and pyrite together. Even t h e word "" marquesset"" , which appears and reappears in contemporary descriptions, is nebulous and is defined as ""a stone participating in the nature of some metal, yet in so small quantity, that the metal cannot be melted from it"" (0.E.D., definition of 1616)."

Jan 1, 1999

By B J. Andrew, M R. Daley

Mount Isa Copper Mines is a world-class mining operation producing approximately six million tonnes of ore per annum. With over 50 years of mining history and over 76 million tonnes of underground resource remaining there are many challenges facing the mine technical team today and into the future. The mine consists of nine distinct areas: the Hangingwall Lens, Footwall Lens, 1100, 1900, N1100, N1900, 3000, 3500 and N3500 orebodies. Each of these areas have different characteristics, requiring varying methods of mine design and ground control for safe and efficient orebody extraction. Each of the areas operate with an independent sequence whilst interacting with the entire underground operation. Within the first five years after graduating mining engineers tend to orient their careers in either a technical or operations direction. Engineers working towards a specialised technical career will often be working as mine planning engineers, whilst others more focused in the operations stream occupy roles such as operations or project engineers. At this stage of a mining engineerÆs career they are not yet categorised into one stream or another, but career decisions made now can generally focus their ultimate career path in one direction or the other. Due to the size of the Mount Isa operations there are many opportunities for engineers pursuing both career path and plenty of room for growth forthose as yet unsure.

Jan 1, 2005

By J. B. Stubbins, R. A. Blais

Extensive geological work was initiated — and continues — when operations of the Iron Ore Co. of Canada commenced in the Labrador-New Quebec area. Such geological operations include: mapping, test pitting, drilling, underground workings, volume factor and structure tests, and the calculation of ore grades and tonnages. Details of such work are given. Development is carried sufficiently ahead of mining to provide reliable tonnage and grade estimates and allow final mine planning. In order to make full use of geology in mining operations, the pit engineer combines the duties of geologist and mining engineer. The iron deposits of the Knob Lake range are located in the central part of the Labrador peninsula, a territory nearly twice the size of Texas, which is bounded by Hudson Bay on the west, Hudson Strait on the north, the Atlantic Ocean on the east and the Gulf of St. Lawrence on the south. The mining district proper is about 1000 miles northeast of Toronto. A 360-mile railroad links this mining area to the port of Sept-Iles on the Gulf of St. Lawrence. Schef-ferville, which is only a few miles from the open-pit mines, is the center of operations of the Iron Ore Co. of Canada. It has a population of nearly 5000. The nearest settlement is Labrador City, some 120 miles to the south, where this company is erecting a large plant for beneficiating its huge reserves of local low-grade iron ores. HISTORY The mineral possibilities of the area were recognized as early as the end of the last century, when A.P. LOW' of the Geological Survey of Canada made his famous trek across the Labrador Peninsula. After mapping several belts of iron formation, Lovr recommended that the area be thoroughly prospected for iron. In 1929, two well known Canadian geologists, J.E. Gill and U'.F. James, led a private expedition in central Labrador and discovered the first deposit of high-grade iron ore near what is now the Ruth Lake Mine. In 1936 the Labrador Mining and Exploration Co. was formed to 11ake over a prospecting concession of over 20,000 sq miles in central Labrador. An adjoining concession of 3900 sq miles in New Quebec was obtained in 1942 by Hollinger Consolidated Gold Mines, which had just Purchased the Labrador Co. The same year the M.A. Hanna Co. Purchased an interest in both exploration companies. From 1942 to 1950 extensive exploration was conducted by the Hollinger-Hanna technical staff to systematically appraise these vast concessions. More than 40 deposits of high grade ore were found and, by the end of 1950, the total ore reserves reached 418 million tons. In 1949 five American steel companies joined the Hollinger-Hanna interests and formed the Iron Ore Co. of Canada. Financing and full-scale construction were decided upon in 1950. This included the construction of a 360-mile railroad through very difficult terrain, the erection of two hydroelectric plants, the installation of terminal port facilities at Sept-IIes, the building of a modern town-site at Schefferville, the construction of crushing and screening plants, and the preparation of deposits for mining. Ore was first shipped in July 1954. Total open-pit mine production to date is 66 million long tons of direct-shipping ore. GEOLOGICAL ENGINEERING The above achievements would not have been possible without irtegrated teamwork of people of diverse skills and extensive use of geology. In their paper on the role of geologists in the development of this iron ore field, (Gustafson and Moss1 rightly emphasized the difficulties facing the early workers in the area. In an uninhabited land with no roads or railroads and no navigable rivers leading to the interior, everything had to be flown in. It was not until 1948 that aerial photographs and adequate base maps became available. In spite of these and other difficulties, an impressive amount of field work has been done since 1942. Nearly all this work has been directed by geological engineers and geologists. About 15,000 :sq miles have been geologically

Jan 1, 1962

By Andrew Kaczmarek

The mining industry is enjoying a much needed and long awaited increase in demand for natural resources. However, consolidations in the mining and mining service industries, along with a generational departure of experienced industry professionals, is challenging today’s mining companies. These challenges are not only in maintaining their existing operations, but also in securing qualified resources for developing new projects. These challenges are compounded for junior mining companies. They oftentimes lack for operating properties to draw experienced professionals from. Also, juniors have to compete with the majors’ “mega-projects” for experienced project personnel from the reduced ranks of engineering companies. This article discusses some strategies developed by Anatolia Minerals Development (Anatolia) in developing its Çöpler gold project in central Turkey.

Jan 1, 2006

By H. W. Gillett, E. L. Mack

"This report describes the trend of developments in electric brass-furnace practice in the last two years, and supplements Bureau of Mines Bulletin 202, ""Electric Brass-Furnace Practice"", which was published in 1922. In that bulletin it -as pointed out that some of the lines on which electric brass-furnace progress would take place were clear, but others were less so.Developments in foreign countries.Foreign brass-melters have not yet adopted electric melting to an extent comparable to its use in the United States. It is doubtful Whether all foreign countries combined use 100 electric brass furnaces; of these about 35 are of American make (Ajax, Detroit, Baily) and are operating in Canada, Mexico, England, France, Japan, Sweden, Switzerland, Spain, Norway, Germany, Argentina and Czecho-Slovakia.`The Rennerfelt furnace finds some use in Sweden (1)c, notwithstanding its high metal loss on alloys high in zinc, Two German firms are reported(2) to be using the Rochling-Rodenhauser induction furnace on bronze, the average energy consumption being given as 400 kw.-h. per ton. No comment is made on any trouble from the ""pinch effect"", A firm in Switzerland is reported (3) to use three 600-lb., direct-arc furnaces of its own design to melt babbitt, antimonial lead, coinage silver, nickel, copper, and brass. The metal loss on yellow-brass turnings is high. Use Of a direct-arc furnace in England, with precautions aimed to prevent surface overheating, vas abandoned (4) in favor of an Ajax furnace."

Apr 1, 1924

By M. G. Eiselein, R. A. Smith, C. H. Sheerin

FMC Gold's Paradise Peak Mine was one of the top two producers of mercury metal in North America in 1988 and 1989. As a by-product, elemental mercury is produced from cyanide soluble mercury minerals, primarily to reduce the health risks incurred with the refining of precious metal precipitate containing elemental mercury and mercury amalgams. A discussion of the design, primarily the Merrill-Crowe units, and permitting for the safe production of mercury will be presented. Additionally, laboratory testwork to determine the effect of mercury on reagent requirements in the Merrill-Crowe process will be discussed.

Jan 1, 1990

By Rhys Baker, Tim O’Brien, Joshua M. Hoffman

This paper discusses this division of power as it relates to the explosives industry. Each branch is responsive to the public and the processes through which each promulgates regulation and legislation require public input in different forms.

Feb 1, 2020

By C. F. Smart

The heat treatment of the bronze composed of 88 per cent. copper, 10 per cent. tin, and 2 per cent. zinc, has been investigated by H. S. and J. G. S. Primrose,' and also by the U. S. Bureau of Standards.2 The results obtained by H. S. and J. G. S. Primrose on dry-sand castings subjected to reheating followed by air cooling, or by quenching in water, are shown in Figs. 1 and 2. The values for tensile strength have been converted from tons per square inch to pounds per square inch. Figs. 3 and 4, have been plotted from values obtained by the Bureau of Standards on material of the same composition and treatment. Both investigations show that the ductility of the cast bronze is improved by heating to 700' C. and cooling in air, the strength not being impaired by this treatment. They are not in agreement, howevcr, as to the effect of quenching, Messrs. Primrose reporting a decrease, and the Bureau of Standards an increase, in both strength and ductility when the cast bronze is heated to 600' or 700' C. and quenched. The present investigation was undertaken to study the effect of annealing followed by different rates of cooling, and, in particular, the

Jan 1, 1921

By Charles Law McCabe, Lyndon H. Everett, Edna A. Dancy

It has been found that the carbide phase present at equilibrium in the system M-H2-CH4, at about 600°C, is MC for the rare-earth metals Ce and Pr. X-ray diffraction analysis showed that the monocarbides have fcc structures with lattice constants of 5.036 + 0.009Å and 5.131 + 0.001Å for CeC and PrC respectively. Gaseous equilibrium measurements were used to calculate the standard free energy of formation of the monocarbides from the elements. for the formation of (+ 1300) for the formation of PrC. THE rare-earthdicarbides, and their crystal structures, have been known for some years,l but only more recently were the carbides CeC,2,3 Ce2C3 2 and CeCS3 reported. In 1958 to 1959, Spedding et al. published work on the lanthanum-carbon system4 and other rare-earth metal-carbon systems,5 proving the existence of M2C3 and MC2, and measuring the lattice constants. They also demonstrated that tri-rare earth carbides, M3C, exist for the rare-earth metals samarium through ytterbium. However, they concluded that the cerium monocarbide reported by Brewer and Krikorian2 and by Warf,3 and given a fcc structure with a lattice constant of 5.130Å bythe former workers, was, in fact, cerium metal with carbon dissolved in it. They were also unable to find any evidence for the existence of Warf's CeC3, for which no structural details had been given. Even more recently, Palenik22 reported the existence of only M2C3 and MC2, having been unable to find any evidence for the existence of any other rare-earth carbides. There are no published experimentally derived thermodynamic data for the formation of any of these carbides, although Brewer and Krikorian6 have estimated values of for CeC, Ce2C3 and CeC2. The objective of the present investigation was; to determine experimentally the free energy of formation of any of the reported carbides of cerium and praseodymium, through a study of the rare-earth metal-hydrogen equilibrium. EXPERIMENTAL A methane-hydrogen mixture was circulated, in a closed system over previously prepared cerium or praseodymium hydride, and when equilibrium had been attained, the gas mixture was analyzed by selectively oxidizing the hydrogen and condensing out the water formed. The metal hydrides were used as starting material for convenience because, otherwise, the hydrogen in the gas mixture would immediately dissolve in the metals; in addition, the metals would not react with methane alone at the experimental temperature (around 600°C). The circulating system was based on that used by Browning, DeWitt, and Emmett7 for similar studies on iron carbides. It consisted of a quartz reaction vessel, all-glass circulating pump, analysis tube containing copper oxide that could be heated to 300" C by means of a small furnace, a solid CO2-methanol trap, and a double limb absolute manometer, Fig. 1. A cathetometer, capable of reading to 0.005 cm, was used to measure the difference in height between the two columns of mercury. In its final form, the reaction vessel was enclosed in an outer jacket, containing approximately the same pressure of hydrogen as that within, to reduce errors due to diffusion of hydrogen out through the fused silica of the reaction vessel., The circulating system was supplied with

Jan 1, 1962

By AIME AIME

THE Industrial Conference appointed by President Wilson has presented the following tentative plan for preventing or retarding strikes and industrial conflicts by proposing new Federal machinery for the adjustment of differences between employers and employees. Theplan is signed by William B. Wilson, Secretary of the Department of Labor, 'as chairman of the conference; Herbert Hoover, former Federal Food Administrator, as vice-chairman; Martin H. Glynn; Thomas W. Gregory, former Attorney Gen¬eral; Richard Hooker; Stanley King; Samuel W. McCall former Governor of Massachusetts; Henry M. Robin¬son; Julius Rosenwald; Oscar S. Straus; Henry C. Stuart, former Governor of Virginia; F. W. Taussig; William O. Thompson; Henry J. Waters; George. W. Wickersham, former Attorney General; and Owen D. Young.

Jan 1, 1920

By Lloyd A. Morley, Alan M. Christman

PART A. ELECTRICAL EQUIPMENT – GENERAL Paragraph 1. Electrical Equipment; Examination. All electric equipment shall be examined, tested, and properly main¬tained by a qualified person to assure safe operating conditions. The examinations and tests shall be performed at intervals not exceeding six (6) months unless otherwise specified in Parts A, B, C, D, and E. When a potentially dangerous condition is found on electric equipment, such equipment shall be removed from service until such condition is corrected. A record of such examinations shall be kept and made available to an authorized representative of the Secretary and to the authorized repre¬sentative of the miners in such mine. Each item of major equipment, in¬cluding substations, switchgear, load centers, and so forth except powered hand tools, shall be recorded separately. The record of such examination shall include all dangerous conditions found, corrective action taken, and name of examiner, and shall be signed by the person responsible for main¬taining the equipment in safe operating condition, who shall also be a qualified person. Paragraph 2. Electrical Work; Qualified Personnel. No electrical work shall be performed on electrical distribution circuits or equipment, except by a qualified person or by a person trained to perform electrical work and to maintain electrical equipment under the direct supervision of a qualified person. Disconnecting devices shall be locked out and prominently tagged by the persons who perform such work, except that in cases where locking out is not possible, such devices shall be opened and prominently tagged by such persons. Locks and tags shall be removed only by the persons who installed them or, if such persons are

Jan 1, 1976

By J. T. Dunham

The Bureau of Mines studied by dilatometry the effect of titanium on the thermal expansivity of hot-rolled zinc and Zn-l percent Cu alloy. The titanium content of the alloys was varied up to 0.3 percent. Expansion coefficients were determined from measurements made both parallel and perpendicular to the plane of the rolled sheet. Titanium reduced expansion parallel to the plane of the sheet, especially in the rolling direction, but increased expansion perpendicular to the sheet. Basal-plane pole figures showed that the degree of preferred orientation increased with the titanium content in the alloy, and that anisotropic expansion can be correlated to sheet texture.

Jan 1, 1965

By M. Elbert Nigri

Radioactive wastewaters from nuclear source of electrical energy production need to be treated and disposed of properly. Sr, Ca, Mg and Ba are common elements in this effluent, which can cause incrustation in process equipments and being unsafe to human health (90Sr). Fixation of CO2 can be applied to remove the ions mentioned before and to provide a solution where CO2 is sequestered and the deleterious elements precipitated, becoming one of the possible steps to reuse the water into the process. Moreover, removal of several metals from distinct wastewater has been evaluated using bone char through adsorption. The chemical similarity between calcium and strontium makes the exchange of these two metals favorable in the hydroxyapatite structure contained in bone char. This paper evaluated the combined action of precipitation and adsorption process with injection of CO2 and bone char addition in simulated nuclear wastewater. Removal levels of 89.0% (Sr) and 83.3% (Ca) were obtained in the combined process. The presence of bone char as seed increased the precipitation kinetics, allowing a Sr removal of 85.2% in five minutes, higher than 75.3% obtained in absence of seeds. However, removal of 91.6% (Sr) and 89.8% (Ca) were obtained in absence of seeds at 24 h. Analysis of solids have evidenced that CO2 was consumed to precipitate the metals as carbonates, since the hydroxides are formed at higher pH’s.

By S. S. Pathak, S. Mishra, M. H. Tyeb, A. K. Majumder

Roping in hydrocyclones is a well-known phenomenon in mining and mineral industries which put serious restrictions on their continuous and maintenance free operation. Roping is mostly observed in association with high underflow solid concentrations which can be attributed to higher fraction of solids reporting to the underflow or the feed solid concentration itself being higher. This paper proposes a newly designed spigot with a truncated conical geometry which can allow for a rope-free discharge at higher feed solid concentrations. The experimental observations revealed that in the operation of a 50.8-mm-diameter hydrocyclone, roping ensued at 10% to 12.5% (wt%) feed solid concentration depending on feed inlet pressure for the cylindrical spigot, whereas with the modified spigot, rope free discharge was attained even at 25% (wt%) feed solid concentration.

Jan 8, 2022

By G. A. Moruzi

Two sulphide dust secondacy explosions have occurred in the mines of the SUdbury operations of Falconbridge Ltd. during the past 18 months. 'Ihe main similarity between the occurrences is that they both happened in vertical crater retreat blasthole stopes. A relatively high p:,v.tier factor was noted in both instances. other details are enumerated and examined, as well as some results of tests done by Noranda Research on company ore samples.

May 11, 1988

By C. F. Smart

THE heat treatment of the bronze composed of 88 per cent. copper, 10 per cent. tin, and 2 per cent. zinc, has been investigated by H. S. and J. G. S. Primrose,1 and also by the U. S. Bureau of Standards.2 The results obtained by H. S. and J. G. S. Primrose on dry-sand castings subjected to reheating followed by air cooling, or by quenching in water, are shown in Figs. 1 and 2. The values for tensile strength have been FIG. 1.-EFFECT OF QUENCHING ON DRY SAND CASTINGS (H. S. AND J. G. S. PRIMROSE.) converted from tons per square inch to pounds per square inch. Figs. 3and 4, have been plotted from values obtained by the Bureau of Standards on material of the same composition and treatment. Both investigations show that the ductility of the cast bronze is improved by heating to 700° C. and cooling in air, the strength not being impaired by this treatment. They are not in agreement, however, as to the effect of quenching, Messrs. Primrose reporting a decrease, and the Bureau of Standards an increase, in both strength and ductility when the cast bronze is heated to 600° or 700° C. and quenched.

Jan 9, 1919