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By Robert F. Shurtz, William J. Verner

Three basic questions must be answered by an engineer performing an economic analysis of a mineral property: (1) How much can the company afford to pay for the property; (2) At what rate should the property be mined; (3) What will be the return on the investment. These questions often defy reasonable analysis, because at the point in time at which they must be answered little may be known about the grade of ore and the reserve tonnage. The purpose of this report is twofold. First, to derive a method of determining purchase price, rate of production and return on investment which is valid under varying conditions of ore grade and tonnage reserve; and, second, to apply this method to the Margay deposit in an attempt to evaluate it as a business enterprise. This is an actual economic analysis of an existing nickel-copper deposit fictitiously named the Margay. It was carried out for a mining corporation and proved to be the determining factor in the subsequent purchase and development of the property. All data referring to costs, quality and quantity of ore, etc., are accurate and truly represented. Prices used are obsolete but the method is not dependent on those variables. Basic assumptions for the analysis are given in Table I, page 71.

Jan 11, 1966

The theme of this conference is æRediscover OtagoÆ and the conference occurs during a resurgence of economic activity in New Zealand, and in particular at a time when the Macraes Gold Project has had a significant effect on mining and business activity in Otago. The Macraes Gold Mine has implemented a Zero Accident Programme and this paper reviews some of the factors responsible for the implementation.

Jan 1, 1992

By C Sylvestre

Leaders have invested heavily in traditional safety management to improve safety performance over the years. This primarily involved: • fixing the environment (eliminating the hazard) • improving the system (more/less rules, procedures etc) • making safety more conscious (more/better interactions about the importance of safety). These approaches have helped improve safety performance significantly during the last 50 years and will continue to play a role in the future. Although these approaches may be part of an overall solution, they are not enough to prevent many incidents. Today, these three approaches are used more than before, and are used better than ever before. Yet, workplace fatalities in Australia have stagnated from 2013 to 2019, as have the number of incidents, even serious ones. In the USA, workplace fatalities have increased by 15 per cent in the same period.

May 5, 2022

By Rudolf E. Pfister

One of the Swiss transalpine highways includes two remarkable tunnels: the 16.3 km long Gotthard Road Tunnel and the 9.3 km long twin tube Seelisberg Tunnel, both presently under construction. Large diameter shafts up to 900 m long are required for ventilation. Excavation techniques for rock formations ranging from loose sedimentary rock to granite and very hard siliceous limestone were carefully evaluated. The methods finally applied include excavation of shafts in hard rock, conventional drilling and blasting, excavation by ripper-tooth excavator ("Big John") in marlstone, shield protected heading in loose material and soft rock, and tunnel and shaft lining, both by poured concrete and by prefabricated elements. A critical review of the success of these methods can now be made after a five year construction period.

Jan 1, 1976

Intermontane valleys form unusual features of compressive mountain belts both in the sharp topographic break they represent and in the strike-slip displacements often associated with the valleys. Such strike-slip motion seems hard to reconcile in the actively deforming Andes where reconstructions have indicated nearly perpendicular Cenozoic plate convergence. Detailed study of a part of the Argentine Andes between latitude 31-33¦S suggests that, although strike-slip displacements may have largely created a prominent intermontane valley system, no Holocene strike-slip displacements are observed amid the relatively active compressional deformation along the mountain belt flanks. New plate reconstructions, treating the Nazca plate as two microplates separated by fractures along the Nazca Ridge, predict large components of strike-slip motion between the South American and Nazca Plates for the period from 10 to 5 Ma. These reconstructed plate motions are consistent with strains derived from recent kinematic analyses of minor faults along the southeast margin of the Puna plateau and the general timing of tectonic phases in the Andes.

Jan 1, 1987

At a special inaugural ceremony in Blue Hill, Maine on August 3rd, Governor John H. Reed detonated the first blast to signify the beginning of development work on a new copper-zinc mining venture that seems destined to focus increased interest in the mineral potential of that State. The property which is the first new base metal mine to be discovered in the northern Appalachians in 30 years, is owned by Black Hawk Mining Co., a subsidiary of Denison Mines Ltd. of Toronto. When it goes on-stream in 1966, it will join Ducktown, Tenn., as the only active copper producing region, east of the Mississippi River. According to official reports submitted by the Company to Robert G. Doyle, Maine's State Geologist, Black Hawk has found ore reserves totalling 4.5 million tons. Assays show 2.8 million tons of 2.0'; copper and 0.4 oz. of silver per ton; 1.2 million tons of 16.75% zinc and 0.58% copper; and 0.5 million tons of 6.75% lead with 4.25 oz. of silver per toil and some zinc.

Jan 9, 1964

By Pedro Augusto Silva de Lima

As ligas do sistema Cu-Al-Ni sofrem Transformações Martensíticas Reversíveis (TMR) e podem apresentar Efeitos Não Elásticos, incluindo o Efeito de Memória de Forma (EMF). Elas podem ser utilizadas nas diversas áreas e são promissoras para substituir ligas do sistema Ni-Ti. Neste trabalho foram estudadas três ligas distintas: monocristalina e policristalina Cu-Al-Ni e policristalina Cu-Al-Ni-Mn-Ti, dando atenção a análise da estrutura e comportamento mecânico, em seu estado inicial e após tratamento de betatização. Nas três ligas foram identificadas as fases martensitas ß1 e Y1e as fases R e ß1. A liga Cu-Al-Ni-Mn-Ti ainda apresentou o composto Cu2AlTi. Durante a deformação, as três ligas sofreram TMR, induzidas por tensão, com reorientação das fases envolvidas. O tratamento de betatização aumentou a plasticidade, sendo mais notável na liga policristalina Cu-Al-Ni. A liga Cu-Al-Ni-Mn-Ti se mostrou como a mais frágil, sofrendo a fratura antes de alcançar 10% de deformação. A liga monocristalina se mostrou a mais promissora para realizar EMF, revelando maior deformação armazenada no patamar de pseudoescoamento.

Aug 17, 2017

By T. F. Morse, R. Lundstrom, A. J. Brammer, D. Peterson, M. Cherniack, T. Nilsson, J. D. Meyer, E. Toppila, G. Neely, N. Warren

HAVIC is a collaboration of investigators from North America, Sweden, and Finland having a scientific mandate from NIOSH, to study the exposure response relationship between vibratory tool exposure and adverse health effects. Five cohorts, the Suomossalmi forest workers cohort, Volvo truck cab workers, Connecticut shipyard workers, and matriculating dental hygiene students and experienced dental hygienists have been under study. In the case of shipyard workers, there was survey and tool exposure data from 1988, although detailed subject testing was only available within the timeframe of the study. The truck cab assembly workforce was an inception cohort that had been followed from 1994 along with age-matched controls. The Finnish forest workers had cumulative health data on a cohort (n=52) that had been studied from 1976. For a subset of these subjects, there was detailed tactometry testing in 1990, 1995, and 2003. Accordingly, there was historical as well as new prospective data for the industrial cohorts. The Suomossalmi cohort was reassembled only for our study, which precluded follow-up evaluation and because of retirement is almost certainly the last time this historic group will be studied. The study features are: • Characterization of the exposure response relationship for hand-arm vibration through a study design, incorporating multiple cohorts, some having existing historical data, • Selection of cohorts to include different types of vibration: oscillatory (forest workers) impact (truck cab workers), high frequency (dental hygienists) and mixed (shipyard workers), • Inclusion of two inception cohorts: dental hygiene students and Swedish truck cab workers, • Methods for multi-site and historical integration A description follows. [ ] Methods The study included surveys, physical evaluation, and a selection of battery of “best tests” (cold challenge plethysmography, multi-frequency tactometry, segmental sensory nerve conduction velocity [SNCV]1,2,3) applied across groups to quantify responses to exposure. Exposure monitoring included exposure characterization through daylong data logging at the individual level. Workers at each site were instrumented with a microcomputer-based Vibration Exposure Monitoring (VEM) system, developed at the Biodynamics Laboratory of UCHC and about the size of a police walkie-talkie, to record user-specific tool-operating times, vibrations, and grip forces throughout all, or a representative part, of their workday. More specifically, data logging methods involved the direct monitoring of work cycles, involving tool operation time and measures of tool vibration, namely the root-mean-square (RMS), root-mean-quad (RMQ), and root-mean-oct (RMO), and grip forces, each calculated per minute. For this study, the questionnaire was homogenized with other vibration studies4,5,6. Cross-translation was directed by the multi-lingual investigators, and then reviewed by the study team. To extend comparability with future international studies, questions were also added from the Vibration Network (VINET) draft questionnaire, the product of a European

Jan 6, 2006

By Daniel W. H. Su

This paper presents a retrospective assessment of ground control research and its successful application by CONSOL Energy over the past 25 years. Recognizing the need to improve the understanding of coal pillar design mechanics under shallow, medium, and deep covers, an extensive underground coal pillar instrumentation program was initiated in the mid 1980s. Combined with sophisticated numerical modeling technique and laboratory tests, results from this instrumentation program were used to advance the concept of coal pillar design and to demonstrate that numerical modeling can be used to predict in situ coal pillar strength, especially under non-ideal conditions where interface friction and roof and floor deformation are the primary controlling factors. To evaluate the impact of longwall mining, a 10-year subsidence research program was initiated in 1986 that encompassed surface, subsurface, and underground measurements, as well as a sophisticated numerical modeling technique. Results from the research revealed that interface friction and shearing between rock layers within the overburden had a profound effect on surface subsidence development and the resulting strain. Recognizing the impact of horizontal stresses on CONSOL?s mining operations, extensive horizontal stress measurements were conducted using the USBM Borehole Deformation Gage and the CSIRO Mininfrac system in the mid to late 80s. Roof extensometers and CSIRO HI Cells were used to measure roof displacement and roof stress concentration in longwall headgates and tailgates, which resulted in the definition of right-hand and left-hand longwall panels. Pillar design modifications, combined with cable bolt application and innovative standing support installation, were then successfully employed to mitigate horizontal stress impact on the right-hand longwall headgates and left-hand longwall tailgates. An in-house floor bearing capacity test apparatus was fabricated and employed underground to determine mine-specific floor bearing capacities which, along with other geotechnical parameters, were then used in the mine-specific shield design. To promote caving of thick, massive sandstone immediately behind longwall face supports and to improve face conditions, the hydraulic fracturing technique was successfully employed by CONSOL to pre-fracture the sandstone prior to longwall mining. Face monitoring and numerical modeling confirmed the effectiveness of the hydraulic fracturing technique. A roof geology reconnaissance program was initiated by CONSOL in the early 1990s to improve roof control, safety, and production. Information obtained from the reconnaissance program was used successfully to guide mine planning decisions and daily roof support practices.

Jan 1, 2011

By D. S. Flett

Abstract. The commercial importance of hydroxyoximes as extractants for copper has given impetus to basic studies on the chemistry of metal extraction by these compounds. The discovery of accelerator compounds which produce catalytic effects on hydroxyoxime extraction rates has led to mechanistic studies of these rate processes. While these studies have highlighted the importance of interfacial chemical reactions in the extraction process, it is not yet possible to unambiguously describe the mechanisms of metal extraction in these systems or the associated catalytic effects. This paper reviews progress in understanding the mechanism of metal extraction by hydroxyoximes.

Jan 1, 1979

By H. Cevizci

In this study, a newly developed plaster stemming method is studied and compared with the usual dry drill cuttings stemming method for surface blasting in mines and quarries. Drill cuttings are generally used in open pits and quarries as the most common stemming material since these are most readily available at blast sites. However, dry drill cuttings eject very easily from blastholes without offering much resistance to blast energy. The plaster stemming method has been found to be better than the drill cuttings stemming method due to increased confinement inside the hole and better utilization of blast explosive energy in the rock. The main advantage of the new stemming method is the reduction in the cost of blasting. In one series of blast tests, blasting costs per unit volume of rock were reduced to 16 per cent by increasing burden and spacing distances. Also, better fragmentation was obtained by using the plaster stemming method. Blast trials showed that plaster stemming produced finer material. In the same blast tests, +30 cm size fragments reduced to 5.4 per cent of the total, compared to 37.7 per cent in the conventional method of drill cuttings stemming. With this method of stemming, vibration and air shock values increased slightly due to more blast energy being available for rock breakage, but these increased values were small and under the permitted limit for blast damage criteria.

Jan 1, 2012

By J. M. Stewart

The purpose of my few comments is to try to create a healthy perspective to constructively link considerations of the sessions to follow to those of the earlier sessions. I propose to do this by considering some of the issues and priorities related to the development of backfill systems and technology for South African gold mines.

Jan 1, 1988

By F. E. Bash

Constantan is an alloy of copper and nickel that is extensively used, under a number of trade names, as a resistance wire with a low temperature coefficient of resistance, and one of the elements of base-metal thermocouples, iron usually being the other thermoelement, although for low-temperature work copper is also used. Before the war, constantan was imported, in common with many other technical necessities. Since it required considerable time to receive the constantan after it was ordered, fairly large stocks were kept on hand; but after the beginning of the war no more was imported and the stocks of foreign material were exhausted about the same time that the steel and munition manufacturers began to need great quantities of it for thermocouples for the heat treatment of steel. To meet this demand, the International Nickel Co. began manufacturing constantan that met all the requirements of the users of resistance wire but did not give the same electromotive force against iron as the German material and consequently could not be used with instruments calibrated for a definite e.m.f.-temperature relation. It so happened that all the constantan made had an e.m.f. lower than that necessary to meet the specifications of the Leeds & Northrup Co. for whom this investigation was carried out. If some had been higher and some lower, good wire could have been obtained by a process of selection, but as it was no wire at all could be procured. To remedy this situation, a thorough investigation was started with the close cooperation of the International Nickel Co. and the Electrical Alloys Co. The specifications to which the constantan had to conform were that it should give an e.m.f. of 47.40 millivolts against pure iron at 1500" F. (816" C.) with the cold-junction temperature at 0" F., or a proportional e.m.f. at temperatures near 1500" F. The method of checking a wire was as follows: It was first welded to a piece of iron wire; Armco iron was found to be satisfactory but iron with greater than 0.1 per cent. carbon would give a lower e.m.f. against the same piece of constantan than pure iron. The couple was then insulated and the fire end was tied to the

Jan 1, 1921

The epithermal silver-gold Red Rock Deposit is hosted in the Late Permian inter- mediate to silicic composition Drake Volcanics of New England, N.S.W. This deposit represents one of the few low sulfur epithermal precious metal systems in eastern Australia, and differ! from epithermal models in that the hydrotherma: system which produced mineralization was active in a shallow water marine environment. The Red Rock Deposit has a resource of 180,000 tonnes of 66g/t Ag and 0.9 g/t Au, and a Ag:Au ratio of 70:1. Mineralization is largely associated with hydrothermal brecciation, and occurs as disseminations, vein stockworks, and struc- turally controlled lodes. Ore minerals comprise acanthite (argentite), electrum, native Ag, Ag- sulfosalts and base metal sulfides, Alteration minerals associated with ore are quartz, cal- cite, adularia, pyrite, illite, illite-mont- morillonite, chlorite and sphene (leucoxene). Illitic and propylitic alteration zones sur- round the hydrothermal breccia. Bulk rock analyses indicate that alteration is character- ized by the addition of Si, K, Fe, Mg and the loss of Na and Ca. Ore was deposited from a boiling fluid in a temperature range of 222- 295¦C, and of 0.5-7 wt. Z NaCl equivalent sal- inity. An upper hydrostatic depth limit of about 800 m is implied for the boiling fluid ii an open vein. Sulfur isotopes indicate a mag- matic sulfur source, and oxygen isotopes imply a predominantly marine ore fluid. Modern analogs of the submarine hydrothermal system that formed the Red Rock Deposit occur in the Taupo Zone, New Zealand, and southern Kyushu, Japan.

Jan 1, 1987

By R. Liu

As Building Information Modeling (BIM) becomes widely adopted by the construction industry, it holds undeveloped possibilities for supporting Facility Management (FM). Some FM information systems on the market claim to address the needs for FM requirement. However, the question of whether the functionalities provided by the current BIM-based FM software companies are those actually required by the FM Professionals still need to be answered. The data is required by FM professionals in the operation and maintenance phases of facilities and type of maintainability problems that frequently occur, which can be solved early in design phase, have not yet been addressed. The aim of this paper is to clarify the frequently occurring maintainability problems and to investigate the potential areas that can use BIM technology to solve the maintenance problems in early the design phase. A survey was conducted to collect perspectives from the industry practitioners for the maintenance problems and their frequency. The survey results indicated that maintainability considerations should be taken into consideration during the facility design phase. The results also address the perceived areas by practitioners that need maintainability consideration in design phase.

Aug 1, 2013

By Jan Pan, Deqing Zhu, Xianlin Zhou, Yanhong Luo, Zixing Xue

"Magnetic roasting process, aiming at obtaining magnetite concentrate, is the principle method of exploiting siderite as a raw material in iron and steel industry. Study on preparing DRI from siderite through coal based reduction technology is sporadic. To make the process of how siderite is reduced to iron clear, roasted ore reduced from siderite by lignite under different time periods were analyzed. The results indicated that: at the temperature of 1050°C, siderite was rapidly decomposed into magnetite, and further reduced as Fe30r?FeO?Fe, the later step was slower than the previous one. A fracture of particles was found during the process of thermal decomposition and the reduction of newly formed magnetite. As the reduction proceeded, metallization rate of products increased, and the iron grain grew along with time.IntroductionWith the rapid development of economy, China demands more and more iron ores for the iron and steel industry. China has rich iron ore resources, but 97% of them are below 30% in iron grade, many are refractory and unutilized [1], therefore large quantities of imported iron ores are in a desperate need. China imported 686 million tons of iron ore in 2011 (data from the China Customs), accounting for nearly 60% of the total consumption. To guarantee the healthy development of iron and steel industry, domestic refractory iron ores have to be utilized both economically and environmentally."

Jan 1, 2013

By J.B. Pullen

The United Verde mine is in the north central part of Arizona, on the northeasterly slope of the Black Hills, near the town of Jerome. Ore was first discovered in the district about 1875, and the first mining claims were located by M. A. Ruff-ner and associates in 1877. In 1888 the late Scnator William A. Clark secured control of the property and under his ownership it developed into one of the country's most important copper producers. The property was sold to the Phelps Dodge Corporation in 1935, and since then has been under this Corporation's management. Except for shutdowns caused by general world-market conditions, production has been continuous from 1890 to date. Geology The mineralized zone ranges in area from approximately 12 acres to less than 5 acres. All mineralization occurs in the pre--Cam-brian intrusives. The first intrusion, according to geologic records, was the quartz porphyry, which later was intruded by augite diorite. Following the diorite intrusion through a series of intrusions of lesser magnitude, a pipelike mass of massive sulphide, quartz and rock was formed. The diorite forms the hanging wall of this mass, and the porphyry the footwall. Between the footwall and the sulphide a band of chlorite schist was formed, probably owing to metamorphic conditions. Commercial ore occurs along the contact of the schist and sulphide extending into the sulphide, sometimes entirely through the schist, and fingering out into the porphyry. The ore deposit was formed by replacement similar to deposits formed in limestone areas. Faulting and deformation occurred in pre-Cambrian times and again in the Tertiary period, removing approximately 2000 ft. from the top of the main United Verde ore body, forming the United Verde Extension ore body, the only other major ore body in the district. Major development work has shown that the sulphide mass extends to the 3300-it. level, and diamond drilling below this level has indicated that the mass might extend below the 3700-ft. level, but in a diminished quantity. While many copper minerals exist in the mine, the chief commercial mineral is chalcopyrite. Aplan and vertical section of the mineralized zone showing the principal geological eatures is shown in Figs. I and 2. General Description and Physical Condition or Mine After over 50 years of active production, ore still exists on almost every level of the mine. This condition is due to many causes —-mine fires, which broke out as early as 1894, caused the abandonment of certain areas; subsidence and ground movements retarded the cleaning up of others. Furthermore, in the early days there was such an abundance of ore that when mining became dificult it was a simple matter to replace the production by going to a deeper level. Several attempts were made to recover the ore in the fire zone, both by glory-holing

Jan 1, 1943

By J. B. Pullen

The United Verde mine is in the north central part of Arizona, on the northeasterly slope of the Black Hills, near the town of Jerome. Ore was first discovered in the district about 1875, and the first mining claims were located by M. A. Ruff-ner and associates in 1877. In 1888 the late Scnator William A. Clark secured control of the property and under his ownership it developed into one of the country's most important copper producers. The property was sold to the Phelps Dodge Corporation in 1935, and since then has been under this Corporation's management. Except for shutdowns caused by general world-market conditions, production has been continuous from 1890 to date. Geology The mineralized zone ranges in area from approximately 12 acres to less than 5 acres. All mineralization occurs in the pre--Cam-brian intrusives. The first intrusion, according to geologic records, was the quartz porphyry, which later was intruded by augite diorite. Following the diorite intrusion through a series of intrusions of lesser magnitude, a pipelike mass of massive sulphide, quartz and rock was formed. The diorite forms the hanging wall of this mass, and the porphyry the footwall. Between the footwall and the sulphide a band of chlorite schist was formed, probably owing to metamorphic conditions. Commercial ore occurs along the contact of the schist and sulphide extending into the sulphide, sometimes entirely through the schist, and fingering out into the porphyry. The ore deposit was formed by replacement similar to deposits formed in limestone areas. Faulting and deformation occurred in pre-Cambrian times and again in the Tertiary period, removing approximately 2000 ft. from the top of the main United Verde ore body, forming the United Verde Extension ore body, the only other major ore body in the district. Major development work has shown that the sulphide mass extends to the 3300-it. level, and diamond drilling below this level has indicated that the mass might extend below the 3700-ft. level, but in a diminished quantity. While many copper minerals exist in the mine, the chief commercial mineral is chalcopyrite. Aplan and vertical section of the mineralized zone showing the principal geological eatures is shown in Figs. I and 2. General Description and Physical Condition or Mine After over 50 years of active production, ore still exists on almost every level of the mine. This condition is due to many causes —-mine fires, which broke out as early as 1894, caused the abandonment of certain areas; subsidence and ground movements retarded the cleaning up of others. Furthermore, in the early days there was such an abundance of ore that when mining became dificult it was a simple matter to replace the production by going to a deeper level. Several attempts were made to recover the ore in the fire zone, both by glory-holing

Jan 1, 1943

By Flann R. C

A small modification to current industrial practice should lead to better nickel powders for use in alloying, electroplating, and powder metallurgy. Nickel powder compacts sold for alloying are not always suitable for electroplating applications, since some presently used commercial powders will expand on sintering. Further, such nickel powders are unsuitable for use in the production of powder metal parts, because of expansion during heating of the near-net-shape preforms. Research in these laboratories has enabled the elimination of expansion, and led to techniques for the production of compacts suitable, in particular, for commercial use in both alloying and electroplating. The techniques include: powder pretreatment, cold pressing and sintering, hot pressing, and hot pressing and sintering. In this way compacts are readily prepared with densities of at least 93 per cent of solid nickel, and these, when used as anodes in Watts general purpose and bright baths, give both cathode current and plating efficiencies of 90-98 per cent.

Jan 1, 1979

By L. H. Morris, M. Mordecai

The emission of firedamp from the strata surrounding active workings of longwall coal faces normally follows a cyclic pattern associated with the mining operations being carried out on the face. Mining a coal seam disturbs the uniform distribution of overburden weight such that the working is enveloped by a region of high stress, both above and below the seam, advancing with the coal face. There is a decrease in stress as the strata is relaxed following the passage of the face (1). The paper describes experimental results obtained during the initial investigations of a study intended to examine the permeability of samples of coal measure strata under various triaxial stress conditions. Several investigators have studied the effect of stress on the permeability of rock, usually in the field of oil reservoir engineering. Two general lines of approach are evident. One used by among others Fatt and Davies (2), McLatchie et a1 (31, Brace et al (4) and Gunther (5) was to subject a rock sample to hydrostatic pressure. Gas or water would be passed through a sealed core mounted inside a high pressure hydraulic bomb. The second approach, favoured by Wilhelmi and Somerton (6) and also by Gray et a1 (7) was to employ a so-called 'triaxial' state of stress. Here radial confining pressure and axial stress are applied independently. The permeability is measured in the direction of the axial load. With the exception of Gunther who tested coals and Brace et a1 who tested a granite, the rocks used have been sandstones with permeabilities generally appreciably higher than British coal measure rocks.

Jan 1, 1971