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By Keith G. Wallace, Gary K. Rogers

As a supplement to an analysis involving methodologies for the estimation of airflow resistance in shafts used for both ventilation and hoisting, a detailed shaft characterization survey was distributed worldwide. The survey provided detailed information which enabled verification of recommended velocities and established limitations on fill factors and relative velocities. This paper evaluates the information obtained for 37 shafts and presents a statistical evaluation of the results. Apart from airflow rates, conveyance rates, and physical characteristics, qualitative information regarding means of conveyance stability and velocity control techniques at unloading and loading points are also presented. Calculations of fill coefficient, free area velocity, and most importantly, relative velocity between the airflow and hoist, are conducted. These results are presented by frequency diagrams which illustrate the trends, as well as provide limitations for these parameters. The data illustrates that, commonly, the fill coefficient for two or more conveyances, does not exceed 30 %. A limit of 50% is suggested for a single conveyance shaft. A recommended free area velocity of 10 m/s (1,970 ft/min) for combined ventilation and hoisting shafts, is sup- ported by these results. Relative velocities of 30 m/s (5,905 ft/min) are most frequent and 50 m/s (9,840 ft/min) being a practical maximum.

Jan 1, 1987

It is suggested that an increase in the production from thin coal seams in South Africa is necessary, and that a substantial amount of any increase will be mined by the bord-and-pillar method. For the purpose of this study, a thin coal seam was regarded as any seam 1,5 m thick or less to the minimum thickness at which mechanized equipment can operate in bord-and-pillar workings. The equipment being utilized in thin-seam bord-and-pillar layouts includes conventional equipment, load-hauldump cars (scoops), and drum-type and Fairchild-Wilcox continuous miners. Comparisons are made of these types of equipment for bord-and-pillar mining at various seam thicknesses within the thin-seam range. The evaluations involved production rates and the cost of extraction for South African conditions, use being made of an existing computer modelling technique in the generation of production rates. The indications are that, for seam thicknesses greater than 0,9 m, drum-type continuous miners utilizing continuous haulage are the most productive and cost-effective equipment at present operating in thin-seam bord-and- pillar workings. Where seams thinner than 0,9 m are to be exploited, Fairchild-Wilcox continuous miners, particularly the Mark 22, produce the most coal at the lowest cost.

Jan 1, 1984

By H. J. Swanepoel, N. B. Strydom

Groups of up to twelve new recruits to the industry were subjected to climatic room acclimatization for either five, seven, eight or nine days prior to being tested for the degree to which they had been acclimatized. These tests were done at 32,2 0C (wet bulb) at a wind velocity of about 0,4 m/sec and the men worked for four hours at a rate of 215,6 kg m/min on one day and at a rate of 431,2 kg m/min on the second day. The results indicated that there is no significant difference between the degrees of acclimatization obtained by the eight- and nineday procedures which confirms the conculsions drawn in a previous report1. The eight-day procedure can thus be claimed to be perfectly adequate and safe. Decreasing the period of exposure to five or seven days would however, not be justified because of the significant differences in physiological responses that were observed on both test days between men acclimatized for these periods and those acclimatized for nine days. It is concluded that it would be unsafe to employ these shorter periods of acclimatization when underground environmental temperatures at which the men are to work, exceed 31 0C (wet bulb).

By A.M. Edwards

1. Book reviews Platinum in South Africa, compiled by A.M. Edwards and M.H. Silk. Randburg, Council for Mineral Technology (Private Bag X3015, Randburg, 2125 South Africa), 1987. 55 pp. U$30. Reviewer: R.D. Wintle Scientific and technological developments in extractive metalurgy-G.K. Wiliams Memorial Volume. Parkvile (Australia), The Australasian Institute of Mining and Metalurgy, 1986. $A12 (incl. surface postage). Reviewer: T.Y. OweD Ion exchange and sorption processes in hydrometa/urgy, edited by M. Streat and D. Naden. Chichester, John Wiley & Sons, 1987. 229 pp. Reviewer: B.R. Green Role of Government in mineral resources development, edited by Michael J. J ones. London, The Institution of Mining and Metalurgy, 1985. 180 pp. £40. Reviewer: K.E. Ducat 2. Recent publications Annual report 1987. International Tin Research Institute, Kingston Lane, Oxbridge, Middlesex UB8 3PJ, England, 1988.Tin and its uses no. 156. Address as above. 3. Mintek reports Application Report no. 5 The production of and alusite and other refractory minerals. 1988. 16 pp. . Application Report no. 6 The development up to commercial application of a process for the recovery of lead, copper, zinc, and silver from the Black Mountain deposit. 1988. 14 pp.

Jan 1, 1988

DR. BANOWSKY: Thank you very much. That was the shortest introduction that I have had lately, and I didn't have time to get my coat on. But I appreciated it, and I'm delighted to be here with an industry with which 1 feel strong affinity. At the University of Oklahoma we have an energy history. We are a little more currently involved in oil and gas, and those of you who know the history of our state would be aware we have an early coal development back really before the turn of the century in the southeast part of our state what we call Little Dixie. How many of you have spent anytime in Oklahoma or are from the state of Oklahoma? I'm not going to ask how many are from OSU or the University of Colorado. We did send you a football coach here from Oklahoma, and 1 see you have exchanged him. Several of you were only interested in the lobby in asking about our football team this year. 1 would like to go somewhere where we can talk about something besides football. I'm just trying to build a University that our football team can be proud of. We're going to be strong again. 1 can assure you. We've got the best football team money can buy. It's not quite as bad as the college president who called the coach in and said, "Coach we're in trouble, you're losing games and the alumni is very unhappy." "What can we do?" the president asked. The coach said, "Well the football team is flunking the admissions test. We can't get them in with the standard achievement and SAT tests." The president said, "What can we do?" The coach said, "Well the coaching staff has substituted for the American College Test the simple fill in the blank questionnaire." The president said, "Let's use it. We have got to get the team in." The first question was, Old MacDonald had a (-). And a couple of the big tackles were taking it and one of them said, "Hey, what did Old MacDonald have?" His friend said, "Stupid, Old MacDonald had a farm." "Well how do you spell farm?" He said, "Stupid, e i e i 0." Now the gentleman who met me at the registration line from Lakewood, Colorado, was asking me about one of our great big tackles; and he is doing well. We call him Doctor Death; he is also a wrestler and that gentleman said, "1 don't know how bright he is." 1 said, "He is bright enough for our academic tutoring that he is going to get through all right." So I'm delighted to see you and be here with my very dear friend, Carl Terzian. Carl and 1 were in Los Angeles together for 10 or 12 years when I was president of Pepperdine University. He and I are exactly the same age. Born in 1935 and 1 a month or two later in 1936. Fewer children were born in that period than in any other period of time in this century. For those of you who remember anything about that period, you will know why no one was having babies during that period. But Carl called and said, "Bill do you know where Vail, Colorado is?" Well when you live in Oklahoma, you learn where Colorado is in a hurry. 1 not only know this beautiful area, but have made too much of an investment here at a place called Beaver Creek. The real estate is cheap over there. 1 play regularly in the Gerald Ford Invitational Golf Tournament here. Hope you will visit Beaver Creek. It's just 10- 12 miles to the west. The sight of the 1976 winter olympics until the people of Colorado voted them out. And now Vail Associates and I are good Oklahoma families. Bass family, Harry Bass of course, many of you know this story, who is chairman of the Board of Vail Associates, is making quite an investment in that year-round resort area. Beautiful golf course now. You can come out and afford the green's fee and beautiful, beauti-

Jan 1, 1982

By Weixiang Meng, Zhao Song, Ming Guo, Zhigao Liu, Shoubao Zhang

"There are many multi-layer coal reserves in China which account for nearly 20 to 25% of the existing proven reserves. When the coals are mined in a descending order using the fully mechanized long wall mining method, they usually have roof collapse with cavity and air leak in roadways and long wall stopes; this is especially relevant when the thickness of the rock between two coals is less than 5.0 m, as the roof stability of lower seam would be greatly reduced. At the Wuhushan Mine, such abnormal strata behavior occurs, including abnormal support stress, irregular period roof pressure, and roof falls in the face. The main reasons for these behaviors include smaller roof thickness, lower rock strength, and mining influence of upper coal; these reasons were determined by analyzing the in situ conditions. A mechanics-based model of the mine geometry was set up to study the sources of stress, the stress evolution of coal, and the discriminant method of roof stability; to obtain the smallest safe thickness of roof between two coal layers, numerical modeling was applied to analyze the relations between the roof thickness and its displacement distribution. Based on the above research, the No.1001 face was divided into easy roof caving zone (ERCZ), roof caving transition zone (RCTZ), and unlikely to roof caving zone (URCZ). In the ERCZ, comprehensive grouting to reinforce the roof was implemented; in the RCTZ, local grouting to reinforce the roof was implemented. Furthermore, a face stability control index and its range were developed in a fully mechanized face combined with mine pressure observation. After implementing this strategy, there have been no unexpected roof caving or other serious strata behaviors.INTRODUCTIONChina is the country with the largest coal production in the world, and the conditions for its coal seams are particularly complicated. For example, in China’s Datong, Wuda, Pingdingshan, and Qinshui mining areas, there are a large number of multi-layer coal seams. The thickness of these coal seams ranges from 1.3 m to more than 10 m, and the spacing between layers is from under 1.0 m to over 30 m. A common problem with these coal seams is that one layer of mining has a large impact on other coal seams, which are customarily referred to as close-distance coal seams. According to statistics, close-distance coal seams account for about 20–25% and 15–18% of China’s coal reserves and production, respectively.From the reference research of Huang (1999, 2002, 2018) and Tu (2010, 2011) we can learn that in the mining process of close-distance coal seams, downward mining is mainly used. When the upper-layer coal is mined, it has a huge mining disturbance effect on the floor (that is, the roof of the lower coal). The mining disturbance increases the mining fissure in the rockmass and weakens the strata strength. The mining problem formed by this issue is that when the lower coal is mined, problems such as difficulty in roadway support, collapse of stope roof, and difficulty in ventilation are often encountered. Especially for the mining of medium-thick coal seam groups with a layer spacing of less than 5.0 m, there has been a large-scale roof collapse accident with a fall height of more than 10.0 m. In response to such problems, domestic and foreign scholars and engineers such as Tan, Zhao, and Xiao (2010), Xie et al. (2017), and others have also carried out targeted theoretical and practical research."

Jan 1, 2019

?General Facts:Barrick?sFirst Mine in Peru Production started in November 1998 ?The Facilities:Open Pit, Primary and Secondary Crusher Valley Fill Heap Leach PadMerrill Crowe PlantRefinery Environmental Facts: High Rainfall - Average Annual Precipitation of 1,200 mm (47 inches) Rainfall Events: Common 20mm daily events High Altitude Site - Elevations range from 3900 to 4250m. Steep topography - Terrain ranges from 3:1 slopes up to cliffs. Water Issues: Sediment Control - Open Pit PAG Encapsulation - Waste Dump Stormwater control - Leach Pad Erosion Control Techniques ? Offsite impacts mitigation Social Issues: 11 communities surrounding the property Town of Huaraz

May 1, 2003

During the interval 1929-41, geophysical exploration in Russia made considerable progress, as reflected in publications. The greater part of these publications was available during the preparation of Geophysical Abstracts and Ms been abstracted in them. The rest was not received and remained unaccounted for. A considerable portion of these lading publications are now listed in bibliographic form, in view of their interest to geophysicists. All publications entered in the bibliography are in Russian. 1. GRAVITATIONAL METHODS 1. Abakelia, M. S. The Organization of Gravitational Observatories in Transcaucasia. Problemy Sovetskoi Geologi, Moscow, vol. 6, No. 5, 1936, pp. 452-454.

Jan 1, 1945

By Brenda Marise Oliveira Custódio Pereira

Este trabalho apresenta uma análise fluidodinâmica de um leito granulado, utilizando-se partículas sólidas de diferentes característica em um leito de área de secção transversal circular. Os materiais utilizados foram aqueles comumente utilizados em um alto-forno a carvão vegetal. Os dados experimentais foram obtidos em um leito fluidizado fixo, de escala piloto, medindo 1,20 x 1,00 m. A fluidodinâmica foi estabelecida pelas medidas da perda de pressão no leito e vazões de ar crescentes. Os valores de velocidade de fluidização foram obtidos a partir dos gráficos de perda de pressão x velocidade do ar.

Aug 1, 2018

By Jr. Matthews

The Candelaria copper-gold deposit is located in Region m of Chile, 805 kilometers north of the capital, Santiago. Candelaria was discovered in 1987, following a six month exploration program. In late 1986, induced polarization (IP) surveys outlined an anomalously high response within the area of interest. The first test hole bad three intersections totaling 49 meters, with an average grade of 1.97% copper. Drilling eventually outlined approximately 390 million tonnes, grading 1.09010 copper and 0.26 grams/tonne gold. Production began in early 1995 and is estimated at 120,000 tonnes copper and 80,000 ounces gold annually.

Jan 1, 1996

By A. H. Ransom, M. E. Robb

The Salmita Gold Mine is located 240 air kilometres northea t of Yellowknife on the east shore of Matthews Lake. Salmita is one of several gold showings which are regionally associated with the steep easterly dipping contact zone between mafic, intermediate and fe lsic volcanics to the west and overlying finely laminated argillaceous sediments to the east. The volcanic assemblage forms a narrow 2 m to 7 m wide north to northwesterly trend ing Belt of Yellowknife Supergroup Archaen greenstone rocks. The contact zone exhibits exhalite character and the increased sulphide content provides a di stinct VLF-EM , IP/Resisti vi ty and/or magnetic signature. Gold occurs at or near this contact in three main settings: associated with si liceous vein-like structures; with finely disseminated sulphides within ericitic altered upper fe lsic tuffaceous unit ; or with quartz in narrow shear zones within the overlying sediment . The B-Vein is of the former type with free mi ll ing gold occurring within a highly sil iceous zone having an average widtn of 1.69 m. Alteration is intense within the immediately su rrounding host lithologies and includes the development of si lica, carbonate, sulphide, sericite and chlorite with minor graphite, epidote. tourmaline and scheelite. The mineable zone above the 4th level (-200 m) ha an average strike of 160 m and is divided into three south plunging ore shoots separated by the regional Salmita Shear Zone in the south and by a low-grade structural hiatus in the north. Production from the B-Vein commenced in August 1983 based on a diluted in situ ore reserve of 140,000 t grading 26.6 git Au . As of December 31, 1985, a total of 131 ,537 t grading 27.8 git Au have been mined at a ra.te of 160 t per day and a 96.4 percent recovery, to produce 3,522 ,000 g (113,227 ounces) of gold . Current (January I, 1986) reserves total 45,500 t grading 37 g/t Au down to the 10th level (-500 m) .

Jan 1, 1986

By P S. Jaitawat, M Sarim, M P. Roy, P K. Singh, A Joshi

Mining is being carried out using the sublevel open stoping method at the Kayad underground mine. The mine will ultimately reach a depth of 390 m. Kayad village is only 100 m (horizontally) from the underground mining areas. As a result, blast-induced ground vibration is one of the major issues for the residents of the village. This paper deals with the process involved in optimising blast design parameters at the development face blast, slot raise blast and ring hole blast to control blast-induced vibration within safe limits while ensuring improved production, productivity and safety. In total, 1041 development face blasts, 110 slot raise blasts and 52 ring hole blasts were conducted, and 2612 vibration data were monitored in the village at different locations. Initially, electronic delay detonators were used, with an emphasis on controlling vibration in the surface structures. Subsequently, shock tube (Nonel) initiations were used as the blasting faces reached lower depths. A comparative study was also performed for both the initiation systems. The orebody width generally varied from 3.1 to 7 m, and ring hole designs were optimised accordingly. The number of holes in a ring was up to seven and the depth was up to 23 m, depending on the size/width of the orebody. The ring blasts were performed with 64–340 kg of emulsion cartridge explosive and detonated with explosive weight per delay of 10.92–17.16 kg. Extensive experiments were performed and blast-induced vibrations were controlled in the village. Deck blasting (ie up to four explosives decks) was used in a blasthole and the explosive charges were separated by delay detonators, which helped to control the vibration in the village. The actual detonation time of each deck was recorded by monitoring the in-hole velocity of detonation of the explosives, and the charging patterns were optimised accordingly to get the desired blast results.CITATION:Roy, M P, Singh, P K, Sarim, M, Jaitawat, P S and Joshi, A, 2015. Blast design and vibration control at Kayad lead-zinc underground mine, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 533–544 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Arnfinn F. Prugger, Fritz F. Prugger

"The Saskatchewan potash beds are overlain by a number of water-bearing formations. There are water zones in the footwall as well. These aquifers created difficulties during the construction of shafts to the potash beds at 1()(}() m depth, and they pose a continuous threat to the safe and efficient operation of potash mines in the province.The first shafts to be sunk in Saskatchewan encountered major problems during shaft sinking. Of the 17 potash shafts started in the province, five had major water inflows during shaft sinking or after production startup, and one was abandoned because of water problems. The biggest obstacle encountered during shaft sinking was a poorly consolidated sand-shale-clay-siltstone unit commonly called the Blairmore Formation, which occurs at a depth of about 500 m. The initial problems with shaft sinking were overcome in the 19605by using European methods of freezing and the installation of cast-iron tubbings or a double-steel lining through water bearing horizons.From the start of production in the early 19605, operators have been aware of the ever-present hazard of potential water inflows into mine openings from permeable units in both the hanging wall (carbonates of the Dawson Bay Formation which occur 15 m to 50 m above the mining level) and the footwall (carbonates of the Winnipegosis Formation which occur 50 m to 150m below). This awareness has been reflected in conservative over-all extraction rates and mining layouts specific to local conditions. In spite of this consciousness, a number of water problems have occurred in operating mines. These have resulted in everything from simple increases in expenditure to the shut-down of one mine in 1987.In this paper a history of water problems in the Saskatchewan potash industry is given, followed by a summary of measures that are now commonly used to avoid these problems. A description of each inflow event is given, and the attempt is made to analyze the causes of each occurrence. Based on what was learned f rom each event, suggestions are made to prevent future water inflows into potash mines."

Jan 1, 1991

By Faruk Oksuz, Dave Schiemann, Matt Trotter, Mike Padilla, Miguel Sanchez, Carmen Scalise

"Chicago’s Tunnel and Reservoir Plan (TARP) is a nearly $4.0 billion and over 30 years long program and arguably the largest and longest combined sewer tunnel and reservoir system in the world. Recently, a massive tunnel construction is underway for connection of the McCook Reservoir to the existing TARP tunnel system. Once completed in two stages in 2017 and 2019, the reservoir will hold 38 billion-liters (10 billion-gallons) of combined sewer overflows (CSO) and flood waters from the city of Chicago and over 20 communities in Cook County, Illinois. McCook Main Tunnel will connect Chicago TARP’s Mainstream Tunnel to the McCook Reservoir. Connecting two 10-meter (33-ft) diameter tunnels at 92 meters (300 feet) underground has not been a simple task for the McCook Tunnel Project participants, the project owner U.S. Army Corps of Engineers (USACE), local sponsor Metropolitan Water Reclamation District (MWRD) of Greater Chicago, designer Black & Veatch, and the contractor, Kiewit Infrastructure Company (Kiewit). Yet alone excavating and lining massive size tunnels, the team is also challenged with live tunnel conditions in TARP Mainstream Tunnel that carries CSO and flood flows from city of Chicago which runs full during rain events and must remain in service at all times. The project is a noteworthy feat for engineering and construction with the upcoming installation of world’s largest underground wheel gates for flow control within the tunnel. In this paper, we describe one of its kind elements of this major tunnel system along with key design and construction considerations, specifically for the live tunnel connection which is a rare occurrence in the tunneling industry. INTRODUCTION The McCook Main Tunnel system consists of a 10 m (33 ft) finished diameter and 490 m (1,600 ft) long hard rock tunnel constructed from a 27.5 m (90 ft) diameter and 92 m (300 ft) deep main gate and tunnel construction access shaft. The gate shaft houses six high head 4.4 m by 9 m (14.5 ft by 29.5 ft) wheel gates to be installed in the bifurcated and steel lined section of the tunnel. The tunnel also includes portal and energy dissipation structures as it daylights into the reservoir."

Jan 1, 2016

By A. M. Cann, C. I. Godwin

"The Kemess porphyry copper-molybdenum deposit occurs in the Intermontane Belt of north-central British Columbia. The deposit is in andesitic to basaltic flows and tuffs which may be correlated with the Savage Mountain Formation of the Upper Triassic Takla Group. Most known chalcopyrite and molybdenite is associated closely with a 500-m-diameter zone of intense quartz-sericite-pyrite alteration. A zone of supergene enrichment, up to 30 m thick, underlies a leached capping about 20 m thick. The age of mineralization and the surrounding granodiorite and quartz monzonite pluton is Early Jurassic. K-Ar and Rb-Sr analyses indicate that the mineralization and alteration is slightly younger (l82±6 Ma) than the granitic intrusion (KAr: about 205±6 Ma; Rb-Sr: 190±4 Ma). The low 87Sr/J6Sr initial ratio for the granodiorite is typical of plutons in the Intermontane Belt.IntroductionKemess is a medium to small porphyry copper-molybdenum deposit with significant gold and silver values (Pilcher and McDougall, 1976). This paper describes the lithologies and alteration at this property; geochronology by Rb-Sr and K-Ar methods defines the ages of mineralization and surrounding plutons to be Early Jurassic.The property, located in the Thutade Lake area of northcentral British Columbia (NTS Map 94E; lat. 57°04'N; long. 126°44'W), is about 425 km northwest of Prince George (Fig. 1). Closest road access is 35 km southeast of Kemess. Final access must be by float plane or helicopter. The British Columbia Railway right of way passes 70 km to the southwest of theproperty.A prominent gossan zone at Kemess was staked in 1967 by Kennco Explorations (Western) Ltd. following detection of geochemical anomalies during stream sampling the previous year. During 1968, 1969and 1971, Kennco completed 232 m of X-ray diamond drilling, conducted geological mapping and carried out geochemical sampling of silts and soils (Stevenson, 1969; B.C. Ministry of Energy, Mines and Petroleum Resources, G.E .M., 1969 and 1971). Getty Mines Ltd. optioned Kemess in 1975and 1976. They remapped the area and diamond drilled 12 BQ and NQ holes, totalling 2065 m (B.C. Ministry of Energy, Mines and Petroleum Resources, Expl. B.C., 1975)."

Jan 1, 1980

By N. I. Fisher, J. Shepherd

Abstract-Statistical studies have been carried out on structural geological data collected across a large zone of roof failure 600 m (1968 ft) wide and at least 800 m (2642 ft) long in the Greta coal seam at Aberdare East Colliery. Two swarms of hundreds 2 of minor, normal faults with throws commonly between 3 and 300 mm in the room and pillar workings are broadly coincident with roof failure. The faults have been classified into dip slip and oblique and strike slip types. Roof conditions have been classified into good; troublesome with subclasses scaly, heavy, gutter falls and wide, flat-roofed falls; and severely failed with subclasses very heavy roof, gutter falls and dome falls. Troublesome conditions are defined as those in which the height of the fall is less than or equal to 0.3 m, and severely failed conditions as those in which the fall height is greater than 0.3 m. Comparison of faults, roof conditions and mining rate on a shift basis indicates that faults and roof failure are much more important than machine breakdowns in reducing mining rate. The effect of faults on roof conditions has been quantified using a concept called the "zone of influence, " a rectangular area around a fault in which the fault has potentially deleterious effects. The spatial comparison of fault "zones of influence" with areas of roof failure using Spearman's rank correlation coefficient shows that, while normal dip slip faults do not appear to be associated with roof failure, oblique slip and strike slip faults appear to be associated with roof classed as severely failed. The "zone of influence" of an oblique slip fault may extend up to 3 m on each side of it in the headings and up to 1.14 m in the cut-throughs. The fault "zone of influence" has geomechanical implications for the design of mine openings and possibly represents the maximum length of a cantilevered roof beam likely to fail during mining, owing to a fault. Roof conditions could possibly be predicted in blocks of virgin coal if the type of fault could be identified in oriented drill cores.

Jan 9, 1978

A C-CORE study on behalf of the government of Newfoundland identified the inner continental shelf off northeast Newfoundland as having a relatively higher potential for hosting placer gold than other parts of the inner shelf. Under the auspices of the Canada-Newfoundland Cooperation Agreement on Mineral Development, the Geological Survey of Canada conducted a three-year project to map the distribution of surficial sediments and the abundance of placer minerals (particularly gold) from White Bay to Cape Freels. Much of the study area is a fjord coast, with steep rocky slopes and scattered gravel beaches. The extreme east, from Hamilton Sound to Cape Freels, has a wide, shallow inner shelf, sandy beaches, and extensive coastal dunes. Relative sea level was high in the late glacial period. It has fallen continuously in the west, but in the east it dropped to -19 m, before rising to within several metres of the present level by 3 ka. In terms of surficial sediments and processes, five zones are identified: (1) Deep offshore deep basins that contain thick postglacial mud overlying glacialmarine gravelly sandy mud. This zone is below a depth of 370 m in White Bay, 300 m in the Notre Dame Basin. 2) Basin transition zone in which the sea bed has been eroded by currents, so that glacialmarine sediments are exposed in places. Winnowing has formed an uppermost layer of muddy gravel. There is a slight potential for enhanced levels of fine particulate gold, but the gold would not be exploitable. (3) Iceberg impacted zone Above 200 m the keels of icebergs impact the sea bed, causing furrowing and pitting. Furrows predominate in deeper areas, and pits are concentrated at the inner boundary of this zone. Iceberg turbates have developed in shallow waters (60-100 m). Combined with winnowing, iceberg turbation could enhance the potential for concentration of fine particulate gold, but not into economic quantities. 4) Wave dominated zone Above approximately 60 m the sea-bed sediments are highly mobile due to waves, currents, and iceberg impact. Sand is either rippled or organised into sand waves. Gravel is either poorly sorted, and organised into

Jan 1, 1995

By N. I. Fisher, J. Shepherd

Statistical studies have been carried out on structural geological data collected across a large zone of roof failure 600 m (1968 ft) wide and at least 800 m (2642 ft) long in the Greta coal seam at Aberdare East Colliery. Two swarms of hundreds of minor, normal faults with throws commonly between 3 and 300 mm in the room and pillar workings are broadly coincident with roof failure. The faults have been classified into dip slip and oblique and strike slip types. Roof conditions have been classified into good; troublesome with subclasses scaly, heavy, gutter falls and wide, flat-roofed falls; and severely failed with subclasses very heavy roof, gutter falls and dome falls. Troublesome conditions are defined as those in which the height of the fall is less than or equal to 0.3 m, and severely failed conditions as those in which the fall height is greater than 0.3 m. Comparison of faults, roof condition and mining rate on a shift basis indicates that faults and roof failure are much more important than machine breakdowns in reducing mining rate. The effect of faults on roof conditions has been quantified using a concept called the "zone of influence," a rectangular area around a fault in which the fault has potentially deleterious effects. The spatial comparison of fault "zones of influence" with areas of roof failure wing Spearman's rank correlation coefficient shows that, while normal dip slip faults do not appear to be associated with roof failure, oblique slip and strike slip faults appear to be associated with roof classed as severely failed. The "zone of influence" of an oblique slip fault may extend up to 3 m on each side of it in the headings and up to 1.14 m in the cut-throughs. The fault "zone of influence" has geomechanical implications for the design of mine openings and Possibly represents the maximum length of a cantilevered roof beam likely to fail during mining, owing to a fault. Roof conditions could Possibly be predicted in blocks of &gin coal if the type of fault could be identified in oriented drill cores.

Jan 1, 1979

By H Hoogvliet

The Goondicum Crater industrial minerals deposit is located about 30 km east of Monto, Central Queensland, Australia. Early exploration programs in the 1990s found alluvial ilmenite along the banks of the Burnett River. This mineralisation was traced upstream to the Goondicum Crater. The Goondicum Crater is a topographic feature centred on a roughly circular 6 km diameter layered gabbro complex. Significant ilmenite, apatite, titano-magnetite and feldspar mineralisation are present in a weathered horizon up to 25 m thick. After several drilling campaigns in the Crater and subsequent feasibility studies, the project was developed by Monto Minerals Ltd, an ASX listed company, in 2007. However, the project never achieved production performance expectations and ran out of commissioning funds. The company subsequently went into voluntary administration in August 2008.In 2009, the RMM Capital group, of Brisbane, took control of Monto Resources Pty Ltd, and renamed the company Belridge Enterprises Pty Ltd (Belridge). Belridge commissioned a redevelopment study aimed at recommencing mining and processing operations. As part of the redevelopment study the authors planned a drilling campaign, managed a quality control program and developed a block model. This paper describes the drilling program, analytical procedures, quality control procedures and the preparation of the block model.The block model for the resource estimate was created using 1 m high blocks, wireframes defining the main material types, and 2.5 m thick horizontal search ellipsoids with a radial pattern. The deposit was ‘flattened’ prior to modelling. To assist with the economic evaluation of the project, each block in the model was assigned a net dollar value based on economic parameters provided by Belridge, including anticipated revenues and costs. This modelling technique allowed for efficient investigation of various scenarios and was used extensively in the development and optimisation of the project’s financial model. At a zero net value per block, comparable to a break-even cut-off grade of four per cent ilmenite equivalent, the Indicated plus Measured resource is estimated at 51 Mt, averaging 4.1 per cent ilmenite, 1.9 per cent apatite and 2.5 per cent titano-magnetite.

Oct 5, 2011

By A. V. Nguye, P. A. Harvey

Previous studies have reported that inorganic electrolytes can enhance floatability of coal. The research has shown that the enhancement, if any, is highly dependent on changes in solution pH, type of electrolyte, and electrolyte concentration. The reasons for this are still not clear. In this study the floatability of coal particles in mono and divalent salt solutions was investigated. The zeta potential and hydrophobicity of the coal was measured experimentally, and a modified Hallimond tube was used to determine the floatability of coal particles by single bubbles, where the collision efficiency was equal to unity. The experimental information was used in conjunction with the Hogg-Healy-Fuerstenau equation to quantify the electrical double layer interaction. It was found that for low electrolyte concentration (less than 0.1 M) solutions the flotation recovery of coal particles was less than that for distilled water, and decreased with increase in concentration. Conversely, at electrolyte concentrations above 0.1 M, flotation recovery increased with increasing concentration. Both of these results are consistent with previous observations, but are inconsistent with expectations when considering the possible influence of electrical double layer interaction. A possible mechanism, based on the existence of the pre-existing submicron-sized gas bubbles, known as bubstons (i.e. bubbles stabilized by ions), present in water in close proximity to the hydrophobic coal surfaces is discussed in line with the early observation of flotation improvements by microbubbles “nucleating” on hydrophobic surfaces. In particular, the dependence of the bubble-particle attachment efficiency on electrolyte concentrations supports hypothesis on the salt-dependent and ion-specific existence of bubstons. However, a theoretical explanation of the transition salt concentration (at about 0.1M) is deficient at present. The existence of these submicrobubbles in close proximity to hydrophobic surfaces is not trivial. They can (as can individual gas molecules or other solutes) mediate and extend the range and magnitude of the attraction between hydrophobic macroscopic surfaces. These bubbstons may explain the curious phenomena of the socalled long-ranged hydrophobic attraction measured with the Surface Force Apparatus and Atomic Force Microscopy, and the slippage at hydrophobic surfaces. Finally, the coalescence of bubbstons affects the rupture of liquid films at a very large thickness (over 100 nm), observed, but unexpected, by flotation chemists.

Jan 1, 2003