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By Golding D

The Charters Towers goldfield is located in the centre of a Lower to Mid-Palaeozoic igneous complex where schistose, amphibolite-grade metamorphic rocks were intruded by multiple phases of medium grained granodioritic rocks. Several generations of mafic and felsic dykes also occur. Two distinct mylonites cut all but the youngest granitoids. Gold mineralisation occurs in quartz veins located in brittley reactivated mylonite and in sympathetic fissures in the undeformed granitoids. The gold-quartz veins occur in complex, gouge-filled, 2.5m thick zones, with minor sulfides, surrounded by zoned phyllic and propylitic alteration assemblages. Four main vein systems are each restricted to separate granitoids or contain oreshoots near granitoid contacts. No genetic relationship between the granitoids and the vein systems can be documented. The early mylonitic fabrics and the granitoid contacts played an important role in ground preparation and in the localization of oreshoots. Non mylonitized granitoids also served as favourable hosts for many of the lodes. Whole rock values of 180 of the granitoids range between 6.5 and 7.9 per mil. Hydrothermal vein quartzes have 180 values between 12.2 and 15.7 per mil. Mylonite quartzes have values of 8.4 per mil. Variation in 180 values of quartzes is in part related to granitoid host rock type.

Jan 1, 1987

By F. R. Ploeger, J. H. Crocket

"IntroductionRocks in the Kirkland Lake district form part of the Timiskaming Group, a south-facing homoclinal sequence of wackes, conglomerate, trachytic flows and pyroclastic rocks and syenitic intrusive rocks. Hewitt (1963) indicates that the thickest section, about 5 km, of the Timiskaming Group rocks is attained in Lebel Township. Several writers (Thomson, 1948; Hewitt, 1963; Hyde, 1978; Jensen, 1978; and Downes, 1979) have observed that the Timiskaming Group unconformably overlies the Keewatin volcanics, particularly along the northern contact. Recent work by Downes (1979) in McGarry and McVittie townships to the east of Kirkland Lake has shown that much of what had formerly been classified as Timiskaming actually belongs to an older group of rocks, the Larder Lake Group (Jensen 1978).General GeologyA series of fluviatile, braided-stream sedimentary rocks (Hyde, 1978) form the oldest of the three major rock suites at Kirkland Lake. Conglomerates constitute a large proportion of these sedimentary rocks and typically contain a large percentage of a variety of locally derived alkalic rock clasts as well as the distinctive red jasper iron-formation pebbles (Fig. 1a). The associated wacke units can be massive to finely bedded and are interbedded with the conglomerate. They also contain a large alkalic tuffaceous component.Interbedded with these sedimentary rocks are alkalic extrusive rocks, including tuffs, agglomerates, breccias and flows, which represent episodes of fissure and explosive crater eruption (Cooke and Moorhouse, 1969). The tuffs, although dominantly alkalic in composition, are commonly reworked and contain sedimentary features such as graded bedding, scouring and crossbedding (Fig. 1 b). The trachytic flows are massive to porphyritic and outcrop mainly east of Kirkland Lake in the adjoining townships. Altered leucitic porphyritic flows, locally referred to as red and green spotted trachytes, commonly occur."

Jan 1, 1982

By Badal R

Rock Discontinuities ("joints") affect blasting results. An investigation was carried out to understand if blast parameter such as spacing needs to be altered with the change in joint direction. Small scale laboratory studies in jointed limestone blocks have been carried out. It is shown that optimum spacing is variable with the "joint" orientations. Evidence is presented from field studies in four limestone quarries supporting laboratory studies. Reasons for success and failure of widespacing technique is also provided. Only with suitable orientations of "joints: widespacing is successful.

Jan 1, 1990

By Jan M. Mutmansky, Christopher J. Rise

"One of the most serious long term health problems associated with underground,mining is Coal Workers Pneumoconiosis (CWI'), more commonly known as Black Lung Disease. It occurs in some coal workers, normally after 15 or more years of exposure to coal mine dust, and leads to a variety of respiratory problems. Two types of pneumoconiosis are recognized simple CWP, which has been estimated to affect 6.9 percent of miners and is a condition that does not impair the miner's ability to work nor reduce life expectancy; and a more severe form of black lung (called progressive massive fibrosis) that occurs in about one percent of the cases and results in severe lung damage.Although the relationship between coal dust and CWP has long been recognized, detailed knowledge of the relationship is insufficient for setting up authoritative guidelines to reduce the health risks for those employed in dusty,underground environments. CWP is not only a health problem for workers that causes considerable distress, it is also a very expensive problem the total annual costs associated with CWP approach two billion dollars.As part of its efforts to combat CWP, the U.S. Bureau of Mines in 1983 established a Generic Mineral Technology Center to carry out basic research into all aspects of respirable coal dust:— control of dust generation — the behavior of dust in the mine — characterization of dust particles interaction of dust and lung— the relationships among dust generation and mobility and the mine environment, geology, and seam characteristics,Penn State, West Virginia University, the University of Minnesota, and the Massachusetts Institute of Technology are involved in this research, which is administered from the Department of Mineral Engineering at Penn State.Our work is one of the seven projects to be conducted at Penn Slate. We are concerned particularly with the characterization of dust and its relationships with the mine environment, and our main goal is to establish standard procedures for describing and measuring these variables.Coal DustCoal dust is a very complex material that varies greatly in chemical and mineralogical properties. Moreover, it is not the only constituent of respirable dust in the mine. When a coal seam is mined, it is inevitable that rock particles other than coal are included in the material. This rock comes from the mine roof, the floor, and the partings and inclusions within the coal scams. Since the roof and floor strata, the partings and inclusions are often stronger than the coal, mining them frequently causes more dust than mining the coal itself. One of the objectives of our research is to find the relationships between a specific coal's characteristics before it is mined and the respirable dust characteristics after it is mined. We are particularly interested in the size distribution of particles, the chemical properties, and the mineralogical properties."

Jun 1, 1988

"It is evident that the incidence of coal worker's pneumoconiosis (CWP) or black lung disease varies in different coal producing regions of the United States. Many people have hypothesized about the reasons for the differing occurrences. Because underground coal mining involves many mining methods under changing geological conditions, several factors may be involved in contracting CWP such as: the amount of quartz in the respirable dust, the trace elements in the respirable dust, the rank of the coal that produced the respirable dust (bituminous, anthracite), the amount and size of respirable dust, etc.Recognizing the uniqueness of underground coal mining and CWP, research investigations involving seam characteristics, mining system and worker position are being conducted in the center to establish standard procedures for characterizing some coal properties that may be involved in workers contracting CWP. This has been accomplished by the in-mine sampling of airborne dust at various worker locations and mining system configuration and by performing laboratory analyses of mined material (coal and rock) taken from the mines. (FIGURE 49 and 50)The investigations includes a method of classifying coal seams according to their potential to generate respirable dust. It includes statistical analyses of the size and locational variations of the elemental compositions of respirable coal mine dust in operating underground mines from seams located in the eastern, midwestern, and western United States, and is currently completing research which is investigating the relationship between the elemental compositions of respirable dust sampled near a continuous-mining machine and a laboratory-produced respirable dust."

Nov 1, 1988

Low-grade, porphyry copper type mineralization at the Moonmera prospect is related to the intrusion of a granodiorite porphyry mass into the Upper Permian "Gracemere granodiorite". Significant copper mineraliza- tion appears to be associated with the alteration assemblage quartz-sericite- kaolinite. The ore shell is surrounded by a zone where montmorillonite and kaolinite are in greater abundance and this assemblage is over- lapped, mainly at depth, by potassium feldspar alteration. Secondary biotite is abundant throughout the mineralized zone. Preliminary sulphur isotope results on the sulphide mineralization are compatible with a magmatic origin for the sulphur.

Jan 1, 1974

"11.1. IntroductionThe recovery of platinum-group elements (POE) from ores is a subject which has received almost no mention in the literature. Edwards (1975) refers to the process used for refining of the POE, throughout the Western World, as a so-called ""conventional"" process .... ""not because of the simplicity or convenience of the operations, but more probably because of the inertia of established processes and the aura of secrecy with which the major platinum refiners have surrounded this process."" There is no doubt in this writer's mind that the latter is also applicable to the dearth of knowledge of the mineralogy, geochemistry and ore deposits of PGE and that the poor recoveries, mainly attributed to the mineral beneficiation stages of concentration, are also affected by this traditional secrecy. Fortunately, this attitude is changing, due no doubt to the advantages that accrue from more open research which may be critically assessed in the literature in the traditional manner. Examples of this more open approach to recoveries and recovery problems are represented by Newman (1973), who gave some typical recovery percentages for Merensky Reef ores, and the recent encouragement and cooperation on mill samples from the Sudbury area by lnco Metals Company (cf. Cabri, 1981a).In general, platinum-group elements are recovered from an ore by the use of a physical concentration method, such as gravity separation or flotation, followed by further upgrading using further physical, wet chemical or pyrometallurgical techniques. The final process of refining in which the individual platinum-group elements are produced in pure form is outside the scope of this chapter.Platinum-group element deposits naturally fall into different categories according to the recovery process best suited for them, viz. those amenable to gravity separation, those amenable to flotation, and those where platinum-group elements are by-products of base metal sulphide, chromite and miscellaneous other deposits."

Jan 1, 1979

THE discussion of this topic at the Open-hearth Conference at Detroit on Nov. 3, 1927, was opened by statements of the general principles involved, made by manufacturers of molds. Because of their general interest they are printed below. WILLIAM HAIL RAMAGE,* Hubbard, Ohio.-I did not come prepared to read a paper, thinking. the most I would be called upon to do would be to make a few, remarks by way of discussion. A number of our friends have pre-viously asked questions. similar to this which really does not permit a direct "yes" or "no" answer. If I may he pardoned for so doing, I believe it advisable to discuss rather what we consider the principal factors which in-fluence mold life. I think possibly a little undue weight has been given to the subject of the analysis of the metal. For the last eight years we have spent a lot of time, effort, and money investigating this very problem from a chemical, physical and microscopic standpoint. We have had the benefit of complete records and history of over 100,000 molds in service at a variety of plants and over long periods of time. Obviously, I cannot be so specific that I should divulge information that is really a trade secret. In our opinion the principal factors influencing mold life are: (1) design of the mold; (2) process of manu-facture, including workmanship; (3) care in the steel plant or what might be termed "the use or abuse" in the steel plant; (4) the analysis of the iron and the physical con-dition of it. Under normal conditions these factors are of importance in the order named, although in specific cases they might be rearranged in any order you choose. For instance, the best mold made can be destroyed in one or two pours by subjecting it to certain conditions which are occasion-ally met in steel plant practice. Obviously, in that case, nothing else matters but that one item. On the other hand, I have seen molds made of such a terrible design that it was a foregone conclusion it would have to be broken after the second pour of the ingot to get it out. In that case, nothing but design mattered. As to the effect of process of manufacture, let me cite a case. Some years ago there were two batches of molds sent to a certain company. They were the same sized molds, used under the same conditions and in the same kind of service. There were, 20 molds in each batch. The second batch sent gave ten times the life of the first batch. It is true that the design was changed a little, but not very much, and it was not. a bad mold to begin with. It is possible that the iron may have been better in the second consignment but not very much. In my opinion, it is con-servative to say that of the 900 per cent improvement in life, 5 per cent was probably due to better iron, 25 per cent to better design and the remaining 870 per cent to process of manufacture and workmanship.

Jan 2, 1928

By T. M. Williams, P. M. Green

Paper presented at Mineralisation in the Caledonides, the Mike Gallagher memorial meeting held in Edinburgh, 27-28 June 1996. The sediment geochemistry of streams draining Southern Uplands and Lake District turbidites was compared with lithogeochemical data for the source greywackes, using stratigraphically defined catchments. Several systematic trends in element abundance variation between source and stream sediment can probably be applied more widely to interpretation of drainage geochemistry. Pb and Zr increase markedly from source rock to sediment, by adsorption on clay and zircon grain concentration. Variation of feldspar-related elements Rb, Sr, K and Ba appears to be controlled by source grain size and compositional maturity. Ni shows surprisingly little change and Fe and Co are only slightly raised. Cr is particularly useful, with variations superimposed in anomalously high regional levels. Abrupt changes in Cr distribution in stream sediment coincide with stratigraphical boundaries, allowing drainage data to be used as a surrogate for whole-rock values

Jun 19, 1905

By Ronald A. Crowson

Detailed stratigraphic studies of the overburden at North Carolina Phosphate Corporation new South Creek Mine have delineated several aquifers and acquicludes within the 30-meter-thick overburden section of late Pleistocene sands and clayey sands. A major aquifer occurs in the 10-meter-thick sequence of shelly sands of the early Pleistocene Croatan Formation. The water-charged Croatan sands thicken into a paleodrainage surface on top of the Pliocene Yorktown Formation, a major aquiclude. A three-phase dewatering program is projected: 1) improve surface drainage around mine perimeter to reduce both flowage into the pit and rainfall recharge; 2) use a wellpoint system to dewater the upper 8 meters; and 3) use recharge wells along the axis of the paleo- drainage to dewater the overburden below 8 meters.

Jan 1, 1983

By Frank Ebbutt

Introduction The property of the Britannia Mining and Smelting Company, Limited, is situated on the east side of Howe sound, about six miles from its head. It is roughly thirty miles by water from Vancouver, one of the important ports of the Pacific and the industrial and financial centre of British Columbia. Howe sound is navigable for ocean-going vessels and Britannia Beach is a daily port of call for the commodious boats of the Union Steam-ship Company, sailing from Vancouver. Few mines are so ideally situated or have so many or varied natural advantages. Copper was first found on Britannia mountain in 1888, by Forbes, but it was not until 1898 that five claims were staked here by Oliver Furry, a trapper. It is from these claims that the major production during the past thirty years has come. In 1900 the Britannia Copper Syndicate was formed and development of the property was commenced. In 1903 the late Grant B. Schley obtained control, and through his efforts the Britannia Mining and Smelting Company was organized in 1908 as a subsidiary of the Howe Sound Company. Since that time, a persistent and progressive policy has been followed, which has resulted in a prolonged and profitable operation. The country in the immediate vicinity of the mine is marked by strong relief, with mountains rising abruptly from tide-water to elevations of 5,000 feet and more. Two broad transverse valleys deeply dissect the area. These are the valleys of Britannia creek and Furry creek. The region has under-gone prolonged and relatively recent glaciation. Over much of the surface there is deep overburden and dense vegetation. The geology of the mine and vicinity has been described in reports by S. J. Schofield (1), H. T. James (2), J. G. Barry, and others (3). The present writer is in accord with much of this literature on Britannia, but during recent years, extended observations made underground have shown that the 'quartz porphyry', or 'mine porphyry', of several of the earlier writers is not the host rock to the commercial mineralization; and he contends that the mineralization occurs in highly altered phases of a complex series of ruffs, flows, and pyroclastics and their autoclastic metamorphosed products.

Jan 1, 1935

By Victor F. Hollister

North American ophiolite complexes are known to contain significant volcanogenic sulfide only in the following five areas: Newfoundland; Quebec; Applegate, Oregon; Rogue, Oregon; and Orca, Alaska. Most North American ophiolites, including the Baltimore, Kings-Sierra Nevada, and Del Puerto complexes, and those associated with the Franciscan, Trinity, eastern Oregon, and Cache Creek groups lack significant volcanogenic sulfide. The characteristics of sulfide-bearing ophiolites are: (1) manganozls cherts, and (2) fine, carbonaceous clastics inter- calated with pillow basalt and chert. It is suggested that sulfide- bearing ophiolite complexes developed in a restricted basin environment, such as is now present in the Gulf of California; whereas sulfide-poor ophiolites, formed in midocean, rises distant from land masses. Sea floor oxidation makes the typical midocean ridge configuration not conducive to sulfde preservation, whereas spreading centers bounded by land masses are more likely to produce anoxic physiographic lows favorable to sulfide accumulation.

Jan 1, 1982

By R. V. Ramani, R. Srikanth, R. Zhao

"A two-pan study was conducted to understand the factors affecting respirable dust generation potential or dustiness of coal seams. In the first part, the data from three prior comprehensive laboratory studies was analyzed to establish quantitative relationships between respirable dust generation potential and coal characteristics. This analysis indicates that respirable dust generation rate is positively correlated with Hardgrove Grindability Index (HGI), fuel ratio (fixed carbon/volatile matter), Vitrinite Reflectance (VR), and Level of Organic Metamorphism (LOM). In the second part, specially-designed single breakage experiments were conducted to determine the primary dust generation potential of 17 coal samples obtained from four continuous miner sections, three longwall sections, and the Penn State Coal Data Bank. The single breakage study indicates that primary dust generation rate is positively correlated with fixed carbon content, fuel ratio (fixed carbon/volatile matter), VR, and LOM. Since VR and LOM are strongly influenced by the process of coalification, differences in respirable dust generation rates in different coal seams may be explained by the thermal metamorphism of sedimentary organic matter during subsurface burial.Mineral particles in the range of one to five microns, if inhaled in sufficient amounts, lead to a number of lung diseases generally referred to as pneumoconiosis. A priori knowledge of the mechanisms and rates of fine particle generation during mining can aid in the development of more effective technology for controlling primary dust generation. Unfortunately, the data and knowledge currently available are not adequate for this purpose. In fact, a committee of the National Academy of Sciences on the measurement and control of dust concluded that the knowledge of the fundamental mechanisms by which coal mine dust is generated and a part of it is entrained in the mine atmosphere as respirable dust is not sufficient to clarify, let alone control, the processes involved (Anon., 1980). Under a research contract from the U.S. Bureau of Mines, Stecklein et al. (1982) have identified a number of fundamental research issues for understanding the coal fragmentation and entrainment processes.Reduction of dust generation is the best means of control since fine particles are difficult to control once they become airborne. Therefore, considerable research efforts have been directed to understand the factors influencing dust generation and entrainment, including machine design, water sprays, and ventilation. Laboratory studies have been conducted on the mechanical action of bits and machine power requirements (Evans and Pomeroy, 1966; Roepke, 1984). Since the physical characteristics of coal play an important role in the process of breakage, a number of laboratory studies have been conducted to study the relationship between coal characteristics and respirable dust generation (Baafi, 1977; Moore, 1986; Polat, 1990; Thakur, 1971). Several studies have been conducted on the relationships between coal characteristics and airborne dust concentrations (Hamilton and Knight, 1958; Khair and Xu, 1991; Organiscak and Page, 1993; Page et al., 1993). A limited number of studies have also been conducted on the relationships between coal characteristics and airborne dust concentrations in mines (Organiscak et al., 1990). Yet, no reliable method has been developed to rank coal seams according to their respirable dust generation potential. The conclusions derived from previous studies can be summarized as follows:"

Dec 1, 1996

By R. V. Ramani, R. Srikanth, R. Zhao

A two-part study was conducted to understand the factors affecting respirable dust generation potential or dustiness of coal seams. In the first part, the data from three prior comprehensive laboratory studies was analyzed to establish quantitative relationships between respirable dust generation potential and coal characteristics. This analysis indicates that respirable dust generation rate is positively correlated with Hardgrove Grindability Index (HGI), fuel ratio (fixed carbodvolatile matter), Vitrinke Reflectance (VR), and Level of Organic Metamorphism (LOM). In the second part, specially-designed single breakage experiments were conducted to determine the primary dust generation potential of 17 coal samples obtained from four continuous miner sections, three longwall sections, and the Penn State Coal Data Bank. The single breakage study indicates that primary dust generation rate is positively correlated with fixed carbon content, fuel ratio (fixed carbon/volatile matter), VR, and LOM. Since VR and LOM are strongly influenced by the process of coalification, differences in respirable dust generation rates in different coal seams may be explained by the thermal metamorphism of sedimentary organic matter during subsurface burial.

Jan 1, 1995

By R. V. Ramani, R. Srikanth

A three-part study was conducted to relate the dust generation propensity of a coal sample, defined here as the dust generation rate (grams of dust generated per tonne of coal broken), to its characteristics, in order to rank coal seams according to their respirable dust generation potential. In this paper, the results of a single breakage study on a variety of coal samples encompassing all coal ranks, and samples from operating mines are discussed. Further, where data are available, the primary dust generation rates of coal samples collected from underground coal mines are compared with the in-mine dust generation rates. The results of this analysis are then used to apply the results of this study to longwall face ventilation design. Vitrinite reflectance, and level of organic metamorphism are highly correlated with primary respirable dust generation rates of bituminous coal samples. The dust generation rates in underground coal mines are an order of magnitude higher than the primary dust generation rates in the laboratory. Depending on the type of coal, production rates, and dust control procedures, the air quantity required for airborne dust control can vary significantly. The air quantities on some high production longwalls are approaching the limits beyond which it may not be possible to reduce ambient ARD concentrations to less than 2 mg/m3 by dilution ventilation alone. In these cases, the miner's exposure should be controlled through the use of personal protective de- vices and administrative practices.

Jan 1, 1997

An extensive laboratory grinding study was carried out on a magnetite ore in order to assess the grinding behaviour of magnetic concentrate and tail from low intensity magnetic separation (LIMS).The test work involved Bond ball mill testing, rod milling, low intensity magnetic separation (LIMS), and batch ball milling down to product sizes of around P80~25 microns. A total of 18 Bond tests and over 150 batch grinding tests and sieve sizing were carried out. Throughout the grinding tests, power draw was continuously monitored. The relationship between the grinding energy and product size was analysed using the conventional energy-size concepts. It was found that the Rittinger equation fits the experimental data well. However, Bond?s equation does not fit the experimental data well, and therefore a modified Bond equation was developed. Differences in grinding properties between the magnetic and non-magnetic component were analysed and compared to the bulk ore. It was found that grinding properties differ significantly and therefore separate grinding test work may be required for each grinding step in the magnetite ore beneficiation flowsheet. Keywords: grinding, iron ores, particle size, modelling.

Jan 1, 2010

By Thomas J. Mason, Geno Saccomanno, Victor E. Archer, Philip C. Prorok

INTRODUCTION A population of several thousand uranium miners in the Colorado Plateau region of the United States has been under surveillance since 1957 using sputum cytology and other procedures. Attempts were made to collect sputum samples annually for those miners showing normal sputum or only minor abnormalities, and on a semi-annual schedule for miners having more severe cytological abnormalities. For individuals having carcinoma in situ or malignant cells in their sputum, samples were taken more frequently. As in any human population, however, these schedules were not always adhered to, and samples were often acquired less often than scheduled. On the basis of the thousands of sputum readings that have resulted from this surveillance, one can calculate the durations or sojourn times which individuals spend in the various cytologic states into which the sputum readings are classified. This paper presents some preliminary, descriptive results concerning relationships among the cytologic state duration distributions in this population, and their associations with other variables such as radiation exposure and cigarette smoking. There are several reasons for studying cytology results in this observational setting. Of considerable interest is the opportunity to gain insight into the preclinical natural history of lung cancer. Such information would be valuable in the future design and interpretation of screening programs for the early detection and treatment of lung cancer, should this activity prove to be of benefit in experimental trials. Secondly, it is of interest to determine if some characteristic of sputum cytology readings can be utilized to determine a decision point at which to transfer a uranium miner to another job category within the industry in order to effectively reduce his probability of developing lung cancer. For example, a reading of moderately atypical cells in the sputum has been suggested as a possible decision event which would be sufficient to warrant such a transfer. In the analysis which follows, an attempt will be made to develop information relevant to these issues. The data base for our analysis, largely developed over a period of more than 20 years by Drs. Geno Saccomanno and Victor Archer, contains sputum readings classified into one of eight cytologic states: normal, metaplasia, mild atypia, moderate atypia, marked atypia, suggestive, suggestive-equivocal, and malignant. The two suggestive states will not be considered as these categories seldom contain enough observations to generate meaningful results. The duration in a given cytologic state for a given individual is calculated as the sum of the intervals between consecutive sputum readings in that state. When two consecutive readings are in two different states, half the between-readings interval is assigned to each of the two states. Among all individuals in the data base, only those having at least two sputum readings are used so that a duration can be calculated. Furthermore, the analysis is limited to individuals whose successive readings are no more than 24 months apart, so as to focus on a population which was under surveillance on a reasonably regular basis. RESULTS The overall distributions for the cytologic states are displayed as histograms in Figures 1-3.

Jan 1, 1981

By Spencer GA, Saul SJ

The flight line spacing in low level aeromagnetic surveys is the principal factor governing both the cost and the amount of geological detail which can be extracted from the data. The rate at which geological resolution diminishes with wider line spacing is illustrated by progressive subsampling of a 200 m spaced data set from the Charters Towers region in Queensland.The usefulness of high frequency type filters in enhancing shallow structural features is seen to be limited to the 200 m data.It is concluded that each data set is suited to a particular scale and style of geological investigation with only the 200 m data having sufficient detail to identify the subtle structural patterns which are crucial to mineral exploration.

Jan 1, 1976

By D. F. Sangster, P. J. Hood, G. A. Gross

"Some results are presented of an integrated geological and geophysical study of Precambrian magnetite-quartz iron-formation in the Kapiko Iron Range north of Nakina, Ontario. Detailed geological and topographical mapping was carried out in conjunction with detailed geophysical investigations such as vertical magnetic field, vertical magnetic gradient, hammer seismic, horizontal-loop electromagnetic and magnetic susceptibility surveys. In addition, oriented drill cores were obtained for magnetic polarization studies.Vertical-force magnetic anomalies within individual rock units showed a strong positive correlation with topographic relief. Moreover, magnetic intensity was found not to be quantitatively proportional to the magnetite content in the rocks, due to the presence of high remanent magnetization of the magnetite. Also, the remanent polarization direction was sub parallel to the plunge of the fold structure and mineral lineation in associated rocks.Vertical magnetic gradient measurements were found to be more accurate in locating buried contacts between magnetite-quartz iron-formation and country rock than the vertical magnetic force data.An in-situ magnetic susceptibility meter was used to measure the magnetite content of iron-formation, and the measurements were subsequently compared with vertical-force magnetic results.The results of the EM survey were inconclusive; some magnetite-rich zones produced anomalies in the out-of-phase component. whereas others did not. The reasons for such inconsistencies are not yet apparent.Longitudinal seismic wave velocities measured parallel to the bedding in magnetite-quartz iron-formation ranged from 10,600 ft/sec. to 14,500 ft/sec. The seismic velocity appears to increase with an increase in deformation of the rocks."

Jan 1, 1966

By C J. Adams, H J. Campbell, A J. Tulloch, I J. Graham

New Zealand can be regarded as a rifted part of mineral-prospective eastern Australia. Geologically credible comparisons between selected trans-Tasman and SW Pacific geological provinces and units, especially those that contain significant mineralisation in Australia, can help provide a useful exploration framework for New Zealand. As part of a six-year Mineral Wealth of NZ and its EEZ (MWE) research programme, we have targeted selected geological units in eastern Australia for comparison and contrast with their potential New Zealand counterparts. In future years, the programme will focus on geological units in New Caledonia.

Jan 1, 2005