scholarly journals Radio tomography and borehole radar delineation of the McConnell nickel sulfide deposit, Sudbury, Ontario, Canada

Geophysics ◽  
2000 ◽  
Vol 65 (6) ◽  
pp. 1920-1930 ◽  
Author(s):  
Peter K. Fullagar ◽  
Dean W. Livelybrooks ◽  
Ping Zhang ◽  
Andrew J. Calvert ◽  
Yiren Wu
Keyword(s):  
Host Rock ◽  
High Frequency ◽  
Hanging Wall ◽  
Massive Sulfide ◽  
Sulfide Deposit ◽  
Radio Tomography ◽  
Single Hole ◽  
Dipole System ◽  
Rock Heterogeneity ◽  
Borehole Radar

In an effort to reduce costs and increase revenues at mines, there is a strong incentive to develop high‐resolution techniques both for near‐mine exploration and for delineation of known orebodies. To investigate the potential of high‐frequency EM techniques for exploration and delineation of massive sulfide orebodies, radio frequency electromagnetic (RFEM) and ground‐penetrating radar (GPR) surveys were conducted in boreholes through the McConnell massive nickel‐copper sulfide body near Sudbury, Ontario, from 1993–1996. Crosshole RFEM data were acquired with a JW-4 electric dipole system between two boreholes on section 2720W. Ten frequencies between 0.5 and 5.0 MHz were recorded. Radio signals propagated through the Sudbury Breccia over ranges of at least 150 m at all frequencies. The resulting radio absorption tomogram clearly imaged the McConnell deposit over 110 m downdip. Signal was extinguished when either antenna entered the sulfide body. However, the expected radio shadow did not eventuate when transmitter and receiver were on opposite sides of the deposit. Two‐dimensional modeling suggested that diffraction around the edges of the sulfide body could not account for the observed field amplitudes. It was concluded at the time that the sulfide body is discontinuous; according to modeling, a gap as small as 5 m could have explained the observations. Subsequent investigations by INCO established that pick‐up in the metal‐cored downhole cables was actually responsible for the elevated signal levels. Both single‐hole reflection profiles and crosshole measurements were acquired using RAMAC borehole radar systems, operating at 60 MHz. Detection of radar reflections from the sulfide contact was problematic. One coherent reflection was observed from the hanging‐wall contact in single‐hole reflection mode. This reflection could be traced about 25 m uphole from the contact. In addition to unfavorable survey geometry, factors which may have suppressed reflections included host rock heterogeneity, disseminated sulfides, and contact irregularity. Velocity and absorption tomograms were generated in the Sudbury Breccia host rock from the crosshole radar. Radar velocity was variable, averaging 125 m/μs, while absorption was typically 0.8 dB/m at 60 MHz. Kirchhoff‐style 2-D migration of later arrivals in the crosshole radargrams defined reflective zones that roughly parallel the inferred edge of the sulfide body. The McConnell high‐frequency EM surveys established that radio tomography and simple radio shadowing are potentially valuable for near‐ and in‐mine exploration and orebody delineation in the Sudbury Breccia. The effectiveness of borehole radar in this particular environment is less certain.

Massive sulfide deposits of the Noranda area, Quebec. III. The Ansil mine

1991 ◽  
Vol 28 (11) ◽  
pp. 1699-1730 ◽  
Author(s):  
T. J. Barrett ◽  
W. H. MacLean ◽  
S. Cattalani ◽  
L. Hoy ◽  
G. Riverin
Keyword(s):  
Hanging Wall ◽  
Volcanic Rocks ◽  
Massive Sulfide ◽  
Hydrothermal Activity ◽  
Sulfide Deposit ◽  
Sulfide Deposits ◽  
Almost All ◽  
Host Rocks ◽  
Low K ◽  
General Range

The Ansil massive sulfide deposit occurs at the contact of the underlying Northwest Rhyolite and the overlying Rusty Ridge Andesite, in the lower part of the Central Mine sequence of the Blake River Group. The orebody, which is roughly ellipsoidal in outline and up to 200 m × 150 m across, contained reserves of 1.58 Mt of massive sulfide grading 7.2% Cu, 0.9% Zn, 1.6 g/t Au, and 26.5 g/t Ag. Production began in 1989. Least-altered host rocks are low-K basaltic andesites and low-K rhyolites. These rocks have Zr/Y ratios of ~5 and LaN/YbN ratios of ~2.3, typical of tholeiitic volcanic rocks, although their major-element chemistry is transitional between tholeiitic and calc-alkaline volcanic rocks.The Ansil deposit, which dips ~50° east, is a single orebody comprising two main massive sulfide lenses (up to ~35 m thick) connected laterally via a thinner blanket of massive sulfides, with thin discontinuous but conformable massive magnetite units at the base and top of the orebody. Sulfide ore consists of massive to banded pyrrhotite–chalcopyrite. In the downplunge lens, up to 10 m of massive magnetite are capped by up to 10 m of massive sulfide. Finely banded cherty tuff, with sphalerite–pyrite–chalcopyrite, forms a discontinuous fringe to the deposit.The two main lenses of massive sulfide have the highest contents of Cu, Ag, and Au and are thought to have formed in areas of major hydrothermal input. Altered feeder zones contain either chlorite + chalcopyrite + pyrrhotite ± magnetite, or chlorite + magnetite ± sulfides. Footwall mineralization forms semiconformable zones ~5–10 m thick that directly underlie the orebody and high-angle pipelike zones that extend at least 50 m into the footwall. Ti–Zr–Al plots indicate that almost all altered footwall rocks were derived from a homogeneous rhyolite precursor. Hanging-wall andesites were also altered. Despite some severe alteration, all initial volcanic rock compositions can be readily identified, and thus mass changes can be calculated. Silica has been both significantly added or removed from the footwall, whereas K has been added except in feeder pipes. Oxygen-isotope compositions up to at least 50 m into the hanging wall and footwall are typically depleted in δ18O by 2–6‰. These rocks have gained Fe + Mg and lost Si. Altered samples in general range from light-rare-earth-element (REE) depleted to light-REE enriched, although some samples exhibit little REE modification despite strong alkali depletion. Mineralized volcanic rocks immediately below the orebody are enriched in Eu (as are some Cu-rich sulfides in the orebody).Contact and petrographic relations generally suggest that the main zone of massive magnetite formed by replacement of cp–po-rich sulfides, although local relations are ambiguous. Magnetite formation may reflect waning hydrothermal activity, during which fluids mixed with seawater and became cooler and more oxidized. Cu-rich feeder pipes that cut magnetite-rich footwall indicate a renewal of Cu-sulfide mineralization after magnetite deposition. Chloritic zones with disseminated sulfides occur up to a few hundred metres above the orebody, attesting to continuing hydrothermal activity.

scholarly journals Mineralogical and geochemical features of pyrite nodules of sulfide turbidites from the Talgan Cu–Zn massive sulfide deposit (South Urals)

2019 ◽  
pp. 518-539
Author(s):  
N. R. Ayupova ◽  
V. V. Maslennikov ◽  
D. A. Artemyev ◽  
I. A. Blinov
Keyword(s):  
Trace Element ◽  
Host Rock ◽  
Inner Core ◽  
Outer Zone ◽  
Massive Sulfide ◽  
Intermediate Zone ◽  
Sulfide Deposit ◽  
South Urals ◽  
Massive Sulfide Deposit ◽  
The Core

Pyrite nodules were found in thin-layered sulfide ores localized at the flanks of the Talgan Cu‒Zn massive sulfide deposit (South Urals). The nodules consist of (1) an inner core of microgranular pyrite with inclusions of authigenic sulfides and host rock minerals, (2) an intermediate zone of anhedral and subhedral pyrite metacrystals, (3) an outer zone formed by parallel subhedral pyrite crystals and (4) dioctahedral chlorite rimming the pyrite crystals of zone 3. Each zone exhibits specific trace element association, which is identified using LA ICP-MS micromapping. The trace element content of pyrite significantly (by 13 orders of magnitude) decreases in a range of microgranular pyrite of the core an- and subhedral pyrite crystals of the intermediate zone subhedral pyrite crystals of the outer zone (average values, ppm): 131069 Zn, 241001783 Pb, 1323134 As, 10271.81 Co, 4564 Ni, 39038 Ag, 0.10.01 Au, 550.6 Te, 9.80.6 Bi. The subhedral pyrite crystals of the outer zone are enriched (ppm, up to) in Cu (8367), Sb (1627) and Mn (734) relative to microgranular pyrite of the core. The extremely high trace element contents are related to the inclusions of authigenic chalcopyrite, sphalerite, fahlore, gold and silver minerals. The host rock components of the nodules include quartz, calcite, chlorite, illite and REE minerals. The ore clasts of distal sulfide turbidites mixed with hyaloclastites, which were altered during dia- and anadiagenesis, were the source of ore material for the nodules.

Geology of the Izok Massive Sulfide Deposit, Nunavut Territory, Canada

2004 ◽  
Vol 13 (1-4) ◽  
pp. 25-36 ◽  
Author(s):  
IAN R. MORRISON
Keyword(s):  
Hanging Wall ◽  
Sedimentary Rocks ◽  
Massive Sulfide ◽  
Economic Feasibility ◽  
Open Pit ◽  
Open Pit Mining ◽  
Sulfide Deposit ◽  
Massive Sulfide Deposit ◽  
West Central ◽  
Nunavut Territory

Abstract The Izok Zn-Cu-Pb-Ag volcanogenic massive sulfide deposit is located 265 km south of Kugluktuk (Coppermine), Nunavut Territory, Canada, in the west-central Slave structural province. The Izok deposit is owned 100% by Inmet Mining Corporation and represents one of the largest undeveloped zinc-copper resources in North America. The Izok deposit is hosted within and near the top of a thick sequence of predominantly felsic pyroclastic rocks of late Archean age. The hanging-wall stratigraphy includes additional felsic volcaniclastic rocks, andesitic and basaltic flows, thin sulfide-rich iron formations, and turbiditic sedimentary rocks. The felsic volcanic rocks are intruded by intermediate dikes and sills, followed by gabbroic dikes and sills. Both intrusive suites are interpreted to be volcanic feeders to the overlying flows. All lithologies are subsequently cut by younger, irregular, granitic pegmatite and diabase dikes. The volcanic and sedimentary rocks are regionally metamorphosed to pyroxene hornfels grade. The massive sulfides occur within a large (kilometer-scale) Na-depleted sericitic alteration zone. The immediate footwall and hanging-wall rocks to the deposit are characterized by zones of muscovite-biotite-sillimanite, lesser chlorite-biotite-cordierite, and locally intense silicification and sodium metasomatism. All lithologies have been affected by younger Ca-metasomatism. As currently defined, the Izok deposit comprises a cluster of five complexly zoned composite lenses: the Northwest, North, Central West, Central East, and Inukshuk lenses. The first four lenses are amenable to open-pit mining, whereas the Inukshuk lens will require underground development. The total indicated mineral resource presently stands at 16.5 million tonnes with a grade of 2.2% Cu, 11.4% Zn, 1.1% Pb, and 60 g/t Ag. Inmet Mining Corporation is presently reviewing the economic feasibility of developing the property.

Petrochemistry, hydrothermal alteration, mineralogy, and sulfur isotope geochemistry of the Turgeon Cu–Zn volcanogenic massive sulfide deposit, northern New Brunswick, Canada

2015 ◽  
Vol 52 (4) ◽  
pp. 215-234 ◽  
Author(s):  
Erik Lalonde ◽  
Georges Beaudoin
Keyword(s):  
New Brunswick ◽  
Hydrothermal Alteration ◽  
Hanging Wall ◽  
Massive Sulfide ◽  
Sulfide Deposit ◽  
Trace Element Geochemistry ◽  
Volcanogenic Massive Sulfide ◽  
Element Geochemistry ◽  
Vms Deposits ◽  
Ocean Ridge

The Turgeon deposit is a mafic-type, Cu–Zn volcanogenic massive sulfide (VMS) deposit. It is hosted by Middle Ordovician pillow basalts of the Devereaux Formation of the Fournier Group within the Elmtree-Belledune inlier, near the Bathurst Mining Camp (BMC) in northern New Brunswick, Canada. The Turgeon deposit consists of two Cu–Zn massive sulfide lenses (“100m Zn”, “48-49”) composed of pyrite, chalcopyrite, pyrrhotite, and sphalerite, which are underlain by chalcopyrite–pyrite stockwork veins. Pyrite is overprinted and replaced by chalcopyrite in the stockwork and vent complex sulfide facies, where both minerals are enriched in Se and Co relative to pyrite and chalcopyrite in the massive pyrite and breccia sulfide facies. In, Se, and Co display a positive covariation with Cu, whereas Zn displays a positive covariation with Cd. Trace element geochemistry indicates that the host rocks are primarily tholeiitic basalts and andesites that have signatures between that of mid-ocean ridge basalt and island-arc tholeiite. The hanging wall rhyolite plots as an ocean ridge rhyolite and is geochemically similar to VMS-bearing FIIIa-type rhyolites. Hydrothermal alteration mineral assemblages in the footwall basalts proximal to mineralization are dominantly chlorite ± quartz in the stockwork zone, which is characterized by compositional gains in Fe and Mg and losses in Na and Ca. The chlorite-altered basalts and andesites have undergone up to 35% mass loss. Stockwork chlorite is an Fe-rich chamosite, whereas chlorite in the massive sulfides is a Mg-rich clinochlore. Chlorite geothermometry yields temperatures of 329–361 °C for chamosite and 246–286 °C for clinochlore. Sulfides at Turgeon have an average δ34SCDT of +6.9‰ (range: +5.8‰ to +10‰), indicating that sulfur was mostly derived from thermochemical reduction of Ordovician seawater sulfate. The Turgeon VMS deposit differs from those of the BMC, which is a reflection of their different tectonic settings; but it is similar to other mafic-type VMS deposits, such as the Betts Cove, Tilt Cove, and Rambler VMS deposits in Newfoundland, Canada.

Interpretation of borehole gravity data of the Lalor volcanogenic massive sulfide deposit, Snow Lake, Manitoba, Canada

2015 ◽  
Vol 3 (3) ◽  
pp. T145-T154 ◽  
Author(s):  
Ernst Schetselaar ◽  
Pejman Shamsipour
Keyword(s):  
Gravity Data ◽  
Hanging Wall ◽  
Bouguer Anomaly ◽  
Massive Sulfide ◽  
Geological Mapping ◽  
Sulfide Deposit ◽  
Massive Sulfide Deposit ◽  
Volcanogenic Massive Sulfide ◽  
Volcanogenic Massive Sulfide Deposit ◽  
Gamma Density

We have acquired borehole gravity data along five drillholes intersecting the Lalor volcanogenic massive sulfide deposit hosted in the eastern Flin Flon greenstone belt at Snow Lake, Manitoba, Canada. Inverted apparent interval density (IAID) logs were calculated from the borehole gravity data and compared with lithofacies and [Formula: see text] logs; the latter of which is a geochemical proxy for differentiating volcanic rocks of felsic to mafic composition. The IAID anomalies predominantly reflect alternating mafic and felsic volcanic rock units in the footwall and hanging wall of the massive sulfide deposit. IAID lows are associated with [Formula: see text] highs that correspond to rhyolite and rhyodacite intervals in the hanging wall. IAID lows with associated [Formula: see text] peaks in the footwall occur within intervals of gneiss and schist formed by metamorphism of hydrothermally altered rocks, suggesting that these IAID lows still reflect the felsic composition of their volcanic protoliths. A significant peak-to-peak Bouguer anomaly of 0.66 mGal caused by an estimated excess mass of 0.7 mT can be correlated with gamma-gamma density signature of the main sulfide ore zone in three boreholes. This anomaly is aligned with the ore zone after restoring the displacement along a northeast-dipping structure. When integrated with drillhole lithology and lithogeochemistry logs, gravity borehole data can, in addition to the direct detection of mineralization, be used as a subsurface geological mapping tool.

Alteration and ore mineral characteristics of the Archean Coniagas massive sulfide deposit, Abitibi belt, Quebec

1998 ◽  
Vol 35 (6) ◽  
pp. 620-636 ◽  
Author(s):  
Pierre Doucet ◽  
Wulf Mueller ◽  
Francis Chartrand
Keyword(s):  
Hanging Wall ◽  
Massive Sulfide ◽  
Sulfide Mineral ◽  
Sulfide Deposit ◽  
Spreading Ridge ◽  
Massive Sulfide Deposit ◽  
Mineral Characteristics ◽  
Fe Content ◽  
Mineralized Zone ◽  
Back Arc

The Coniagas Mine in the northeastern Abitibi greenstone belt is a small, isolated Archean, volcanic-hosted, massive sulfide deposit rich in Zn-Pb-Ag. The Main lens, which is part of four massive sulfide lenses, is restricted to a 40 m thick massive felsic lapilli tuff unit of the 280 m thick sequence. The massive sulfides, a product of subsurface replacement, have features common to both Mattabi- and Noranda-type deposits. The Coniagas Mine sequence represents part of a small subaqueous volcanic edifice that probably evolved close to an arc or back-arc spreading ridge. A distinct alteration halo of chlorite + sericite ± epidote ± spessartine garnet in the immediate footwall and a hanging wall alteration assemblage of quartz + sericite ± epidote ± chlorite characterize the deposit. The sphalerite + pyrite + galena ± chalcopyrite sulfide mineral assemblage in the Main lens differs significantly from the pyrite + chalcopyrite + sphalerite + pyrrhotite ± galena assemblage in the stringer zone. Chlorite compositions are Fe rich close to the mineralized zone, with an Fe/(Fe + Mg) ratio of 0.38-0.48 in the hanging wall and 0.65-0.70 below the ore. Delicate sulfide textures including colloform pyrite and concentric sphalerite are consistent with a low temperature of formation, whereas higher temperatures are inferred for the stockwork zone. Electron probe microanalysis of sphalerite supports inferred hydrothermal fluid temperatures. The low Fe contents (6.7-10.8 mol% FeS) in sphalerite associated with colloform pyrite of the Main lens contrast with the elevated Fe content (12.7-14.1 mol% FeS) in sphalerite from the stockwork.

Mise‐a‐la‐masse survey for an auriferous sulfide deposit

Geophysics ◽  
2001 ◽  
Vol 66 (1) ◽  
pp. 70-77 ◽  
Author(s):  
B. B. Bhattacharya ◽  
Dinesh Gupta ◽  
Buddhadeb Banerjee ◽  
Shalivahan
Keyword(s):  
Massive Sulfide ◽  
Sulfide Deposit ◽  
Sulfide Mineralization ◽  
Gold Exploration ◽  
Copper Mineralization ◽  
Geophysical Surveys ◽  
Sulfide Content ◽  
Equipotential Map ◽  
Massive Sulfide Mineralization ◽  
Gold Bearing

A mise‐a‐la‐masse survey was carried out in Bhukia area, Banswara district, Rajasthan, India for auriferous sulfide occurrences. This area was originally surveyed for copper mineralization. Exploratory drilling, however, proved it to be economically not viable. The area was reopened for geophysical surveys when grab samples indicated the presence of gold. Initial geophysical surveys for copper mineralization showed electromagnetic, induced polarization, and resistivity anomalies. At first, one borehole was drilled for gold exploration on the basis of initial geophysical surveys. It encountered massive sulfide mineralization in association with gold. Borehole logging and a mise‐a‐la‐masse survey were carried out in this borehole. Three further boreholes drilled on the basis of the mise‐a‐la‐masse results encountered massive sulfide mineralization in association with gold. One of the three boreholes, 100 m from the first borehole along strike, was used for another set of mise‐a‐la‐masse measurements. A composite equipotential map was prepared using the results of mise‐a‐la‐masse results of both the boreholes. The equipotential contours show a north‐northwest‐south‐southeast trend of mineralization. The boreholes drilled on the basis of the mise‐a‐la‐masse results have delineated a strike length of more than 500 m of gold‐bearing sulfide mineralization. The sulfide content ranges from 10 to 40% and gold concentration ranges from 2 to 6 ppm. The dip and plunge of the lode, as anticipated from the mise‐a‐la‐masse results, are toward the west and north, respectively. Mise‐a‐la‐masse surveys are continuing in the adjoining areas.

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