scholarly journals Mineralogical investigation of low-grade nickel drill core from claims near Giant Mascot Mines Limited, British Columbia

1972 ◽  
Author(s):  
L J Cabri ◽  
J H G Laflamme
Keyword(s):  
British Columbia ◽  
Low Grade ◽  
Drill Core ◽  
Mineralogical Investigation

scholarly journals Endoscopic Mucosal Resection: Early Experience in British Columbia

2010 ◽  
Vol 24 (4) ◽  
pp. 239-244 ◽  
Author(s):  
Mayur Brahmania ◽  
Eric Lam ◽  
Jennifer Telford ◽  
Robert Enns
Keyword(s):  
British Columbia ◽  
Barrett’S Esophagus ◽  
Endoscopic Mucosal Resection ◽  
Barrett's Esophagus ◽  
Low Grade ◽  
Complication Rates ◽  
The Third ◽  
Mucosal Resection ◽  
The Mean

BACKGROUND: Endoscopic mucosal resection (EMR) has been proposed as a primary method of managing patients with dysplasia- or mucosal-based cancers of the esophagus.OBJECTIVES: To evaluate the use of EMR for the treatment of Barrett’s esophagus with dysplasia or early adenocarcinoma, assessing efficacy, complication rates and long-term outcomes.METHODS: All patients who underwent EMR at St Paul’s Hospital (Vancouver, British Columbia) were reviewed. Eligible patients were assessed with aggressive biopsy protocols. Detected cancers were staged with both endoscopic ultrasound imaging and computed tomography. Appropriate patients were offered EMR using a commercially available mucosectomy device. EMR was repeated at six- to eight-week intervals until complete. Patients with less than one year of follow-up or who were undergoing other ablative methods were excluded.RESULTS: Twenty-two patients (all men) with a mean (± SD) age of 67±10.6 years were identified. The mean duration of gastroesophageal reflux disease was 17 years (range four to 40 years) and all were receiving proton pump inhibitor therapy. The mean length of Barrett’s esophagus was 5.5±3.5 cm. One patient had no dysplasia (isolated nodule), three had low-grade dysplasia, 15 had high-grade dysplasia (HGD) and three had adenocarcinoma. A mean of 1.7±0.83 endoscopic sessions were performed, with a mean of 6±5.4 sections removed. Following EMR, three patients developed strictures; two of these patients had pre-existing strictures and the third required two dilations, which resolved his symptoms. There were no other complications. Three patients underwent esophagectomy. Two had adenocarcinoma or HGD in a pre-existing stricture. The third patient had an adenocarcinoma not amenable to EMR. One patient with a long segment of Barrett’s esophagus underwent radiofrequency ablation. At a median follow-up of two years (range one to three years), the remaining 18 patients (82%) had no evidence of HGD or cancer.CONCLUSION: Most patients with esophageal dysplasia can be managed with EMR. Individuals with pre-existing strictures require other endoscopic and/or surgical methods to manage their dysplasia or adenocarcinoma.

Seismic and potential‐field imaging of the Guichon Creek batholith, British Columbia, Canada, to delineate structures hosting porphyry copper deposits

Geophysics ◽  
2000 ◽  
Vol 65 (5) ◽  
pp. 1418-1434 ◽  
Author(s):  
Baishali Roy ◽  
Ron M. Clowes
Keyword(s):  
British Columbia ◽  
Seismic Reflection ◽  
Porphyry Copper ◽  
Regional Scale ◽  
Low Grade ◽  
Depth Range ◽  
Porphyry Copper Deposits ◽  
Near Surface ◽  
Copper Deposits ◽  
South Central

The Guichon Creek batholith (GCB), located in south‐central British Columbia, contains several large, low‐grade copper deposits of considerable economic importance. The surface geology of the Guichon batholith and its surrounding region have been well mapped; however, little information about subsurface features is available. The batholith consists of four major phases, emplaced radially outward, which can be separated on the basis of their texture and composition. Previous interpretation of gravity data suggests a mushroom‐shaped structure for the batholith. Data from Lithoprobe seismic reflection line 88-11, acquired across the batholith in 1988, reveal weakly coherent east‐dipping reflections on the west side and west‐dipping reflections on the east in the upper 10 km. To determine if these are related to structures associated with the batholith, we reprocessed the upper 6 s with particular emphasis on applications of signal enhancement techniques (e.g., pattern recognition methods, refraction statics, dip moveout corrections) and correlation of the improved subsurface images with the geological environment associated with porphyry copper deposits. Low near‐surface velocities correlate well with the phases of the batholith hosting the major copper deposits, which structurally lie in faulted and brecciated regions. Although the top 1.5 km cannot be imaged by the regional‐scale seismic reflection data, the reprocessed seismic section helps define the edges of the batholith, its various concentric phases, and the stem in the depth range of 1.5 to 10 km. The seismic results are complemented by 2.5-D (profile sense) modeling and 3-D inversion of regional‐scale gravity and high‐resolution aeromagnetic data. These show a low‐density and low‐magnetic‐susceptibility region associated with the batholith that extends to more than 10 km depth. The region of active mining interest lies above a circular low‐susceptibility area at 2 km depth and a low‐velocity region. Integrated interpretation of geophysical results and geological observations indicates the GCB is a funnel‐shaped feature in which mineralization is located above the stem of the batholith.

Constraints on temperature–pressure conditions and fluid composition during metamorphism of the Sullivan orebody, Kimberley, British Columbia, from silicate–carbonate equilibria

1995 ◽  
Vol 32 (11) ◽  
pp. 1937-1949 ◽  
Author(s):  
Glen R. De Paoli ◽  
David R.M. Pattison
Keyword(s):  
British Columbia ◽  
Ore Deposits ◽  
Garnet Growth ◽  
Fluid Composition ◽  
Exchange Equilibrium ◽  
Low Grade ◽  
Metamorphic Temperature ◽  
Lower Temperature ◽  
Silicate Carbonate ◽  
Peak Metamorphic Temperature

The Sullivan mine, in southeastern British Columbia, is one of the world's largest sediment-hosted, massive sulphide deposits. It has undergone at least one period of metamorphism since it was deposited in mid-Proterozoic times. Mineral textures within the deposit are predominantly of metamorphic origin. A well-constrained estimate of metamorphic conditions is required to understand how the original, depositional character of the orebody has been modified by metamorphism. Metamorphic conditions were estimated using multiequilibrium thermobarometric techniques involving silicate–carbonate–fluid equilibria. Peak metamorphic temperature constrained by calibration of the garnet–biotite Fe–Mg exchange equilibrium is 450 ± 50 °C. Lower temperature estimates from some samples are interpreted to record the temperature of cessation of garnet growth prior to the attainment of peak metamorphic temperature. Peak metamorphic pressure as determined from equilibria applicable to the assemblage garnet–biotite–muscovite–chlorite–calcite–quartz–fluid is 380 ± 100 MPa. The fluid composition accompanying this pressure estimate is [Formula: see text], [Formula: see text]. This estimate is particular to one sample and may not be representative for the deposit as a whole. Metamorphic fluids at the estimated P–T conditions would not have contained significant concentrations of C–O–H–S species other than H2O and CO2. Textural evidence and temperature–pressure results from a titanite-bearing metamorphosed mafic intrusion in the deposit suggest published titanite ages near 1330 Ma in the area of the mine represent the age of the peak metamorphic event. The results of this study carry tectonic implications for the Sullivan area, and may have application to other metamorphosed ore deposits and low-grade metamorphic settings.

Regional implications of Upper Triassic metavolcanic and metasedimentary rocks on the Chilkat Peninsula, southeastern Alaska

1980 ◽  
Vol 17 (6) ◽  
pp. 681-689 ◽  
Author(s):  
George Plafker ◽  
Travis Hudson
Keyword(s):  
British Columbia ◽  
Volcanic Rocks ◽  
Upper Triassic ◽  
Late Triassic ◽  
Low Grade ◽  
Lake Area ◽  
Metasedimentary Rocks

A low-grade metamorphic sequence consisting of thick mafic volcanic rocks overlain by calcareous flysch with very minor limestone underlies much of the Chilkat Peninsula. Fossils collected from both units are of Triassic age, probably late Karnian. This sequence appears to be part of the Taku terrane, a linear tectono-stratigraphic belt that now can be traced for almost 700 km through southeastern Alaska to the Kelsall Lake area of British Columbia. The age and gross lithology of the Chilkat Peninsula sequence are comparable to Upper Triassic rocks that characterize the allochthonous tectono-stratigraphic terrane named Wrangellia. This suggests either that the two terranes are related in their history or that they are allochthonous with respect to one another and coincidentally evolved somewhat similar sequences in Late Triassic time.

Metamorphism and deformation of the Grand Forks complex: implications for the exhumation history of the Shuswap core complex, southern British Columbia

2012 ◽  
Vol 49 (11) ◽  
pp. 1329-1363 ◽  
Author(s):  
Joel F. Cubley ◽  
David R.M. Pattison
Keyword(s):  
British Columbia ◽  
High Temperature ◽  
Granulite Facies ◽  
Greenschist Facies ◽  
Contact Metamorphism ◽  
Low Grade ◽  
Core Complex ◽  
The West ◽  
Grand Forks ◽  
Exhumation History

The Grand Forks complex (GFC) is an elongate, north–south-trending metamorphic core complex in the Shuswap domain of southeastern British Columbia. It comprises predominantly upper-amphibolite- to granulite-facies paragneisses, schists, orthogneisses, amphibolites, and calc-silicates of the Paleoproterozoic to Paleozoic Grand Forks Group. The GFC is juxtaposed against low-grade rocks of the Quesnel terrane across two bounding Eocene normal faults: the Kettle River fault (KRF) on the east flank and the Granby fault (GF) on the west flank. Peak metamorphic Sil + Kfs ± Grt ± Crd (Sil, sillimanite; Kfs, potassium feldspar; Grt, garnet; Crd, cordierite) assemblages in paragneiss and Hbl ± Opx ± Cpx (Hbl, hornblende; Opx, orthopyroxene; Cpx, clinopyroxene) assemblages in amphibolite in the GFC formed at 750 ± 25 °C, 5.6 ± 0.5 kbar (1 kbar = 100 MPa; 20 ± 2 km depth). Stratigraphically overlying Sil + St-bearing pelitic schists (St, staurolite) within the complex record peak conditions of 600 ± 15 °C, 5.5 ± 0.25 kbar. Crd + Ilm + Spl (Crd, cordierite; Ilm, ilmenite; Spl, spinel) and Crd + Qtz (Qtz, quartz) coronal textures in paragneiss, and Cpx + Opx + Pl + Mt (Pl, plagioclase; Mt, magnetite) symplectites in amphibolite, formed at 735 ± 20 °C, 3.3 ± 0.5 kbar, indicating high-temperature, near-isothermal decompression of the GFC of ∼2.3 ± 0.7 kbar (∼8.2 ± 2.5 km) from peak conditions. Transitional greenschist–amphibolite metamorphic assemblages in the hanging wall of the KRF indicate conditions of ∼425 ± 25 °C and 2.2 ± 0.6 kbar (∼8 ± 2 km depth), with local contact metamorphism around Jurassic intrusions as high as 630–650 °C at ∼2.5 ± 0.5 kbar. The pressure contrast across the Kettle River fault prior to greenschist facies displacement was ∼0.8 ± 0.7 kbar, for a vertical offset of ∼2.9 ± 2.5 km. This is similar to estimates for the Granby fault on the west flank of the GFC. The GFC therefore experienced a two-stage exhumation history: early high-temperature decompression at upper-amphibolite- to granulite-facies conditions, followed by low-temperature exhumation at greenschist-facies conditions owing to movement on the Eocene Granby and Kettle River faults.

Geology of the Matthew Creek metamorphic zone, southeast British Columbia: a window into Middle Proterozoic metamorphism in the Purcell Basin

2000 ◽  
Vol 37 (7) ◽  
pp. 1073-1092 ◽  
Author(s):  
C RM McFarlane ◽  
D RM Pattison
Keyword(s):  
British Columbia ◽  
Transition Zone ◽  
Ductile Deformation ◽  
Low Grade ◽  
Core Zone ◽  
The Core ◽  
Pelitic Schist ◽  
Metamorphic Zone ◽  
Structural Dome ◽  
Middle Proterozoic

Southwest of Kimberley, southeastern British Columbia, the Matthew Creek metamorphic zone occupies the core of a structural dome in Mesoproterozoic rocks of the Lower Aldridge formation (lower Purcell Supergroup). It comprises (1) a core zone of ductilely deformed sillimanite-grade metapelites, thin foliated mafic sills, and sheared quartz-plagioclase-tourmaline pegmatites; and (2) a thin transition zone of ductilely deformed metasediments which marks a textural and metamorphic transition between the core zone and overlying regionally extensive, brittlely deformed, biotite-grade semipelitic Lower Aldridge formation metasediments and thick Moyie sills. The core zone and transition zone in combination cover an area of 30 km2. The deepest exposed rocks in the core zone have a strong foliation and lineation (D1 deformation) formed during late M1 metamorphism at conditions of 580–650°C and 3.5 ± 0.5 kbar. The timing of this metamorphic-structural episode is constrained to the interval 1352–1341 Ma based on near-concordant U–Pb ages from monazite in pelitic schist near the mouth of Matthew Creek. Later, weaker metamorphic and deformation episodes variably overprinted the rocks of the Matthew Creek metamorphic zone. The juxtaposition of low-grade, weakly deformed rocks above high-grade, strongly deformed rocks across a zone of ductile deformation is interpreted to be due to a subhorizontal shear zone.

P–T–t path for the lower plate of the Eocene Tatla Lake metamorphic core complex, southwestern Intermontane Belt, British Columbia

1992 ◽  
Vol 29 (5) ◽  
pp. 972-983 ◽  
Author(s):  
R. M. Friedman
Keyword(s):  
British Columbia ◽  
Metamorphic Core Complex ◽  
Crustal Thickening ◽  
Lower Plate ◽  
Normal Faults ◽  
Low Grade ◽  
Core Complex ◽  
T Path ◽  
C 50 ◽  
Metamorphic Core

The Tatla Lake metamorphic complex (TLMC) is a metamorphic core complex located along the western edge of the Intermontane Belt in southwestern interior British Columbia. Low- to moderate-angle normal faults separate lower plate greenschist- and amphibolite-grade, highly strained, commonly mylonitic rocks from unstrained to weakly deformed strata of the upper plate. The lower plate is divided into a core of granoblastic gneiss and migmatitic tonalite and an overlying, 1–2.5+ km thick mylonitic package called the ductilely sheared assemblage (DSA). Amphibolite-grade metamorphism of the gneissic core (Mc) largely accompanied the development and folding of gneissic layering (ca. 107–79 Ma). Eocene (ca. 55–47 Ma) fabric and mineral assemblages in the DSA (Ms) obscure any earlier history. Three metamorphic zones are observed within southern DSA metapelites with increasing structural depth: chlorite–biotite, garnet–staurolite, and garnet–staurolite–kyanite–sillimanite. The middle zone is about 300 m thick; the latter zone is now about 4 km below low-grade upper plate rocks, indicating late- or post-Ds metamorphic omission. DSA P–T conditions are calculated with the garnet–biotite thermometer and garnet–Al2SiO5–quartz–plagioclase (GASP) and total Al in hornblende barometers. Southern DSA metapelites record Eocene Ms conditions of 480–619 °C (± 50 °C), generally increasing with depth. One sample gave a calculated P–T of 0.72 ± 0.15 GPa and 500 ± 50 °C. P–T data from this area suggest that up to 10 km of structural section may be missing. Zoned garnet (pre-Ds) core to rim GASP pressures of 0.70–0.36 ± 0.15 GPa, for an outcrop-sized pelitic xenolith within a Late Cretaceous tonalitic body (U–Pb: 71 Ma) in the northwestern DSA, record its ascent during pluton emplacement and subsequent Eocene tectonic uplift. A total Al in hornblende crystallization pressure of 0.54 ± 0.1 GPa was calculated for the surrounding body. Biotite and hornblende K–Ar dates of 53.4–45.6 Ma for DSA and gneissic core rocks record cooling of the lower plate through the 530–280 °C (± 40 °C) interval. Mc metamorphism in the gneissic core is thought to have developed in response to crustal thickening and compression, beneath a regional mid-Cretaceous thrust belt. Characteristics of Eocene Ms metamorphism in the DSA, such as truncated and thinned metamorphic zones, are consistent with development during extensional tectonic exhumation of the lower plate.

Flotation and Purification Research on Low Grade Magnesite in Kuandian of Liaoning

2010 ◽  
Vol 92 ◽  
pp. 97-102 ◽  
Author(s):  
Qiang Li ◽  
Wan Zhong Yin ◽  
De Shan Zhu ◽  
Zhen Fu Lv
Keyword(s):  
Open Circuit ◽  
Low Grade ◽  
Reverse Flotation ◽  
Optimum Conditions ◽  
Silicate Minerals ◽  
Systematic Process ◽  
Mineralogical Investigation

Low grade magnesite coexisting with dolomite was purified by flotation. A process of reverse flotation to remove silicate minerals- positive flotation to concentrate magnesite was explored after the systematic process mineralogical investigation. Influence of different conditions such as grinding fineness experiment, collector experiment and combined modifiers experiment was also investigated. Open-circuit flotation test was carried out under the optimum conditions. It was showed in the result that the MgO content in concentrate was increased from 32.36% to 42.25%, the CaO and SiO2 contents in concentrate were decreased from1.08% and 17.70% to 6.73% and 0.19% respectively, but the recovery of MgO was not satisfactory.

Sign in / Sign up

Export Citation Format

Share Document