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Caving and drawing methods
Published in M.L. Jeremic, Ground Mechanics in Hard Rock Mining, 2020
In the Mahtab & Dixon description of the San Manuel mine, three prominent orthogonal fracture sets are delineated in two of the three principal rock types (quartz, monzonite and monzonite porphyry). However, only two fracture sets, both vertical, were found to be present in the third rock type (rhyolite).
Heap leaching in extreme northern climates — Overview of Brewery Creek Mine, Yukon, Canada
Published in John E. Udd, A.J. Keen, Mining in the Arctic, 2020
Thrust faults, which tend to be localized along contacts between foot wall graphitic argillites and the more brittle quartz monzonites of the hanging wall, commonly resulted in stacked, southerly dipping mineralized zones generally contained within altered and fractured rocks lying above the faults. A secondary control on gold mineralization appears to have been exerted by sub-vertical shears in the hanging wall rocks. Gold occurs primarily as micron-sized particles in solid solution with arsenopyrite and pyrite growth bands around larger sulfide grains. Within the extensive zone of weathering, which reaches an average depth of 50m. sulfides have in general been converted to hydrous iron and arsenic oxide minerals. Eighty percent of gold mineralization is contained within limonitic. altered quartz monzonite. The remainder is primarily contained within thinly intercalated shales and graywacke. The style of mineralization has been tentatively classified as a high level Adularia-Sericite epithermal deposit, characterized by a low sulfide content, and a gold, mercury, arsenic. antimony and haruim geochemical response.
Early Proterozoic Magmatism and Geodynamics — Evidence of a Fundamental Change in the Earth’s Evolution
Published in O.A. Bogatikov, R.F. Fursenko, G.V. Lazareva, E.A. Miloradovskaya, A. Ya, R.E. Sorkina, Magmatism and Geodynamics Terrestrial Magmatism Throughout the Earth’s History, 2020
This has been described by Bogatikov and Birkis (Bogatikov, 1979), and is located in western Latvia. The pluton, which is completely overlain by a platform cover, 900–1,800 m thick, has been recognized from drilling records. The pluton is irregular-oval in shape. Its northern part is formed of rapakivi granite. In addition to rapakivi, drilling logs indicate the presence of granosyenite, quartz-syenite, quartz-monzonite and monzonite to the south. Abundant basic rocks (predominantly anorthosite and norite–anorthosite, in places supplemented with norite and gabbronorite containing thin layers of troctolite and plagioclase olivinite), appear in the southern part of the pluton. As in the Korosten pluton, the rocks form separate sublatitunidal bodies (blocks). The bodies are 100–200 km2 in size, with the largest of them (Priekule) reaching 1,000 km2 in area.
Oldest syenitic intrusions of the Yilgarn Craton identified at Karari gold deposit, Carosue Dam camp, Western Australia?
Published in Australian Journal of Earth Sciences, 2023
W. K. Witt, C. Fisher, S. G. Hagemann, M. P. Roberts
Granitic rocks, which dominate the near-surface geology of the Yilgarn Craton, have been subdivided into two major and three minor groups, by Champion and Sheraton (1997). Cassidy et al. (2002) subdivided the groups into supersites and suites. One of the minor groups, named the Syenitic Group, is equivalent to the Gilgarna Supersuite of Witt and Davy (1997a, 1997b). This association comprises alkali-rich, quartz-poor intrusions classified as monzodiorite, syenite, quartz syenite, quartz monzonite and alkali granite. Ferromagnesian minerals are typically clinopyroxene (including aegirine and aegirine-augite) and, in some cases, blueish sodic amphibole (Libby, 1989; Witt & Davy, 1997a). Typical accessory minerals are magnetite, titanite and apatite. The Syenitic Group intrusions are mostly restricted to the Kurnalpi Terrane of the Kalgoorlie-Kurnalpi Rift, in the Eastern Goldfields Superterrane (Figure 1; Witt et al., 2018).
A geometallurgical study of flotation performance in supergene and hypogene zones of Sungun copper deposit
Published in Mineral Processing and Extractive Metallurgy, 2021
Ataallah Bahrami, Yosef Ghorbani, Jafar Abdollahi Sharif, Fatemeh Kazemi, Morteza Abdollahi, Abbas Salahshur, Abolfazl Danesh
The Sungun porphyry copper deposit (PCD) is located in East Azerbaijan, in northwestern of Iran. This deposit is created from calk alkaline intrusive rocks in Sahand-Bazman’s volcanic belt, which has more than 750 million tons of copper sulfide ore (0.76%) and molybdenum (approximately 0.01%) (Esmaeili and Mor 2012). The felsic rocks occur as stocks and dykes ranging in composition from quartz monzodiorite through quartz monzonite. Stocks are classified into porphyry stocks I and II. Porphyry stock II, hosting the copper ore, has experienced an intense hydro-fracturing leading to the formation of stock work-type veinlets and micro-veinlets of quartz, sulphides, carbonates and sulphates. Three different types of hydrothermal alteration and sulphide mineralisation are recognised in Sungun (1) hypogene, (2) contact metasomatic (skarn), and (3) supergene. Hypogene alteration is developed in four types: potassic, phyllic, propylitic and argillic (Asghari et al. 2009). The first two types occurred almost simultaneously shortly after replacing porphyry stokes. The third type occurred after stokes is appeared on the ground. Extremely large fractures and abundant sulfides in these rocks have caused alteration factors to have significant effects on these rocks (Alavi et al. 2014). Figure 1 illustrates different zone of Sungun copper deposit introduced above.
Structural and non-structural statistical methods: implications for delineating geochemical anomalies
Published in Applied Earth Science, 2020
Bijan Roshanravan, Seyed Hasan Tabatabaei, Oliver Kreuzer, Hamid Moini, Mohammad Parsa
Located in the Tertiary Loot Block volcanic-plutonic belt, covers an area of about 8 km2 (Figure 1(a)), the Shadan porphyry copper–gold deposit comprises a cluster of around 17 diorite and syenite intrusions (Hoshmandzadeh 2014). The Cenozoic calc-alkaline volcanic rocks, which contain andesitic lavas and dacitic to rhyodacitic tuffs, are prevalent in the east, northeast and central portions of the study area (Figure 1(b)). They are extensively altered near younger intrusive dikes, which are exposed along northwest-south east oriented post-intrusion reverse faults (Figure 1(b)). The subvolcanic intrusive rocks are divided into five compositional groups, the relative ages of which has been established based on crosscutting relations and alteration type. From oldest to youngest, these groups are (a) hornblende quartz monzonite, (b) biotite-hornblende quartz monzodiorite to monzonite porphyry, (c) hornblende monzonite to monzodiorite porphyry, (d) monzonite porphyry and (e) hornblende diorite porphyry (Karimpour et al. 2014). Laser-ablation U-Pb dating of syn-mineralisation dykes of the shadan deposit show that these groups were crystalised ∼39 Ma (Karimpour et al. 2014).