Ounces Of Gold Research Articles

Natural Resource Management: Legal and Governance Issues of Reko Diq Project

Balochistan Province of Pakistan is gifted with enormous reserves of minerals owing to its unique geological condition. One of the most important mineral resource projects is the Reko Diq mining project which is one of the largest projects of its kind globally. The Reko Diq mineral resource located in the mineral-rich Tethyan belt was discovered by the Geological Survey of Pakistan (GSP) from 1960 to 1970. The estimated reserves of Reko Diq comprise 12.3 million tons of copper and 20.9 million ounces of gold. However, the Reko Diq project became embroiled in legal disputes and controversy when the Balochistan government, represented by the Balochistan Development Authority, signed agreements with foreign investment companies for gold and copper exploration in the area of Reko Diq at Chagai. This research paper examines the establishment of the Chagai Hills Exploration Joint Venture Agreement (CHEJVA), analyzes the Supreme Court's decision on Pakistan regarding Maulana Abdul Haq Baloch's case against the government of Balochistan, and highlights the arbitration proceedings of the International Centre for Settlement of Investment Disputes. The research also concludes that an American mineral company Broken Hills Proprietary (BHP), took advantage of the unstable political situation in Balochistan under the caretaker government in 1993. The Balochistan Mineral Rules, 2002, were enacted to grant undue relaxations favoring foreign companies. These issues significantly impacted the validity of the Reko Diq agreement. Consequently, this case created an impression that foreign investments are not secure in Pakistan, necessitating actions to protect their interests. Moreover, the Reko Diq case had various economic impacts on Pakistan and hindered the development of the province and the country. This research paper recommends reforms in the legal framework of the mineral sector and advocates for advanced equipment in exploration to create employment opportunities. Additionally, establishing a domestic dispute resolution forum is proposed as a more favorable approach for settling such disputes, rather than resorting to international jurisdictions.

Geología, alteración hidrotermal y mineralogía del sistema de vetas Sofía-Julia-Valencia, distrito minero Andacollo, Neuquén, Argentina

The Sofía-Julia-Valencia vein system, located in the Andacollo mining district in central west Argentina, is hosted by ENE-WSW oriented strike-slip faults which are the result of reactivation of normal faults affecting Carboniferous to Jurassic rocks during Upper Cretaceous-Paleogene. These veins contain a total resource of 22,900 Oz of gold with 5.5-6.7 g/t AuEq. Geologic mapping and a U-Pb age of 71±1Ma in zircon, obtained in an altered and mineralized dacitic dyke of the district, allowed to associate the mineralizing event to the Naunauco Andesitic belt magmatism (Upper Cretaceous-Paleogene) and to the Cretaceous-Paleogene Metallogenic Belt of the Andes in southwestern Argentina. The ore bodies are made up of multiple veins and veinlets that, from oldest to youngest, correspond to: (1) scarce early quartz+pyrite+molybdenite+iron poor-sphalerite veinlets, (2) quartz+epidote+calcite±albite (apatite+rutile+titanite+light rare earth elements bearing phosphates) associated with quartz+biotite, epidote (actinolite)+chlorite+calcite, with pyrite+pyrrhotite±chalcopyrite±(iron rich-sphalerite), marcasite veins. These veins are cut and reopened by (3) polymetallic veins and veinlets formed by quartz+sericite±carbonates (chlorite), with iron-gold rich sphalerite+silver rich-galena+chalcopyrite+pyrite, native gold±arsenopyrite±(pyrrhotite, bornite, argentite). Pyrite (4) and (5) carbonate+framboidal pyrite veinlets cuts all the previous ones. Multistage carbonate generation brecciate and cut previous veins and veinlets. Quartz shows granular, comb textures and some calcites developed platy textures. Four hydrothermal alteration types affected the veins host rock: (1) patches of early potassic alteration; (2) widespread propylitic alteration with disseminated sulfides; (3) later phyllic alteration overlapped to the previous ones; and (4) late supergene alteration. The sphalerite and chlorite composition in the veins (1 and 2) along with their mineral assamblages indicates they were formed by initially alkaline fluids (e.g., feldspar stable) with intermediate sulfur and oxygen fugacity and mesothermal temperature conditions (~400-240 °C), that evolved to conditions of lower sulfur (e.g., pyrrhotite stable) and oxygen fugacity, temperature

The Pesa, a Bimetallic Unit of Account in Tenth and Eleventh-Century Catalonia

Between 957 and 1040, land purchases in Catalonia were often settled in pesas. This term denoted a unit of account equalling two ounces of gold or ten of silver. Both precious metals came to Catalonia from Al-Andalus in the form of dinars and dirhams. However, for many years these coins were traded not according to their nominal value, but according to their metal weight. Frankish regulations, requiring foreign currencies to be converted into local deniers, provided the legal framework. The pesa system, created by the Counts of Barcelona, allowed Andalusi coins to be traded in domestic transactions as well as in bilateral trade with Al-Andalus. This policy shows the degree to which the Catalan Counties had become alienated from the West Frankish Kingdom to which they officially belonged.

THE RUSH STARTED HERE, PART III: ‘THE STREETS ARE PAVED WITH GOLD’—SPECULATION, GREED, AND DISAPPOINTMENT, 1849–2010

ABSTRACT Profitable gold mining began in the United States with the accidental discovery in 1799 of a seventeen-pound gold nugget in Cabarrus County, North Carolina. North Carolina’s gold production peaked between the 1830s and 1840s as hundreds of mines contributed hundreds of thousands of dollars a year to the national economy, necessitating the 1837 construction of a federal Branch Mint in Charlotte to process Piedmont gold. Gold mining suffered a major decline in North Carolina after the discovery of the richer and more extensive gold deposits in California in 1848. However, the North Carolina gold miners who did not join the western rush continued to work the shafts of the Piedmont using increasingly sophisticated European and South American technology, as well as new innovations such as hydraulic mining techniques from California, until the advent of the Civil War. From the end of Reconstruction (1877) to 1920, gold mining in North Carolina was sporadic and often funded by outside investors or used as a ruse in gold and stock scams. Copper mining, with gold and silver as secondary products, using increasingly complex technology and associated environmental issues, drove most of the mining fervor during this period. Following the Great Depression of the 1930s, gold production slowly increased until the Second World War, but never became a major industry as they were out-competed by the more profitable gold fields in the western United States, Alaska, Canada, Australia, and South Africa. From the 1970s to today, dependent upon the price of gold in the market and the requirements of environmental regulation, prior mining districts in North (and South) Carolina have continued to be examined, explored and cautiously mined using cyanide heap leach techniques. Although few in number, these limited lease mining projects have extracted over two million troy ounces of gold and nearly a million troy ounces of silver by 2010. Future extraction by the ongoing Haile Mine (South Carolina) project will increase this amount substantially in the next decade. Nevertheless, Cabarrus County continues to hold the world’s record for producing the greatest number of large (a pound or more) gold nuggets and was the epicenter of North America’s first gold rush.

The impact of the COVID-19 pandemic on the gold market in Kazakhstan

The purpose of this article is research of the impact of the global pandemic COVD-19 on the gold price in Kazakhstan. Research methodology. The authors used such methods to study the problem of general scientific methods and mathematical methods of cognition. The research was conducted by statistical methods, methods of analysis, modeling, as well as by comparison. Data were collected on the price of ounces of gold and the dollar index in Kazakhstan in 2017-2020, as well as the bottom data on the number of monthly infections with the coronavirus COVID-19 and the number of gold bars sold in Kazakhstan from January 2020 to December 2021. Originality / value of the research. The article analyzes the impact of the COVD-19 pandemic on the gold market, as well as makes an economic and statistical analysis of the price of gold and the number of gold bars sold. Changes in the price of gold over the past 5 years and the volume of gold sold have been determined. The results of correlation-regression analysis of the impact of gold prices on demand in the event of a crisis are shown. Findings. The authors concluded that the number of coronavirus infections caused by the pandemic caused a change in the price of gold. As a result of the correlation-regression analysis of the study, we found out that the growth of the coronavirus epidemic aff ected the high price of gold and the number of gold bars sold. Despite the high prices, we found that the demand for gold did not decrease.

The Mining Legacy of William S. Godbe

The Mining Legacy of William S. Godbe

Investigating the effect of US dollar, gold and oil prices on the stock market

The capital market, as one of the main components of the financial markets, plays an important role in the economic development of countries. As financial markets become more globalized through the free flow of capital and international trade, price fluctuations in financial assets also affect other assets and markets. Due to the high impact of foreign exchange, gold, and oil markets on other financial markets, this study examined the impact of these markets on the Tehran Stock Exchange market from April 2015 to March 2021. In this regard, US dollar, ounces of gold, and crude oil are used as independent variables, and Tehran Price Index (TEPIX) is considered as a dependent variable. The results of the final model indicate that the prices of dollars, gold, and oil had significant effects on the total price index of the Tehran Stock Exchange.

Looting in the NWFP and Punjab: Property and Violence in the Partition of 1947

According to Police Special Branch intelligence reports, amidst the chaos of Partition, over 60,000 ounces of gold were stolen from fleeing Hindus and Sikhs in 1947. Alongside political identity and religious organisation and territorialisation, desire for wealth or property was a key trigger for the continuation of the Partition violence. This article documents organised communal violence which erupted in the NWFP and Punjab during 1946–47 using largely underutilised police and intelligence reports from the period. The empirical focus of the article is two-fold. First, to show that the intercommunity violence triggered in these provinces was organised and funded by the Muslim League through its volunteer wings, even if specific perpetrators were locals. Second, that looting was a feature of locally-rooted violence to acquire property owned by non-Muslim minorities. As well, individual motives for revenge or a desire to best one’s business rival fuelled the violence alongside ideological imperatives such as the commitment to the idea of Pakistan.

Exploration-resource assessment of productive felsic volcanic centers in the Paleoproterozoic Penokean Volcanic Belt of northern Wisconsin, Michigan and east-central Minnesota, USA

Five productive felsic volcanic centers have been identified in the Paleoproterozoic Penokean Volcanic Belt (PVB). Each center hosts at least one potentially economic polymetallic volcanogenic massive sulfide (VMS) deposit. To date, these drill-defined (inferred + indicated + measured) resources collectively contain over 93 million tonnes of VMS-style, base (Cu, Pb, Zn) and precious metal (Ag, Au) mineralization including nearly 4 million ounces of gold. This does not include smaller, less defined (mostly inferred) deposits in the belt that would increase the total to at least 150 million tonnes. From this resource base only 1.73 million tonnes of actual ore production has occurred. However, previous positive feasibility studies completed on the Crandon (1994), Lynne (1995) and most recently (2020) Back Forty deposits verify a total of approximately 44 million tonnes, or 47% of the total drill-defined resource base, are potentially minable reserves. Currently the PVB resource base remains as unrealized new wealth.Mineral resource assessments completed in 1996 and 2007 collectively suggest there is a high probability of at least 4 to 22 (average ~13) or more VMS deposits remaining to be discovered in the Ladysmith-Rhinelander complex and to a lesser extent the Wausau complex of the PVB. These newly discovered VMS deposits will fill out the tonnage distribution for this belt by following a natural geometric (log normal) progression consistent with established grade-tonnage models. It is postulated that among these will be one giant (>100 million tonnes) deposit. If verified, potentially economic VMS mineralization hosted by the PVB would be comparable to other productive Paleoproterozoic greenstone belts in the Canadian Shield such as Flin Flon (>200 million tonnes) or even approach that of the prolific Neoarchean Abitibi (~775 million tonnes).Exploration to date suggests that many of these undiscovered VMS deposits will be identified in five, highly permissive felsic volcanic centers. These centers, which comprise less than 2% of the known belt, are distributed within the Highway 8 intra-arc rift basin of the 1,880 to 1,860 Ma old Ladysmith Rhinelander volcanic complex. Exact aerial boundaries are poorly defined. However, extrapolation of geophysical, drill hole and rare outcrop data provides a reasonable estimate. Each productive center is stratigraphically associated with major, district-scale, commonly mineralized, meta-argillite formations or formational groups. Felsic centers are identified in the Wausau complex but have thus far been barren of significant VMS-style mineralization as is the adjacent Wausau basin.Future exploration for new VMS deposits should be focused within the productive felsic centers where a number of prospective targets and prospects have been previously identified. Other significant felsic centers likely exist within the Highway 8 basin particularly in Cambrian sandstone-covered areas along the western and eastern margins of the belt. Additionally, at least one felsic center may be present in the Milaca complex which could have VMS potential.Of particular note is the VMS potential of a second mostly Cambrian sandstone-covered, greenstone belt in the Marshfield subterrane (Eau Claire complex). Geophysical data suggest possible back-arc or intra-arc rift basins may be present and historical drilling has identified at least one VMS occurrence. This highly prospective volcanic complex is essentially new hunting ground with its own deposit tonnage distribution of potentially supergene-enriched VMS deposits. Based on criteria set out in a 2007 mineral assessment, this belt has the potential to host at least 1 to a maximum of 15 deposits.

Intrinsic Value of the Dollar: An Evaluation, and Scrutiny of the Absolute Worth of The U.S. Dollar.

The debate on the intrinsic value of the U.S. Dollar has intensified recently and been an ongoing one, ever since 1971, when, President Richard Nixon, announced the abandonment of the Gold standard. In the debate on the intrinsic value of the Dollar, it may be argued, that Gold has been seen as a currency with an 'absolute worth' greater than all fiat currencies, due to Gold's historical acceptance power, and prominence as 'money.' With the abandonment of the Gold standard, and the Dollar, fundamentally, not being pegged to Gold, or any other units of intrinsic value, critics, ever since, have raised concerns regarding the absolute, or intrinsic value of the U.S. Dollar. This paper scrutinizes the intrinsic value of the U.S. Dollar, with an alternative perspective applied to gauge the Dollars' intrinsic value; the evaluation has been carried out through established financial models for a holistic assessment. The paper elaborates an alternative mechanism through which the Dollar derives its intrinsic value, and quantifies the nominal value backing the USD, $1079.3 trillion, and a real value, in 1970 Dollars, of $208.4 trillion; this value, aligned with the Gold standard peg of 1970, stands at 5.95 trillion ounces of Gold.

Mineralogy and sulfur isotope geochemistry of polymetallic, porphyry-epithermal mineralization peripheral to the Golden Sunlight gold mine, Montana

The Golden Sunlight mine, located 50 km east of the famous Butte porphyry/lode deposit, is the largest gold mine in Montana, and has produced over 3.6 M oz of gold in its 36-year history. Most of this gold has come from the Mineral Hill breccia pipe (MHBP), a west plunging, cylindrical body of brecciated latite porphyry and siliciclastic sedimentary rocks of the Mesoproterozoic Belt Supergroup. This paper focuses on four areas of mineralization outside the MHBP termed the Apex, Bonanza, North Pit, and 102/Sunlight zones. The Apex and 102/Sunlight areas consist of auriferous, pyrite-rich veins cutting Precambrian sediments and the Cambrian Flathead Quartzite, whereas the Bonanza and North Pit areas are polymetallic Mo-Cu-Ag-Au prospects hosted in latite porphyry and Belt sediments. Recent dating (40Ar/39Ar of igneous biotite) shows the porphyry at Bonanza was emplaced at 78 ± 1 Ma, which is several m.y. younger than the porphyry associated with the MHBP (81.9 ± 1.9 Ma, zircon U/Pb), and several m.y. older than the main phase of the Boulder Batholith that hosts the Butte deposit.Overall, the ore and gangue mineral assemblages in the peripheral deposits are similar to those described previously for the MHBP deposit. Pyrite, locally As-rich, is abundant in all settings, with varying amounts of galena, sphalerite, chalcopyrite, bornite, molybdenite (at Bonanza), tetrahedrite-tennantite, and traces of pearceite, tetradymite, aikinite, calaverite, petzite, goldfieldite, buckhornite, gold and electrum. Gangue minerals include quartz, carbonates (Fe-dolomite, siderite, magnesite), barite, anhydrite, adularia, and alumino-phosphate sulfate (APS) minerals. Spectral analysis indicates that some of the adularia is ammonium rich, i.e., buddingtonite.Values of δ34S for sulfide minerals from the peripheral deposits overlap with values obtained by previous workers from the MHBP. The bulk of the analyses (including all samples from the porphyry-hosted Bonanza deposit) have δ34S values between −12 and −4‰, with a tail to heavier values >+5‰. It is postulated that most of the lighter S was introduced into the district by late Cretaceous magmatic/hydrothermal fluids, whereas the heavier S is attributed to sedimentary pyrite in the Precambrian Greyson and LaHood formations. A weak negative correlation exists between gold grade and the δ34S of associated pyrite: all samples in this study that contain >0.1 oz/ton Au have δ34S < −5.9‰. Two possible explanations for the isotopically light S at Golden Sunlight are explored: 1) assimilation of biogenic pyrite from underlying sedimentary units; and 2) fractionation of S isotopes between SO4 and H2S in a system where oxidized S > reduced S.

Macroeconomic Cycle Made Visible in Real Terms as Protection against Asset Illusion

The current historically unparalleled global debt crisis and the resulting momentous valuation anomalies notably affecting the stock and bond markets (the historically low-interest rate level) are making it increasingly difficult for both institutional and private asset managers to generate an actual yield above the inflation rate. The problems with building wealth, and hence with pensions plans, first began at the turn of the millennium when the burst of the largest stock market bubble of all time firmly put the price distortions of assets into the public eye. This milestone also marked the beginning of a secular bust phase, which has been on a real gradual downtrend and despite nominal price increases is still ongoing today. However, this problem only becomes visible upon real evaluation, in ounces of gold. Contrary to the ubiquitous nominal view in uncovered paper currencies, only this real view, valued in ounces of gold, protects both private and institutional investors from an illusion of wealth.

РУДНО-МАГМАТИЧЕСКАЯ СИСТЕМА SUKUMALAND (ТАНЗАНИЯ)

The overwhelming part of the gold ore potential of the United Republic of Tanzania is confined to the systems of the Neoarchaean greenstone belts (GSB) of the metallogenic province of Lake Victoria in the northwestern part of the country. Based on the interpretation of space imagery, in the western part of the province the Sukumaland ore-magmatic system of concentric-zonal structure has been distinguished. It is formed by a group of arched greenstone belts and associated gold deposits. They form two arcuate branches: the internal and external branch, differing in their composition and structure. The internal arc is represented by the Rwamagaza and Kahama GSB with gold deposits of Tulawaka, Buckreef, Mawe-Meru, Tembo, and Bulyanhulu. The external arc is represented by Geita and Mabale-Buhungurica GSB with gold deposits of Ridge-8, Nyankanga, Geita, Matandani, Kukuluma, Nyanzaga, Kitongo, Golden Ridge, Nyakafuru, and Miabu. Their huge gold potential (over 50 million ounces of gold) stipulates for the urgency of the study of this gigantic structure. GSB of the inner arc (Rwamagaza and Kahama) are characterized by a predominance of basic volcanic rocks, and GSB of the external arc (Geita and Mabale-Buhungurica) – by sedimentary and volcanic-sedimentary formations, in particular, banded ironstone formations (BIF). Accordingly, gold deposits of the inner arc are mainly associated with basic volcanic rocks (Tulawaka, Buckreef, Mawe-Meru, Bulyanhulu, Tembo) while gold deposits of the external arc – with BIF (Geita, Nyankanga, Kukuluma, Matandani). The nuclear part of the ore-magmatic system is of special interest, although manifestations of volcanism are absent there and gold or other mineral deposits are unknown yet, but a tectonic pattern of its structural elements indicates its significant ore potential. In particular, the presence of numerous spatially close systems of radial-circular faults attests to the presence of weakened zones in the space above the core of a hypothetical magma chamber. Gold deposits of different geological and industrial types, yet undiscovered, as well as manifestations of diatreme magmatism may be associated with these weakened zones. In particular, one cannot exclude the possible presence of diamond-bearing volcanic pipes. It is assumed that the ore-magmatic system has originated and evolved in the course of a complex multi-stage ore-magmatic process under the influence of ascending flows of depth fluids due to the long-term functioning of a zone with anomalously heated mantle in that area. During further geological exploration it is recommended to take into account the predictable availability of a single integrated ore-magmatic system of longdevelopment and its structural features.

Sediment‐Hosted Gold Deposits in Southeast Asia

AbstractSediment‐hosted gold (SHG) deposits are becoming more widely recognized in the Southeast Asian region. They are characterized by very fine‐grained gold, typically occurring in stratabound jasperoid replacement and structurally controlled orebodies in calcareous or carbonaceous sedimentary rocks, which are commonly distal to porphyry copper–gold deposits. Gold mineralization is associated with anomalous As‐Sb‐Hg‐Tl and is normally concentrated in the arsenic‐rich rims of pyrite and arsenopyrite grains (commonly refractory). The examples discussed in this paper are located in Southeast Asian countries, and all occur in island or continental arc terrains. SHG deposits have many features comparable to the Carlin deposits in Nevada; however, they differ in tectonic setting, their shallow level of emplacement, fluid composition, and probable metal source. As such, the Southeast Asian examples described in this compilation may be classified as “Carlin‐like” but not “Carlin‐type.” Furthermore, they appear to represent a subclass of low‐temperature epithermal deposits, with most occurrences showing late‐stage colloform quartz vein events. Indeed, they are better described as sediment‐hosted epithermal gold deposits.Several examples are multimillion ounce deposits, such as Sepon, Laos, with its endowment of more than 4 million ounces of gold. Mesel, Sulawesi, and Bau (Jugan and Tai Parit), Sarawak, also possessed multimillion ounce resources prior to mining. Two centuries of Chinese alluvial and eluvial mining at Buduk in northwest Kalimantan has produced a significant unrecorded amount of gold. Structurally controlled feeder zones frequently contain higher‐grade gold mineralization (e.g. Mesel), and constitute valid exploration targets. More recently discovered deposits, such as those in Myanmar (Gegalaw, Taungzaw, and Katsena) and the Philippines (Hijo and Las Cogon), remain to be thoroughly explored. Most of the deposits (Sepon, Mesel, Abong, Sihayo, Jugan, Tai Parit, Hijo, and Lascogon) can be directly linked spatially and genetically to gold–copper porphyry intrusive centers. It is postulated that localities with no obvious connection to known porphyry deposits (Buduk, Ban Bak, Kyaukpahto, Gegalaw, Taungzaw, and Katsena) may represent district‐scale exploration targets for porphyry copper–gold deposits. In terms of discovery techniques, of the 13 SHG deposits discussed here, several were sites of historical mining (Mesel, Bau, and Kyaukpahto). The majority, however, are virgin deposits discovered in the past 25 years by intuitive area selection followed by systematic regional geochemical exploration programs and routine geological inspections. At the project scale, electrical resistivity techniques, such as controlled‐source audio frequency magnetotellurics (CSAMT) and induced polarization (IP), have proven to be useful for mapping blind jasperoid bodies and associated feeder zones and silicified structures. Traditional field mapping and stream float sampling in tropical regions are also effective exploration tools. Deposits that have significant jasperoid development may have conspicuous positive topographic relief, depending on erosion level.

Origin of the high-grade Early Jurassic Brucejack epithermal Au-Ag deposits, Sulphurets Mining Camp, northwestern British Columbia

The high-grade (8.1 million ounces of gold; 15.6 Mt grading 16.1 g/t Au; Pretium, 2016) Brucejack epithermal Au-Ag deposits are located in the Canadian Cordillera of northwestern British Columbia, and formed in association with extensive early Mesozoic island arc magmatism. Porphyry-type Cu-Au-Mo mineralization occurs nearby at the Kerr-Sulphurets-Mitchell (196–190 Ma; Febbo et al., 2015), Bridge Zone (191.7 ± 0.8 Ma, 191.5 ± 0.8 Ma), and West Zone (188.9 ± 0.9 Ma) prospects. Gold-silver vein-type mineralization at Brucejack is hosted by variably altered and deformed Early Jurassic porphyritic latite lava flows, volcaniclastic rocks, and volcanic-derived sandstones, siltstones, and conglomerates. This study focuses on the Valley of the Kings Zone at Brucejack, where host rocks have been dated at 188–184 Ma (U-Pb, zircon). Post-mineralization (but not post-alteration) basaltic and trachybasaltic dikes that cut the veins are geochemically similar to the host volcanic sequence and follow the same structural trends of the mineralized vein corridors. We suggest these dikes are broadly coeval with mineralization, and that ore formation at the Valley of the Kings formed during the overall Jurassic tectonomagmatic event.Gold-silver mineralization is hosted by quartz-carbonate veins that cut sericitized and pyritized volcaniclastic rocks. Six stages of veining are defined, with Au-Ag mineralization (electrum) focused in stages III–V: stage I–III veins consist of quartz with minor carbonate, chlorite, sericite, and sulfide minerals; stage IV quartz veins contain more abundant base metal sulfides (pyrite, sphalerite, and galena with minor sulfosalts); stage V veins are dominantly calcitic; late post-mineralization stage VI veins are quartz-calcite and contain sparse pyrite and chlorite, but no electrum. The veins are interpreted to be syn- to late-tectonic, with deformation decreasing from locally penetrative in the host-rocks prior to veining (resulting in local foliation of sericite and pressure shadows around pyrite), to dismemberment and shearing of early stage I–II quartz veins, brittle disruption of stage III–IV quartz and stage V carbonate veins, and minimal deformation of post-mineralization stage VI quartz-carbonate veins. A much younger set of extensional muscovite veins locally cuts the deposit with Late Cretaceous apparent ages, and appears to be associated with a weak thermal overprint that has reset K-Ar and 40Ar/39Ar ages in sericite throughout the district.The deformation experienced by the vein system, particularly in the later stages (III–V), was not uniform, and original undeformed vein textures and fluid inclusion assemblages are locally preserved. We report fluid inclusion microthermometric data from carefully selected primary fluid inclusion assemblages from quartz, calcite, and sphalerite from vein stages III–IV, many of which show evidence for boiling (coexisting liquid- and vapor-rich primary fluid inclusions). Liquid-rich fluid inclusions from stage III and V veins have moderate homogenization temperatures (∼170 °C and ∼160 °C respectively) and salinities of 2–8 wt% NaCl equiv., whereas inclusions from base-metal-sulfide-bearing stage IV veins show evidence of mixing with a cooler, more saline brine (∼140 °C, ∼10–15 wt% NaCl equiv.). Carbon dioxide was observed as clathrate during cooling in some fluid inclusions, suggesting that minor amounts of CO2 were present in the fluids.Calculated oxygen isotopic compositions of fluids in equilibrium with quartz and calcite from vein stages III–V range from δ18Ofluid = −10.7 to +1.8‰, whereas δ13CCO2 ranges from −9.5 to −4.5‰, and δ34Spyrite ranges from −1.7 to +0.6‰. Taken together, these data suggest a magmatic source for S and some C, carried by a fluid of evolved or diluted magmatic origin, which variably mixed with meteoric-derived groundwater or seawater containing carbon of sedimentary (organic) origin. Mixing is supported by large salinity ranges of vein stage IV fluid inclusions, where individual assemblages range from ∼1 to 15 wt% NaCl equiv.These fluid temperatures, salinities, and isotopic compositions are typical of epithermal deposits where distal magmatic fluids mix with local heated groundwaters. The low fluid temperatures but evidence of boiling suggest formation at shallow crustal depths. This is despite the evidence for penetrative deformation in the sericitized volcanosedimetary host rocks, which we attribute to rapid uplift immediately prior to or during the earliest stages of mineralization. The vein system is therefore interpreted to have formed during the later stages of a deformational event related to arc accretion.

Laser Ablation ICPMS Analysis of Pyrite and U-Pb Zircon Dating of Host Rocks From the Tersang Gold Deposit, Malaysia

The Central gold belt of peninsular Malaysia comprises a number of gold deposits located in the east of the N-S striking Bentong-Raub Suture Zone. The Tersang gold deposit is a mesothermal, orogenic gold deposit, which is hosted in sandstone, shale, rhyolite and breccia. The deposit has an inferred and indicated resource of 120,000 ounces of gold in the JORC category. Detrital zircon grains from the host sandstones returned a maximum depositional age ranging from Early Carboniferous to Early Permian (333.5 ± 2.5 Ma-261.5 ± 4.9 Ma) and those of the rhyolite indicated a crystallization age of 218.8 ± 1.7 Ma. Pyrite trace element mapping has revealed four pyrite phases. Laser Ablation ICPMS analyses on pyrite has shown that pyrite phase 1 has the lowest Au concentration (mean 0.4 ppm) and is interpreted to have preceded the main Au mineralisation stage. Pyrite phases 2 and 3 are the main Au mineralisation stage with Au mean range from 1.5 to 4.5 ppm and contributed most of the invisible gold to the ore-forming system. Pyrite phase 4 has low gold concentrations (mean 0.5 ppm) and post-dated the main Au mineralisation stage recorded in pyrite phases 2 and 3. The trace element chemistry of pyrite indicates that Au mineralisation recorded in pyrite is likely a product of four stages ore forming system centred on the rhyolite corridor. In terms of gold exploration, gold has a positive correlation with As, Ag, Cu, Se, Sb, Pb and Tl in pyrite. These metals can be used as pathfinders to detect proximity to ore for orogenic gold deposit type in the central gold belt of Peninsular Malaysia.

Trace element and sulfur isotopic evidence for redox changes during formation of the Wallaby Gold Deposit, Western Australia

Wallaby is a major gold deposit of the St Ives Gold field of Western Australia, with an estimated resource of 8 million ounces of gold. It has a well-established paragenesis across five vein sets that displays macroscopic evidence of changing redox through time; from hematite to magnetite. Micro-analysis of pyrite from each vein generation shows a progressive and gradual change in redox conditions. The sulfur isotope composition has a δ34S range of −7.7 to +9.8‰ using 3μm spots on the Sensitive High Resolution Iron Micro Probe-Stable Isotope (SHRIMP-SI). Negative values indicative of an oxidized sulfur signature are found in the earliest generation of pyrite (which coexists with hematite) that also contains high concentrations of As, Ni, Zn, Ag, Sb, Cu and Pb. Conversely, positive values representative of reduced sulfur are found in later generations of pyrite, with lower concentrations of As, Ni, Sb, Cu, Zn and Pb. These later pyrite crystals display higher As/Ni, As/Sb, and As/Bi, and lower Cu/Te. These geochemical trends are the result of redox controlled transport and partitioning into pyrite of minor and trace elements now within the pyrite structure. Previous studies suggested a single orogenic event formed the Wallaby Deposit. This is not supported by the present study. Trace element ratios such as As/Ni clearly delineate the high Au generations and could be used as an exploration tool. It is suggested that pyrite from the Wallaby Gold Deposit formed via desulfidation and a gradual change in redox conditions within an evolving fluid and did not result from mixing of two separate fluids as previously advocated. Utilizing pyrite to link the entire fluid history of Wallaby demonstrates the general use of pyrite as a valuable mineral tracer in gold-bearing fluid systems.

The Youga gold deposit, Burkina Faso

The Youga gold deposits are located in southern Burkina Faso, close to the border with Ghana and classified as epigenetic mesothermal orogenic type gold deposits. They are hosted within or adjacent to Tarkwaian-type metasediments of the Youga Basin, composed of a succession of arkosic sandstones, conglomerates and subordinate chlorite schists. The Youga deposits are characterized by two distinct styles of mineralization; the moderately to weakly silicified host rock with quartz stockwork veining and pyrite as the predominant sulphide which generally grades between 0.5 and 2g/t and the intensely silicified arkose with abundant quartz veins and more diverse sulphides (pyrite, arsenopyrite, chalcopyrite, pyrrhotite and galena) which generally grades >3g/t. The alteration paragenesis associated with the mineralized vein stockwork is characterized by quartz, ankerite, albite, chlorite and pyrite. The first mineralization episode occurred under brittle-ductile conditions during the D1Y deformation event characterized by E–W trending penetrative to discrete structures. Gold is concentrated in zones affected by irregular fracturing, quartz veining and occasional brecciation. Reworking of these structures during D2Y, by N–S to NE-trending sub-vertical shear zones, lead to further economic concentration of gold found in eight individual deposits, all localized in or immediately adjacent to Tarkwaian-type sediments (Main, East, West Zone 1, 2, and 3, A2NE, NTV and Zergoré). Absolute age of mineralization is unknown as well as that of the host sediments; however stratigraphic and structural craton-wide correlations suggest that the mineralization occurred after 2110Ma if not much later. Commercial production was achieved at the Youga Gold Mine in 2008 and as of December 31st, 2014 has produced 537,621oz of gold.

Gold mineralisation in the Essakane goldfield in Burkina Faso, West African craton

The West African craton is known for its structurally hosted Au deposits in Ghana, Burkina Faso, Côte d'Ivoire, Mali and Niger. The Essakane goldfield in northeast Burkina Faso has produced 1 606,000oz of gold since 2010 from the Essakane Main Zone. The Essakane goldfield is made up of several exploration and artisanal sites that include; Essakane Main Zone, Gossey, Falagountou, Sokadie, Tin Zoubratan, Essakane North and South, Korizéna, Bom Kodjélé, Tin Taradat, Tassiri, Gaigou, and Takabangou. Gold mineralisation in sheeted and stockworks quartz–carbonate and tourmaline veins occurs with pyrite, arsenopyrite, and traces of pyrrhotite, galena and hematite. It is hosted in sheared, folded and contact metamorphosed volcanic, volcanoclastic and sedimentary Birimian Supergroup sequences. The maximum age of gold mineralisation in the Essakane goldfield is syn-deformational and formed during the Eburnean Orogeny (D2) at 2130–1980Ma.

Chinese Gold Miners and the "Chinese Question" in Nineteenth-Century California and Victoria

During the second half of the nineteenth century the largest gold deposits yet known in the world were discovered in the American West, Australasia, South Africa, and western Canada. From 1848 to 1891 a series of gold rushes—quick, short-term bonanzas (or failures) for individual miners—swept those regions, drawing hundreds of thousands of gold seekers from around the world. In fewer than fifty years miners and mining companies extracted from the earth some 435 million ounces of gold—more than the total that had been mined in the previous three thousand years. The sudden increase in world gold production in the late nineteenth century was produced by Anglo-American settler colonialism and capitalist development. Since ancient times gold has been valued for its beauty and purity. Indigenous populations on the settler-colonial frontiers were long aware of alluvial gold deposits in their midst, but they did not value gold as a money commodity. Thus, gold rushes furthered the dispossession of native peoples and transformed the Pacific worlds where gold was discovered, as well as the global economy. Sustained exploration and extraction required capital investment, deep-mining technology, mass labor migration, and long-distance transportation. Such activity accelerated the economic development of the gold-mining regions and strengthened the international financial power of Great Britain and the United States as creditor and investor nations.1