Exploration geochemistry of surficial media over the high-grade McArthur River uranium deposit, Saskatchewan, Canada

2021 ◽  
Vol 59 (5) ◽  
pp. 913-945
Author(s):  
Steve R. Beyer ◽  
Kurt Kyser ◽  
Tom G. Kotzer ◽  
Kevin Ansdell ◽  
David Quirt
Keyword(s):  
Pinus Banksiana ◽  
Hanging Wall ◽  
Coarse Fraction ◽  
Mining Activity ◽  
Alteration Zone ◽  
High Grade ◽  
Soil Geochemistry ◽  
Mine Site ◽  
Ore Body ◽  
Mine Effluent

ABSTRACT An orientation survey using surficial media was performed over the high-grade McArthur River unconformity-related U deposit (Saskatchewan, Canada) to test whether or not secondary dispersion of elements related to the ore body or alteration zone can be detected at the surface more than 500 m above the deposit. Organic-rich Ah-horizon soils, Fe-rich B-horizon soils, C-horizon soils, tree cores of Jack pine (Pinus banksiana), and glacially dispersed boulders of Manitou Falls Formation sandstone that host the U deposit were collected in four sampling grids near the mine site. Two of the grids overlaid the trace of the P2 fault that hosts the deposit and extends nearly to the surface, one grid overlaid both the P2 fault and one of the high-grade ore bodies (Zone 4), and one grid was located 2.5 km away from the ore body surface trace in the barren hanging wall of the P2 fault. The grid overlying the Zone 4 ore body had the highest proportion of samples with elevated U and low 207Pb/206Pb ratios, the latter indicative of radiogenic Pb from a high-U source, measured in two size fractions of Ah-horizon soils using Na pyrophosphate leach, pine tree cores using total digestion, and sandstone boulders using 2% HNO3 leach. A handful of pathfinder elements, such as As, Co, Ni, and Pb, are variably associated with the U and radiogenic Pb. Sandstone boulders with an assemblage of dravite + kaolinite ± illite, determined using shortwave infrared (SWIR) spectroscopy and matching the alteration mineralogy in the Manitou Falls Formation above the U deposit, were prevalent in the grid above the Zone 4 ore body and in the adjacent grid in the direction of glacial dispersion. A coarse fraction of the B-horizon soils, leached with 5% HNO3, highlighted the grid above the Zone 4 ore body to a lesser extent, whereas HNO3 leaches and aqua regia digests of C-horizon soil separates did not highlight the P2 fault or ore body trace due to influence by parent till mineralogy. Results of environmental monitoring at the mine site, which was active at the time of sampling, suggest that dust containing U, Pb, and radionuclides from waste rock piles and a ventilation shaft could influence A-horizon soil geochemistry near the mine site, and that U and radiogenic Pb anomalies in B- and C-horizon soils near the water table are close to a treated mine effluent discharge point. However, older trees that record elevated U and radiogenic Pb in annual rings that pre-date mining activity, and alteration mineralogy and geochemistry of boulders that are less susceptible to the influences of mining activity, add confidence that the geochemical anomaly in diverse surficial media above the Zone 4 ore body represents secondary dispersion from the underlying U deposit.

scholarly journals Peculiarities of the underground mining of high-grade iron ores in anomalous geological conditions

2019 ◽  
Vol 28 (4) ◽  
pp. 706-716
Author(s):  
Mykhailo V. Petlovanyi ◽  
Vladislav V. Ruskykh
Keyword(s):  
Iron Content ◽  
Underground Mining ◽  
Hanging Wall ◽  
Slope Angle ◽  
High Grade ◽  
Ore Deposit ◽  
Ore Body ◽  
Subsequent Decrease ◽  
Geological Conditions ◽  
The Difference

This paper is dedicated to research into the geological peculiarities, shape of the ore body and the occurrence of the host rocks in the hanging wall of the Pivdenno-Biloz- erske deposit , as well as their influence on the degrees and quality of high-grade iron ore extraction. It is noted that in the interval of 480 – 840 m depths, a decrease is observed in the stability of the natural and technogenic massif, which is caused by the increase in rock pressure with depth, the influence of blast- ing operations on the massif and the difference in geological conditions. This has led to the collapse of hanging wall rocks and backfill into the mined-out space of chambers in certain areas of the deposit, the dilution of the ore and deterioration of the operational state of the underground mine workings. Attention is focused on the causes and peculiarities of consequences of the collapse of the hanging wall rocks during ore mining, which reduce the technical and-economic indexes of the ore extraction from the chambers. A 3D-model of an ore deposit with complex structural framework has been developed, which makes it possible to visually observe in axonometric projection the geological peculiarities and the shape of the ore body. The parameters have been studied of mining chambers in the 640 – 740 m floor under different changing geological conditions of the ore deposit and hanging wall rocks occurrence – the northern, central and southern parts. The difference in the iron content in the mined ore relative to the initial iron content in the massif has been defined as an indicative criterion of the influence of changing conditions on the production quality. The reasons have been revealed which contribute to the collapse of the rocks and the subsequent decrease in the iron content of the mined ore in ore deposit areas dif- fering by their characteristics. It has been determined that within the central and half of the southern ore deposit parts with a length of 600 m, an anomalous geological zone is formed, the manifestation of which will be increased with the depth of mining. It was noted that within this zone, with the highest intensity and density of collapse of hanging wall rocks, the influence of decrease in the slope angle and change in the strike direction are of greatest priority, and such geological factors as a decrease in hardness, rock morphology, deposit thickness increase this influence significantly. To solve the problems of the hanging wall rocks’ stability, it is recommended to study the nature and direction of action of gravity forces on the stope chambers in the northern, central and southern parts, as well to search for scientific solutions in regard to changes in the geometric shapes of stope chambers and their spatial location, improving the order of reserves mining in terms of the ore deposit area, the rational order of breaking-out ore reserves in the chambers with changing mining and geological conditions of the fields’ development.

Study on the Ore-Controlling Structure of Yanglin’ao Tungsten Deposit and the Mineralization Prediction, Hunan Province

2012 ◽  
Vol 524-527 ◽  
pp. 73-80
Author(s):  
Yao Jian Xu ◽  
Ping Zheng ◽  
Man Xiang Huang
Keyword(s):  
Hanging Wall ◽  
Hunan Province ◽  
Formation Mechanisms ◽  
Tungsten Deposit ◽  
Geological Characteristics ◽  
Ore Body ◽  
Ore Bodies ◽  
Sandstone Formation ◽  
Set Up ◽  
Prospecting Prediction

Yanglin’ao tungsten deposit is a typical mesothermal to hyperthermal filling-metasomatism postmagmatic deposit. It is featured with the structure-controlling distribution of ore-body and mineralization; while veinlet-type ore-bodies are particularly situated at the hanging wall of F24(No.24 of Fault Fracture), and the mineralization is especially concentrated below and above the unconformable surface between Proterozoic Banxi slate group and Middle DevonianYanglin’ao sandstone formation. Geological characteristics, structure forms and its formation mechanisms of ore-controlling structure were studied in this paper and a special tectonic-controlled model was initially set up. Furthermore the author also made mineralization prospecting prediction based on structure characteristics.

Characterization of selected conservative and non-conservative isotopes in mine effluent and impacted surface waters: Implications for tracer applications at the mine-site scale

2018 ◽  
Vol 91 ◽  
pp. 1-13 ◽  
Author(s):  
Clayton Larkins ◽  
Kaisa Turunen ◽  
Irmeli Mänttäri ◽  
Yann Lahaye ◽  
Nina Hendriksson ◽  
...  
Keyword(s):  
Surface Waters ◽  
Mine Site ◽  
Mine Effluent

Geology of the shear-hosted Brookbank gold prospect in the Beardmore–Geraldton belt, Wabigoon subprovince, Ontario

2007 ◽  
Vol 44 (7) ◽  
pp. 925-946 ◽  
Author(s):  
Jerry C DeWolfe ◽  
Bruno Lafrance ◽  
Greg M Stott
Keyword(s):  
Shear Zone ◽  
Hanging Wall ◽  
Shear Zones ◽  
Gold Deposits ◽  
Iron Formation ◽  
Alteration Zone ◽  
Gold Deposition ◽  
Low Grade ◽  
Metasedimentary Rocks ◽  
Polymictic Conglomerate

The Beardmore–Geraldton belt consists of steeply dipping, intercalated panels of metavolcanic and metasedimentary rocks along the southern margin of the granite–greenstone Wabigoon subprovince in the Archean Superior Province, Ontario. It is an important past-producing gold belt that includes classic epigenetic iron-formation-hosted deposits near Geraldton and turbidite-hosted deposits, north of Beardmore. The Brookbank gold prospect belongs to a third group of related gold deposits that formed along dextral shear zones localized at contacts between panels of metasedimentary and metavolcanic rocks. The Brookbank prospect occurs along a steeply dipping shear zone at the contact between footwall polymictic conglomerate and hanging-wall calc-alkaline arc basalt. Early during shearing the basalt acted as a structural and chemical trap that localized brittle deformation, veining, and gold deposition, ankerite–sericite–chlorite–epidote–pyrite alteration, and the replacement of metamorphic magnetite and ilmenite by gold-bearing pyrite. This produced a low grade (≤5 g/t Au) ankerite-rich alteration zone that extends up to 20 m into the hanging-wall basalt. Later during shearing, gold was deposited within higher grade (≤20 g/t Au) quartz–orthoclase–pyrite alteration zones superimposed on the wider ankerite-rich alteration zone. Auriferous quartz–carbonate veins oriented clockwise and counter-clockwise to the shear zone walls are folded and boudinaged, respectively, consistent with dextral slip along the shear zone. A key finding of the study is that different groups of gold deposits in the belt, including epigenetic iron formation gold deposits near Geraldton, formed during post-2690 Ma regional dextral transpression across the belt.

Deformation at the southern boundary of the late Archaean Atâ tonalite and the extent of Proterozoic reworking of the Disko terrane, West Greenland

1999 ◽  
pp. 155-169 ◽  
Author(s):  
John Grocott ◽  
Steven C. Davies
Keyword(s):  
Large Scale ◽  
Hanging Wall ◽  
Shear Zones ◽  
High Grade ◽  
Southern Boundary ◽  
Late Archaean ◽  
West Greenland ◽  
North West ◽  
North East ◽  
The North

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Grocott, J., & Davies, S. C. (1999). Deformation at the southern boundary of the late Archaean Atâ tonalite and the extent of Proterozoic reworking of the Disko terrane, West Greenland. Geology of Greenland Survey Bulletin, 181, 155-169. https://doi.org/10.34194/ggub.v181.5123 _______________ The c. 2800 Ma old Atâ tonalite in the area north-east of Disko Bugt, West Greenland has largely escaped both Archaean and Proterozoic regional deformation and metamorphism. At its southern margin the tonalite is in contact with migmatitic quartz-feldspar-biotite gneiss and to the south both are progressively deformed in a high-grade gneiss terrain. The main deformation in the high grade gneisses involved hanging wall north-west displacements on a system of low-angle ductile shear zones that structurally underlie the Atâ tonalite. This shear zone system is folded by a large-scale, steeply inclined and north-west-trending antiform defined by the change in dip of planar fabrics. Minor folds related to the antiform are present and there is some evidence that folding was synkinematic with emplacement of a suite of c. 1750 Ma old ultramafic lamprophyre dykes. In much of the north-east Disko Bugt area it remains difficult to separate Archaean from Proterozoic structures and hence the extent of the Archaean terrane that has escaped intense Proterozoic reworking remains uncertain.

Himalayan inverted metamorphism and syn-convergence extension as a consequence of a general shear extrusion

2001 ◽  
Vol 138 (3) ◽  
pp. 253-276 ◽  
Author(s):  
JEAN-CLAUDE VANNAY ◽  
BERNHARD GRASEMANN
Keyword(s):  
Simple Shear ◽  
Thermal Evolution ◽  
Pure Shear ◽  
Hanging Wall ◽  
Ductile Deformation ◽  
Metamorphic Rocks ◽  
High Grade ◽  
The South ◽  
Main Central Thrust ◽  
Shear Component

Two paradoxical geological features of the Himalaya are the syn-convergence extension and the inverted metamorphic isograds observed in the crystalline core zone of this orogen. This High Himalayan Crystalline Sequence corresponds to an up to 40 km thick sequence of amphibolite to granulite facies gneiss, bounded by the Main Central Thrust at the base, and by the extensional faults of the South Tibetan Detachment System at the top. Geochronological and structural data demonstrate that coeval movements along both the Main Central Thrust and South Tibetan Detachment System during Early to Middle Miocene times were related to a tectonically controlled exhumation of these high-grade metamorphic rocks. The High Himalayan Crystalline Sequence systematically shows an inverted metamorphic zonation, generally characterized by a gradual superposition of garnet, staurolite, kyanite, sillimanite + muscovite and sillimanite + K-feldspar isograds, from the base to the top of the unit. Recent kinematic flow analyses of these metamorphic rocks demonstrate the coexistence of both simple shear and pure shear during the ductile deformation. The simple shear component of such a general non-coaxial flow could explain a rotation of isograds, eventually resulting in an inversion. The pure shear component of the flow implies a thinning of the metamorphic sequence that must be balanced by a perpendicular stretching of the unit parallel to its boundaries. Inasmuch as seismic data show that both the Main Central Thrust and South Tibetan Detachment System converge at depth, a thinning of the wedge-shaped High Himalayan Crystalline Sequence should induce a ductile extrusion of these high-grade rocks toward the surface. Rapid extension at the top of the sequence could thus be the consequence of a general shear extrusion of this unit relative to its hanging wall. Moreover, this extensional movement should decrease with depth to become zero where the boundaries of the unit meet, accounting for the paradoxical convergence of the South Tibetan Detachment System toward the Main Central Thrust. Furthermore, a general flow combining simple shear and pure shear can reconcile inverted isograds with the lack of inverted pressure field gradient across the High Himalayan Crystalline Sequence, despite an intense non-coaxial deformation. In good agreement with the seismic, kinematic and P–T–t constraints on the Himalayan tectono-thermal evolution, general shear extrusion provides a consistent model accounting for both inverted isograds and rapid extension in a compressional orogenic setting.

scholarly journals A New Mining Scheme for Hanging-Wall Ore-Body during the Transition from Open Pit to Underground Mining: A Numerical Study

2018 ◽  
Vol 2018 ◽  
pp. 1-17
Author(s):  
Baohui Tan ◽  
Fengyu Ren ◽  
Youjun Ning ◽  
Rongxing He ◽  
Qiang Zhu
Keyword(s):  
Underground Mining ◽  
Numerical Study ◽  
Hanging Wall ◽  
Slope Instability ◽  
Open Pit ◽  
Ore Body ◽  
Instability Development ◽  
Induced Caving ◽  
Iron Mine ◽  
Mining Scheme

A new mining scheme by employing the induced caving mining method to exploit hanging-wall ore-body during the transition from open pit to underground mining is proposed. The basic idea is to use the mined-out area generated by the planned mining of the hanging-wall ore-body to absorb the collapsed slope body, so as to avoid the influence of the inner-slope mining to the normal open-pit mining and guarantee mining efficiency during the transition stage. Numerical simulation study on the process of induced caving mining of hanging-wall ore-body is carried out based on the practical engineering setting of the Hainan iron mine, China, by employing the numerical method of discontinuous deformation analysis (DDA). The impact of rock mass structure on the mechanism of slope instability development and the mining hazard assessment in the new mining scheme is investigated. The influence of mining sequence on slope instability development and mining safety is also analyzed by taking the hanging-wall ore-body mining under the southern anti-dip slope at the Hainan iron mine as an example, and eventually a reliable mining scheme via induced caving is obtained. The numerical study proves the feasibility of the proposed new mining scheme for hanging-wall ore-body and provides theoretical and technical support for its application in practical mining activities.

scholarly journals Vectors to ore in replacive VMS deposits of the northern Iberian Pyrite Belt: mineral zoning, whole rock geochemistry, and use of portable XRF

2021 ◽  
Author(s):  
Guillem Gisbert ◽  
Fernando Tornos ◽  
Emma Losantos ◽  
Juan Manuel Pons ◽  
Juan Carlos Videira
Keyword(s):  
Hydrothermal Alteration ◽  
Hanging Wall ◽  
Iberian Pyrite Belt ◽  
Major Elements ◽  
Massive Sulphide ◽  
Alteration Zone ◽  
Portable Xrf ◽  
Sequence Characterization ◽  
Vms Deposits ◽  
Mineral Zoning

Abstract. Volcanogenic Massive Sulphide (VMS) deposits represent a major source of base, precious and other metals of economic and industrial importance. As in other mineral systems, progressive exhaustion of the shallowest and most easily accessible deposits is leading to increasingly complex exploration. In this context vectors to ore play a vital role. The Iberian Pyrite Belt (IPB) is an outstanding VMS district located in the SW Iberian Peninsula, which represents the main mining area in Spain and one of the main zones of base metal production in Europe. But the work on vectors to ore in the IPB is far from systematic or complete. In this work we have performed a detailed study of the main vectors to ore related to mineral zoning and whole rock geochemistry that are currently used in the exploration of VMS systems to a representative volcanic rock hosted replacive VMS deposit located in the northern IPB, the Aguas Teñidas deposit. Results have been compared to other deposits in the IPB and in other VMS districts. The investigated vectors include: mineralogical zoning, host sequence characterization and mineralized unit identification based on whole rock geochemistry, the study of the characteristics and behaviour of whole rock geochemical anomalies around the ore (e.g. alteration-related compositional changes, characteristics and extent of geochemical halos around the deposit), with definition of threshold values for the mineralization-related indicative elements, and application of portable XRF analysis to the detection of the previous vectors. In the footwall, a concentric cone-shaped hydrothermal alteration bearing the stockwork passes laterally, from core to edge, from quartz (only locally), to chlorite, sericite–chlorite, and sericite alteration zones. The hydrothermal alteration is also found in the hanging wall despite its thrusted character: a proximal sericite alteration zone is followed by a more distal albite one, which is described here for the first time in the IPB. Whole rock major elements show an increase in alteration indexes (e.g. AI, CCPI) towards the mineralization, with a general SiO2 enrichment, FeO enrichment in the central portion of the system, K2O and Na2O leaching towards the outside areas, and a less systematic MgO behaviour. Copper, Pb and Zn produce proximal anomalies around mineralized areas, with the more mobile Sb, Tl and Ba generating wider halos. Whereas Sb and Tl halos form around all mineralized areas, Ba anomalies are restricted to areas around the massive sulphide body. Our results show that proposed vectors, or adaptations designed to overcome p-XRF limitations, can be confidently used by analysing unprepared hand specimens, including the external rough curved surface of drill cores. The data presented in this work are not only applicable to VMS exploration in the IPB, but on a broader scale they will also contribute to improve our general understating of vectors to ore in replacive-type VMS deposits.

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