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The void closure model is urgently needed for the subsequent hot forming process of additive manufacturing (AM) products. The influence of temperature, Lode parameter, and hydrostatic integration (Gm) on void closure was studied by representative volume element (RVE) simulations. The results show that Gm and the Lode parameter significantly influence void closure, and the temperature effect is related to material properties. A new model accounting for Gm and Lode parameter in evaluating void closure was developed using linear regression with an average error of 2.1% in comparison to RVE simulations. X-ray computed tomography (CT) was carried out at different high reductions for the AM cylinder's hot forging experiments. The new and stress-triaxiality-based (STB) models were integrated into the ABAQUS and compared with the CT measurements. Results indicate that the model is more precise than the STB model, suggesting that the model can be appropriately applied to forecast void closure during the hot forging process for AM products.

Late-stage metamorphic (ca. 2.64 Ga) and punctuated magmatic-hydrothermal mineralization models (2.67–2.64 Ga) are proposed for gold mineralization in the Kalgoorlie gold camp (~ 2300 t Au; Archean Yilgarn craton, Western Australia). We present structural, whole-rock geochemical, pyrite trace element, and multiple sulfur isotope data to evaluate these models. Both the Fimiston and Hidden Secret lodes were emplaced in ca. 2675 Ma D2b transtensional settings as releasing bends developed along the Golden Mile and Towns faults, respectively, and are related to the ingress of a H2O-CO2-Au-Te-As-S-K-Rb-Ba fluid concomitant with the intrusion of andesitic dikes. In the Hidden Secret orebody, this magmatic-hydrothermal fluid evolved from an early, As-enriched, greenstone-buffered fluid during the formation of disseminated pyrite mineralization (δ34Spyrite = 3.42 to 3.85‰; Δ33Spyrite = 0.25 to 0.43‰) to an Ag-Cu-Pb-Sb-Te-Tl-V-Zn–enriched fluid during the development of banded quartz-carbonate-sericite-pyrite veins (δ34Spyrite = - 10.74 to - 0.17‰; Δ33Spyrite = 0.06 to 0.19‰). Oroya gold-telluride lode mineralization formed during later, ca. 2660 Ma D2c transpression from a V-S–Au-Ag-Hg-Te–enriched magmatic-hydrothermal fluid represented by δ34Spyrite = - 11.56‰ to - 4.96 and Δ33Spyrite = 0.08 to 0.17‰. The Fimiston/Hidden Secret and Oroya mineralization events record oxidized magmatic-hydrothermal fluids represented by δ34Spyrite ≤ 0‰ and Δ33Spyrite ~ 0.0 to 0.2‰. These oxidized magmatic-hydrothermal fluids interacted with surrounding wall rock, which lowered fluid fO2 and buffered δ34Spyrite/Δ33Spyrite values to δ34Spyrite = ~ 1 to 5‰/Δ33Spyrite = ~ 0.2 to 0.7‰ in greenstone rock environments and to δ34Spyrite = ~ 1 to 5‰/Δ33Spyrite = ~ ≤ 0.3‰ and ≥ 0.7‰ in black shale environments. Anomalous Δ33S values in ore-stage sulfides formed locally due to the incorporation of sulfur during fluid-wall rock interaction. The early, magmatic-hydrothermal Fimiston/Hidden Secret and Oroya gold-telluride lodes differ texturally, geochemically, and mineralogically from the D3 Mt. Charlotte stockwork veins, which formed subsequent to ca. 2650 Ma and better adhere to a late-stage metamorphic devolatilization model.

Lode gold deposits are among the most economically important types of gold deposits in the world. Globally, they formed mainly in three time intervals, 2.8 to 2.5 Ga, 2.1 to 1.8 Ga, and 700 Ma to the present. Sources of ore-forming fluids and other components are of critical importance in a better understanding of the genesis and the geodynamic controls of these deposits. Although ore-forming fluids were mostly derived from devolatization of sedimentary and/or volcanic sequences during greenschist to amphibolite facies metamorphism associated with orogenic deformation, magmatic hydrothermal fluids have been increasingly shown to be important in many gold deposits in various regions. In this review paper, we summarize the major features of lode gold deposits, possible sources of ore-forming fluids, and mechanisms of gold mineralization. While we acknowledge the critical role of metamorphically derived fluids in the genesis of such deposits worldwide, we emphasize that mantle- or basaltic magma-derived fluids may have been much more important than commonly thought. We use the Liaodong peninsula of the North China Craton as an example to demonstrate the significance of mantle-derived fluids. Integrating earlier studies and new data, we show that some of the late Mesozoic lode gold deposits in the North China Craton may have formed from magmatic hydrothermal fluids due to the extension and partial melting of the hydrated, metasomatized subcontinental lithosphere mantle, as best exemplified by the Wulong gold deposit.

A double notched central hole, i.e., DNC specimen, which contains a center hole with a left side notch and a right side notch accompanying the slope α, is proposed to simultaneously achieve dual values of stress triaxiality and Lode parameter from one specimen in the present study. Analytical and numerical approaches are carried out under decent assumptions to characterize the plane strain behavior of DNC specimen along with the slope α. Quasi-static tensile tests with conventional specimens and DNC specimens revealed plastic strains at fracture for each specimen case in accordance with stress triaxiality and Lode parameter by digital image correlation. It is found that one DNC specimen successfully provides dual values of stress triaxiality and Lode parameter at the same time; therefore, it saves up to 50 % of experimental time and labor of conventional specimens.

Quartzite is a mountain igneous sedimentary rock formed by fusion of quartz sand with other minerals. The volume of its consumption is increases constantly. For this reason resolution of the problem of the feasibility of developing a new formation or a new site (lode) of an existing quartzite deposit depends directly on its properties. This is especially true for the use of quartzite in the metal industry where it is exposed to high temperature. As a rule studying properties of quartzite for water absorption, open porosity and apparent density is performed at room temperature. Macro and microstructures are studied before and after calcining at 1450°C using optical microscopes that make it possible to conduct X-ray phase analysis.

In 2009, Harvard Business Review published “Why Sustainability is Now the Key Driver of Innovation.” The authors write, “sustainability is a mother lode of organizational and technological innovati...

Morphologic and placer features were used to characterize, determine the provenance, and transport distances of gold grains within the River Gagare drainage basin of the Wonaka Schist Belt. Field studies, scanning electron examination coupled with energy dispersive spectrometry and binocular microscopy were utilized to study the spatial distributions, shape, size, inclusions, primary and fluvial transport-induced deformations, as well as Cailleux flatness indices. The grains are dominantly subrounded (71%), with the length between 35 – 800 µm and width of 10 – 778 µm while the rounded grains have a mean length of 292.5 µm and width of 179 µm. Similar values for circularity and sphericity are observed in the sub-rounded grains, with slight variations of 2.7 circularity and 2.6 sphericitydistinguished in the rounded grain subset. The Cailleux flatness index range from 2.5 to 9 for subrounded grains and 2 – 15.5 for the rounded, indicating the multisource nature of the grains. The grains are consistent with short to moderate transport distances from the lode sources. The similarities in physical features, lack of delicate secondary growth structures and irregular grain outlines point to a detrital source for the placer deposits. Evidence of emulsion crystallisation type is indicated by the presence of sub- to anhedral inclusions within the Au grains. Keywords: Placer gold, Cailleux flatness indices, Wonaka Schist Belt, Provenance, Northwest Nigeria

Purpose: HER2 directed neoadjuvant therapies for locally advanced HER2-positive breast cancer have improved complete pathologic response and event-free survival. For T1 breast cancer, lymph node status often determines whether neoadjuvant treatment is indicated. The aim of this study was to identify patient and tumor characteristics using the National Cancer Database.Methods: A retrospective review of patents diagnosed with T1 clinically node negative (cT1N0) HER2-positive breast cancers was performed using the American College of Surgeons National Cancer Database (ACS NCDB) from 2004-2016. Exclusion criteria included age Results: A total of 57,366 T1 HER2-positive patients were identified with 8,994 patients (15.68%) having positive lymph nodes. Characteristics associated with lymph node involvement included age (p Citation Format: Laura DeCesare, Claudia Perez, Neha Nimmagadda, Yanyu Zhang, Samantha Terranella, Nicholas Skertich, Aaron Wiegmann, Andrea Madrigrano, Rosalinda Alvarado, Cristina O'Donoghue. Pathologic lymph lode status of patients with T1 HER2-positive breast cancer who did not receive neoadjuvant chemotherapy using the national cancer database [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS1-20.

The features of impurity element distribution in native gold of two ore formation gold deposit types are con- sidered. A typomorphic set of elements for gold-polysulfide-quartz and gold-quartz low-sulfide mineralization was determined. Geochemical indicators for estimating ore formation types of native gold are offered. The differences in gold composition due to metallogenic specialization of regions are established. Data on the distribution of rare-earth elements in native gold are obtained, which allows to predict igneous rocks composition during gold-polysulfide-quartz deposit formation.

Main features of the Archean gold deposits spatial distribution are outlined. Geology and ore composition of two deposits within the Canadian shield distinguished by tectonic position and host rock lithology are described. Delineation of two separate genetic types of the Archean gold deposits, orogenic and granitoid-related, similar to Phanerozoic accretion-collision belts is validated on that basis.

This work presents a detailed study of platinum-group mineral (PGM) assemblages from the Malaya Kamenushka River placer, whose formation is associated with the weathering of the Kamenushensky Uralian–Alaskan type massif, Middle Urals, Russian Federation. The deposit is characterised by the dominance of isoferroplatinum, together with significant numbers of inclusions of Os–Ir–Ru alloys and platinum-group element (PGE) sulfides. A study of the Os–Ir–Ru alloys permitted recognition of two types of iridium with different morphology and composition. The similarity of the PGM assemblages from the Malaya Kamenushka River placer and the lode mineralisation of the Kamenushensky massif is demonstrated. A comparison of PGM assemblages from the Malaya Kamenushka River placer with other placers and massifs of the Ural platinum belt demonstrates significant differences in the number of Os–Ir–Ru inclusions. Such differences for minerals of refractory elements cannot be explained by the vertical zoning of the lode mineralisation. Most probably this is associated with the enrichment of the primary substrate with Os, Ir and Ru and/or the degree of melting, depending on the chosen model of formation of the Uralian–Alaskan type massifs.

This paper investigates the failure strain as a dependence of the stress triaxiality and the Lode angle parameter for polyurethane rigid foams (PUR) of two densities (100 and $$300\,\hbox {kg/m}^{3})$$ . Tests were carried out in tension for various configurations, resulting in different states of stress triaxiality at various Lode angles in the critical areas. The failure strain was determined for each setup using finite element analysis, as the tests were replicated with numerical models. The displacement at failure recorded in the experiments was imposed for the models, determining the failure strain as a function of stress triaxiality and the Lode angle parameter. The results were validated through the analysis of the failure of sandwich structures with aluminium faces and PUR cores.

The lode angle dependency introduced by anisotropic damage evolution laws is analyzed in detail for initially isotropic materials. Many rupture criteria are obtained, under the proportional loading assumption, by the time integration of different anisotropic damage evolution laws [Formula: see text] among the three existing families: strain governed, stress governed and plastic strain governed. The cross-analysis of path independent rupture criteria and of anisotropic damage evolution laws finally allows us to improve the Lode angle dependency of (fully coupled) anisotropic damage models.

The Epilchik Ural-Alaskan type mafic-ultramafic zoned complex, located in the northernmost part of the Koryak-Kamchatka Platinum Belt (Russian Far East), contains lode platinum mineralization. The outcrops of the complex are crossed by the Snegovaya River, which hosts placer platinum-group minerals (PGM) occurrences. The primary PGM assemblage of the Epilchik lode chromitites is typical for Ural-Alaskan type complexes, dominated by Ir-rich isoferroplatinum which occurs as small euhedral inclusions within chromite. Secondary alloys include tetraferroplatinum (PtFe), tulameenite (Pt2FeCu), an unnamed Fe3Pt compound, and Pt-bearing native iron, which form alteration rims around isoferroplatinum or occupy fractures in chromite. Other secondary minerals from lode chromitites are hollingworthite (RhAsS) and Os-Fe alloy (“hexaferrum”). The PGM assemblages of the Snegovaya River placer occurrences are comparable with those of the lode chromitites with a predominance of Ir-rich isoferroplatinum and secondary alloys, including tetraferroplatinum, tulameenite, and an unnamed Fe3Pt compound. However, placer occurrences are much richer in regard to mineral diversity, comprising native osmium (Os,Ir), native iridium (Ir,Os), laurite (RuS2), erlichmanite (OsS2), cuprorhodsite (CuRh2S4), cuproiridsite (CuIr2S4), Co-malanite (Cu(Pt,Co)2S4), unnamed sulfides Rh3S4, (Rh,Pt)S, sperrylite (PtAs2), platarsite (PtAsS), irarsite (IrAsS), hollingworthite (RhAsS), osarsite (OsAsS), cooperite (PtS), native gold, unnamed telluride (Pt2Te), and an unnamed Fe-Ir-Rh alloy. Similarities between lode and placer mineralization indicate that the Epilchik complex was the dominant source for the placers. The larger diversity of PGM in placers may be attributed to the heterogeneity of samples which could be derived from unsampled or unexposed outcrops of the complex. Alteration of isoferroplatinum to secondary intermetallic compounds occurred via progressive development of reduced conditions as a result of serpentinization. Subsequent pervasive As-mineralization redistributed platinum-group elements, including Os and Ir. A final mineralizing pulse deposited sporadic native gold and Pt telluride minerals. A comparison of key mineralogical and physical features between the Epilchik complex and other Ural-Alaskan type complexes is used to determine the economic potential for placers along the Snegovaya River. Key criteria include (1) the size and degree of erosion of the outcrop area of the complex; (2) the predominance of isoferroplatinum over native platinum; (3) high Ir content in Pt-Fe alloys; and (4) the predominance of secondary intermetallic compounds over sulfides. Based on these criteria, the occurrences associated with the Epilchik complex are considered prospective for high volume and economic grade accumulations of PGE. This method is useful for assessing the economic potential of placer occurrences during indirect early-stage prospecting with a limited sample suite.

Power output can be used to control training load. However, it is important to know if different power meters are reliable, because variations in their measures have direct repercussions on the training program. The aim of this study was to verify the reliability of the power output during two different pedaling protocols (incremental and variable tests) obtained with GARMIN Vector pedals and to compare it with the gold standard LODE Excalibur cycle ergometer. Fourteen male cyclists (30 (6) years of age, maximal power 423 (23) W) performed a maximal test (initial load 100 W with 25 W/min increments) and a variable load test (100–400 W) with the LODE Excalibur cycle ergometer instrumented with GARMIN Vector pedals (coupled on the LODE Excalibur cranks). Student’s t test, intraclass correlation coefficient (ICC), and Bland-Altman analysis were used to evaluate meters’ differences and reliability, respectively. All measures performed in the incremental test (100–400 W) and two measures (100 W, 150 W) of the variable load test showed no power output measurements’ reliability between the GARMIN Vector pedals and the LODE Excalibur cycle ergometer (p

Low saline aqueous carbonic fluids are considered to be the ore forming solutions for orogenic lode gold deposits. Phase separation/fluid immiscibility of the ore fluid is quite common and is one of the major reasons for deposition of gold in these deposits. Abundant carbonic fluid inclusions have been observed in quartz grains of Hira-Buddnini Gold Deposit. Theoretical estimation indicates that more volume of H2O compared to CO2 is likely to be trapped in inclusions at different P-T conditions. Preferential loss of H2O from fluid inclusions during ductile deformation of quartz grains have been attributed as the suitable reason for abundance of carbonic fluid inclusions.

This paper presents new data for historical vein-hosted copper sulfide deposits in the Late Paleozoic Munster and South Munster basins of SW Ireland. Detailed mapping, 3D modelling, fluid inclusion microthermometry and geochronology from the Allihies area of the Beara Peninsula have led to a new interpretation of the timing and development of ore mineralization. Macro- and microstructural studies reveal that the ore-bearing, mainly east–west-striking quartz veins are directly related to early extensional, basinal normal faults. Molybdenite Re–Os dating of the main-stage Cu lode yields ages from 367.3 ± 5.5 to 366.4 ± 1.9 Ma. This early vein system experienced subsequent late Carboniferous Variscan deformation, including cleavage development, sinistral SW–NE strike-slip faulting, cataclastic deformation and recrystallization. The new timing of Cu mineralization in SW Ireland has major implications for its relationship to the base metal deposits of the Irish Midlands. Supplementary material: A video file showing a 3D model of the major lodes and the underground workings at Mountain Mine, and Excel spreadsheets showing fluid inclusion measurements and sample locations of the Allihies Copper Mining District are available at https://doi.org/10.6084/m9.figshare.c.4875015

In this study, the distinct element method (DEM) was employed to numerically explore the mechanical responses of granular soils and to extract key components for an elastoplastic constitutive model for them. Considering the irregular shapes of real particles, a contact model considering rolling and twisting resistances was used in the DEM simulations. It is shown that this contact model can successfully capture the density-dependent, pressure-dependent behavior of granular soils as well as stress–dilatancy behavior. A critical state-based, double yielding surface constitutive model was used to describe the mechanical behavior of the DEM numerical material. A marked feature of the proposed constitutive model is the incorporation of a flow rule that defines the relationship between the stress Lode angle and strain Lode angle in the deviatoric plane. The model parameters were completely determined from DEM simulation results. The agreement between the DEM simulation results and the constitutive model prediction indicates that realistic complex mechanical behavior of granular soils in generalized loading paths can be reproduced well in both discrete and continuum ways. This will allow effective coupling of discrete–continuum modeling (such as DEM–FEM) in solving geotechnical boundary value problems with large deformation, where a consistent representative of soil is required for the near-field DEM modeling and far-field FEM modeling.

The Wulong lode gold deposit is located in the Liaoning Province, northeast part of North China Craton. Gold ore bodies are mainly hosted in the Late Jurassic granite and structurally controlled by northeast-trending faults. Gold occurs in disseminated and auriferous quartz–sulfide veins and veinlets within hydrothermally altered rocks. Mineralization can be divided into three stages: (1) quartz–pyrite stage, (2) quartz–polymetallic sulfides stage, and (3) quartz–carbonate stage. Gold formed mainly in the middle stage. Quartz formed in the two earlier stages contains three compositional types of fluid inclusions, i.e., pure CO2, CO2–H2O and NaCl–H2O, but the late-stage minerals only contain NaCl–H2O inclusions. The inclusions in quartz formed in the early, main, and late stages yield total homogenization temperatures of 317–383 °C, 260–380 °C and 159–234 °C, respectively, with salinities of 5.14–9.44, 2.95–6.20, 1.23–4.34 wt% NaCl equivalent, respectively. Trapping pressures estimated from CO2–H2O inclusions are 200–390 MPa in the main stage. Fluid boiling and immiscibility caused rapid precipitation of sulfides and gold. Through immiscibility and inflow of meteoric water, the ore-forming fluid system evolved from CO2-rich to CO2-poor in composition, and from magmatic to meteoric, as indicated by δ18Owater values (4.5‰–7.3‰). The carbon (−12.2‰ to −11.5‰), sulfur (0.9‰–2.6‰), and lead isotope (207Pb/204Pb of 15.606–15.618) compositions suggest the host rocks to be a significant source of ore metals. Integrating the data obtained from the studies including regional geology, ore geology, fluid inclusion, and C–H–O–S–Pb isotope geochemistry, we conclude that the Wulong deposit is a decratonization gold deposit formed during lithospheric thinning associated with destruction of the North China Craton triggered by the subduction of the Paleo-Pacific Oceanic plate in the Early Cretaceous.

Based on a Gibbs potential formulation for implicit elastic bodies, we propose a new strain limiting constitutive relation using Lode invariants of stress, and numerically study a non-dimensionaliz...

In recent years, the Lode angle was found to have a significant effect on plasticity and fracture strain of ductile metal under shear dominant loading, and the classical J2 plasticity theo...

Magmatic-hydrothermal gold–copper deposits in post-subduction settings represent essential targets for mineral exploration, but controls on their formation remain controversial. The early Cretaceous lode Au districts that formed during lithosphere destruction of the North China Craton provide an ideal opportunity to better understand the key tectono-magmatic factors responsible for the genesis of Au-rich deposits in post-subduction settings. Here, we present a LA-ICP-MS study of silicate melt inclusions and sulfide inclusions from ore-related mafic to intermediate rocks in the central Taihangshan Au district in the interior of the North China Craton to constrain the content and evolution of magmatic ore metals ± volatiles. The results, combined with numerical modeling, suggest that the ore-related magmas contained only a few ng/g Au, which is similar to the Au content of non-mineralization-related mafic to intermediate magmas worldwide. The low Au content of the lode Au-related magmas suggest that large volumes of magmas had to accumulate in the middle to lower crust through trans-lithospheric fault systems to produce the lode Au deposits. It is further suggested that the lode Au-related magmas were alkali-rich, hydrous, oxidized and relatively rich in sulfur and chlorine (mafic melt inclusions contain 0.14‒0.24 wt% S and 0.1‒0.2 wt% Cl). These properties are considered critical for the generation of auriferous ore fluids. By comparing the tectono-magmatic setting of the giant Jiaodong Au province (~ 4000 t Au) with the central Taihangshan district (~ 150 t Au), we propose that the much larger total Au tonnage of the Jiaodong district results from the accumulation of a much larger volume of ore-forming magmas at deep crustal levels, induced by a stronger degree of lithosphere modification. In addition, given that the composition of lode Au-related magmas is similar to that of porphyry Cu–Au-related magmas, the lack of giant, early Cretaceous porphyry Cu–Au deposits in the North China Craton suggests that strong extensional settings favor the formation of lode Au deposits instead of porphyry Cu–Au deposits. The present study, therefore, has general implications for the genesis of Au-rich deposits in strongly extensional settings.

Machine learning has been a popular tool in many different fields, including procedural content generation. However, procedural content generation via machine learning (PCGML) approaches can struggle with controllability and coherence. In this paper, we attempt to address these problems by learning to generate human-like paths, and then generating levels based on these paths. We extract player path data from gameplay video, train an LSTM to generate new paths based on this data, and then generate game levels based on this path data. We demonstrate that our approach leads to more coherent levels for the game Lode Runner in comparison to an existing PCGML approach., 7 pages, 6 figures, Workshop on Procedural Content Generation

Le poète Hérondas connaît la théorie et la pratique de la rhétorique. Les Mimes représentent des situations qui peuvent être interprétées en fonction des grilles et des procédés de la rhétorique. L’aptitude oratoire, qui sert au comique, se révèle une qualité essentielle pour le poète et son public. The poet Herodas knows the theory and the practice of rhetoric. Mimes represent situations that can be interpreted according to the codes and procedures of rhetorical art. Oratorical aptitude, which serves the comic, is an essential quality for the poet and his audience. Il poeta Eroda conosce la teoria e la pratica della retorica. I Mimi presentano situazioni interpretabili secondo codificazioni e procedure retoriche. L’attitudine oratoria, che è funzionale alla dimensione comica, è una qualità essenziale per il poeta e il suo pubblico.

This paper discusses models showing the formation of the Central Mediterranean region and the geodynamic setting of the Apennine Peninsula. Cataclastic analysis is used for a repeated reconstruction of the Central Mediterranean region. The catalogue of earthquake focal mechanisms includes 662 events (3.6≤Mb≤6.5) recorded in the study area from 1977 to 2015 (Global CMT, http://www.globalcmt.org; RCMT, http://rcmt2.bo.ingv.it/index.html; Italian CMT dataset, http://rcmt2.bo.ingv.it/Italydataset.html). The reconstruction yielded the directions of principal stresses (including algebraically maximum and minimum ones), locations of domains differing in geodynamic regime, Lode – Nadai coefficients, and orientation of tangential shear stresses acting from the mantle to the crust. By comparing our results to the published data obtained by M.‐L. Zoback’s method, we have identified differences in the orientations of maximum horizontal compression axes at points where the stress ellipsoid takes on its critical values. It is revealed that the strongest earthquakes (M>6) were generated in the areas characterized by the minimum and average relative stress magnitudes.

We have analysed s large public-domain TDEM datasets acquired by Ministry of Northern Development and Mines – MNDM of Ontario Canada. Geophysical data set 1076 (6,500 out of the original 10,000 lin...

The Borden Gold deposit (9.3 Mt @ 5.3 g/t Au) is a structurally controlled Archean mesothermal lode gold deposit within the Kapuskasing Structural Zone, in northern Ontario. Helicopter VTEM and mag...

The Cretaceous sedimentary sequence of the Asu River Group in Ameri, southeastern Nigeria play host to lead-zinc ore deposits in irregular mineralized veins of non-uniform geometry. Two deposits (designated DEPOSIT A and DEPOSIT B) were economically assessed using an integrated approach. This was performed by employing a geometry-based classical scheme involving the mathematical relationship between the three cardinal variables of ore reserve estimation namely: surface area, thickness and density. Firstly, detailed and extensive geological mapping was carried out to establish the geological attribute of the mineral deposits. Since reserve estimation extends beyond exposed faces, spontaneous potential traverse, vertical electrical sounding and horizontal profiling, being orthogonal to the trend of the enclosing veins were used to characterize the existing sub-surface stratification and create forward models that revealed the concealed ore geometry (limiting depth, lateral extents and thickness variations). Subsequent to delineation, the depth to the top of the target ore lodes was obtained by implementing the Peter's half slope technique on self-potential curves. Thickness values of the ore bodies of interest were applied in three numerical classical integration techniques, i.e. Trapezoidal, Simpson's and Simpson's third-eight rule, for volume estimation. To overcome the non-uniqueness problem of DC resistivity data interpretation, the available drilling data was applied. Samples retrieved from each lode were subjected to mass and volume analysis using the CS200 electronic balance and water displacement technique, to determine the average density of each lode. Results from 2D subsurface resistivity sections showed the lead-zinc deposits as zones of low resistivity in a background of high resistivity. The 1D stratigraphic models reveal a mean thickness estimate of 11.85 m and 10.50 m for DEPOSITs' A and B, respectively. Sample densities correlate well with the average density of pure galena. Applying the scalar-geometric rule, a combined estimate of 10,778.95tonnes was obtained, representing a relatively economically viable quantity worthy of medium scale extraction. Keywords: Ameri, Reserve estimation, Resistivity, Deposit, Vein, Profile

To investigate the influence of stress Lode angle on frozen soil, a series of directional shear tests was conducted on artificial frozen clay at three temperatures (–6, –10, and –15 °C) and five stress Lode angles (θσ= –30°, –16.1°, 0°, 16.1°, and 30°) using a hollow cylindrical apparatus. An elliptical function was proposed according to the strength envelope evaluation with the mean principal stress (p) in the p–q plane. In addition, generalized nonlinear strength theory (GNST) was introduced in the π plane to describe the evolution of the strength envelope with increasing mean principal stress. Then a strength criterion for frozen clay in three-dimensional principal stress space was proposed by combining strength functions in the p–q and π planes. The temperature effect was also introduced into the strength criterion. The proposed strength criterion can predict the multi-axial strength characteristics of frozen clay and reveal the influence of the stress Lode angle.

The distribution of major gold deposits in the Earth’s history is discussed. The primary heterogeneity of the Archean crust in terms of gold mineralization is demonstrated. Characteristics of the main auriferous metallogenic epochs are given. The predominant associations of the orogenic gold deposits with volcanogenic massive sulfide and copper–nickel deposits during the early periods of the Earth (Archean–Proterozoic) and those with tungsten, molybdenum, copper, antimony, mercury, and tin during the Phanerozoic are demonstrated. The analysis of the distribution of the mineralogical and geochemical types of gold mineralization proper also demonstrates their substantial diversity in the Phanerozoic compared to the Precambrian. These data reflect the mantle–crustal origin of gold mineralization in general and attest to an increase in the contribution of the crustal material into gold mineralization with the age of the Earth. The known gap in lode gold formation (1.7–0.8 Ga), which was caused by the stable cratonic regime of the long-lived Columbia (Nuna)–Rodinia supercontinent is discussed.

Felsic schist units in the Lone Star Ridge area of the northern Klondike Gold District, Yukon, Canada, host both locally gold-bearing orogenic quartz veins and much more extensive zones of disseminated gold mineralization that is stratabound within specific schist units and is interpreted to be syngenetic in origin. Scarcity of outcrop and the difficulty in distinguishing between subtly different schist units has hampered correlation between surface exposures and drill core, and production of a detailed geological map of the area. Lithogeochemistry offers an alternative, unbiased way to map and interpret the various subunits of the felsic schist package that host disseminated gold mineralization and gold-bearing veins in parts of the Klondike, and that can potentially form the basis for correlations between various drill holes, and between drill holes and surface exposures. A detailed investigation of 4590 multi-element geochemical analyses (by 4-acid digestion) from a set of 27 diamond drill holes in the vicinity of the Boulder Lode open cut (Lone Star gold occurrence) on Lone Star Ridge has revealed several lithogeochemical signatures that correlate closely with gold content and to some extent with lithological units distinguished during initial logging of the drill core. Research quality geochemical analyses for a suite of representative rock units selected from the 2005 drill holes have been used to verify the multi-element geochemical analyses, and to determine the petrochemical character of some of the individual rock units. Results of this study demonstrate that it is possible to construct a chemostratigraphic framework for the felsic schist units in the vicinity of the Boulder Lode. Distinctive rock units can be broken out that have very consistent geochemical signatures, and elevated gold values related to the presence of disseminated gold appear to be consistently associated with specific rock units. These chemostratigraphic marker units have been utilized to constrain the geology and structure of the immediate study area, and in particular to define the geometry of the schist units that contain disseminated gold. The same approach has also been applied to a very extensive set of geochemical data (comprising nearly 34,000 individual samples) from chip samples, diamond drill core, reverse circulation drill samples, and conventional soil samples obtained during other historical and more recent exploration programs, to better resolve the geological interpretation of entire Lone Star Ridge area.

Rock strength criterion is a basic subject in mining engineering and petroleum engineering. It has important guiding significances to the process of underground energy exploitation. Different rocks have different strength envelopes. Most strength criteria have only one type of envelope in π plan. Thus, these criteria cannot predict different rock strengths accurately. Most criteria consider only the hydrostatic stress and the Lode angle effects and neglect their interaction. However, based on the experimental results in this study, there is an evident interaction between the two effects. In this study, a new strength criterion is proposed considering the hydrostatic stress and Lode angle effects, as well as the effect of hydrostatic stress on the Lode angle effect. Applicable results of previous experimental data showed that the proposed strength criterion has good applicability for different rocks. Compared with other strength criteria, this criterion has the advantage of being able to adjust the strength of the Lode angle effect based on the hydrostatic stress. This advantage allows the strength criterion to show different types of strength envelopes in the π plan and to accommodate different rocks under different stress states. The effect of hydrostatic stress on the Lode angle effect of rock may be caused by the proportion of particles destroyed in the rock.

The initiation of ductile fracture in grade DH36 shipbuilding steel was modeled using the Hosford-Coulomb fracture model. The hardening and ductile fracture characteristics of DH36 were assessed by performing experiments on notched tension, central hole tension, plane strain tension and shear specimens. Detailed finite element analysis of each experiment was performed to evaluate the evolution of local stress and strain fields. The loading paths to ductile fracture initiation were determined in terms of the stress triaxiality and Lode angle parameter histories extracted from finite element analyses with very fine solid element meshes. The Hosford-Coulomb fracture model parameters were identified using the extracted loading paths and adopting a linear damage accumulation law. It has been found that ductile fracture behavior of DH36 is dependent not only on the stress triaxiality but also the Lode angle.