胶东深部金矿三维成矿预测及巨大的资源潜力

我国重要矿产资源严重短缺,深部找矿成为解决资源危机的必然选择,深部矿产资源预测则是深部找矿的前提和基础。然而,深部矿床埋藏深度大,主要根据地表物化遥和地质信息进行成矿预测的常规方法已不适用于深部成矿预测,三维成矿预测是解决深部找矿靶区圈定难题的关键方法。胶东是具有世界影响的金成矿区,深部找矿成果和勘探深度位居国内前列,对其进行三维成矿预测具备得天独厚的条件,对于推动我国深部找矿具有重要的示范作用。简要介绍了胶东三维成矿预测的方法、依据和预测结果。主要采用地质和地球物理相结合的方法建立了胶东区域三维地质模型,采用钻探与地球物理相结合的方法建立了主要金矿床集中区的三维地质模型。根据三维空间上的金矿断裂控矿规律,提出了基于阶梯成矿模式、重点根据断裂倾角梯变和缓倾角段控矿规律的深部找矿靶区预测方法和基于控矿断裂浅部资源量的深部金矿资源潜力预测方法。根据胶东区域三维地质模型和深部地球物理探测结果,圈定了3处找矿新靶区;根据金矿床集中区三维地质模型,提取了断裂缓冲区、断裂倾角、断裂表面变化率、矿体等间距分布等特征变量,在焦家断裂和三山岛断裂圈定了5处深部找矿靶区;根据三山岛、焦家、招平3条控矿断裂-2 000 m标高以浅已探明的金资源量,预测三者-2 000~-5 000 m深度金资源量达到3 377~6 490 t,认为胶东金资源总量有望超过万吨目标。新的预测成果,揭示了胶东地区令人振奋的深部金矿资源潜力,为进一步开展深部找矿奠定了基础。

肖家山锑矿地质特征及找矿前景

肖家山梯位于北秦岭同寨-毛羽沟-竹园断裂带的南侧，分南北两个矿段。矿体主要赋存在钙质粉砂岩及长石石英砂岩体内，矿化受褶皱、断裂控制，含矿岩性钙质粉砂岩及长石石英砂岩，容矿构造为构造裂隙，矿床成因类型为沉积-再造型层控梯矿床。

催化反应──导数示波极谱法测定痕量钨

在盐酸介质中，痕量钨（Ⅵ）对钛（Ⅲ）还原金莲花橙ＯＯ的缓慢反应有强烈催化作用，在ＮａＯＨ介质中金莲花橙ＯＯ于－０．５０Ｖｖｓ·ＳＣＥ产生一灵敏的导数示波极谱波。据此，建立了一个检测限和测定范围分别为０．８ｎｇ／ｍＬ和１．６～８０９／ｍＬＷ的催化反应一示波极谱新方法，用于钢和矿样中钨的测定，获得满意结果。

Feasibility of stochastic gradient boosting approach for predicting rockburst damage in burst-prone mines

The database of 254 rockburst events was examined for rockburst damage classification using stochastic gradient boosting （SGB） methods. Five potentially relevant indicators including the stress condition factor, the ground support system capacity, the excavation span, the geological structure and the peak particle velocity of rockburst sites were analyzed. The performance of the model was evaluated using a 10 folds cross-validation （CV） procedure with 80%of original data during modeling, and an external testing set （20%） was employed to validate the prediction performance of the SGB model. Two accuracy measures for multi-class problems were employed： classification accuracy rate and Cohen’s Kappa. The accuracy analysis together with Kappa for the rockburst damage dataset reveals that the SGB model for the prediction of rockburst damage is acceptable.

Research on the Application of Residual Apparent Polarization to Surveying Deep Jiaojia-type Gold Mines

The theory and equations of the residual apparent polarization method are proposed and described in this article. Based on studies of existing mines, the residual apparent polarization ηα^sy, calculated from the induced-current middle-gradient apparent polarizations ηα^sy at large and small electrode spaces over the known deep Jiaojia-type gold mines, have been shown to separate the effects of mines from the anomalous polarizations generated from the strongly altered rocks in fracture zones.

Changes of Clay Mineral Association After High-Gradient Magnetic Separation

The changes of clay mineral association after high-gradient magnetic separation (HGMS) treatment, and the effects of chemical and physical technologies on concentrating Fe oxides for main soils in central and southern China were investigated by means of X-ray diffraction (XRD) and chemical analysis methods. Results indicated that the concentrating times of Fe oxides by HGMS treatment were the largest for 0.2-2 μmsize fractions in the examined soils. For the soils in which 2: 1 phyllosilicates were dominant, concentrating times of iron oxides by HGMS treatment were larger than by 5 mol L-1 NaOH treatment. Phyllosili-cates were decreased after HGMS treatment; however, the decrease was less than that of kaorolinite. The goet bite / (goethite + hematie) values in Fe oxides of the soils kept virtually constant after HGMSt reatment.

Gradient principle of horizontal stress inducing rock burst in coal mine

Based on the stress distribution characteristics of rock burst multiple sites, the criterion of horizontal stress inducing layer dislocation rock burst was established. Accordingly, the influencing factors were analyzed. The analysis results indicate that the stress condition, edge of etastic zone depth, supporting strength, and the friction angle and cohesion among coal stratum, roof and floor are sensitive factors. By introducing double-couple model, the layer dislocation rock burst was explained and the energy radiation characteristics were analyzed. The SOS micro-seismic monitoring system was applied to observe the rock burst hazards about a mining face. The results show that P- and S-wave energy radiations produced by rock burst have directional characteristics. The energy radiation characteristics of the 22 rock bursts occurring on 79Z6 long-wall face are basically the same as theoretical results, that is, the ratio of S-wave energy of sensor 4 to 6 is about 1.5 and that of P-wave is smaller than 0.5. The consistency of the monitored characteristics of the energy radiation theoretically increases with the total energy increasing.

Accelerated Interfacial Charge Transfer in Br-Gradient MAPbI_(3-x)Br_(x) Perovskite Thin Films

Mixed halide perovskites(MHPs)are a class of semiconductor materials with great promise for many optoelectronic applications due to their outstanding photophysical properties.Understanding and tailoring the photogenerated carrier dynamics is essential for further improvement of perovskite performance.Herein,we report a study about the carrier transport and interfacial charge transfer dynamics in Br-gradient MAPbI_(3-x)Br_(x) perovskite thin films prepared by surface ion-exchange method.Driven by the bandgap gradient in MAPbI_(3-x)Br_(x) films,the accelerated internal hole transport and enhanced interfacial extraction efficiency were both observed.Meanwhile,the interfacial electron transfer was also found to be evidently facilitated due to the surface modification during post-treatment.Our findings suggest the possibility of simultaneous acceleration of interfacial electron and hole transfer processes in halide perovskite films via surface post-treatment technique,which is of great importance in further improving the power conversion efficiency of perovskite solar cells.

Monitoring mine collapse by D-InSAR

For harmful ground collapse and its special deformation characteristics,which causes SAR images to lose coherence,InSAR technology cannot be applied in monitoring surface collapse in mining areas.We took the Shenmu mining area in northern Shaanxi province as an example to study subsidence in mining areas and proposed an interpolated multi-view processing method.The results show that this method can improve the detectable deformation gradient to a certain extent and can become a good reference value for monitoring large scale gradient deformation.We also analyzed the rules for temporal decorrelation in mining.

A column study of the hydro-mechanical behavior of mature fine tailings under atmospheric drying

In this paper, the hydro-mechanical behavior and physical properties of mature fine tailings(MFT) under atmospheric drying are investigated through a column study. In the study, evaporation takes place in the development of suction in the upper parts of the column and increasing suction leads to higher strength in the tailings. After 5 days, the suction in the first lift is around 17 k Pa in the upper part of the column.When a second lift is added, the first lift initially loses strength but over a 30 days' period, the strength is recovered to its prior value and suction in the second lift reaches 500 k Pa. The vane shear strength values show a substantial increase in the strength of the MFT after 30 days under atmospheric drying and drainage. The 90% strength found in the column exceeds the threshold(5 k Pa). The hydraulic-mechanical properties of the deposited tailings are closely coupled due to several mechanisms, such as evaporation,drainage, self-consolidation, suction and crack development. The findings of this study will provide a better understanding of the placement behavior of multiple lifts of MFT and thus contribute to reclamation design standards and reduce the use of dedicated disposal areas.

Gradient based restoration of coal mine images obtained by underground wireless transmissions

Curvature-driven diffusion (CDD) principles were used to develop a novel gradient based image restora- tion algorithm. The algorithm fills in blocks of missing data in a wireless image after transmission through the network. When images are transmitted over fading channels, especially in the severe circum- stances of a coal mine, blocks of the image may be destroyed by the effects of noise. Instead of using com- mon retransmission query protocols the lost data is reconstructed by using the adaptive curvature-driven diffusion (ACDD) image restoration algorithm in the gradient domain of the destroyed image. Missing blocks are restored by the method in two steps: In step one, the missing blocks are filled in the gradient domain by the ACDD algorithm; in step two, and the image is reconstructed from the reformed gradients by solving a Poisson equation. The proposed method eliminates the staircase effect and accelerates the convergence rate. This is demonstrated by experimental results.