Predicting pillar stability for underground mine using Fisher discriminant analysis and SVM methods

The purpose of this study is to apply some statistical and soft computing methods such as Fisher discriminant analysis （FDA） and support vector machines （SVMs） methodology to the determination of pillar stability for underground mines selected from various coal and stone mines by using some index and mechanical properties, including the width, the height, the ratio of the pillar width to its height, the uniaxial compressive strength of the rock and pillar stress. The study includes four main stages： sampling, testing, modeling and assessment of the model performances. During the modeling stage, two pillar stability prediction models were investigated with FDA and SVMs methodology based on the statistical learning theory. After using 40 sets of measured data in various mines in the world for training and testing, the model was applied to other 6 data for validating the trained proposed models. The prediction results of SVMs were compared with those of FDA as well as the measured field values. The general performance of models developed in this study is close; however, the SVMs exhibit the best performance considering the performance index with the correct classification rate Prs by re-substitution method and Pcv by cross validation method. The results show that the SVMs approach has the potential to be a reliable and practical tool for determination of pillar stability for underground mines.

Fruit Anatomy of sect. Paracamellia with Reference to Their Significance of Germplasm Resources Exploitation

[Objective] To utilize the germplasm resources,new systematic evidence for the classification of sect.Paracamellia,genus Camellia is found in this article.[Method] Fruit anatomy of 10 species representing sect.Paracamellia was investigated.And the main component of sect.Paracamellia in the genus Camellia was studied by MVSP software.[Result] The exocarp was thin;mesocarp was broad,having a large number of stone cells;endocarp was lignified,and separated easily from seed.The principle components analysis suggested that the distance between species was far,showing far relation;the current study did not support the formation of Camellia grijsii（C.grijsii）and Camellia yuhsienensis（C.yuhsienensis）,Camellia shensiensis（C.shensiensis）should not be recognized as a variety of C.yuhsienensis.In addition,it also proved Ming＇s combining of Camellia confusa（C.confusa）and Camellia kissi（C.kissi）was unnatural.[Conclusion] The study provided theoretical basis for the development and application of sect.Paracamellia in the genus Camellia.

龙泉县发现恙虫病8例

恙虫病又称丛林斑疹伤寒,龙泉县以往无病例报道,1987年7月～1989年9月全县发生8例,其中3例住本院治疗,有一例曾误诊为“流行性出血热”。现报告如下:本组3例,均系男性青壮年,农民,年龄25～52岁,发病时间在7～9月,有二例系同一村庄,

宋大剖腹记

宋大是江西省铜鼓县棋坪乡的一位单身老汉，59岁，思想迷信，信奉鬼神。并自称能为人治病。山上陈山柱的小孩病了。陈山柱象迎贵客一样地把宋大请进家门，宋大翻看孩子的眼皮，摸摸滚烫的前额，侧耳听听心的跳动，然后对陈山柱说：“孩子病得不轻呵！他是被狐狸精缠住了，治起来恐怕还有一点麻烦。”

春打六九头

1、英武山上 [李家庚躺在一道土坎儿下边呆呆的发愣.土坎儿上方,墩儿头用马竿牵着身背柴筐的老盲爷上. ……

长篇叙事诗的一个突破——读严阵的《山盟》

这是近年来少见的一部规模宏大的长诗。这是诗人经过20年反复吟咏反复锤炼的结晶。这就是人民文学出版社于1989年出版的诗人严阵的长诗《山盟》(上下集),也是当时人民文学出版社推出的向建国四十周年的献礼作品之一。中国是一个诗的国度。近年来我们的诗仍然浩如烟海,在诗的海洋中也不乏精彩玲珑晶莹如玉的佳作,但令人失望的诗也确然太多,有的无病呻吟,有的晦涩得连诗人自己也不知所云地梦呓一般。对于我们这个民族所经历的无数苦难,对于我们曾经受到过的严酷的战争洗礼,对于在血与火的陶冶中成长起来的中华民族的优秀儿女,我们的诗人,至少是一部分诗人,却似乎忘却了,缺乏应有的诗情。这不能说不是诗的遗憾。

Stability analyses of bleeder pillars in longwall mines by displacement-discontinuity method

Caving in coal mines releases significant amounts of dust and gas. This is exhausted from the mine by forcing the air to travel through the caved zones into a set of roadways known as bleeders. These bleeder entries are operated for the life of the mine, and therefore, they have to be kept in stable condition. Caving operations in coal mines are associated with Iongwall mines and complete pillar extraction. The pillars adjoining the caved zone sometimes show rib failures, posing a hazard for mine personnel travelling through the entry. In this paper, we present the results from analyses of bleeder pillars that are near the caved zones and are susceptible to damage because of the transfer of load during the caving process. In this study, bleeder pillars were simulated in a displacement discontinuity program. Results showed that the vertical stresses on bleeder pillars increased while the safety factor of bleeder pillar decreased during the caving process; however, when the caved zone completely consolidated, both the stresses and safety factor did not change for the remaining extraction. When similar extraction was performed at deeoer denths, vertical stress on pillars increased significantly_

Analysis of roof and pillar failure associated with weak floor at a limestone mine

A limestone mine in Ohio has had instability problems that have led to massive roof falls extending to the surface. This study focuses on the role that weak, moisture-sensitive floor has in the instability issues.Previous NIOSH research related to this subject did not include analysis for weak floor or weak bands and recommended that when such issues arise they should be investigated further using a more advanced analysis. Therefore, to further investigate the observed instability occurring on a large scale at the Ohio mine, FLAC3 D numerical models were employed to demonstrate the effect that a weak floor has on roof and pillar stability. This case study will provide important information to limestone mine operators regarding the impact of weak floor causing the potential for roof collapse, pillar failure, and subsequent subsidence of the ground surface.

没想到我去了一次台湾

去年底,一个偶然的机会,使我踏上了台湾岛。在台湾旅游对于久居国外的人来说也许没什么新鲜,可在我的脑子里台湾却是一个非常神秘的地方。从我记事的时候起就听到了有关它的许多传说,尽管它是中国的一部分,可与大陆隔绝近40年,比我的年龄还长十几年,那里究竟是什么样子?实在是满脑子问号。飞机终于降落了,我跟着人群走近大厅,猛的看到了青天白日的旗子,我觉得是在做梦,真有点不敢相信已经踏上了台湾土地。我聚精会神地注视着每一位海关、边检和保安人员,兴奋而又紧张。为了顺利过关,我特意选了一个标有“幸运号”字样的关口。

白茉莉

2001年2月23日上午,我在县城的家中写小说。这几年我在县报上发了十几篇小说,身边人包括村里的父老爷们就把我当成了作家。狗屁,这个年代的作家多如牛毛,但能被后人视为作家的,绝不会是许许多多像我这种活得潇潇洒洒、写得顺风顺水的时代宠儿,而是那些甘于寂寞、准备用一生的心血为这个时代写一部真实大书的人。真正能够传世的作家在那里默默地写作,伟大的作品堆在他们的案头或在他们抽屉里锁着(暂且不会让它们问世),别人也许不信,反正我信。10点钟的时候,我的小说刚开了个头儿,门铃忽然响个不停。敞开门一看,村里的玉娇大婶站在门外。大婶气喘吁吁,满头汗水,一进门就哭出声来说:新生,你大叔闯下大祸了。我心里一惊:大叔闯了什么祸?他把宫长根的腿打伤了。用什么打的?用枪。真的?真的,不是真的我能来找你?

“迟来”的儿媳

我有两个儿子,大儿子山柱,憨厚勤劳,成家后分出去单过,两口子到市里去打工做小买卖,一年收入上万元;二儿子山林,聪明机灵,高中毕业后在家帮我种地、养蜂,日子过得也不错。可是自从娶来了漂亮的二儿媳妇,家里就不得安宁了。二儿媳叫玉花,长得可说是百里挑一,但心气儿太盛,总好跟别人攀比,见谁家穿得比她好,或者添了什么新家电,她就嫉妒得不行,非让山林给她买不可,不买就又吵又骂,直到达到目的为止。这年俺这儿大涝,地里只收了三成,蜂子也损失了大半。年末山柱两口子回来过年,玉花见他大哥两口子在外边挣了那么多钱,心里就不平衡了,大骂山林是个笨猪,智商低没本事。

西藏的云

西藏的云,给我无穷的震撼。临近林芝,透过飞机小小的舷窗,突然发现远处白云间隐隐有灰色的影子,定睛细看,竟是棉花般厚实的白云包裹着的嶙峋山峰,有些难以置信,突然就觉得是置身在海上,而非空中。后来才知道,西藏的云,似乎都是飘浮在半空中的。它离我们是那么的近,近得似乎一举手间,就能真实地触摸到那份柔软。

建国后天安门修缮大事记

一九四九年,为迎接开国大典,重点对天安门城楼多年来积存的鸽粪、蒿草等污物,破损的砖瓦、门窗等构件进行了彻底的清理和整修。 一九五二年,更换破损的门窗和腐朽的梁木,对屋顶梁枋和天花藻井的彩绘重新进行了彩画。取出了城楼西木梁上三颗未爆炸的八国联军炮弹。 一九五六年,对城楼东北翼角及劈裂、脱榫的角梁进行了翻修。 一九六三年。

Crustal velocity structure in the Emeishan large igneous province and evidence of the Permian mantle plume activity

The Emeishan large igneous province(ELIP) in SW China is interpreted to be associated with an ancient mantle plume. Most of the constraints on the role of mantle plume in the generation of the Emeishan flood basalts were provided by geological and geochemical methods, but the geophysical investigation is very limited. In order to better understand the deep structure and features of ELIP, we have studied the crustal velocity structure using the data acquired from the Lijiang-Panzhihua-Qingzhen wide-angle seismic profile. This profile crosses the three sub-zones of the ELIP(the inner, intermediate, and outer zones), divided based on the differential erosion and uplift of the Maokou limestone. The results provided by the active source seismic experiment demonstrate:(1) The average depth of the crystalline basement along the profile is about 2 km.(2) The middle crust in the Inner Zone is characterized by high-velocity anomalies, with the average velocity of 6.2-6.6 km/s, which is about 0.1– 0.2 km/s higher than the normal one. The velocity of the lower crust in the inner zone is 6.9-7.2 km/s, higher than those observed in the intermediate and outer zones(6.7-7.0 km/s). Relatively low velocity anomalies appear in the upper, middle and lower crusts near the junction of the inner zone and intermediate zone, probably due to the effect of the Xiaojiang fault(XJF).(3) The average velocity of the crust is comparatively low on both sides of XJF, especially on the east side, and the average velocity of the consolidated continental crust is also low there. This may suggest that the XJF extends at least down to 40 km deep, even beyond through the crust.(4) The depth to the Moho discontinuity decrease gradually from 47-53 km in the inner zone, via 42-50 km in the intermediate zone to 38-42 km in the outer zone. In the inner zone, the Moho uplifts locally and the(consolidated) crust is characterized by high-velocity anomalies, which are likely related to intensive magma intrusion and underplating associated with melting of plume head. Overall the crustal velocity structure in the study area recorded the imprint left by the Permian Emeishan mantle plume.

Thermal history of the Sichuan Basin,SW China:Evidence from deep boreholes

The Sichuan Basin is a superimposition basin composed of terrestrial and marine sediments that is well known for its abundant petroleum resources. Thermal history reconstruction using paleogeothermal indicators, including vitrinite reflectahoe and thermochronological data, shows that different structural subsections of the Sichuan Basin have experienced various paleogeothermal episodes since the Paleozoic. The lower structural subsection comprising the Lower Paleozoic to Middle Permian （Pz-P2） successions experienced a high paleogeothermal gradient （23.0-42.6℃/km） at the end of the Middle Permian （P2）, whereas the upper structural subsection comprising Late Permian to Mesozoic strata underwent a relatively lower paleogeothermal gradient （13.2-26.9℃/km） at the beginning of the denudation （Late Cretaceous or Paleocene in the different regions）. During the denudation period, the Sichuan Basin experienced a successive cooling episode. The high paleogeothermal gradient resulted from an intensive thermal event correlated to the Emeishan mantle plume. The heat flow value reached 124.0 mW/m2 in the southwestern basin near the center of the Emeishan large igneous province. The low geothermal gradient episode with heat flow ranging from 31.2 to 70.0 mW/m2 may be related to the foreland basin evolution. The cooling event is a result of the continuous uplift and denudation of the basin.

Thermal evolution and dynamic mechanism of the Sichuan Basin during the Early Permian-Middle Triassic

The Sichuan Basin, located in the western margin of Yangtze Plate, is one of the important oil-gas-bearing basins in China. During the Early Permian-Middle Triassic, the Sichuan Basin experienced regional lithospheric extension and Emeishan basalt activities, both of which influenced the basin development and thermal evolution. Here we simulated the thermal effects of lithospheric extension and the Emeishan mantle plume based on different geodynamical models. Modeling results indicated that the lithospheric temperature together with the basement heat flow was generally increasing with time due to extension. As the stretching factor was relatively small, the thinning of lithosphere, and consequently the thermal disturbance, was not great. The lithospheric extension yielded about 20% increase of the basement heat flow, with maximum value of 60?62 mW m?2 in the Early Triassic. Mantle plume model shows that the thermal evolution of the inner zone above the plume head was influenced greatly by plume activity. But the outer zone and its outside area where the Sichuan Basin is located were affected only slightly. The basalts that had erupted in the southwestern basin might disturb the basin temperature significantly, although shortly and locally. Generally, the thermal history of the Sichuan basin during the Early Permian-Middle Triassic was controlled by the lithospheric extension, but locally it superimposed thermal effects of basalt activities in its southwestern area.

Origin and source of CO_2 in natural gas from the eastern Sichuan Basin

The CO2 contents of natural gas from the eastern Sichuan Basin were mainly less than 2%, and they were generally large when the H2S contents were over 5%. The natural gas in the eastern Sichuan Basin showed high δ13C1 values uncorrelated with H2S contents, and the oil-associated gas generally displayed carbon isotopic reversal between methane and ethane, whereas the coal-derived gas samples displayed positive series. The δ13c values of CO2 in the natural gas could be divided into two types, one with low values （-24‰-12‰） and the other with high values （-8‰-4‰）. The natural gas had low R/Ra values and broad COj3He values distinct from the mantle-derived gas, and the CO2 was typical of crustal origin. Natural gas with high δ3Cco2 values is distributed in the north region of the eastern Sichuan Basin, and CO2 in H2S-poor and H2S-free reservoirs was mainly derived from the thermal decomposition of carbonate rocks under Permian magmatism and high heat flow, whereas CO2 in the gas reservoirs with high TSR extent was derived mainly from the dedolomitization of carbonate reservoirs under acidic formation water, and the CO2 of TSR origin generally entered into the secondary calcite. The CO2 in natural gas in the south-central region of the eastern Sichuan Basin, which had been rarely affected by the Emeishan mantle plume, displayed low δ13C values and was of organic origin. Though the natural gas in Wolonghe gas field had experienced TSR, the low reac- tion extent and weak acidity of formation water could hardly have resulted in the dedolomitization, and therefore CO2 in the natural gas was mainly of TSR origin with low δ13C values.