矿山固体废弃物对地质环境的影响分析

在山西省重点地区固体废弃物现状调查研究的基础上,通过试样试验,分析研究了固体废弃物对土壤、大气、水环境的污染,探讨了对固体废弃物的治理及利用,为研究矿山生态环境地质研究提供参考,同时积累工作经验。     

Rare Earth Deposits of North America

Rare earth elements (REE) have been mined in North America since 1885, when placer monazite was produced in the southeast USA. Since the 1960s, however, most North American REE have come from a carbonatite deposit at Mountain Pass, California, and most of the world’s REE came from this source between 1965 and 1995. After 1998, Mountain Pass REE sales declined substantially due to competition from China and to environmental constraints. REE are presently not mined at Mountain Pass, and shipments were made from stockpiles in recent years. Chevron Mining, however, restarted extraction of selected REE at Mountain Pass in 2007. In 1987, Mountain Pass reserves were calculated at 29 Mt of ore with 8.9% rare earth oxide based on a 5% cut‐off grade. Current reserves are in excess of 20 Mt at similar grade. The ore mineral is bastnasite, and the ore has high light REE/heavy REE (LREE/HREE). The carbonatite is a moderately dipping, tabular 1.4‐Ga intrusive body associated with ultrapotassic alkaline plutons of similar age. The chemistry and ultrapotassic alkaline association of the Mountain Pass deposit suggest a different source than that of most other carbonatites. Elsewhere in the western USA, carbonatites have been proposed as possible REE sources. Large but low‐grade LREE resources are in carbonatite in Colorado and Wyoming. Carbonatite complexes in Canada contain only minor REE resources. Other types of hard‐rock REE deposits in the USA include small iron‐REE deposits in Missouri and New York, and vein deposits in Idaho. Phosphorite and fluorite deposits in the USA also contain minor REE resources. The most recently discovered REE deposit in North America is the Hoidas Lake vein deposit, Saskatchewan, a small but incompletely evaluated resource. Neogene North American placer monazite resources, both marine and continental, are small or in environmentally sensitive areas, and thus unlikely to be mined. Paleoplacer deposits also contain minor resources. Possible future uranium mining of Precambrian conglomerates in the Elliott Lake–Blind River district, Canada, could yield by‐product HREE and Y. REE deposits occur in peralkaline syenitic and granitic rocks in several places in North America. These deposits are typically enriched in HREE, Y, and Zr. Some also have associated Be, Nb, and Ta. The largest such deposits are at Thor Lake and Strange Lake in Canada. A eudialyte syenite deposit at Pajarito Mountain in New Mexico is also probably large, but of lower grade. Similar deposits occur at Kipawa Lake and Lackner Lake in Canada. Future uses of some REE commodities are expected to increase, and growth is likely for REE in new technologies. World reserves, however, are probably sufficient to meet international demand for most REE commodities well into the 21st century. Recent experience shows that Chinese producers are capable of large amounts of REE production, keeping prices low. Most refined REE prices are now at approximately 50% of the 1980s price levels, but there has been recent upward price movement for some REE compounds following Chinese restriction of exports. Because of its grade, size, and relatively simple metallurgy, the Mountain Pass deposit remains North America’s best source of LREE. The future of REE production at Mountain Pass is mostly dependent on REE price levels and on domestic REE marketing potential. The development of new REE deposits in North America is unlikely in the near future. Undeveloped deposits with the most potential are probably large, low‐grade deposits in peralkaline igneous rocks. Competition with established Chinese HREE and Y sources and a developing Australian deposit will be a factor.     

Mechanism for the rapid motion of the Qianjiangping landslide during reactivation by the first impoundment of the Three Gorges Dam reservoir, China

The first impoundment of the Three Gorges Dam reservoir in China started from a water surface elevation of 95 m on June 1, 2003 and reached 135 m on June 15, 2003. Shortly after the water level reached 135 m, many slopes began to deform and some landslides occurred. The Qianjiangping landslide is the largest one; it occurred on the early morning of July 14, 2003 and caused great loss of lives and property. Field investigation revealed that, although failure occurred after the reservoir reached 135 m, the stability of the slope was already reduced by preexisting sheared bedding planes. To study the mechanism of the rapid motion of this reactivated landslide, two soil samples were taken from a yellow clay layer and a black silt layer in the sliding zone, respectively, and a series of ring shear tests were conducted on the samples. One series of ring shear tests simulates the creep deformation behavior, while the other series simulates different shear rates. Conclusions drawn from analysis of the ring shear tests indicate that the mechanism of the rapid motion of the reactivated landslide was caused by the rate effect of the black silt layer during the motion phase after the creep failure. The yellow clay layer did not play any important role in the rapid motion in the 2003 event.     

Zircon M257 ‐ a Homogeneous Natural Reference Material for the Ion Microprobe U‐Pb Analysis of Zircon

We introduce and propose zircon M257 as a future reference material for the determination of zircon U‐Pb ages by means of secondary ion mass spectrometry. This light brownish, flawless, cut gemstone specimen from Sri Lanka weighed 5.14 g (25.7 carats). Zircon M257 has TIMS‐determined, mean isotopic ratios (2s uncertainties) of 0.09100 ± 0.00003 for ²⁰⁶pb/²³⁸U and 0.7392 ± 0.0003 for ²⁰⁷pb/²³⁵U. Its ²⁰⁶pb/²³⁸U age is 561.3 ± 0.3 Ma (unweighted mean, uncertainty quoted at the 95% confidence level); the U‐Pb system is concordant within uncertainty of decay constants. Zircon M257 contains ～ 840 μg g^?1 U (Th/U ～ 0.27). The material exhibits remarkably low heterogeneity, with a virtual absence of any internal textures even in cathodoluminescence images. The uniform, moderate degree of radiation damage (estimated from the expansion of unit‐cell parameters, broadening of Raman spectral parameters and density) corresponds well, within the “Sri Lankan trends”, with actinide concentrations, U‐Pb age, and the calculated alpha fluence of 1.66 × 10¹⁸ g^?1. This, and a (U+Th)/He age of 419 ± 9 Ma (2s), enables us to exclude any unusual thermal history or heat treatment, which could potentially have affected the retention of radiogenic Pb. The oxygen isotope ratio of this zircon is 13.9%o VSMOW suggesting a metamorphic genesis in a marble or calc‐silicate skarn.     

Composition-Induced Variations in SIMS Instrumental Mass Fractionation during Boron Isotope Ratio Measurements of Silicate Glasses

An analytical artefact is reported here related to differences in instrumental mass fractionation between NIST SRM glasses and natural geological glasses during SIMS boron isotope determinations. The data presented demonstrated an average 3.4‰ difference between the NIST glasses and natural basaltic to rhyolitic glasses mainly in terms of their sputtering-induced fractionation of boron isotopes. As no matrix effect was found among basaltic to rhyolitic glasses, instrumental mass fractionation of most natural glass samples can be corrected by using appropriate glass reference materials. In order to confirm the existence of the compositionally induced variations in boron SIMS instrumental mass bias, the observed offset in SIMS instrumental mass bias has been independently reproduced in two laboratories and the phenomenon has been found to be stable over a period of more than one year. This study highlights the need for a close match between the chemical composition of the reference material and the samples being investigated.     

煤炭采空区处理的新方法与实例分析

位于乌鲁木齐市南湖路以西的煤炭采空区面积达67 100.5m^2,区内构造从南到北主要由八道湾向斜和七道湾背斜组成,地层产状变化不大。该矿区开采较深,且采空区塌陷区有明显的地下水活动迹象。在对深孔大体积采空区注浆时,比较各种常见注浆治理方法,均存在不同的制约因素,故决定采用灌浆爆破压密法对采空区进行压实加固。经现场爆破试验,该区重复爆破次数在3～5次左右。灌浆爆破压密处理后,对不同土层进行取样对比分析,得到其相应密度（增加）及空隙比（减少）的变化分别为：杂填土14.1%,-7.9%;素填土5.9%,-3.3%;塌落煤层7.8%,-7.7%。根据压缩数据及现场测量,处理后的土体沉降2～4m,部分空体地段的沉降量达10～20m,治理效果明显。     

塔河油田2区三叠系油藏类型初步探讨

塔河油田2区三叠系油藏是西北分公司开发较早的碎屑岩油藏之一,开发层系有上油组、中油组,油柱高度在15～20m,储层为辫状三角洲相辫状三角洲前缘亚相水下分流河道、河口坝、分流间湾微相沉积,非均质性严重。本区上油组砂体厚度40～0m,中油组25～35m,分布较稳定,物性为中孔、中高渗储层,原油属低粘度轻质油。但2区三叠系油藏实钻变化大,见水快、产量递减快、含水上升快、采出程度低,开发效果较差,经过多次调整虽有一定程度改善,仍存在一些问题。本文认为2区三叠系油藏开发效果较差的原因之一是对本区油藏类型的认识上存在问题即2区三叠系油藏是以断裂控制的断块油藏而非背斜油藏,并延伸分析正在投入开发评价的S96-T901井区、TK232-T453井区及T206-T208井区等都为断块（断背斜）油藏。应用断块油藏的观点对塔河地区三叠系油藏勘探开发有重要指导意义。     

研究“源兆”的若干问题及途径分析

从位场理论的观点讨论了场和源的概念,建议将“场兆”改称为构造前兆,将“源兆”称为震源前兆。文中还分析了震源体与各种前兆观测方法探测的深度,并根据地磁与重力观测方法不同的物理基础和地质基础,指出震磁效应对于研究震源前兆的特殊意义,文中还介绍了１９７６唐山地震观测到震源前兆的部分实际地磁资料。     

关于海平面上升及其环境效应

沿海地区地质环境复杂。由于国民经济的迅速发展,人类活动日益增多,对地质环境进一步造成严重的不利影响。特别是“温室效应”引发的海平面上升,使各种地质灾害更加激化。文章详细探讨了海平面上升的影响因素,理论海平面与相对海平面升降幅度的评估,以及海平面上升所造成的地质环境效应与相应的防治对策,特别强调控制沿海城市地面沉降,以减轻海平面相对上升造成的危害,具有特殊而重要的意义。     

SOME NEW UNDERSTANDINGS OF LAND-SURFACE PROCESSES IN ARID AREA FROM THE HEIFE*

The survey for the HEIFE(Atmosphere-Land Surface Processes Experiment at Heihe River Basin,Western China) is given in the paper.The following basic subjects for land-surface processes in arid areas are studied:(1) the general characteristics of the energy budget on ground surface in arid areas;(2) the parameterization of the land surface processes;(3) the interaction between oasis and its desert circumstances,a special phenomenon in arid areas.The analysis shows that the sensible heat flux in the surface energy budget is in the majority,and the latent heat flux may be neglected.The influence of atmospheric stratification stability on the turbulent transfer of energy and substance must be considered in parameterization of land surface processes in arid areas.The "cold island effect" phenomenon in oasis and the "humidity inversion" phenomenon in desert near oasis are the result of the interaction between them.The results would improve the understanding of land surface processes in arid areas.