石灰石岩极厚矿体的大规模开采工艺

随着我国经济的快速发展,采矿业得到了逐步发展,经济的改善导致人们生活质量的提高。因此,对矿产资源的需求也大大增加了。因此,对石灰石的需求延吉厚矿的开采技术也提出了更高的新要求,有必要对技术进行改进以改善环境问题,以破坏开采过程中的环境。目前,我国还提出了一系列改善措施。本文还分析了地下石灰石岩石开采技术的发展和改进。

甘肃酒钢西沟石灰石矿地质特征及成因探讨

矿区位于祁连地槽,次级单元位于北祁连地向斜带妖魔山-青山地向斜狼豺沟脑-寺台子山褶皱束中,构造较为复杂。石灰岩矿位于北祁连地向斜带北缘,成矿时代为中奥陶世,产于中奥陶统妖魔山组地层中,属地槽型浅海沉积矿产。已探明的矿山为西沟大型石灰岩矿,储量在2亿吨以上。本区石灰岩属地槽型浅海相化学沉积矿床,后经区域变质作用普遍重结晶,形成细晶灰岩。

金关铁锁古浪峡

金关铁锁古浪峡张奋武古浪峡位于河西走廊东端，是古丝绸之路从兰州经永登、天祝、古浪至武威一段的必经之地。因其位置扼控河西，哨卫金城，故为古今兵家必争之地。史有“秦关”、“雁塞”之称，被称为中国西部的“金关铁锁”。古浪峡两山夹峙，南北走向，东西二山为乌鞘...

沙漠古镇的重现

沙漠古镇的重现《古兰经》把它比作罪恶之源，邪恶之地，它的毁灭已成为《天方夜谭》中的传奇故事。现在，研究人员用航天飞机在太空中拍摄的照片已经发现了这座埋没在阿曼南部沙漠中的古城镇———乌巴城。这项工作于１９８１年就开始了，当时一位名叫尼古拉斯·克拉普的...

Effect of Perched Water Tables on Aluminosilicate Stability and Soil Genesis

The mineral stability and solute activities of soil solution extracted from selected horizons of seven studied pedons of Alfisols in Kentucky, USA, and the relationship between distribution of iron-manganese concretions and the restrictive layers were investigated. The results showed that the genesis and development of these soils and mineral weathering trends were strongly influenced by the depth of bedrock and the presence of perched water tables at lithic (limestone) interfaces due to the dissolution and buffering effect of limestone bedrock. The extractable Mg/Ca ratio as depth function and soil depth above bedrock could be used as indices of weathering and degree of soil development. Maximum iron-manganese concretion accumulation was found to occur in the horizon overlying clay horizon (>40% clay) with a sharp increase in clay content (>10%), which suggested that zones of Fe-Mn concretion accumulation in soils of the Inner Bluegrass Region appeared to be a sensitive genetic indicator of argillic horizons with restrictive permeability.

Characteristics and distributions of humic acids in two soil profiles of the southwest China Karst area

Characteristics and distributions of humic acid(HA) and soil organic matter(SOM) in a yellow soil profile and a limestone soil profile of the southwest China Karst area were systematically investigated to reveal their evolutions in different soils of the study area. The results showed that characteristics and distribution of SOM along the two soil profiles were notably different. Total organic carbon(TOC) contents of soil samples decreased just slightly along the limestone soil profile but sharply along the yellow soil profile. TOCs of the limestone soils were significantly higher than those of the corresponding yellow soils, and C/N ratios of SOMs showed a similar variation trend to that of TOCs, indicating that SOM can be better conserved in the limestone soil than in the yellow soil. The soil humic acids were exhaustively extracted and further fractionated according to their apparent molecular weights using ultrafiltration techniques to explore underlying conservation mechanisms. The result showed that C/N ratios of HAs from different limestone soil layers were relatively stable and that large molecular HA fractions predominated the bulk HA of the top soil, indicating that HA in the limestone profile was protected while bio and chemical degradations were retarded. Combined with organic elements contents and mineral contents of two soils, weconcluded that high calcium contents in limestone soils may play a key role in SOM conservation by forming complexation compounds with HAs or/and enclosing SOMs with hypergene CaCO_3 precipitation.

Comparative Study on Debris Flow Initiation in Limestone and Sandstone Spoil

Large spoil tips from reconstruction works as a result of the Wenchuan Earthquake in China are new debris flow hazards to the human society.However,there is a lack of detailed comparative study on debris flow initiation in different spoil materials.This paper describes a series of tests and analyses on debris flow characteristics(initiation,scale and mechanism) at six sites with limestone and sandstone materials near the Dujiangyan area.Research shows the limestone spoil contains debris flow prone clay content with high concentration of montmorillonite(highly expandable).In addition,limestone spoil is of such a low permeability that water mainly concentrates in the upper surface layer.Those factors make it easy for the increase of pore water pressure,decline of internal friction and conhesion force,leading to the occurence of large debris flows.In contrast,the sandstone spoil is less problematic and causes no major debris flow threats.Based on our research on the mechanism,the"stereometric drainage"method is sucessfully applied to control limestone spoil debris flows.

Effects of Limestone Powder on Rheological Properties of Cement - Fly Ash Mortar

This article studies the effects of limestone powder on rheological properties of cement - fly ash mortar with RHEOLAB QC type rotation viscometer. The Bingham fluid model is introduced to fit the yielding stress and plastic viscosity of the mortar. The POWER LAW fluid model is introduced to fit the rheological index of the mortar. The results show that, adding limestone powder and fly ash to the cement mortar significantly decreases the yield stress of the mortar, changes the plastic viscosity of the mortar, increases the rheological index, decreases the degree of shear thinning of the mortar, and thereby improves the mortar＇ s workability. In the case of cement - fly ash mortar, with the increase of limestone powder content, both the yield stress and plastic viscosity of the mortar increase. When the limestone powder content is not higher than 14%, the increase of yield stress is not significant. When the limestone powder content is lower than 8%, the increase of plastic viscosity is not significant. When the content of limestone powder is higher than 22%, the rheological index of the mortar decreases and the degree of shear thinning increases. The effects of limestone powder＇ s packing density, shape and size, specific surface area, and fluid volume, are found to be the four major factors responsible for the changes ofrheological properties of the mortar.

The Effect of Tree Species on the Chemical Properties of Soil in the Rehabilitation of a Limestone Quarry at Athi River, Kenya

A comparison of field performance of Acacia xanthophloea, Schinus molle, Casuarina equisetifolia and Gravellia robusta plant species was made in an exhausted limestone quarry, backfilled with limestone mine waste in a semi-arid area in Athi River, Kenya. The aim of the study was to determine if the tree species had an influence on the soil chemical properties. The soil had alkaline pH ranging from 8.0 to 8.98, low nitrogen content （〈 0.03%）, moderate phosphorus concentrations ranging from 44.15 ppm to 21.33 ppm and high to moderate exchangeable cations （Na, Ca, Mg and K）. All the tree species exerted a positive influence on soil properties necessary for plant growth. The pH values and total phosphorus were relatively lower in soils close to the trees （0.5 m） and increased with distance from the trees, while the soil values for total nitrogen and exchangeable cations were relatively higher close to the trees. C. equisetifolia had the best growth performance and a higher positive influence on the soil chemical properties necessary for plant growth followed by A. xanthophloea. It was concluded that trees should remain a feature of quarry rehabilitation because of their role in maintaining the biophysical environment.

Origin of the Furongian limestone breccias in the North China Platform

Limestone breccias are a common phenomenon in the Cambrian successions worldwide. They bear important geological im- plications that have attracted geologists for several decades. There are, however, still controversies on their origins, especially those of the breccias with abundant vertically orientated clasts. The Furongian （upper Cambrian） Chaomidian Formation of the North China Platform contains numerous levels of limestone breccias and conglomerates that provide an excellent example to look into their formative processes. These breccias and conglomerates have been the focus of study and discussion since the 1980s, but yet there is still no consensus with respect to their geneses. Recently, Van Loon and others argued that the vertically orientated clasts of the breccias developed by a number of simultaneous ＂fountains＂ on the paleo-seafloor; the ＂fountains＂ formed by upward-directed fluidized flows originated from the sediment underlying the brecciated limestones. While the novel ＂fountain＂ hypothesis is not impossible, based on field evidences and theoretical considerations, however, it is most likely that the vertically orientated clasts resulted from their re-orientation by gillaceous sediment that was interbedded with brecciated limestone took place under shallow burial. upward flow of thixotropically liquidized, uncemented ar- fragments. Besides, the deformation processes most likely

Bio-Fertilizer,Ground Magnesium Limestone and Basalt Applications May Improve Chemical Properties of Malaysian Acid Sulfate Soils and Rice Growth

Acid sulfate soils are normally not suitable for crop production unless they are appropriately ameliorated. An experiment was conducted in a glasshouse to enhance the growth of rice, variety MR219, planted on an acid sulfate soil using various soil amendments.The soil was collected from Semerak, Kelantan, Malaysia. Ground magnesium limestone(GML), bio-fertilizer, and basalt(each 4t ha-1) were added either alone or in combinations into the soil in pots 15 d before transplanting. Nitrogen, P and potash were applied at 150, 30, and 60 kg ha-1, respectively. Three seven-day-old rice seedlings were transplanted into each pot. The soil had a p H of 3.8 and contained organic C of 21 g kg-1, N of 1.2 g kg-1, available P of 192 mg kg-1, exchangeable K of 0.05 cmol c kg-1,and exchangeable Al of 4.30 cmol c kg-1, with low amounts of exchangeable Ca and Mg(0.60 and 0.70 cmol c kg-1). Bio-fertilizer treatment in combination with GML resulted in the highest p H of 5.4. The presence of high Al or Fe concentrations in the control soil without amendment severely affected the growth of rice. At 60 d of growth, higher plant heights, tiller numbers and leaf chlorophyll contents were obtained when the bio-fertilizer was applied individually or in combination with GML compared to the control. The presence of beneficial bacteria in bio-fertilizer might produce phytohormones and organic acids that could enhance plant growth and subsequently increase nutrient uptake by rice. Hence, it can be concluded that addition of bio-fertilizer and GML improved rice growth by increasing soil p H which consequently eliminated Al and/or Fe toxicity prevalent in the acid sulfate soil.