Recycling of abrasives in abrasive water jet cutting with different types of granite

The cost of abrasives has restricted usage of abrasive water jet (AWJ) technology in natural stone cutting applications. However, recycling of the abrasives makes the technology more economical, effective, and environmentally friendly. In this study, significant rock properties affecting the recycling of abrasives in AWJ cutting of granites are investigated. Abrasive mass percentage above 106 μm (AMP_106μm) is considered as a performance criterion in terms of recycling of abrasives since these abrasives can be effectively reused in the rock cutting applications. The study reveals that a considerable amount of used abrasives is in a reusable form. Among the rock properties, the microhardness is statistically determined as the most significant rock property affecting the AMP_106μm. It is also concluded that theAMP_106μm can be explained with high accuracy by the proposed model including the microhardness, the quartz content, and the plagioclase content.     

赣东北三清山地区花岗岩的类型与“三清山式”花岗岩峰林的成因

对世界自然遗产地三清山及其外围地区的花岗岩地质与花岗岩地貌的科学价值作进一步讨论,认为:①三清山及其外围的怀玉山燕山期花岗岩区可划分为3型（扬子型、南岭型、沿海型）、4式（铜厂式、银山式、三清山式、灵山式）,它们具有鲜明的成矿与造景的专属性。②三清山花岗岩原态保留较好,形成于燕山陆内造山末期,是南岭型花岗岩演化至最后阶段形成的超酸性碱长花岗岩的典型代表。③三清山式花岗岩地貌为典型的水蚀型幼年期到壮年期早期的峰林地貌,以山峰尖峭和石柱、石锥、石芽发育完美为标志。④三清山式花岗岩峰林地貌的形成是年青的超酸性岩石、岩体与围岩差异风化,节理发育,雨水丰沛,受控于仍在缓慢抬升的“三角形”“隆上隆”断块构造等诸因素最佳耦合的产物。     

ELEMENTAL CONCENTRATIONS OF CHINESE ROCK STANDARDS GSR 1–6: A COMPARISON WITH THE CERTIFICATE VALUES

Data are presented for the six new Chinese rock standards, GSR 1 through 6. These samples include a granite, an andesite, a basalt, a sandstone, a shale, and a limestone, providing a wide range of sample types of geochemical interest. The certificate values were tested using XRF and ITNA for the major and trace elements and colorimetry, coulometry, and thermogravimetry for the ferrous iron and the volatile constitutents. Excellent agreement was obtained for the 50 elements measured, implying these standards have been well characterized generally and should be of immediate use to geochemists.     

Optimized extraction of dimension stone blocks

The profitable production of dimension stone mainly depends on the extractable block size. The regularity and volume of the blocks are of critical importance, and are controlled by the three-dimensional pattern of the discontinuity system. Therefore, optimization of block size has to be the aim when quarrying for natural stone. This is mainly connected to the quantification of joints and fractures, i.e., their spacing and orientation. The problem of finding unfractured blocks within arbitrarily oriented and distributed planes can be solved effectively by a numerical algorithm. The main effects of joint orientations on block sizes and shapes will be presented in this article. Quantification of unfractured blocks with the aim of optimization is illustrated by detailed studies on several quarries. The algorithm used in this study can be applied as a powerful tool in the planning of a quarry and the future exploitation of dimension stone. Application of the described approach is demonstrated on practical examples of quarrying natural stones, namely, sandstone, granite, rhyolite, etc. Block quarrying can be optimized by using the new 3D-BlockExpert approach. The quantification of unfractured rock masses is also shown to contribute to a more ecological protection and the sustainable use of natural resources.     

Abrasivity Assessment of Granitic Building Stones in Relation to Diamond Tool Wear Rate Using Mineralogy-Based Rock Hardness Indexes

The objective of the present study was to determine the abrasive wear potential of granites in circular sawing using some mineralogy-based rock hardness indexes. A literature study indicated that little or no attention has been given to assessing this kind of relationship in the field of stone processing. To accomplish this objective, sawing experiments were performed on nine different granites used widely as building and decorative stone materials. The measured sawblade-specific wear rates were correlated with three different rock hardness indexes attained by combining the percentage content of hard mineral constituents with their known hardness values. Statistical analysis of the experimental data revealed that rock hardness indexes that are based on both Vickers hardness number and Rosiwal hardness could be accepted as reliable indicators of granite abrasivity. These two indexes were also found to correlate well with the average power drawn during the process. However, the rock abrasivity index based on Mohs relative scratch hardness did not show statistically significant correlations with sawblade wear rate and power drawn. Although quartz percentage content is regarded as an important abrasivity parameter by practitioners, the observations made here indicate that consideration of quartz percentage content alone is not sufficient to describe the abrasive potential of granites, and thus incorporation of other hard mineral constituents could be more suitable.     

福建石牛山水蚀花岗岩石蛋地貌特征及成因研究

石牛山主峰出露晚白垩世石牛山组晚期侵入相钾长花岗斑岩,山体浑厚壮观,石蛋千姿百态。石蛋、石堡及崖壁上分布着深浅不一的石脊、石槽及大小不同的石臼、石盆、石穴等微地貌,构成独具特色的“水蚀花岗岩石蛋地貌”。经研究,钾长花岗斑岩是形成水蚀花岗岩石蛋的物质基础,风化剥蚀、大气降水击蚀及其流水侵蚀是形成石脊、石槽、石臼、石盆、石穴的主要外动力地质作用。     

The Effects of Operational Parameters on a Mono-wire Cutting System: Efficiency in Marble Processing

Mono-wire block cutting machines that cut with a diamond wire can be used for squaring natural stone blocks and the slab-cutting process. The efficient use of these machines reduces operating costs by ensuring less diamond wire wear and longer wire life at high speeds. The high investment costs of these machines will lead to their efficient use and reduce production costs by increasing plant efficiency. Therefore, there is a need to investigate the cutting performance parameters of mono-wire cutting machines in terms of rock properties and operating parameters. This study aims to investigate the effects of the wire rotational speed (peripheral speed) and wire descending speed (cutting speed), which are the operating parameters of a mono-wire cutting machine, on unit wear and unit energy, which are the performance parameters in mono-wire cutting. By using the obtained results, cuttability charts for each natural stone were created on the basis of unit wear and unit energy values, cutting optimizations were performed, and the relationships between some physical and mechanical properties of rocks and the optimum cutting parameters obtained as a result of the optimization were investigated.     

陕西省观赏石资源的分类

陕西省观赏石资源分为单矿物玉石类、岩石玉类、卵石与水冲石及古生物化石四大类。著名的观赏石有水晶、萤石、绿松石、五彩石、芙蓉石、商洛翠玉、粉翠、菊花石、蓝田玉、洛南翠、黄陵石、磬玉石、墨玉、汉江石、秦岭石、泾河石、洛河源头石、陕西省黄河石、嘉陵江石及古生物化石等。     

准噶尔盆地环玛湖地区三叠系百口泉组物源分析

通过对百口泉组重矿物特征研究、古流向分析、砾石成分特征研究及地层含砂率特征研究,讨论了环玛湖地区百口泉组沉积时期的物源方面和母岩性质。采用重矿物Q型聚类分析,结合重矿物ZTR等值线图以及地层倾角测井古流向分析,指出环玛湖地区百口泉组存在3大物源体系,分别为北部夏子街物源、西部黄羊泉物源以及东部夏盐物源;通过砾岩成分以及重矿物组合类型研究,认为北部物源和西部物源成分存在差异:北部夏子街物源及夏盐物源成分以凝灰岩和中酸性火山喷出岩为主;西部黄羊泉物源成分以凝灰岩、沉积岩和花岗岩为主。西部物源中花岗岩岩屑含量较高,致使储层刚性颗粒含量高、抗压实能力强,这是西部扇体储层物性普遍优于北部扇体储层物性的原因之一。各物源方向及物源体系与扇三角洲的推进方向具有较好的一致性,因此,利用多种方法结合来划分环玛湖地区百口泉组沉积时期物源是十分有效的。     

北天山冰草沟铀磷矿床元素地球化学特征及其指示意义

北天山冰草沟铀磷矿床严格受玄武安山岩与砂岩的接触界面控制,属于典型的热液铀磷矿床。本文利用显微镜、X荧光光谱仪、电感耦合等离子质谱仪等手段,对该矿床典型剖面展开了元素地球化学研究。成矿过程中,铀与磷同步富集。在剖面上,与新鲜砂岩相比,原岩为砂岩的矿石除富集U和P外,还高度富集Ca、Sr、Zr、HREE和Y,同时亏损Rb等元素。表明成矿过程中,成矿流体带来了大量的Ca、P、U、Sr、Zr、HREE和Y,同时,Rb等元素活化迁出。与新鲜玄武安山岩相比,蚀变玄武安山岩明显亏损Rb、Ba和Sr。矿石OX值(Fe2O3/Fe O)介于16. 92～26. 46之间,远高于赋矿围岩OX值。新鲜玄武安山岩具有相对较高的Fe O含量(4. 74%)和较低的OX值(0. 9),蚀变后玄武安山岩则具有相对较低的Fe O含量(0. 86%)和较高的OX值(7. 18),显示成矿流体具有强氧化性,新鲜玄武安山岩表现出较强的还原能力,可能为铀矿体的空间定位提供了还原障。     

基于VGG模型的岩石薄片图像识别

岩石薄片图像的复杂性和多解性,导致岩石薄片分类难度较大。尝试将深度学习方法应用于岩石薄片图像分类。实验选取了安山岩、白云岩、花岗岩等6种常见岩石种类的薄片图像,每类1000张图像作为实验数据,建立了岩石薄片分类的VGG模型,经过9万次训练后,测试集识别准确率达到了82%。对实验结果进行了分析,发现相似组成成分的岩石图像容易混淆,如白云岩与鲕粒灰岩均属于碳酸盐岩,容易相互误判。在安山岩特征图中提取出了斜长石斑晶和微晶及隐晶质或玻璃质基质,在鲕粒灰岩特征图中提取了鲕粒及填隙物中的亮晶方解石,也验证了方法的可靠性。     

Numerical experimental study on failure process of sandstone containing natural damage under freeze-thaw cycle北大核心CSCD

Natural damage such as fissures and pores make the rock microstructure show strong heterogeneity,which influences the failure process and mode. In this paper,the numerical test of freeze-thaw sandstone splitting failure with natural damage was carried out based on CT non-destructive identification technology,combined with digital image processing technology and CASRock numerical simulation software. The analysis of splitting failure mode,deformation localization and crack evolution process of freeze-thaw sandstone with natural damage reveals the failure mechanism of sandstone with natural damage under freeze-thaw and load. The results show that the expansion of primary pores（cracks）and the formation of new pores in sandstone are the main forms of freeze-thaw rock failure evolution. The failure of rock containing natural damage under freeze-thaw and load is related to the degree and distribution of natural damage. The generation of secondary cracks mostly occurs in natural damage-intensive areas. During the loading process,the stress in the localized damage zone is far greater than sandstone’s overall stress,and rock’s failure in the localized damage zone is synchronized with the energy release and stress release in the region. Localized damage reflects the evolution of cracks in rocks and helps to predict the direction of sandstone crack development. The failure mode of rock is related to the number of freeze-thaw cycles. The freeze-thaw cycles make the sandstone with natural damage gradually change from brittle failure to ductile failure,and the change of the overall strength of the rock is a gradual deterioration process. © 2022 Science Press (China).     

循环冻融条件下安山岩和花岗岩的物理力学特性试验研究

结合青藏铁路块石护坡路基处于青藏高原特殊的气候条件,对用于青藏铁路护坡的两种主要岩石（花岗岩和安山岩）进行循环冻融试验.结果表明:两种岩石在经历了数次冻融循环后都出现了微细裂纹;声波监测表明,超声波速同冻融循环周期呈指数下降关系,显示了冻融循环对岩石风化的影响以及循环后岩石物理力学参数变化的趋势.结果说明,花岗岩的冻融...     

东准噶尔卡拉麦里蛇绿岩带南侧侵入体的岩石学、地球化学及年代学特征

东准噶尔卡拉麦里蛇绿岩带南侧分布有大量的石炭纪侵入体,主要出露于五彩城、滴水泉一带及野马站地区。通过对卡拉麦里断裂以南侵入体岩石类型、锆石年代学、地球化学的综合分析,划分出早石炭世后碰撞I型花岗岩类及晚石炭世陆内双峰式侵入岩(碱长花岗岩+角闪辉长岩)。结合断裂以北黄羊山、老鸦泉岩体新近发表的数据及区域内火山岩的研究成果,对卡拉麦里地区石炭纪—二叠纪构造-岩浆演化过程给出了新认识,即卡拉麦里地区从后碰撞到陆内伸展的构造转换时间为早石炭世末期—晚石炭世早期,后碰撞阶段岩浆岩以钙碱性I型花岗岩、玄武安山岩、安山岩为特点,陆内伸展阶段以典型的双峰式岩浆岩(辉长岩+花岗岩、玄武岩+流纹岩)及A型花岗岩为特点,卡拉麦里地区具有正εNd值的花岗岩类来源于亏损地幔形成的年轻地壳的部分熔融。     

中国花岗岩型铀矿区域地球化学指示元素特征及异常模式

我国铀矿床主要划分为四大类型,包括花岗岩型铀矿床、火山岩型铀矿床、砂岩型铀矿床和碳硅泥岩型铀矿床。花岗岩型铀矿约占我国已探明铀矿总资源储量的三分之一以上,是我国重要的铀矿化类型。地球化学勘探方法对花岗岩型铀矿床勘查具有良好的效果。根据全国铀矿资源潜力评价项目研究成果,在大量研究中国花岗岩型铀矿化水系沉积物地球化学异常特征基础上,总结了一套对花岗岩型铀矿化勘查稳定的、行之有效的指示元素及其组合,确定了花岗岩型铀矿化地球化学异常模式,并以实例说明典型花岗岩型铀矿化异常模式。水柰沉积物地球化学异常是进行铀矿产预测评价的有效手段,对铀矿资源的潜力评价发挥了重要作用。     

Fluid metasomatic genesis of stratiform skarn in the Suoerkuduke Cu-Mo deposit,East Junggar,NW China

Stratiform skarns associated with ore deposits are widespread in the north of East Junggar, particularly in the Suoerkuduke Cu-Mo deposit. The Suoerkuduke stratiform and stratoid skarns are hosted by Devonian intermediate-mafic volcanic and pyroclastic rocks, mainly andesite, andesitic porphyry and tuffaceous sandstone, without carbonate or calcareous rocks. The skarns consist of dominant andradite-grossular, epidote, diopside-hedenbergite and minor actinolite, quartz, magnetite and metallic sulfides. The garnet and epidote composition, especially Fe^3 + and Al contents, is largely a function of the bulk composition and physicochemical environment (particularly fO₂) during crystallization. Such mineralogy indicates a relatively oxidizing environment and medium acidity of solution during skarnization.The Suoerkuduke skarns are distinct from typical contact metasomatic skarn in wall rock, as no carbonate or calcareous rocks were found, and differ in the distribution patterns of skarn zonation in that gradually weakened skarn zones are not quite symmetrically distributed on both sides of the alteration center (a garnet skarn). Abundant remnants of andesite, andesitic porphyry and tuffaceous sandstone in the weakened skarn zone indicate that the protolith of the skarn is andesite, andesitic porphyry and tuffaceous sandstone. Magmatic water, meteoric and seawater are involved in skarn alteration. Moyite and granitic porphyry are not coeval with skarn, and their emplacement resulted in the hornfelization of wall rock instead of skarnization, and themselves keep away from skarn alteration. Therefore, there was probably a huge batholith supplying magmatic fluid for skarn formation. Mass balance estimates suggest that hydrothermal fluid must contribute a portion of Ca and Fe to ensure sufficient supply for skarn formation in the absence of local carbonate and calcareous rocks. In conclusion, the stratiform skarns in the Suoerkuduke are products of intermediate-mafic volcanic and pyroclastic rocks metasomatised by hydrothermal fluid that probably leached calcareous wall rock during ascent.     

鄂尔多斯盆地西缘马家滩地区石盒子组砂岩的岩石学、地球化学与成岩作用特征

鄂尔多斯盆地马家滩地区石盒子组是天然气的重点勘探层位。对马家滩地区石盒子组的岩石学特征和成岩作用研究表明,石盒子组的储层岩石类型主要为石英砂岩、岩屑石英砂岩,少量的长石岩屑砂岩。储层砂岩的成岩作用类型主要有压实和压溶、石英次生加大、胶结、溶解。根据成岩作用特征,建立了研究区储层砂岩的成岩共生序列: 自生伊利石--自生绿泥石--石英次生加大--高岭石--方解石。鄂尔多斯盆地作为中国CO2 地下埋藏的潜在目标区,开展CO2 可能埋藏层段的岩石学特征和成岩作用研究,可为CO2 地质储存的数值模拟研究提供岩石学信息。     

复合岩层中滚刀旋转切割破岩效率试验研究

TBM掘进经常遇到复合岩层,在该地层中施工对滚刀破岩非常不利。为了提高掘进效率,降低工程造价,开展复合岩层滚刀破岩效率研究很有必要。鉴于此,采用滚刀岩机作用综合试验台对砂岩、花岗岩复合(复合比例为4(25) 6)而成的岩层进行5组刀间距下3种贯入度的3把滚刀同步旋转切割试验;试验过程中监测破岩总法向力、总扭矩,并分别收集两种岩石的岩渣进行筛分、称重;依据试验结果分析不同刀间距、贯入度下的法向力、扭矩及比能的关系。研究表明:不同刀间距时,平均法向力、平均扭矩随贯入度的增加而增大但两者的增加趋势不同,即平均法向力随着贯入度的增加几乎呈直线增大,而平均扭矩随着贯入度的增加其递增趋势减小;不同贯入度下存在不同的最优刀间距;砂岩、花岗岩切割轨迹长度比例为4:6时刀间距与贯入度的比值在14左右,破岩效率最高。     

南昌市梅岭花岗岩石蛋地貌的特征与发育机制初探

梅岭主要以新元古代花岗岩为地质基础,在长期的构造抬升和风化侵蚀作用下,形成了以垄状山脊/锯状山脊和侵蚀沟谷为组合的地貌特征,其代表性地貌为大小不同和圆度各异的石块堆积,广泛分布于山顶、山谷和缓山坡上,对于其形成机制,过去常被认为是冰川遗迹或倒石堆。通过研究这些石块堆积的形态特征和分布规律,笔者认为属石蛋地貌,可分为裸露型石蛋地貌和埋藏型石蛋地貌。二者的广泛分布,表明梅岭处于花岗岩地貌演化的幼年期晚期—青年期早期阶段,发育机制与当地的地质构造背景和湿热气候环境密切相关,其中的裸露型石蛋主要与埋藏型石蛋剥露、裸露岩石的球状风化和倒石堆的球状风化有关,沟谷中的石蛋流主要形成于裸露岩石崩解破碎后顺坡滚动、土体崩塌导致埋藏型石蛋出露和顺坡滚动、洪水搬运、季节性冻融作用使岩石顺坡蠕动等方式的综合作用下。埋藏型石蛋主要是在花岗岩内部裂隙和节理的控制下,形成于温度和降水对不同深度花岗岩的差异性风化作用。