Three-dimensional orebody modelling and intellectualized longwall mining for stratiform bauxite deposits

Acoupled biharmonic spline and linear interpolation algorithm was proposed to create a three-dimensional smooth deposit model with minimal curvature containing grade and position data. To obtain the optimal technical parameters, such as cuttingheight and drum diameter, a virtual longwall mining procedure was modelled by simulating the actual fully mechanized longwall mining process. Based on the above work, a bauxite deposit in a longwall mining panel was modelled by scattered grade data from ores sampled on the entry wall. The deposit was then demarcated by industrial indexes and sliced according to the virtual longwallmining procedure. The results show that the proposed interpolation algorithm can depict the stratiform structure of bauxite depositsand that the uncovered bauxite deposit has high proportions of high-grade and rich ore. The ranges of optimal cutting height and drum diameters are 1.72-2.84 m and 1.42-1.72 m, respectively. Finally, an intellectualized longwall mining procedure was designed to guide the mining process with the lowest dilution and loss rates.

Outline of Metallogenic Regularity of Bauxite Deposits in China

Among the abundant aluminum ore resources in China, bauxite is dominated, which is mainly distributed in 19 provinces and regions, including Shanxi, Henan, Guizhou and Guangxi. The major deposit type of bauxite is paleo-weathering crust sedimentary type, and the other one is the accumulation type. The main metallogenic period is the late Paleozoic Era followed by the Cenozoic Era. The metallogenic tectonic background is characterized by a cratonic environment. This paper summarizes the bauxite metallogenic regularity based on the characteristics of bauxite resources, bauxite deposit type, bauxite metallogenic belt and metallogenic series in China, and 15 bauxite metallogenic belts, 8 bauxite metallogenic series and 7 bauxite ore concentrated areas were identified in the study. This paper also provides a theoretical basis for the evaluation of the potential of bauxite resources.

Red Clay Type Gold Deposits in China

Red clay type gold deposits,located in the south of China,are situated not only in orogenic belts,but also in inner cratons,where climate is tropical-subtropical with clear arid and humid.The lateritic weathering crust often can be divided into five zones,including topsoil,siliceous duricrust zone,multi-color zone(or red clay zone in some deposits),pallid zone and saprolite zone from surface to the base rock,several of which are absent in some deposits.The base rocks are composed mainly of carbonate rocks with minor clastic rocks,intermediate-basic volcanic rocks and intermediate-acid and alkalic intrusions.The orebodies are mainly located in the multi-color zone with part of them in the pallid and saprolite zones.The ore sources include orebodies of Carlin-type gold deposits and porphyry gold deposits,as well as gold-rich base rocks.The red clay type gold deposits experienced early-stage endogenic gold mineralization and laterization during the Tertiary and Quaternary.The areas with endogenic gold deposits,especially Carlin-type gold deposits and porphyry gold deposits in karst depressions on the plateau,structual erosional platforms in the middle-lower mountains,and intermountain basins in southern China are well worth studying to trace red clay type gold deposits.

A New Type of REE Deposit Found in Clay Rock at the Top of the Permian Emeishan Basalt in the Yunnan-Guizhou Area

Objective A set of REE-rich clay rocks is formed at the top of the Emeishan basalt in the eastern Yunnan-Western Guizhou area,accompanied by Nb,Zr,Ga.It is a new type of REE deposit and has great resource potential.This paper introduces its metallogenic conditions and element occurrence states,discusses the genetic mechanism.

A Study on Palaeogeography and Metallogenic Conditions of Early Carboniferous Bauxite Deposits of Old Weathered Crust in Guizhou, Sichuan, Hunan and Hubei Provinces

There are four subtypes. namely, Ia, Ib, Ic and Id of the Early Carboniferous bauxite deposits of the old weathered crust type in Guizhou, Sichuan, Hunan and Hubei provinces. They are all distributed in the Upper Yangtze old land. As a result of the Hunan-Guizhou palaeo-faulting, the crust on the northern side of the fault was uplifted and became land, thus suffering denudation. The bauxitic substances left in the weathered crust evolved and were reworked into bauxite. On the other hand, the crust on the southern side of the fault sank and remained to be part of an ocean. The bauxite deposits of Ia and Ib subtypes were formed by in-situ enrichment of residual bauxitic substances in the weathered crust of the old land, but bauxite deposits of Ic and Id subtypes resulted from transportation, accumulation and sedimentation of allothogenous bauxitic substances on the weathered crust of the old land. The processes of transportation may be distinguished as dry transportation and wet transportation, both of which proceeded under atmospheric conditions.

Composition, Source and Environmental Indication of Clay Minerals in Sediments from Mud Deposits in he Southern Weihai Offshore, Northwestern Shelf of the South Yellow Sea, China

Studying the sedimentary characteristics of the muddy area along the Yellow Sea shelf is of great significance for deep-ening the understanding of the climate and environment evolution since the last glacial period.Recently,a small muddy area developed in the southern Weihai offshore has attracted a lot of attention.Based on high-resolution grain size,clay mineral,AMS14C,and OSL data of sediments from the core WHZK01 in the muddy area,we acquired a new understanding of sedimentary characteristics,sources and paleoclimatic environment during the last 13 kyr.The results show that the core WHZK01 sediments were mainly from the Yellow River and local rivers along the coast.However,the sources varied for different deposition units.The riverbed(before 13 kyr BP)and fluvial plain deposits(13-10 kyr BP)were mainly from local river inputs.The very thin littoral deposits from 10 kyr BP to 8 kyr BP also mainly originate from coastal river inputs,while the littoral-neritic deposits since 8 kyr BP were dominated by the Yellow River materials and partly supplied by the coastal rivers and the island erosion.In addition,five events related with the strong East Asian winter monsoon(EAWM)during the intervals of 13.0-11.0 kyr BP,10.0-8.2 kyr BP,7.0-5.0 kyr BP,3.5-2.5 kyr BP,and 1.2-0.5 kyr BP were iden-tified.Three events related with the enhancement of the EAWM since the middle Holocene have strengthened the transport capacity of the coastal currents of the Shandong Peninsula.Meanwhile,more Yellow River-derived distal sediments were deposited to the southern Weihai offshore and formed wedge-shaped muddy bodies.In short,the ratio of smectite/illite could be used as an effective EAWM indicator since 13 kyr BP on the northwestern shelf of the South Yellow Sea.

Industrial Potentiality of Alluvial Clays Deposits from Cameroon: Influence of Lateritic Clayey Admixture for Fired Bricks Production

The cartography and characterization of an alluvial clay deposit from Ebebda (Central region of Cameroon) were carried out in order to assess its suitability for the production of fired clay bricks. The clayey area investigated is ~ 50,000 m2 with an average thickness of the exploitable layer of 2.2 m, suggesting a deposit of about ~2.2 × 105 tonnes of clay. Mineralogy, physico-chemical and thermal analyses as well as firing properties were performed on representative clay samples. Kaolinite and quartz are the major minerals associated to illite. Upon heating to 900℃ - 1200℃, the linear shrinkage varies from 1.5% to 15%, the water absorption from 1.5% to 24% and the bending strength from 2 to 12 MPa. The admixture of lateritic clays (widely available) at 50%, 60%, 70% and 80% allow to decrease the shrinkage and bending strength, and to increase the water absorption. Overall, properties were satisfying the requirement for fired brick with 70% of laterite in the mixture.

Classification and mineralization of global lithium deposits and lithium extraction technologies for exogenetic lithium deposits

A reasonable classification of deposits holds great significance for identifying prospecting targets and deploying exploration. The world ’s keen demand for lithium resources has expedited the discovery of numerous novel lithium resources. Given the presence of varied classification criteria for lithium resources presently, this study further ascertained and classified the lithium resources according to their occurrence modes, obtaining 10 types and 5 subtypes of lithium deposits(resources) based on endogenetic and exogenetic factors. As indicated by surveys of Cenozoic exogenetic lithium deposits in China and abroad,the formation and distribution of the deposits are primarily determined by plate collision zones, their primary material sources are linked to the anatectic magmas in the deep oceanic crust, and they were formed primarily during the Miocene and Late Paleogene. The researchers ascertained that these deposits,especially those of the salt lake, geothermal, and volcanic deposit types, are formed by unique slightly acidic magmas, tend to migrate and accumulate toward low-lying areas, and display supernormal enrichment. However, the material sources of lithium deposits(resources) of the Neopaleozoic clay subtype and the deep brine type are yet to be further identified. Given the various types and complex origins of lithium deposits(resources), which were formed due to the interactions of multiple spheres, it is recommended that the mineralization of exogenetic lithium deposits(resources) be investigated by integrating tectono-geochemistry, paleoatmospheric circulation, and salinology. So far, industrialized lithium extraction is primarily achieved in lithium deposits of the salt lake, clay, and hard rock types. The lithium extraction employs different processes, with lithium extraction from salt lake-type lithium deposits proving the most energy-saving and cost-effective.

PROSPECTING FOR LARGE TRIHYDROXY BAUXITE DEPOSITS IN CHINA: THINKING AND PERSPECTIVE

Large trihydroxy bauxite deposit was once considered unavailable in China.With the prospecting think-ing of diwa theory,the author has drawn a contrary conclusion.From the view of the law of progression with transformation between mobile and stable regions and the metallogenic specialization of tectonic elements,he reveals the principal reason why the known bauxite deposits in China are mostly of monohydroxide type,and acquires the way of searching for trihydroxide bauxite deposits.He considers that the residual-mobility period of the diwa stage in the crustal development in South China pocesses-tectonic conditions favourable to the formation of bauxite deposits of this type.He believes that the Cenozoic structural sublayer of the residual-mobility period of the diwa stage developed on the carbonate rock of the Paleozoic platformal structural layer is the preferrential target of prospecting.With this thinking and many years of efforts,we have gained prelimi-nary achievements and have discovered Guigang-type latee-ritic trihydroxied bauxite deposits in Guangxi.In future,by extension and analogy of the thinking,we are likely to find large,high-grade bauxite deposits in its vicinity and to discover weathering-type bauxite deposits with other parent rocks.

Investigating the Industrial Potentials of Some Selected Nigerian Clay Deposits

One of the most important useful and widely abundant industrial minerals in the world is the clay minerals. Their applications in various industries are dependent on their properties. In this study, the mineralogical and physico-chemical properties of RahinSho (RC), Major Porter (MP), Wereng camp (WC), Kwi (KC) and Naraguta (NC) clay deposits in Plateau State, Nigeria were investigated to evaluate their potentials for some industrial uses. The x-ray diffraction studies revealed the kaolins as the dominant clay minerals in all the samples. The non-clay minerals found were quartz and muscovite. The chemical analyses by x-ray fluorescence also indicated that the silica (SiO2) values of the samples ranged from (41.20 - 62.26)% while the alumina (Al2O3) range was (17.25 - 37.15)%. Some considerable amounts of impurities found were Fe2O3 (0.43 - 27.52)%, TiO2 (0.05 - 3.28)%, K2O (0.13 - 3.01)%. The oxides of Na, Ca and Mg were within acceptable limits in the clays for most purposes. The loss on ignition ranged from 4.30% - 12.43%. The physical properties investigated were particle size distribution that contained heavy clay-size materials ranging from 67.88% - 91.88%, plasticity index had range of values from 15.90% - 33.68%, and drying and firing shrinkages were 1.10% - 2.22% and 1.65% - 4.49% respectively. All the samples attained a temperature of 1500°C without fusion except Naraguta clay that fused at 1300°C. At the temperature of 1200°C, RC, MP and WC clays retained their natural colours of white and near-white respectively, while KC and NC clays changed colours from orange pink and light brown to moderate pink and moderate reddish brown respectively. These results compare very well with several clays elsewhere. Based on these characteristics, the clays were observed to be potentially suitable for the production of paints, tiles, ceramics, refractories, sanitary wares and clay bricks. Minimal processing will increase the potential of RC and MP to meet up with specification for paper, fertilizer and/or pharmaceutical uses.

Bauxite washing for the removal of clay

Clay impurities associated with bauxite negatively affect the Bayer process for alumina production. These impurities should be removed as far as possible by a beneficiation technique before the ore is used as feed for the Bayer process. In this current investigation, bauxite washing was conducted in the laboratory. Bauxite washing is a physical process that causes the disintegration and deagglomeration of the clay matrix, and bauxite is liberated from the clay（mainly rich in silica）. Subsequently, separation occurs with the assistance of wet screening at a predetermined cut size. Three techniques were investigated in the laboratory： drum washing, water-jet washing, and ultrasonic washing. Various operating parameters were investigated for drum washing and water-jet washing, including materials retention time, drum rotation speed, solid concentration, water-jet spray duration, pressure, and height. We concluded that the retention time of bauxite inside the drum at a solid concentration of 55wt% and a drum rotation speed of 31 r/min is the dominant parameter for the removal of clay from the bauxite surface.

Super Large-scaled Bauxite Deposit Detected in Guizhou Province

Recently, the Bureau of Geology and Mineral Exploration and Development of Guizhou Province detected an about 140 million tons resource in Zheng＇an County, 100 million tons of which was bauxite. This is the second detected super large-scaled bauxite deposit after the Dazhuyuan bauxite deposit in Wuchuan County.

Geotechnical Properties of Some Clay Deposits in Some Parts of Southwestern Nigeria in Relation to Its Engineering Implications on Constructions

Twenty-two clay samples from Oduna,Okada,and Etsako clay deposits in Southwestern Nigeria were subjected to Geotechnical analysis to evaluate their impact on engineering,especially on construction.The results revealed that the clays deposits were majorly fine-grained texture(<60%),with Plasticity ranging from 23%to 121%,Liquid Limit(25%~205%)having plasticity of medium to very high with a specific gravity from 1.93 to 2.58.Using the American association of state highway and transportation office(AASHTO)and Unified system classification scheme(USCS),the samples fell within A-7-6(clayey soil)indicating a subgrade that is fair to poor and within the CL-CH category of fine-grained soil with medium to very high plasticity.Compaction having maximum dry density(MDD)to optimum moisture content(OMC)ranges from 0.94 g/cm^(3)~1.68 g/cm^(3)to 11.9%~44.5%,Triaxial result with cohesion between 0.33~35 and shear strength from 44~120 and California bearing ratio for unsoaked bottom 7.52~40,top 4.82~39.18 and soaked bottom 2.89~30.41,top 4.21~33.53.The geotechnical properties of the clay deposits do not meet the standard requirement hence the implication in engineering might be susceptibility to construction failures.

豫西夹沟铝土矿床古地理环境分析

夹沟铝土矿赋存于奥陶系碳酸盐岩古风化剥蚀面上,含矿层位为上石炭统本溪组,为一大型铝土矿床。查阅前人对该区的研究成果,结合矿区大量基础资料,从矿床地质特征、沉积相、古气候、地球化学、生物生态等多角度开展综合研究,表明该区矿床古地理环境是气候湿热的近海陆交互环境。通过对其古地理环境的分析,提高该区古地理环境研究程度,也为后续矿山开发利用和矿区深部找矿提供指导。

中国伴生稀土元素资源类型及资源潜力

中国的稀土元素(REE)资源丰富,矿床类型多样,其中轻稀土元素(LREE)绝大多数来自于碱性岩-碳酸岩有关的REE矿床,而重稀土(HREE)主要来自离子吸附型(或称风化壳型)REE矿床,其他稀土矿床类型还包括REE砂矿和伴生的REE矿床等。目前,中国的REE资源开发主要是针对碳酸岩-碱性岩型LREE矿床和离子吸附型HREE矿床,REE砂矿和其他矿床中伴生的REE资源尚未得到有效利用。文章在综合已有研究成果的基础上,对中国伴生的REE矿床的类型、资源潜力进行评述。结果表明,中国伴生的REE资源类型包括海相沉积磷矿床、煤矿床、铝土矿床、岩浆型磷-铁磷矿床等,其潜在的REE资源巨大,特别是海相沉积磷矿床和铝土矿床中伴生的REE资源。铝土矿床中伴生的REE以LREE为主,且其中的Sc具有重要的资源意义。沉积磷矿床中伴生的HREE(含Y)占比高,特别是产于四川德阳地区的什邡式磷矿上部层位的富硫磷铝锶型矿石,其中的REE含量明显高于磷块岩型矿石,且中、重REE占50%以上,还伴生有多种关键金属,具有重要的资源意义和经济价值。另外,岩浆型(铁)磷矿床、煤矿床、油页岩矿床、金矿床中伴生的REE资源也值得重视。但由于缺少详细的勘查数据,目前对中国伴生的REE资源家底不清,资源综合利用水平及REE回收和提取技术也有待提高。而加强中国伴生REE资源的评价和综合利用水平,充分利用生产矿山中伴生的REE资源,特别是磷矿床和铝土矿床,不仅可以有效缓解中国HREE资源供应压力,还是贯彻中国节约资源和保护环境基本国策的重要举措。

河南偃龙地区晚石炭世风化作用与铝土矿成矿过程

通过对偃龙地区铝土矿成矿的古地理环境特征、含矿岩系的岩相学特征、岩石矿物特征、成矿元素富集特征的研究,分析了晚石炭世本溪组铝土矿风化成矿作用的三个阶段脱硅富铝的动态变化过程,进而探讨了本区晚石炭世风化作用条件下的铝土矿成矿过程。研究结果认为,在风化作用为主的铝土矿成矿过程中,含矿母岩首先生成黏土矿物,然后当岩石中Al_(2)O_(3)含量接近35%时,开始生成以三水铝石为主的最初铝土矿,最后铝土矿在盖层覆盖下,在一定的温度压力条件下三水铝石转化为一水硬铝石,并最终形成“煤-黏土-铝土-铁质黏土”这种本溪组铝土矿系的典型结构。

铝土岩系和煤系地层中沉积黏土型锂矿床:研究现状与展望

沉积岩型锂矿是自然界中最主要的锂矿床之一,我国铝土岩系和煤系地层中沉积黏土型锂矿主要分布在扬子地块西南部和华北地块,该类型锂矿分布广、储量大,对其进行研究对破解我国未来锂资源困局具有重要意义。本文总结了我国铝土岩系和煤系地层中黏土型锂矿的分布状况,锂的赋存状态、来源,以及开发利用现状等方面的研究进展。锂的富集过程主要与风化-沉积作用及火山岩浆活动有关,锂主要来源于火山凝灰岩、早期形成的岩浆岩、黏土岩等富锂基底岩石。锂以锂绿泥石独立矿物或者类质同象/吸附在黏土矿物、三水铝石和勃姆石中。锂的提取流程与锂的赋存状态密切相关。随着实验及工业提锂技术的发展,该类型锂资源具有广阔的前景。

重庆南川区大佛岩铝土矿床有益元素分布特征及可利用性评价

为了理清重庆市南川区大佛岩铝土矿床有益组分分布特征及伴生元素可利用性,本文通过剖面测量、实地调查和样品分析等工作方法,对南川区大佛岩铝土矿床及其伴生元素的分布特征进行了深入研究,并建立了矿产资源可利用性评价模型。Ga质量分数高值区呈北东向和近南北向分布,中西部Ga质量分数高,北东部Ga质量分数较低。Li质量分数在梁山组中上部最高,最高为致密状铝土矿,其次为铝土岩,土状铝土矿中较低。Li的富集与铝土岩的关系较为密切。稀土元素的富集部位更容易出现于赋矿地层底部。评价模型对矿区铝土矿资源的评价结果为可利用。在开发利用铝土矿资源的过程中,可以考虑回收利用Ga元素。但是,由于Li、Sc、REE元素受到选冶技术和选矿成本等因素的限制,现阶段回收利用技术上虽然可行,但经济性存在瓶颈。因此,在开发利用铝土矿资源的同时,还需要探索更经济的回收利用技术,以提高资源的利用率。本文所建立的评价模型结合了评价指标体系,可为铝土矿资源的利用和评价提供科学参考,同时也为其他矿产资源的评价提供借鉴。当然,对于评价指标的选择和权重的确定需要根据不同的矿产资源和应用场景进行调整、优化,才能更好地满足实际需求。

黔中麦西铝土矿地质特征及矿床成因

麦西铝土矿位于黔中扬子地块内部的修文-清镇矿集区,矿区内褶皱和断裂构造发育,铝土矿产于下石炭统九架炉组含铝岩系中,资源储量丰富。本文以岩石学、矿物学和地球化学等方法对矿区的成矿物质来源、矿床地质特征及成因开展了系统研究。结果表明:矿区成矿物质可能来源于下伏寒武系娄山关组碳酸盐岩,并且经历了“风化初始富集-胶体聚合-脱硅富集-风化淋滤改造成矿”等多阶段复杂的成矿过程。本次研究基于“矿层露头-含矿地层-构造”的多元找矿标志,推测矿区东部及北部外围为下一步的找矿远景区。

黔北地区安场铝土矿矿床地质特征及成因初探

安场铝土矿矿床位于黔北-渝南成矿带西南部的安场向斜,区内铝土矿富集成矿条件优越。本文基于已有地质工作,分析矿床地质特征,探究赋矿地层与铝土矿富集规律、成矿物质来源,以及基底微地貌变化和气候等对铝土矿富集的约束。研究表明,安场铝土矿床为沉积型矿床,含矿岩系为大竹园组。矿石以含铁高硫型为主,有土状-半土状铝土矿石、致密状铝土矿石、碎屑状铝土矿石和豆状铝土矿石等4种;矿体主要分布在华尖-天峰寺一线北西部,11号矿体是黔北地区发现最大的单矿体,达大型矿床规模,矿体深部、边部往向斜轴部延伸应具有较好的找矿前景;韩家店组泥页岩是成矿物质主要来源,黄龙组灰岩是重要的物源;基底地貌起伏控制含矿岩系沉积,在负地形洼地区域含矿岩系厚度大,同时也往往是铝土矿矿体厚度较大的区域,充分暴露淋滤则控制铝土矿的富集,韩家店和黄龙组基底可能是成矿物质来源,基底暴露地表,经淋滤脱硅富铝成矿。