Spatial Modeling of Geometallurgical Properties: Techniques and a Case Study

High-resolution spatial numerical models of metallurgical properties constrained by geological controls and more extensively by measured grade and geomechanical properties constitute an important part of geometallurgy. Geostatistical and other numerical techniques are adapted and developed to construct these high-resolution models accounting for all available data. Important issues that must be addressed include unequal sampling of the metallurgical properties versus grade assays, measurements at different scale, and complex nonlinear averaging of many metallurgical parameters. This paper establishes techniques to address each of these issues with the required implementation details and also demonstrates geometallurgical mineral deposit characterization for a copper–molybdenum deposit in South America. High-resolution models of grades and comminution indices are constructed, checked, and are rigorously validated. The workflow demonstrated in this case study is applicable to many other deposit types.     

Modeling Spatial Processes of Urban Growth in African Cities: A Case Study of Nairobi City

Africa's urban population growth has been especially rapid, averaging about 5% per year over the past two decades. As a result, many urban areas have experienced dramatic growth that is seriously outstripping the capacity of most cities to provide adequate services for their residents. Although population growth and urbanization rates in Africa have slowed recently due to a number of factors including HIV/AIDS, urban growth is still expected to double by 2030, leading to dramatic sprawl with serious environmental and social consequences. Using Nairobi as an example of a rapidly urbanizing African city, we studied the dynamics of land use and land cover change using satellite data and addressed the need for models and urban management tools that can guide sustainable urban planning policies. Cellular Automata, which integrate biophysical factors with dynamic spatial modeling, are used in this study. The model was calibrated and tested using time series of urbanized areas derived from land use/cover maps, produced from remotely sensed imagery, with future urban growth projected to 2030. Model assessment results showed high levels of accuracy, indicating that simulation findings were realistic, thereby confirming the effectiveness of the model. Results further showed that the model is a useful and effective tool to foresee the spatial consequences of planning policies in the context of many African cities. The forecast for Nairobi showed unsustainable sprawl.     

贝叶斯方法在犯罪时空格局研究上的应用——以长春市为例

对比分析了2008年和2018年长春市犯罪空间格局的变化特征,进而构建了贝叶斯时空分析模型,整合了犯罪时空格局演化中的固定效应、空间随机效应和时间随机效应,基于R环境中的INLA程序包对模型的各个参数进行了拟合,结合GIS制图,识别出异于总体趋势的犯罪相对风险高值区,并进一步解析了犯罪格局形成和演化的过程和规律。研究发现,犯罪总量在10 a间显著下降,犯罪数量较高的警区数量明显减少。长春市周边地区犯罪率有所提高,而城市中心区域的多数警区则明显下降。贝叶斯时空模型表明,虽然城市犯罪相对风险的平均水平较低,但其总体上却呈现出显著的增加趋势。空间效应的高值区主要集中在城市中心核心区域,特别是传统的商业网点或经济活动较为集中的警区。时间效应的高值区主要集中在城市外围地区,尤其是国家级开发区所在的警区。综合空间效应和时间效应,城市中心区域存在既是空间效应的高值区也是时间效应高值区的时空共同高风险区。贝叶斯方法在数据整合、区域异质性识别以及灵活性方面具有明显的优势,对于犯罪时空格局形成和演化规律的理解和把握上均有所助益。     

城市居住人口空间分布的模拟研究——以广州市天河区为例

为解决以行政区为单位的人口数据空间表示法无法准确反映人口实际分布的问题,文章以广州市天河区为例,利用高分辨率遥感影像数据,采用面向对象法对建筑进行提取和分类,并结合广州市土地利用现状图对分类结果进行验证和修订.在此基础上,利用土地利用密度法估算研究区各街道居住建筑的人口密度,并采用格网法进一步构建城市人口空间分布模型模拟城市居住人口的空间分布.结果表明,广州市天河区的人口主要集中在广园快速公路以南的带状区域内,中心商业区和工业密集区的人口密度最大,主干道附近区域的人口密度显著大于其他区域;距离城市中心较远的新塘、凤凰、长兴、龙洞等街道的人口密度整体偏低,模拟结果与研究区的实际情况相符.文章采用的数据可获得性强,操作方法简单,估算精确度高;研究提高了建筑解译和分类的效率,真实地反映了城市人口的空间分布特征,建模方法和研究思路具有一定推广意义.     

Geostatistical Modeling of Ore Grade Distribution from Geomorphic Characterization in a Laterite Nickel Deposit

Due to growing consumption of nickel (Ni) in a range of industries, the demand for Ni has increased rapidly around the world. This trend requires a more precise estimation of available Ni grade deposits and an identification of factors controlling the grade distribution. To achieve these requirements, this study applies geostatistical techniques to spatial modeling of the Ni grade in a laterite Ni deposit, with reference to geomorphic features such as slope gradient and the thickness of limonite and saprolite zones. The Sorowako area in Sulawesi Island, Indonesia, was chosen as a case study area because it has a representative laterite Ni deposit with large reserves. Chemical content data from drillhole cores at 294 points were used for the analysis. The slope gradient was found to have a remarkable correlation with the thickness of the limonite zone, but there was no correlation between the thickness of the limonite and the saprolite zones above the bedrock. One important feature was a general correlation between the thickness of the saprolite zone and the maximum Ni grade in this zone: the grade increases with the thickness of the zone. Co-kriging was adopted to incorporate this correlation into estimating the maximum Ni grade in the saprolite zone. As a result, the maximum Ni grade in the saprolite zone tends to be high mainly in areas of slight slope. The Ni accumulation at this topographic feature probably originates from deep weathering by groundwater infiltrating through well-developed rock fractures.     

大柴旦低品位硼矿的富集研究

在对大柴旦盐湖湖底低品位硼矿的组成、伴生矿物种类、含量等因素进行分析的基础上,依据各矿物物理性质的差异,通过正交试验法,确定采用旋流方法分离低品位硼矿中的石膏和碳酸盐,分别得到以碳酸盐为主要杂质的低品位硼矿和以硫酸盐为主要杂质的低品位硼矿,然后进行分别加工,有效降低大柴旦盐湖低品位硼矿加工过程分解剂的消耗,为大柴旦盐湖低品位硼矿的加工利用提供了一条新的途径。     

Systematic Geography for Grade 4: A Spatial Systems Approach

Abstract

Various social and geographical strategies that have been used to assign children to schools in the United States are examined in order to: 1) support the contention that social space and geographic space are rarely considered in concert in the context of community problem solving, 2) point out the need for the consideration of various socio-spatial concepts such as action space, territoriality, and neighborhood in social scientific research addressing itself to the understanding of social issues, and 3) urge consideration of the fundamental changes overtaking American society, particularly the processes of time-space convergence which underlie the socio-geographical reorganization of earth space.     

都市自行车旅游慢行系统空间布局优化研究——以杭州市为例

自行车骑行是旅游者体验目的地城市的重要方式,规划建设高效合理的自行车旅游慢行系统已经成为众多旅游城市共同面临的重要任务。以著名旅游城市杭州为对象,利用实地调查获得的数据和相关研究成果,从空间布局视角分析了杭州自行车旅游慢行系统的发展现状和存在的主要问题,提出了优化和完善自行车旅游慢行系统的对策。结果发现,目前杭州的自行车服务点与休闲旅游点的空间耦合度较低、与旅游流网络特征的协调性较差。最后提出了解决上述问题的主要措施。     

城市生产性服务业空间分布研究：以南京为例

20世纪90年代以来,随着信息技术的发展和应用,城市与区域空间结构也逐渐发生了相应的变化,这已成为西方学术界研究的重点问题。作为长江三角洲三大中心城市之一,南京城市空间发展也日益受到了信息化、全球化的影响,并表现出了新的结构特征。本研究从全球、国家及区域背景出发,分析南京城市生产性服务业的空间变化,及其所带来的空间结构的转型。这包括城市商务中心功能的强化与边缘商务空间的培育、信息产业密集区出现、学习型区域的空间重构几个方面。     

Non-stationary Geostatistical Modeling: A Case Study Comparing LVA Estimation Frameworks

Incorporating locally varying anisotropy (LVA) in geostatistical modeling improves estimates for structurally complex domains where a single set of anisotropic parameters modeled globally do not account for all geological features. In this work, the properties of two LVA-geostatistical modeling frameworks are explored through application to a complexly folded gold deposit in Ghana. The inference of necessary parameters is a significant requirement of geostatistical modeling with LVA; this work focuses on the case where LVA orientations, derived from expert geological interpretation, are used to improve the grade estimates. The different methodologies for inferring the required parameters in this context are explored. The results of considering different estimation frameworks and alternate methods of parameterization are evaluated with a cross-validation study, as well as visual inspection of grade continuity along select cross sections. Results show that stationary methodologies are outperformed by all LVA techniques, even when the LVA framework has minimal guidance on parameterization. Findings also show that additional improvements are gained by considering parameter inference where the LVA orientations and point data are used to infer the local range of anisotropy. Considering LVA for geostatistical modeling of the deposit considered in this work results in better reproduction of curvilinear geological features.

     

大城市地域空间结构划分研究——以广州市为例

采用定性与定量相结合的"三步法"进行广州市城市地域空间结构的划分:第一步采用区位商法,以区(市)级行政区为基本单位,选择能够反映城市地域特征的6个指标,进行地域结构的大致划分;第二步以镇(街)主要经济社会指标为依据,进行边缘区进一步细分;第三步参照城市意象分析方法,根据主要景观轴的景观梯度变化验证城市地域结构划分效果.划分结果比较符合广州市的地域空间格局,有助于广州市城市地域空间管理,也为国内其它城市地域结构划分提供新的思维与方法.     

城乡过渡带空间演进与空间交互强度分析

采用NPP/VIIRS夜间灯光数据提取广州市城乡过渡带边界,利用基于sDNA模型修正的引力模型测算2012—2019年广州市城乡过渡带的空间交互强度,分析其空间演进特征与社会经济发展的关系。研究表明：1）2012—2019年广州市城乡过渡带总体呈扩大趋势,以北偏东方向发展为主,破碎区块逐渐演变为连续区域;2）广州市城乡过渡带之间的空间交互网络结构呈现“多方向化”趋势,从最初的西南侧单线网络结构逐步发育成多方向闭合网络联结结构,目前演变为南北两支、东西向的强空间交互态势,以白云区为代表的北部区域和以番禺区为代表的南部区域是广州市城乡过渡带的重要战略节点地域;3）广州市城乡过渡带社会经济优势度呈现出由内向外的3个空间层级结构,并由城市核心区辐射带动,向北、东北与东南3个方向推动发展为城乡过渡带;4）各城乡过渡带的发展速度不均衡现象仍较明显,广州市应结合本区域优势产业和自然资源,走联合与互补发展并存的道路,重视城乡过渡带区域发展引擎,增强其与周边地区联系的潜力。     

市域空间发展类型区划分的方法探讨 ——-以江苏省仪征市为例

市域空间发展类型区划分是新时期我国从空间管治角度落实科学发展观的重要举措。 这一工作一方面是我国既有区划工作的延续,另一方面又隐含着重大的方法论创新的内在需 求,即需要由原来的基于均质区域背景的区划论升格为基于均质区域与功能区域并重的新的区划论。为此,我们专门开发了适合于空间发展类型区划分的信息系统(SPIS),以解决不同类型因子的空间赋值以及分值迭加问题,尤其是侧重解决不同等级、不同形态的服务设施, 基于路网结构的不同类型、不同方式、不同半径的空间扩散的技术实现问题,在此基础上首次提出了空间发展类型区划分的指标判别法和指标迭加法,并以仪征为例进行了空间发展类型区划分的有效尝试。由于以自己开发的专用软件为定量分析工具,故整个区划过程公开透明,提供了从原始资料的收集、整理、分析、系统处理、多方案比较的动态分析过程,从而为空间发展类型区划分的科学性、规范性,以及有深度的定量分析提供了方法论角度的探索。     

喀斯特城市空间结构研究:以贵州省为例

以喀斯特面积分布最广的贵州省为研究区域,从城市空间形态、主导功能、驱动力、伸展轴等空间发展要素出发,对贵州省喀斯特地区的城市空间结构形态进行研究,将贵州省喀斯特山地城市的空间结构分为5种模式:组团模式、绿心环状模式、带状城市、团状模式和串珠状放射模式.     

北京市制造业和服务业空间组织特征与类型

产业在城市内部的空间组织形式是形成城市内部空间结构的主导力量.要认识城市内部空间结构的形成机制和合理地进行城市功能区规划,都离不开对城市内部产业空间组织规律的了解与掌握.产业的空间组织形式是各种集聚与分散力量综合作用达到平衡时的结果.鉴于现有研究尚未系统探讨产业空间组织的不同特征与类型,本文利用2001年北京市基本单位...     

就近入学空间模型分析——以河南省巩义市初级中学为例

从地理空间的角度理解我国义务教育就近入学政策与择校现象,引入空间模型模拟学校与居民点之间的供需关系,并尝试解释与择校现象密切相关的"热校"和"冷校"问题。使用最近距离模型、引力模型和Huff模型,以河南省巩义市50所初级中学和1 276个居民点为例,在ArcGIS软件中进行模型分析。在模型有效性检验的基础上,引入学校热度指标鉴别"热校"和"冷校",并统计各类学校的规模、生均资源分配和平均入学距离等指标。研究表明:Huff模型能较好地模拟义务教育供需现状;"热校"、"冷校"与其他学校的规模、生均资源和入学距离存在显著差异。该研究对于就近入学政策实施和学校布局调整具有参考价值。     

城市人居环境类型及空间格局研究——以大连市沙河口区为例

从人居环境系统视角出发,以大连沙河口区199个典型住宅小区为研究对象,实证探索了城市人居环境类型及空间格局。研究结果表明：① 影响城市人居环境六大主因子为居住质量、邻里关系、自然环境、生活便利度、轻轨交通、教育医疗;② 以六大因子与不同收入群体的人居活动交互作用为依据把大连沙河口区人居环境分为低收入群体——居住质量差型、中等收入——居住系统均衡型、高收入——居住质量高和公共设施良好型、高端人士群体——自然环境优越型,以及非自由选择分配住房的单位制居民——邻里关系密切型;③ 5种城市人居环境类型“同质”集聚与“异质”集聚并存,形成以海岸线三圈层结构为主的南高北低态势,辅以中东部商圈高收入居住区,中西部混合异质区的复合圈层空间格局。     

A Chart for Judging Optimal Sample Spacing for Ore Grade Estimation: Part II

Natural Resources Research - Resources of mineral deposits are commonly estimated using data extracted from rock cores obtained by drilling. Information of good quality and quantity is essential to...     

道路影响域的界定及其空间分异规律 ——-以纵向岭谷区为例

以纵向岭谷区道路网络为研究对象,考虑地形等相关因子,利用GIS 图形叠加分析得到区域道路影响域的范围,进一步统计道路影响域面积与区域面积的比例,探寻道路对区域影响的空间分异规律,并分析其与道路密度、人口密度、村庄数目、生态承载力、平均海拔高度等因素的相关性。结果表明：纵向岭谷区道路不同等级具有不 同的影响域范围,区域道路影响的空间分布存在差异,由省会昆明逐渐向周边辐射减小,红河流域高于澜沧江流域和怒江流域。在纵向岭谷区东部、北部、西南部部分地区道路影响呈现显著的空间集聚效应。影响因子的相关性分析表明,道路影响域比例与平均海拔高度不相关,与道路密度、人口密度、村庄数目、生态承载力相关显著。     

Geometallurgical Domaining by Cluster Analysis: Iron Ore Deposit Case Study

Natural Resources Research - Geometallurgy integrates many aspects of geology, mineralogy, resource modeling, mine planning, metallurgy, and process control to optimize mining operations....