煤系石墨矿产资源评价方法初探

A preliminary evaluation method for coal-based graphite

  • 摘要: 煤系石墨属战略性矿产资源,在核石墨、军用飞机轮胎等方面具有独特优势,煤系石墨矿产资源评价对于煤系石墨矿产资源勘查开发、提级增储及战略资源保障至关重要 。由于煤系石墨与高变质煤存在连续过渡性质,导致部分煤系石墨被当作无烟煤处理,现有煤系石墨查明资源量可能被大大低估,实际上煤系石墨资源量与高煤级煤的资源量有直接关系。因此,在我国无烟煤等高煤级煤勘查区内,开展煤系石墨资源调查评价工作,将会取得较好效果,预期发现一批新的煤系石墨资源潜力区。通过分析我国目前已知的湖南、福建、吉林等地典型煤系石墨资源分布特征,总结了煤系石墨找矿标志,包括层位、矿化、岩体、构造和围岩蚀变等标志。在高煤级煤勘查区内,基于煤田构造、含煤岩系沉积环境、岩浆活动、煤岩煤质特征、煤类分布与变质情况等资料,结合煤系石墨找矿标志,进行煤系石墨资源调查评价。以科学性、系统性和可操作性为评价原则,依据工作程度、地质条件、矿产条件3类参数,采样点密度、构造变形程度、构造应力、岩体规模与热作用强度、岩体与煤层距离、初步鉴定、精确鉴定7个指标,初步提出了煤系石墨矿产资源评价方法。将实测数据分别与对应指标的预设值比较,利用平面直线拟合方程计算指数特征值,依据7个评价指标及权重对煤系石墨矿产资源进行评价,以期为我国煤系石墨资源评价工作提供科学依据。以闽西南龙岩−永定煤田漳平可坑矿区为例进行煤系石墨资源评价,其煤系石墨资源评估值为(A1, A2, A3)=(0.735, 0.793, 0.838),表明本研究区工作程度较好,地质条件较好,开采难度较小,矿产条件为煤系石墨一号,建议进一步加密采样点,布置资源勘查工作。

     

    Abstract: Coal-based graphite is a type of strategic mineral resource and has unique advantages in the fields such as nuclear graphite and military aircraft tires. The evaluation of coal-based graphite is crucial to its exploration and development, upgrading and storage increase, and strategic resource security. Owing to the continuous transition between coal-based graphite and highly metamorphosed coals, some coal-based graphite tends to be wrongly treated as blind coal, and, accordingly, the identified resources of existing coal-based graphite may have been greatly underestimated. In fact, the resources of coal-based graphite are directly related to those of high-rank coals. Therefore, it is significant to survey and evaluate coal-based graphite in the exploration areas of high-rank coals (e.g., blind coal) in the expectation of discovering new areas with potential for coal-based graphite. By analyzing the distribution of typical coal-based graphite resources in Hunan, Fujian, and Jilin in China, this study summarized the prospecting indicators of coal-based graphite, including horizons, mineralization, rock masses, structures, and wall rock alteration. Based on data on coal field structures, the sedimentary environment of coal-bearing strata, magmatic activity, characteristics of coal petrology and coal quality, and coal distribution and metamorphism, as well as the prospecting indicators of coal-based graphite, this study surveyed and evaluated these typical coal-based graphite resources. Accordingly, on the evaluation principle of scientificity, systematicness, and operability, this study proposed a preliminary evaluation method for coal-based graphite based on three parameters, namely exploration level, geological conditions, and mineral conditions, and seven indicators, namely sampling point density, the degree of tectonic deformation, tectonic stress, rock mass scale and thermal action intensity, the distance between rock masses and coal seams, basic identification, and precise identification. In this method, the measured data are compared with the preset values of the corresponding indicators first, then the characteristic values of the indicators are calculated using a fitting equation for planar straight lines, and finally, coal-based graphite is evaluated based on the seven evaluation indicators and their weights. The purpose is to provide a scientific basis for the evaluation of coal-based graphite resources in China. Using the proposed evaluation method, this study evaluated the coal-based graphite resources in the Kekeng mining area in Zhangping, Longyan Yongding coalfield, southwest Fujian, determining an evaluation value of (A1, A2, A3) = (0.735,0.793,0.838). This value indicates that the Kekeng mining area has a high exploration level, favorable geological conditions, minor difficulties with mining, and mineral condition of coal-based graphite No. 1. It is recommended to further densify sampling points and deploy resource exploration.

     

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