| I Iron ore is a strategic mineral resource. Hebei Qianan iron ore is one of the national resource base of iron ore. After more than 50 years of exploration and development, more than 30 iron ore deposits have been found in Qianan iron ore district, and many mining areas have been closed after 40 years of mining. Since 2005, China Geological Survey of the Ministry of land and Resources and National Key Technology Support Program have been established projects in this area to explore the resources reserves in the deep area of digging mine, and research the deep ore-controlling model. This paper is based on the sub-project "Qianan iron ore area in Eastern Hebei gravimetry and deep ore body information extraction, processing technology research" of National Key Technology Support Program, the gravity and magnetic survey were carried out in the Hebei Qianan area. On the premise of physical difference of ore(host rocks) and surrounding rocks, combined with previous geological and geochemical research foundation, this paper studied the evaluation of deep resources of iron ore which has great significance for understanding the genesis of deep ore deposits, summarizing the prospecting method, guiding the practice of deep prospecting.This paper sets out the angle of deep ore prospecting, summaries the regional metallogenic geological background, analyzes the typical ore deposit metallogenic regularity. The high-precision gravity and magnetic profile measurements have been carried out in mineralization favorable areas of Hebei Qian’an. According to the geological, geochemical, gravity and magnetic data of the typical ore deposits in the mining area, the abnormal data extraction, filtering, field separation, physical property forward and inversion and comprehensive interpretation have been carried out. This paper summed up an effective set of comprehensive geological geophysical interpretation method which provides the gravity and magnetic methods for finding and evaluation of metamorphic iron ore. The research contents, main work and achievements of this paper as follows:(1) According to the aviation magnetic gradient data of the study area, using data processing method as leveling, filtering etc., and obtained the high precision magnetic gradient data;(2) Using analytic signal Euler deconvolution method to process the aeromagnetic gradient data, the mineralization favorable areas of Hebei Qian’an have been delineated.(3) According to the favorable target area, the large scale gravity profile is distributed, filtering and field separation process of data which provide the support for density inversion of next step;(4) Two dimensional density inversion is carried out for typical targets,and the results are used as the base model of human computer interaction, to provide an accurate range of iron ore distribution;(5)To form a set of iron ore resources exploration technology based on the regional magnetic data and the data of the profile. |
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