内蒙古毕力赫大型金矿勘查突破过程及启示意义

内蒙古毕力赫金矿原为一资源严重危机的小矿山.为缓解资源危机,维持矿山可持续发展,笔者等应邀对该矿床进行了资源潜力评价,并开展接替资源勘查工作.在对该矿床进行详实的野外地质调查和资源潜力分析的基础上,确定了针对矿山地质工作程度并结合矿床具体特点、采用以现有资料综合分析为基础、以针对性的地质科研引路、以有效的勘查方法技术组合配套使用为手段、适时设计验证工程、分期分阶段有重点地加以实施的找矿勘查思路.通过3年多的研究与勘查,实现了找矿的重大突破,在原矿区外围新发现了Ⅱ号金矿带.通过系统勘探,发现大型高品位隐伏斑岩型金矿体,提交新增金资源/储量21.916 t,使一个名不见经传的小矿一跃而成为大型金矿床.经验表明,要实现危机矿山的找矿突破,扎实的基础地质工作、科学的资源潜力评价和有针对性的找矿勘查思路是成功的关键.

Prospecting process of Bilihei large_sized gold deposit in Inner Mongolia and its revelatory significance

The Bilihei gold deposit in Inner Mongolia is a very small gold deposit whose resource was previously in a state of fearful crisis. In order to get rid of such a situation, the authors were invited to evaluate the resource potential and conduct resource prospecting. The early geological survey shows that the deposit is located in an important ore_forming belt in the north margin of the North China plate. The ore bodies are controlled by structures of volcanic craters and different trends of faults, and the country rocks are mainly of the intermediate_acid volcanic series. Mineralization was related to the concealed granodiorite porphyry. Detailed observations of the exploratory and mining tunnels revealed that mineralization at surface and shallow places is of the epithermal type, which may convert into the porphyry type in depth. Nevertheless, no typical porphyry type ore bodies were discovered before this prospecting. On the basis of geological investigation of the exhaustive field and comprehensive analysis of the resource potential, a scientific resource prospecting plan was put forward and performed, with the porphyry type ore body in depth being the main exploratory target. Through more than three years' research and prospecting work, a new survey area named No. 2 mineralization zone was detected on the periphery of the formerly_discovered ore district. It was in the No. 2 mineralization zone that a large_sized concealed high_grade gold ore body was found, with more than 21000 kg gold resource being so far proved. It is the first large porphyry Au deposit ever discovered in middle_east Inner Mongolia. The authors have come to the conclusion from their experience that the key factors to successful prospecting are detailed basic geological work, scientific resource potential evaluation and pertinent prospecting thinking.