Discovery of mineral deposits and geological exploration work

Qiyugou gold deposit is the earliest discovered large-scale cryptoexplosive breccia gold deposit in China, and it is a typical representative of cryptoexplosive breccia gold deposit. The mining area is located in Taocun, northwest of Songxian County, Henan Province, on the north side of Qinling orogenic belt. This area has been rich in placer gold since ancient times, with many mining traces and obvious surface mineralization, but the discovery of rock gold deposits has gone through a long history and repeated understanding.

From 1956 to 1957, the Qinling survey team conducted a regional geological survey of1∶ 200,000 in this area, and determined the existence of cryptoexplosive breccia tubes in this area, and delineated the "Jin 1 1" anomaly. 195910 ~19610. on this basis, the fifth team of Henan metallurgical geology carried out geological exploration in qiyugou area, with the investment of 5115.

During the period of 1965 ~ 1967, the 18th geological team of Henan Geological Bureau made a geological evaluation of the 1, 2/and 4 bugle breccia in this area, and put it into an exploratory trench 1500 m3, with a shallow well of 55.8 m and a exploratory pit of 438 m, and submitted "Qi County, Henan Province"

During the period of 1969, No.3 Team of Geological Bureau of Henan Province made supplementary investigation on breccia bodies 1, No.2 and No.4 in this area, invested 8900 m3 of exploratory trench, 243 m of adit, 60.8 m of shallow well and drilled 484 m, and submitted the Detailed Investigation and Evaluation Report of Qiyugou Gold Mine in Songxian County, Henan Province, to analyze the causes of faults containing Jinjiao breccia series.

From September 1975 to September 1978 to February 1978, the third geological team of Henan Geological Bureau made a preliminary exploration of the 2 horn conglomerate exposed on the surface of the mining area, and conducted a general survey of 3 horn conglomerate, 4 horn conglomerate, 5 horn conglomerate and 6 horn conglomerate, and conducted a 2508 m3 trench and/kloc-. In 4 horn conglomerate, 229 1.27m was drilled, and the Preliminary Exploration Report of 2 horn conglomerate and other rocks in Qiyugou Gold Mine, Songxian County, Henan Province was submitted. The exploration metal amount of Erhao conglomerate is 1.82t, and the general survey metal amount of Sihao conglomerate is 4. 1.4t, which basically determines the industrial significance of the deposit. During this period (65,438), it is first proposed in this work report that the formation of ore-bearing breccia in this area is cryptoexplosion, and gold mainly occurs in the cement of breccia.

With the continuous expansion of mine production scale, by 1984, the ore resources of breccia were nearly exhausted. The mine began to consider the development and utilization of No.4 breccia, and at the same time, Henan No.2 Nonferrous Geology Team conducted exploration work in the middle sections of No.580 and No.550 in the upper part of No.4 breccia. By the end of1987,65438+February, 20 boreholes have been completed, and the drilling control of 60m×30 m grid of rock mass has been basically completed. At the beginning of 1988, the Geological Report on Detailed Survey of Tetrabreccia was submitted, and the surface gold reserves of Grade D were 12.400 t and 0.730 respectively. 1988 to 1990. On the basis of detailed investigation, the second geological team of Henan Nonferrous Geological Exploration Bureau made the first exploration of the gold ore bodies above 490 m above sea level in the breccia body, completed the tunnel of 2293.2 1 m and the hydrological drilling of 269.22 m, and added three boreholes, totaling 65,432. However, due to insufficient engineering control, no C-level reserves were found. In June 1990+065438+ 10, a detailed geological survey report was still submitted. The off-balance sheet and on-balance sheet gold reserves of Grade D were 2.339 t and 0. 193 t respectively. During the period of 1992 ~ 1993, the second geological team of Henan Nonferrous Geological Exploration Bureau carried out the second phase exploration of the 490~320 m elevation gold ore body in the breccia, completed the roadway of 2377.75 m, and obtained the internal and external gold reserves of C+D grade of 6.325t and 0.848t respectively, and submitted the report "Qiyugou, Songxian County, Henan Province" The above-mentioned geological exploration work is perfect, but due to the unclear understanding of the mineralization characteristics and mineralization enrichment law of hornfels, the above-mentioned exploration work has not achieved the best results in No.4 (Cao Yifu et al., 1999). According to the verification of mine production, most of the ore bodies delineated in the middle sections of 580 and 550 do not exist. 460, 430 middle metal submission is 5.6t, the continuity of ore body is poor, the grade changes greatly, and the negative change is serious, and the mine production is basically in the state of exploration and mining, which is difficult to meet the requirements of mine design and production. This reflects the complexity of cryptoexplosive breccia deposition from one side.

1993, the mine turned to the stage of production prospecting. With the deepening of the mining and research work of breccia, the understanding of the metallogenic characteristics and ore body shape of breccia is becoming more and more perfect. Up to now, the exploration depth of No.4 Horn conglomerate has reached 340 m in the middle section, reaching 1999, and the accumulated proven reserves have reached 24 t, making Qiyugou gold mine rank among the large-scale deposits. At the same time (1994 ~ 1997), Henan Jinyuan Gold Mining Co., Ltd. (formerly Qiyugou Gold Mine) also stepped up its geological prospecting efforts, and successively discovered gold-bearing quartz vein-type ore bodies in Gong Yu area in the northwest of the mining area, and carried out exploration, * * * completed 300 1 m pit exploration. Thus, the types of gold mineralization in the mining area are enriched and the prospecting ideas and horizons are broadened. At present, the production prospecting work in the mine and its periphery is still in progress.