*5.2. Resource Potential of the Jiaojia and Zhaoping Faults*

The prediction range of the Jiaojia fault is as follows. Its southern boundary was the exploration line No. 408 on the southernmost side of the Qianchen ore block and its northern boundary was the exploration line No. 201 on the northernmost side of the Xincheng ore block. Its eastern and eastern parts were the outcrops of the Jiaojia fault and the production of the Jiaojia fault on the ground surface, respectively. Moreover, it had an elevation of −5000 to −2000 m.

For the purposes of this study, the Zhaoping fault was divided into two prediction sections: the northern section and the central-southern section. The prediction range of the Lingnan-Shuiwangzhuang gold concentration area in the northern Zhaoping fault is as follows. Its southern boundary was exploration line No. 9 of the Lingnan ore block and its northern boundary was exploration line No. 29 on the northernmost side of the Shuiwangzhuang ore block. Moreover, its western and eastern parts were the outcrops of the Zhaoping fault and the projection of the Zhaoping fault on the ground surface, respectively. The prediction range of the Dayin'gezhuang gold concentration area in the central-southern section of the Zhaoping fault is as follows. Its southern and northern boundaries were exploration lines No. 54 and No. 120 of the Dayin'gezhuang gold orefield, and its western and eastern parts were the outcrops of the Zhaoping fault and the projection of the Zhaoping fault on the ground surface, respectively. The prediction range of the Xiadian ore block concentration area in the central-southern section of the Zhaoping fault is as follows. Its southern boundary was exploration line No. 441 of the Xiadian ore block, and its northern boundary was exploration line No. 35 of the Daobeizhuangzi ore block. Moreover, its western and eastern parts were the outcrops of the Zhaoping fault and the projection of the outcrops on the ground surface, respectively. The elevation range of the prediction areas of the Zhaoping fault was −5000 to −2000 m. The proven resources and the parameters for resources prediction of Jiaojia and Zhaoping faults were determined

using the same procedure as the Sanshandao fault zone. The predicted results are listed in Table 8.


**Table 8.** Predicted gold resources of major ore-controlling faults in the northwest Jiaodong Peninsula.

In sum, for the metallogenetic belts of the Sanshandao, Jiaojia, and Zhaoping faults in the Jiaodong Peninsula, their predicted gold ore reserves and predicted gold metal reserves at an elevation of −5000 to −2000 m were approximately 1217–2237 × Mt and 3377–6490 t, respectively, and their total gold ore reserves and gold metal reserves at an elevation of −5000 m and above were approximately 2310–3330 × Mt and 7073–10,150 t, respectively. As the metallogenic conditions in the deep prediction area are different from those in the shallow area, the accuracy of the geophysical method will decrease with the increase in the depth, so the error of the prediction results is uncertain.

The above forecast data are only the predicted results of the deep parts of the main known gold deposits in the northwest Jiaodong Peninsula. In combination with the future prediction and prospecting of other areas in the Jiaodong Peninsula with great potential for deep prospecting, the total resources of gold deposits in the Jiaodong Peninsula will possibly double in quantity and increase from the current 5000 t to 10,000 t. Therefore, the Jiaodong gold concentration area is expected to become the world's second largest gold metallogenic area.

At present, the exploration depths of identified gold deposits in the Jiaodong Peninsula are mostly less than 2000 m, with only a few exploratory boreholes reaching a depth of more than 3000 m [61,62]. For example, exploratory borehole ZK96-5 in the Xiling mining area in the northern Sanshandao fault has a final hole depth of 4006.17 m, making it the deepest borehole for gold exploration in China [62]. This borehole revealed a fractured alteration zone with a thickness of tens of meters at a depth of approximately 3500 m. Borehole K01 drilled in the deep part of the Jiaojia supergiant gold deposit in the middle part of the Jiaojia fault by the Shandong Institute of Geological Sciences has a depth of 3266.06 m. It revealed multi-layer industrial orebodies at a depth of 2810–2854 m [61]. Borehole K3401 drilled in the deep part of the Shuiwangzhuang mining area in the northern Zhaoping fault by the Shandong Provincial No. 6 Exploration Institute of Geology and Mineral Resources has a final hole depth of 3000.58 m. It revealed a fractured zone in the Jiuqujiangjia 208 fault at an elevation of approximately −2700 m. The sampling analysis indicated that the fractured zone has a maximum gold grade of nearly 7 g/t. The metallogenic information obtained from these deep exploratory boreholes is consistent with the predicted results of this study, indicating that the deep parts at an elevation of −2000 m and below have great potential for deep prospecting. In addition, geological and geophysical explorations show that the Jiaojia and Sanshandao faults' dip angles gradually decrease towards their deep parts along their dip directions and that the two faults intersect at the elevation of approximately −4500 m [42,43,59]. These findings, combined with the comprehensive analysis of the evidence of denudation degree, metallogenic depth, deep drilling verification, and the extension of faults towards deep parts, have led to the conclusion that the Jiaojia and

Sanshandao faults have favorable gold metallogenic conditions and enormous prospecting potential at an elevation of −4500 m and below.
