Assessment of Fractures in Excavation Damaged Zone around Roadways of an Iron Mine Using Optical Televiewer Detecting Method

Table 4

Support improvement scheme of Xingshan iron mine.

Rock mass quality	IV	III	II
Footwall	1. Shotcrete, bolt, and metal mesh	1. Shotcrete and bolt	40 mm thick shotcrete
	2. Initial shotcrete within 4 hours after excavation blasting	2. Initial shotcrete within 3 days after excavation blasting
	3. Install bolt and metal mesh within 12 hours after initial shotcrete	3. Install bolt within 14 days after initial shotcrete
	4. Secondary shotcrete within 15–20 days after installing bolt and metal mesh	4. Thickness of shotcrete is 110–120 mm
	5. Thickness of shotcrete is not less than 140 mm
	1. Shotcrete, bolt and metal mesh`	1. Shotcrete and bolt
	2. Initial shotcrete within 1 day after excavation blasting	2. Initial shotcrete within 3–5 days after excavation blasting
Hanging wall and orebody nearby	3. Install bolt and metal mesh within 7–10 days after initial shotcrete	3. Install bolt within 7–10 days after initial shotcrete	—
	4. Secondary shotcrete within 20–30 days after installing bolt and metal mesh	4. Thickness of shotcrete is 40–100 mm
	5. Thickness of shotcrete is 100–140 mm
Most orebody	1. Shotcrete or shotcrete and bolt
	2. Initial shotcrete within 7 days after excavation blasting	—	—
	3. Install bolt within 30 days after initial shotcrete
	4. Thickness of shotcrete is 40–80 mm