Large-Deformation Failure Mechanism of Coal-Feeder Chamber and Construction of Wall-Mounted Coal Bunker in Underground Coal Mine with Soft, Swelling Floor Rocks

Table 5

Calculation of the economic benefits (unit: million UD).

Cost of coal bunker #214		Cost of the WMCB
Construction cost	Construction time	Cost of repair of coal bunker #214 every year			Construction cost	Construction time	Delayed production efficiency
		Repair cost	Failure time	Delayed production efficiency
A = 0.398	Two months	B = 0.294	Three months	C = 23.22	D = 0.582	Two months	E = 15.48
Net benefit over five years		A + (B + C) × 5 − D − E = 101.906