Evaluation of Underground Zinc Mine Investment Based on Fuzzy-Interval Grey System Theory and Geometric Brownian Motion

Table 3

Relative and absolute error of the model.

Year	Original values ($/t)	Simulated values ($/t)	Whitenization 𝜔 = 0.5		Relative error	Absolute error	Relative error (%)
			Original	Simulated
2009	[1385, 1931]	[1385, 1931]	1658	1658	0	0	0
2010	[2016, 2304]	[1941, 2466]	2160	2204	−44	44	−2.03
2011	[2057, 2333]	[1792, 2404]	2195	2098	97	97	+4.42
2012	[1895, 2005]	[1647, 2346]	1950	1997	−47	47	−2.41
2013	[1849, 1971]	[1505, 2293]	1910	1899	11	11	+0.57