4. PROPERTY, PLANT AND EQUIPMENT, NET (Tables)

9 Months Ended

Sep. 30, 2020

Property, Plant and Equipment [Abstract]

Property, plant and equipment

	September 30, 2020			December 31, 2019
At cost:
Mineral rights	$	2,831,963		$	2,764,462
Buildings		61,342,699			59,880,567
Plant and machinery		240,399,030			234,669,007
Motor vehicles		6,278			6,129
Furniture, fixtures and office equipment		3,314,744			3,235,736
Construction in process		8,748,307			1,204,742
Total		316,643,021			301,760,643
Less: Accumulated depreciation and amortization		(162,126,742	)		(146,330,705	)
Impairment		(17,860,707	)		(17,434,989	)
Net book value	$	136,655,572		$	137,994,949