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

6 Months Ended

Jun. 30, 2020

Property, Plant and Equipment [Abstract]

Property, plant and equipment

	June 30, 2020			December 31, 2019
At cost:
Mineral rights	$	2,724,154		$	2,764,462
Buildings		59,007,466			59,880,567
Plant and machinery		231,247,364			234,669,007
Motor vehicles		6,039			6,129
Furniture, fixtures and office equipment		3,188,556			3,235,736
Construction in process		5,562,402			1,204,742
Total		301,735,981			301,760,643
Less: Accumulated depreciation and amortization		(151,706,607	)		(146,330,705	)
Impairment		(17,180,774	)		(17,434,989	)
Net book value	$	132,848,600		$	137,994,949