14. INCOME TAXES (Details 2) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Deferred tax liabilities	$ 0	$ 0
Deferred tax assets:
Impairment on property, plant and equipment	2,764,893	2,974,542
Impairment on prepaid land lease	814,620	826,673
Exploration costs	1,758,563	1,784,583
Compensation costs of unexercised stock options	74,883	171,672
PRC tax losses	20,571,271	18,737,005
US federal net operating loss and foreign tax credit	311,000	432,000
Total deferred tax assets	26,295,230	24,926,475
Valuation allowance	(8,796,686)	(8,985,833)
Net deferred tax asset	$ 17,498,544	$ 15,940,642