4. PROPERTY, PLANT AND EQUIPMENT, NET (Details) - USD ($)	3 Months Ended	12 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Mineral rights	$ 2,722,033	$ 2,764,462
Buildings	58,961,513	59,880,567
Plant and machinery	231,067,278	234,669,007
Motor vehicles	6,035	6,129
Furniture, fixtures and office equipment	3,186,073	3,235,736
Construction in progress	4,743,600	1,204,742
Total	300,686,532	301,760,643
Less: accumulated depreciation and amortization	(147,486,310)	(146,330,705)
Impairment	(17,167,394)	(17,434,989)
Net book value	$ 136,032,828	$ 137,994,949

Vehicles Gross

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Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation of building structures held for productive use including addition, improvement, or renovation to the structure, including, but not limited to, interior masonry, interior flooring, electrical, and plumbing.

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Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

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Amount before accumulated depreciation of equipment commonly used in offices and stores that have no permanent connection to the structure of a building or utilities. Examples include, but are not limited to, desks, chairs, tables, and bookcases.

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Carrying amount at the balance sheet date of mineral properties, gross of adjustments.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount before accumulated depreciation, depletion and amortization of other physical assets used in the normal conduct of business to produce goods and services and not intended for resale.

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The charge against earnings resulting from the aggregate write down of tangible assets from their carrying value to their fair value.

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