5. PROPERTY, PLANT AND EQUIPMENT, NET (Details) - USD ($)	3 Months Ended	12 Months Ended
Mar. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Mineral rights	$ 4,896,244	$ 4,711,822
Buildings	70,400,195	67,748,512
Plant and machinery	208,538,996	200,742,652
Motor vehicles	9,136	8,792
Furniture, fixtures and office equipment	4,313,043	4,150,588
Construction in progress	190,200	183,036
Total	288,347,814	277,545,402
Less: Accumulated depreciation and amortization	(174,767,162)	(163,597,407)
Impairment	(19,528,775)	(18,833,491)
Net book value	$ 94,051,877	$ 95,114,504

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 of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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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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