XML 26 R13.htm IDEA: XBRL DOCUMENT v3.8.0.1
Property, Plant and Equipment, net
 3 Months Ended
Mar. 31, 2018
Property, Plant and Equipment [Abstract]  
Property, Plant and Equipment, net
Property, Plant and Equipment, net
Net property, plant and equipment consisted of:
 
 
March 31, 2018
 
December 31, 2017
Machinery, equipment and tooling
$
10,529

 
$
8,242

Vehicles
1,544

 
1,546

Furniture and fixtures
730

 
720

Plant and building
83,057

 
81,561

Real estate properties
4,432

 
4,432

Railroad and sidings
25,286

 
10,254

Land improvements
23,156

 
16,378

Asset retirement obligation
8,657

 
8,408

Mineral properties
9,879

 
9,878

Deferred mining costs
657

 
657

Construction in progress
71,639

 
56,493

 
239,566

 
198,569

Less: accumulated depreciation and depletion
29,529

 
26,367

Total property, plant and equipment, net
$
210,037

 
$
172,202


Depreciation expense was $3,158 and $1,662 for the three months ended March 31, 2018 and 2017, respectively. Depletion expense was $2 and $5 for the three months ended March 31, 2018 and 2017, respectively.
The Company capitalized no interest expense associated with the construction of new plant and equipment for the three months ended March 31, 2018 and 2017.