Note 8 Inventories

The composition of inventory at each period-end is as follows:

Type of inventory	12/31/2017 ThUS$		12/31/2016 ThUS$		12/31/2015 ThUS$

Raw material reserves		9,364		7,536		4,844
Supplies for production reserves		22,257		23,610		29,353
Products-in-progress reserves		456,333		482,261		478,627
Finished product reserves		414,120		479,665		491,022
Total		902,074		993,072		1,003,846

As of December 31, 2017, the Company has inventory of caliche ore (in piles or undergoing leaching process) available for processing valued at ThUS$62,476 (ThUS$ 43,400 as of December 31, 2016), (included in work in progress).

Inventory reserves recognized as of December 31, 2017 amount to ThUS$96,284, and ThUS$81,295 as of December 31, 2016 and ThUS$ 80,369 as of December 31, 2015. Inventory reserves have been made based on a technical study that covers the different variables affecting products in stock (density and humidity, among others).

In the case of inventories of raw materials, supplies, materials and parts, provisions have been made at the lower value associated with the proportion of obsolete, defective or slow-moving materials.

The breakdown of inventory reserves is detailed as follows:

Type of inventory	12/31/2017 ThUS$		12/31/2016 ThUS$		12/31/2015 ThUS$

Raw material reserves		93		93		93
Suministros para la producción		-		920		920
Products-in-progress reserves		80,249		50,925		53,187
Finished product reserves		15,942		29,357		26,169

Total		96,284		81,295		80,369

The Company has not delivered inventory as collateral for the periods indicated above.

As of December 31, 2017, 2016 and 2015, movements in provisions are detailed as follows:

Reconciliation	12/31/2017		12/31/2016		12/31/2015
	ThUS$		ThUS$		ThUS$
Opening balance		81,295		80,369		82,966
Changes
Additional provisions		21,953		9,831		18,461
Increase (decrease) in existing provisions		(6,964)		(8,905)		(21,058)
Total changes		14,989		926		(2,597)
Final Balance		96,284		81,295		80,369