INCOME TAXES (Mining Royalty Taxes) (Details) (Chile [Member])	12 Months Ended
	Dec. 31, 2017 Stabilized Rate [Member]	Dec. 31, 2016 Stabilized Rate [Member]	Dec. 31, 2015 Stabilized Rate [Member]	Dec. 31, 2014 Stabilized Rate [Member]	Dec. 31, 2013 Stabilized Rate [Member]	Dec. 31, 2012 Stabilized Rate [Member]	Dec. 31, 2011 Stabilized Rate [Member]	Dec. 31, 2010 Stabilized Rate [Member]	Dec. 31, 2017 Special Mining Burden [Member]	Dec. 31, 2016 Special Mining Burden [Member]	Dec. 31, 2015 Special Mining Burden [Member]	Dec. 31, 2014 Special Mining Burden [Member]	Dec. 31, 2013 Special Mining Burden [Member]	Dec. 31, 2023 Minimum [Member]	Dec. 31, 2022 Minimum [Member]	Dec. 31, 2021 Minimum [Member]	Dec. 31, 2020 Minimum [Member]	Dec. 31, 2019 Minimum [Member]	Dec. 31, 2018 Minimum [Member]	Dec. 31, 2012 Minimum [Member] Special Mining Burden [Member]	Dec. 31, 2011 Minimum [Member] Special Mining Burden [Member]	Dec. 31, 2010 Minimum [Member] Special Mining Burden [Member]	Dec. 31, 2023 Maximum [Member]	Dec. 31, 2022 Maximum [Member]	Dec. 31, 2021 Maximum [Member]	Dec. 31, 2020 Maximum [Member]	Dec. 31, 2019 Maximum [Member]	Dec. 31, 2018 Maximum [Member]	Dec. 31, 2012 Maximum [Member] Special Mining Burden [Member]	Dec. 31, 2011 Maximum [Member] Special Mining Burden [Member]	Dec. 31, 2010 Maximum [Member] Special Mining Burden [Member]
Mining royalty taxes by location [Line Items]
Mining royalty tax rate	4.00%	4.00%	4.00%	4.00%	4.00%	4.00%	4.00%	4.00%	4.00%	4.00%	4.00%	4.00%	4.00%	5.00%	5.00%	5.00%	5.00%	5.00%	5.00%	4.00%	4.00%	4.00%	14.00%	14.00%	14.00%	14.00%	14.00%	14.00%	9.00%	9.00%	9.00%