MINING PROPERTIES

Mining properties consist of the following (in thousands):



December 31, 2018	Palmarejo			Rochester			Silvertip			Kensington			Wharf			Sterling			La Preciosa		Other			Total
Mine development	$	239,780		$	200,126		$	101,933		$	324,414		$	41,761		$	4,070		$	—	$	—		$	912,084
Accumulated amortization	(163,414		)	(151,141		)	(1,411		)	(198,456		)	(18,759		)	(14		)	—		—			(533,195		)
	76,366			48,985			100,522			125,958			23,002			4,056			—		—			378,889
Mineral interests	629,303			18,521			252,899			—			45,837			95,499			49,085		5,171			1,096,315
Accumulated amortization	(472,448		)	—			(4,105		)	—			(26,667		)	—			—		(417		)	(503,637		)
	156,855			18,521			248,794			—			19,170			95,499			49,085		4,754			592,678
Mining properties, net	$	233,221		$	67,506		$	349,316		$	125,958		$	42,172		$	99,555		$	49,085	$	4,754		$	971,567



December 31, 2017	Palmarejo			Rochester			Silvertip		Kensington			Wharf			La Preciosa		Total
Mine development	$	214,383		$	193,881		$	57,214	$	298,749		$	40,618		$	—	$	804,845
Accumulated amortization	(146,598		)	(144,390		)	—		(178,632		)	(15,748		)	—		(485,368		)
	67,785			49,491			57,214		120,117			24,870			—		319,477
Mineral interests	629,303			—			245,116		—			45,837			49,085		969,341
Accumulated amortization	(435,215		)	—			—		—			(24,034		)	—		(459,249		)
	194,088			—			245,116		—			21,803			49,085		510,092
Mining properties, net	$	261,873		$	49,491		$	302,330	$	120,117		$	46,673		$	49,085	$	829,569

Palmarejo is located in the State of Chihuahua in northern Mexico and consists of the Palmarejo mine and mill, the Guadalupe underground mine, the Independencia underground mine, and other deposits and exploration targets. Palmarejo commenced production in April 2009.

The Rochester silver and gold mine, located in northwestern Nevada has been operated by the Company since September 1986. The mine utilizes heap-leaching to extract both silver and gold from ore mined using open pit methods. In October 2018 the Company and Rochester entered into an Asset Purchase Agreement to acquire the Lincoln Hill and related assets, which was consummated in November 2018. The acquired asset property package is adjacent to the Rochester operation and it consists of the Lincoln Hill Project, Wilco Project, Gold Ridge Property and other nearby claims.

The Silvertip is a silver-zinc-lead mine located in northern British Columbia, Canada. The Silvertip mine reached commercial production in September 2018. The determination of commercial production (or ready for intended use) was based on many factors requiring the exercise of judgment. Factors that were considered when determining if intended use had been achieved included achievement of continuous production or other output, mineral recoveries at or near expected levels, the absence of routine take-downs of the plant to address commissioning issues and fix problems, and the release of the commissioning team.

Prior to commercial production, costs related to mine development, construction of long-lived assets, and inventory were capitalized; all other costs were expensed in the period incurred. Amortization of mining properties commenced when the mine reached commercial production.

The Kensington mine is an underground gold mine and consists of the Kensington and adjacent Jualin properties located north-northwest of Juneau, Alaska. The Company commenced commercial production in July 2010.

The Wharf gold mine is an open pit gold mine located near the city of Lead, South Dakota. The Company acquired Wharf in February 2015.

In October 2018 the Company completed its acquisition of Northern Empire. Northern Empire’s principal asset is the Sterling project, which is located 115 miles (185 km) north of Las Vegas, Nevada.The Sterling project is a past-producing mine with all major permits in hand that has near-term, low-cost, low-capital production potential. The remaining deposits include Daisy, Secret Pass and SNA, collectively known as the Crown Block, contain significant exploration potential. The underexplored land package also includes multiple new, undrilled targets previously identified by Northern Empire that remain untested.

The La Preciosa silver-gold project is located in the State of Durango in northern Mexico. The Company completed a feasibility study in 2014 and has deferred construction activities until expected returns improve.

Asset Sales

In February 2018, the Company completed the Manquiri Divestiture. Pursuant to the terms of the agreement, the Company received, among other consideration, the NSR. Coeur estimates the value of this net smelter returns royalty to be approximately $7.1 million, which is included in Other. In September 2018, the Company entered into the Letter Agreement, pursuant to which the Company agreed to suspend the quarterly payments in respect of the NSR until October 15, 2019. Based on the Company’s evaluation of the terms of the Letter Agreement, the Company recorded a write-down of $1.9 million on the NSR. See Note 10 -- Fair Value Measurements and 21 -- Discontinued Operations for additional detail.