Golden Minerals Company is precious metals mining company, and we own the Velardeņa Properties and associated oxide and sulfide processing plants in the State of Durango, Mexico, the El Quevar advanced exploration property in the province of Salta, Argentina, and a diversified portfolio of precious metals and other mineral exploration properties located primarily in or near historical precious metals producing regions of Mexico. Our common stock is publicly traded on the Toronto and NYSE American stock exchanges.
We are primarily focused on evaluating and searching for mining opportunities in North America (including Mexico) with near term prospects of mining, and particularly for properties within reasonable haulage distances of our Velardeņa Properties. Golden Minerals is also reviewing strategic opportunities, focusing primarily on development and operating properties in North America, including Mexico. We are continuing exploration efforts on selected properties in our portfolio of approximately 10 exploration properties located primarily in Mexico. We continue to hold our El Quevar advanced exploration property on care and maintenance until we can fund further exploration ourselves or find a partner to further advance the project.
We leased the oxide mill at Velardeña to Hecla Mining Company in July 2015, and that arrangement has provided Golden Minerals with net operating margin of approximately $2.2 million in 2017 (through June 30) as well as approximately $4.4 million in 2016. The lease has been extended several times, most recently on August 2, 2017 when Golden granted Hecla an option to secure the use of the oxide mill for an additional two years, through December 31, 2020.
Golden Minerals reported a balance of approximately $2.7 million cash and cash equivalents as of June 30, 2017, as compared to $2.1 million at March 31, 2017 and $2.6 million at December 31, 2016. The Company has no outstanding debt.
We are led by a management team with more than 60 years of combined experience in mining exploration, project development, construction and operations all over the world. Our executive officers have held senior positions at various large mining companies including, among others, Cyprus Amax Minerals Company, INCO Limited, Meridian Gold Company, Barrick Gold Exploration and Noranda Exploration. Our executive team has a proven ability to manage large projects in challenging environments.