A man wearing a “Pinhead” mask walks through the grounds of St Mary's Church, Whitby, during the Whitby Gothic festival taking place this weekend, on April 27, 2014. The twice yearly event attracts Goths from across the UK and beyond to the historic fishing town and is a great boost to the local economy. (Photo by Anna Gowthorpe/PA Wire)

Ingots of 99.99 percent pure silver are cast at the Krastsvetmet Krasnoyarsk non-ferrous metals plant in the Siberian city of Krasnoyarsk, Russia, June 5, 2015. Krastsvetmet is one of the world's largest players in the precious metals industry. REUTERS/Ilya Naymushin

People leave a camp after a Peruvian police operation to destroy illegal gold mining camps in La Pampa, in the southern Amazon region of Madre de Dios, Peru August 11, 2015. Picture taken August 11, 2015. (Photo by Sebastian Castaneda/Reuters)

A mine worker is seen outside “The Progreso” gold mine near La Paz, November 13, 2014. According to local media, the president of the Central Bank of Bolivia (BCB) Marcelo Zabalaga said on Thursday that the falling price of oil and minerals in the international market will not affect the national economy. (Photo by David Mercado/Reuters)

An engineer (L) talks to a driver of a dump truck loaded with gold-bearing soil at the Vostochny opencast of the Olimpiada gold operation, owned by Polyus Gold International company, in Krasnoyarsk region, Eastern Siberia, Russia, June 30, 2015. Polyus Gold International is the largest gold producer in Russia and one of the top 10 gold miners globally by ounces produced, according to the official web site of the company. Olimpiada is Polyus Gold's largest operation. (Photo by Ilya Naymushin/Reuters)

A boy carries a dog as he stands after a Peruvian police operation to destroy illegal gold mining camps in a zone known as Mega 14, in the southern Amazon region of Madre de Dios July 14, 2015. Peruvian police razed dozens of illegal gold mining camps at the edge of an Amazonian nature reserve this week, part of a renewed bid to halt the spread of wildcatting in a remote rainforest region. (Photo by Janine Costa/Reuters)

Astronaut Edward H. White II, pilot for the Gemini-Titan 4 (GT-4) spaceflight, floats in the zero-gravity of space during the third revolution of the GT-4 spacecraft on June 3, 1965. White wears a specially designed spacesuit. His face is shaded by a gold-plated visor to protect him from unfiltered rays of the sun. In his right hand he carries a Hand-Held Self-Maneuvering Unit (HHSMU) that gives him control over his movements in space. White also wears an emergency oxygen chest pack; and he carries a camera mounted on the HHSMU for taking pictures of the sky, Earth and the GT-4 spacecraft. He is secured to the spacecraft by a 25-feet umbilical line and a 23-feet tether line. Both lines are wrapped together in gold tape to form one cord. Astronaut James A. McDivitt, command pilot, remained inside the spacecraft during the extravehicular activity (EVA). Astronaut White died in the Apollo/Saturn 204 fire at Cape Kennedy on January 27, 1967. (Photo by NASA)

In this May 4, 2014 photo, a miner holds an amalgam of mercury and gold he mined after working a 28-hour shift at an illegal gold mining process, in La Pampa, in Peru's Madre de Dios region. Thousands of artisanal gold miners sweat through the long shifts and endure, for a few grams of gold, the perils of collapsing earth, limb-crushing machinery and the toxic mercury used to bind gold flecks. (Photo by Rodrigo Abd/AP Photo)