Bolivian miners have staged a major protest at the San Cristóbal mine, one of the world’s largest silver mines, San Cristobal Mine is the world’s third-largest producer of silver and the sixth-largest producer of zinc, it produced some 620,000 kilograms of fine silver in 2009, according to official data, and its output accounts for about half of the country's total mining exports.The Union decides to continue indefinite strike and they are blocking the entrance to the mine .There is neither production nor exports, because there's a blockade as part of the strike , this is all bullish for the silver price worldwide and it is probably what have caused the recent silver prices surge , experts are now expecting $50 an ounce for silver as early as next month . The price ratio gold / silver has moved in favor of silver in the last couple of months. A large number of investors have seen silver more affordable than gold. Because of this demand, dealers in precious metals in the United States and China have warned of a shortage of supply. Many investors are very worried about the continued devaluation of the currencies in the leading nations. The policies pursued by the U.S. central bank, the Federal Reserve (Fed) are eroding confidence in the dollar, leading many Americans to buy silver. Many Chinese are also buying silver as a hedge against rapidly rising inflation in China. The demand for silver in Traded Funds (ETFs) has increased dramatically in recent years