this is from an article by david morgan, who reminds us that not every company with silver in its name is really a silver company. offhand i can think of sabina silver (zinc) and esperanza silver (gold.)

First it must be understood that the universe of true silver stocks is extremely small. My definition of a true silver stock is a company whose primary revenue stream is based on silver. This is an unusual creature because approximately 75 percent of all silver comes from the mining of other metals. Depending upon which study you examine, about 25 percent of silver mined is a result of copper mining, 33 percent is a result of lead/zinc mining, and even 14 percent of silver comes out of the ground as a result of gold mining.

The reason an investor wants a primary silver producer is the fact that the stock price will be leveraged to the price of silver. If an investor buys a stock that has its primary metal as copper yet still yields quite a bit of silver, the company is more apt to move on the price of copper not silver.

Additionally, most miners who are base-metal miners and have a great deal of silver in the mix really do not care about the silver price, and they sell it for "peanuts" to use the proceeds against their primary mining activity. You may find other information on a huge universe of silver stocks available, but take your time to study and educate yourself. Just because a company has silver in its name, or is exploring to find silver, that does not make it a silver company.

http://news.silverseek.com/SilverInvestor/1249012084.php