https://minerals.usgs.gov/minerals/pubs/commodity/silver/mcs-2016-silve.pdf This is the last available annual report from USGS Looking at "World Mine Production and Reserves: Reserves" We see in terms of mine production (2015), the top producers are Mexico, China and Peru, in metric tonnes, where world production was 27300 Mexico 5400 (19.8%) China 4100 (15%) Peru 3800 (13.9%) Adding up, the fraction for these 3 countries is 48.7% of world production for 2015, if this report is accurate. Where things become more interesting is in terms of reserves. World terrestrial silver reserves were estimated as 570,000, but this is almost certainly a wild underestimate. Poland and Australia have estimates of 85000t (14.9% each) of reserves and Chile 77000t (13.5%), ie in aggregate 43.3%. Peru has 120,000t estimated ie 21.1%. Bear in mind estimates probably reflect technology and capital available to estimate. Mexico has just 37t reserves calculated. Reality may prove different, but for now it seems other countries could beef up production, depending on logistical, legal and financial constraints, should Mexican silver become less available to the US for political reasons. Maybe a greater supply is more likely (from Mexico) if the Mexican economy takes a turn south in the next year or two. As Mexican production is estimated as about a fifth of total world supply, changes in this could impact on the POS if involved in the political fallout.
Teeny error - Mexico has 37000 tonnes (per that estimate of reserves), ie 6.5% or world reserves. If you like, assuming this is fixed (which it probably isn't), also assuming current annual production until exhaustion at the same rate, then there is 6.85 years left in Mexico. So, should Mexico increase production, then it should hit the wall sooner, bar any new reserves or technology improving yield.
