I purchased this horseshoe from someone based in the United Kingdom. Her father had been a coal mining enthusiast and collected many items as souvenirs, including this pony shoe. It was believed to have been from a mine in Wales.
Coal miners used to use ponies to haul loads of coal, as a larger horse would not have had enough head clearance in the tunnels. They had to have solid copper or brass shoes on the horses to prevent sparks that might cause fires what with all of the flammable coal present. This shoe, I believe, is copper. It is not magnetic.
There are two small toe clips present (the clips on this shoe have been bent slightly from handling, particularly since copper is softer than iron, which is what most shoes are made from). With toe clips present, it is safe to say that this particular shoe is dated anytime after 1850, since that is the time that toe clips were invented.
Absolutely one of my favorite finds! Remember, when looking for a pit pony shoe, always check to see if it is magnetic as there are shoes out there that have only been plated or painted with copper or brass for aesthetic purposes and are not actually pit pony shoes.