Are there any old coal mines nearby. The spike could be from the coal mining car tracks, they were typically smaller than regular rail spikes, as were the rails as well. The tag looks like a miner ID tag. The coal miner would hang the tag on a pegboard on the outside of the mine before they entered, and on any rail cars they loaded. The first tag helped identify wich miners were in the mine in case of an emergency. They were also used to mark any cars they loaded, so they could get credit for there work. Back in the day they were paid by the weight of the coal they loaded not the hours they worked. "You load 16 ton what'a'ya get, another day older and deeper in debt". The number on the tag is the miners ID and the initials are those of the mining company. They would keep there tags on brass clip like the one below. Hope this helps.
