What is the possessive form of miners?

The Word 'miners' (the plural of miner) has no apostrophe. An apostrophe is put on a Word for one of three purposes.

1. As a contraction: The miner's always at home. (Contraction of 'miner is.')

2. As a singular possessive noun: This is the miner'spickax.

3. As a plural possessive noun: These are the miners'pickaxes.