Fast forward to : Powerbang Gaming released a video showing how his clan has found success using Miners at TH10 (despite the title being about a TH9 golem avalanche attack).
But then in the March of 2017 balancing update, their hitpoints were increased. In October 2016 they were tweaked to pause a split second while above ground after destroying a building. Miners have had a few changes over the past year.
Update : This post was completely revamped with newer videos since the June 2017 balancing update.