Here is why in my view.
Start of January miners are very over-sold at that time. Technical bounce very warranted and justified. Miners went up in January and it was absolutely justified.
In February gold was on a run and miners continued up and this was justified although miners got a bit overextended but nothing crazy yet.
March, gold basically flat for the month and miners not over-sold at all anymore however momentum carried them on. Movement starting to get silly.
April, gold still basically flat since March 10th. Miners now parabolic. Extremely over-priced and over-bought. Momentum has matured into a full blown pump job.
I look around and analysts are recently upgrading miners. Great of them to do. Where were they in January? Nope they wait until miners have gone up 150% in 3 months. Articles and media all over the place pumping miners now. Everyone loves the mining sector now that it is up 150% in 3 months. Bad balance sheets, huge debt burdens, gold being flat over the last month, Huge valuations of 60-80 times earnings, parabolic chart move. All ignored right now because a pump job is happening. What was justifiable in January and February and then turned a little too optimistic in March has now become a full blown pump job IMO.
This by the way is very normal in the stock market. All sectors do this from time to time. From one extreme to the other.