You completely missed my point.
Lets see a graph/chart depicting the network's hashrate entire history. This will give us an idea of how big the whales are and may help with revealing other flashmine sessions.
Actually I didn't.
And if you really were interested in such information and couldn't find it anywhere else, I would imagine that you could start plotting the hashrate (from the wallet) and the difficulty from the blockchain explorer over a few days time to get a correlation between the two (difficulty response time and increase/decrease in response to hashrate changes) then apply that data using the diff history in the blockchain explorer to reverse plot the hashrate as far back as you wish. It might not be perfect, but I bet it would be close enough to prove or disprove your theory. I mean if you really wanted to know...