However,I feel it's unfair to disrespect Ashio(and Furukawa Ichibei),so I would like to give them a little excuse as well.
Since the Besshi Copper Mine was a privatize mine (the government was not involved in planting trees or purchasing uninhabited islands), Iba Sadakane was able to move freely.
Ashio,on the other hand,was a national project, and its development was related to the ups and downs of the Meiji government at the time.
Therefore,stopping the mining business was not opinion.
At the time,international relations with the Qing dynasty over the Korean peninsula were in a state of flux.
However,the Meiji government was not monolithic, either,and was divided between the main faction and the cautious faction.(Mutsu Munemitsu was a main fighter.)
As such,the Ashio Copper Mine development further expanded.
Nevertheless,Furukawa must have had a guilty consciousness.
He built a dike to prevent sewage from flowing into the Watarase River,allowing only a certain amount of filtered water to flow. Of course,the government backed him up. He himself was in some ways native in thinking that this would quiet the residents.
However,these half-hearted measures taken by Furukawa led to a major incident.