According to source, MINIES CLUB was a rogue circle with ties in the yakuza business, which made profit by reprinting doujinshi with or without consents of the original artists. They also printed uncensored pornographic books and videos apparently, and were cracked down by the japanese police for that reason around 1990.
Unfortunately the police found the uncensored doujin books among the other 'illegal' contents. This led to another crack down on manga shops selling 'harmful books' the year after, and to the almost cancellation of the August 1991 comiket. Its relocalization to the current site and self-regulation (censorship) rules were settled at that time.