Experienced mining executive Rob McDonald will be New Century's new chairman, with Evan Cranston stepping down to a non-exec directorship.
Kumova exits having played a "pivotal role" in the growth of the business, "in particular the completion of successful financing of over A$98 million in equity and $100 million in debt facilities".
As of 12 months ago Kumova had interests in nearly 18 million shares and 30 million options in New Century.
New Century shares have been haemorrhaging on the market of late, losing nearly two-thirds of their value since April. The market selling has come with a few bedding-down issues at the new world scale zinc operation and a slide in the price of the metal from around US$2,900 per tonne to lows around $2,400/t over the same period.
Shares in New Century were down 6% to A35.2c in morning trade, capitalising the company at about $178 million.