Nova Resources, a company owned by Novachuk and Kaz director Vladimir Kim, will pay 640 pence per Kaz share, the miner said.
Kaz shares scaled their highest in one and a half years in early trade. They were up 10% at 629 pence by 0811 GMT.
Novachuk and Kim already own stakes of 7.8% and 31.6% in Kaz, respectively, according to Refinitiv data.
The consortium believes Kaz's long term interests are best served as a private company, the miner said.
Kaz Minerals, the largest copper producer in Kazakhstan, said an independent committee considered the terms of the deal to be "fair and reasonable".
Like miners across the globe, Kaz earlier this year cut its 2020 capital spend and warned of production delays as it dealt with disruptions due to the coronavirus crisis.
(Reporting by Muvija M in Bengaluru; Editing by Aditya Soni)