This follows 18 months of planning, which included a competent person's report and the hiring of Jacques Pretorius as Langpan's general manager.
The plant's first delivery of chrome concentrate is scheduled for June 8 or later.
Mantengu chief executive Mike Miller said the initial chrome mill was built to accommodate a monthly output of 30 000 tonnes (t), or 70 t/h.
However, the new chrome plant's commissioning has increased production capacity to 36 000 t per month, or 100 t/h.
The plant is projected to generate around 18 000 t of chrome concentrate per month, with a chrome percentage ranging from 42% to 44%.
The second plant will have a monthly capacity of 30 000 t, while the third plant will have a monthly capacity of 14 000 t.
Mantengu intends to commission both plants in August.
The Langpan chrome reserve is estimated to be 2.17 million tonnes.
Mathew Nyaungwa, Editor in Chief of the African Bureau, Rough&Polished