Petropavlovsk nears first gold production at POX plant

Petropavlovsk has made significant progress on the commissioning its Pressure Oxidation (POX) Hub project at the Pokrovskiy mine in the Russian Far East, with first refractory ore concentrate processing scheduled for November 28.

During the week commencing November 5, the group’s in-house POX experts together with Outotec, MOGAS Systems & Consulting and representatives from various equipment manufacturers, successfully commenced hot commissioning of the first of four autoclaves, associated flash tanks, high pressure circuits and concentrate re-grinding and lime preparation sections of the POX facility.

The hot commissioning process involved filling autoclave 1 with an acid solution that replicates the usual operational conditions under which the autoclave is processing refractory concentrate. The autoclave vessel was heated in stages over a period of three days, before being allowed to cool down over a period of two days.

“The hot commissioning process helped to expose certain minor defects, including a leak caused by a faulty seal within an agitator. All defects have now been rectified and the autoclave is being heated in preparation for final commissioning tests with refractory ore concentrate, scheduled for November 28,” Petropavlovsk said.

The flash tanks and receivers associated with autoclave vessel 1 have also successfully passed the hot commissioning stage.

In the update today, management also confirmed both the cold and wet commissioning of all other principal equipment at the POX and filtration sections of the plant have been completed, with wet commissioning confirming the quality of the welding and piping work at the POX section of the plant.

The concentrate loading, re-grinding and lime preparation sections (formerly part of the Pokrovskiy resin-in-pulp plant) have also been commissioned, and first concentrate and limestone are currently being loaded into the plant ahead of autoclave commissioning using refractory ore concentrate.

The oxygen plant has been fully commissioned and is being prepared to commence oxygen production to supply autoclave 1 once tests on refractory concentrate begin later this week.

Petropavlovsk says the company is on track for maiden gold production from the POX plant shortly, with a plan to ramp up to sustainable commercial production throughout 2019.

The development of the POX hub is aimed at supporting estimated production of 500,000-550,000 oz/y over the next five years, up from 420,000-450,000 oz expected this year.