Koniambo Nickel SAS operates a $7bn USD pyrometallurgical smelter to produce ferronickel on the Vavouto site, in the Voh commune, North Province New Caledonia. The Metallurgical Plant has two identical production lines, which successively grind, dry, calcine, reduce and then smelt ore. At full capacity, the Metallurgical Plant will produce 60,000 tonnes of nickel annually.
At 6:35 a.m., 26th December, a metal spill occurred at tap hole A of the Line 1 electric furnace. At 6:57 a.m., a second spill occurred at tap hole B. The fracturing of the expansion joint binding system on the furnace sidewall caused this spill. During the next three hours, several hundred tonnes of molten metal spilled onto the floor on the Refinery aisle side, damaging the equipment, steel structures, electrical cables and instrumentation in its path.
The Metallurgical Plant and nearby buildings were evacuated as a precautionary measure to ensure the safety of personnel. The incident did not cause any injuries.
On the day of the incident, and in accordance with the regulations, Koniambo Nickel notified DIMENC (New Caledonia’s Department of Industry, Mines and Energy) and sent a Declaration of Incident to it.
In a decree dated 31st December 2014, the Government of the Northern Province ordered Koniambo Nickel to obtain an independent expert assessment of the consequences of the metal spill on Line 1, to issue a set of recommendations for avoiding a similar incident, and to assess the feasibility of restarting the electric furnace on Line 2. Their focus will be on the acceptability of the tap-hole repairs and on any other factor identified while reviewing the furnace 1 problems.
Les Nouvelles Calédoniennes ‘KNS VA RÉDUIRE LA VOILURE’
As a consequence of this a purchase order was raised by Koniambo Nickel SAS for Tim cousins Australia to investigate the issues and to run failure analysis workshops jointly with XPS Consulting & Testwork Services.
The investigation of the initial furnace leak revealed an underlying issue with the design of both furnaces known as the ‘Shrinking Furnace’. The investigation involved working in New Caledonia, Australia and in Vienna, Austria.
Three causation hypotheses were presented in the final workshop held 13th-15th April 2015 in Koniambo.
1: ‘Creep’ : Hatch Technologies: Furnace Group
2: ‘Skew Cracking’ : MacRae Technologies
3: ‘Inward Ratcheting’ : Tim Cousins
The furnace was ultimately rebuilt and the first official metal tap occurred on Wednesday 20th January 2016.