JOHANNESBURG (miningweekly.com) - ASX-listed Grange Resources' profit after-tax reached $60.7-million for the year ended December 31, despite a combination of iron-ore market uncertainty and operational difficulties experienced in the first half of the year.

The company's operations were restored back to full production in the second half of the year, which coincided with an improvement in iron-ore prices.

This enabled Grange to declare a final dividend of 1c apiece.

In Tasmania, Grange Resources is set to reach an important milestone of 50 years of operation on March 6.

The company has also recently completed investment in its concentrator, with the upgrade of autogenous mills and other refurbishment projects to support more efficient production.

The south deposit tails storage facility is also ready for operation and Grange will start transitioning to the new facility in the coming months.

Investment into sustaining maintenance will also continue, with the company investing around $20-million in a refurbishment programme for its mining truck fleet over the next two years and structural refurbishments of key infrastructure at Port Latta, including the pellet plant and the offshore structure estimated at around $8-million.

Looking ahead, Grange noted that, while production continued from the North pit, it would work through an optimisation project to review the optimal slope angles to improve stability.

Work is progressing on feasibility studies for the Centre pit and long plains areas of the deposit, which have potential as additional ore sources for blending, supporting extended life and providing risk mitigation against any wall instability in North pit.

Investigation has also commenced into the ability to access the orebody in the North pit through underground development.

Conceptual studies have indicated that an underground block cave may be a suitable method to extract ore at greater depth. The board has approved expenditure of $10-million for the first stage of a feasibility study to define the extent of the orebody and locate the position of an exploration decline.