The Perth-based mining services provider said the revised post-tax figure was due to client decisions to curb development activity were a response to challenging market conditions.

This included the delay or slowdown of iron ore projects, international freight rail projects and major construction of coal projects.

After assessing the aggregate effect of continued project delays, volatility in key markets and deferment of mine and rail investment commitments, Calibre revised its fiscal 2013 revenue guidance from $780-810 million to $680-695 million.

Adjusted earnings were revised from $90-95 million to $50-55 million.

Calibre expects market volatility and uncertainty to remain a feature of the operating environment for the foreseeable future, but says it is well-positioned to navigate the current market.

In February, the company announced a profit of $27.5 million for the six months ending in December 2012, up 15% on the previous half-year.

In a statement today, it noted that its forward order book remained at $1.3 billion.

Calibre was last trading 54.5% down today at an all-time low of A55c.