No injuries were reported and the incident followed several days of rain in the Orange area.

The slip occurred midway up the pit and the situation is being assessed.

A Newcrest spokesperson told MiningNews.net the situation was being assessed as to the most appropriate means of regaining access, but would not be drawn on the timing.

In a note released today by Macquarie Private Wealth in which it downgraded production estimates from Cadia, it noted that higher grade ore (around 1gpt gold) was sourced from the bottom of the pit.

"While Newcrest has indicated that it has more than six months of stockpiled ore (average grade of 0.5gpt gold) that will ensure adequate plant

feed while the slip is rectified, we have revised our FY12 production for the open pit to 206,000oz down from 236,000oz(vs guidance of 220-230,000oz)due to the lower grade," Macquarie said.

"At this point in time the ongoing impact of the slip is unknown,however we forecast it to impact both the December and March quarter from a grade and cost perspective."

In the September quarter, Cadia produced 150,277 ounces of gold and 11,763 tonnes of copper at cash costs of $A281/oz, while in the June three-month period volumes reached 151,251oz of gold and 12,341t of copper at cash costs of $309/oz.

Shares in Newcrest were down 2.2% or 73c in morning trade to $33.77.