Shares in contract driller and miner Ausdrill were sold off hard on Thursday after a large profit downgrade spooked investors and soured sentiment towards the sector.
Ausdrill closed down 28.7 per cent at 98¢ in heavy trade, with more than 20.3 million shares changing hands, several times the usual daily volume.
Boart Longyear fell to a record low of 38¢, down 2¢, although Imdex recovered from earlier weakness to close up 1¢ at 71¢, benefiting from its exposure to the oil sector.
Earlier in the week, trading in Ausdrill shares was suspended as it finalised an earnings revision.
Before the sharemarket opened on Thursday it warned net profit in the year to June 2014 would fall to $35 million to $45 million, well below the $90.4 million earned last financial year.
Revenue is now expected to be $825 million to $925 million, short of the $1.13 billion booked last year.
It blamed "challenging market conditions" that would remain soft until the start of the new year, when a recovery in selected markets would occur.
In contract mining, several projects have reduced waste volumes, while mining has halted at three mines in west Africa, with blast and drilling services stopping at two others.
Similarly, exploration activity remained subdued, with "no signs of a recovery in the near term", and no rise in equipment hire expected for the time being, along with lower maintenance spending.
"All mining services companies are trying to work out where the bottom is," said Argonaut analyst Ian Christie.
Whether the shares were worth buying at this stage depended on whether the investor was looking to the short or longer term, he said, especially if buying in anticipation of mining sector spending picking up. "Near term, the focus will be on cash flow and debt reduction," Mr Christie said.
Concerns over debt levels prompted Standard & Poor's to place its long-term BB credit rating on Ausdrill on "creditwatch with negative implications".
"If Ausdrill's performance were to deteriorate further after fiscal 2014, this will worsen the company's financial credit metrics to the extent that they may not support our view of its ... 'intermediate' financial risk profile," S&P credit analyst Craig Parker said.