Stocks of interest on the Australian Securities Exchange on Wednesday:

AGL – AGL ENERGY – down nine cents, or 0.6 per cent, at $14.85

AGL Energy is free to resume coal seam gas operations at a site in northern NSW after an investigation into the detection of dangerous chemicals found no harm to the environment.

BHP – BHP BILLITON – down 50 cents, or 1.7 per cent, at $29.63

FMG – FORTESCUE METALS GROUP – down seven cents, or 3.1 per cent, at $2.22

RIO – RIO TINTO – steady at $57.45

The heads of BHP and Rio have hit out at calls by Fortescue Metals founder Andrew Forrest for a parliamentary inquiry into iron ore prices and his claims that the two mining giants are oversupplying the market to squeeze out smaller operators.

Also, Rio has signed an agreement to develop and finance the stalled Oyu Tolgoi copper and gold underground mine in Mongolia.

ORI – ORICA – down 21 cents, or one per cent, at $20.95

Orica has appointed Alberto Calderon as its new chief executive, almost two months after he temporarily stepped in to the role following the sudden departure of Ian Smith.

S32 – SOUTH32 – up 28 cents, or 13.7 per cent, at $2.33

Shares in BHP spin-off South32 have rallied after a lacklustre first day on the share market on Monday.