L IKE giant fishing rods, a score of home-made hoists loom over the elephant grass, regularly dipping below the surface in the hope of a catch of gems among the basketfuls of dark earth. The hill tribe operators of the wood and bamboo machines are trawling for zircon, rubies and sapphires in the soil of northeast Cambodia's Ratanakiri province, probably unaware that their days as treasure hunters are numbered.

"It is not legal," Industry Minister Pou Sothirak confirmed in his Phnom Penh office, hundreds of kilometers and a world away from the rolling forest-clad hill country of the underdeveloped border province.

Similarly illegal small-scale gem and gold mining is being done by Vietnamese fortune seekers and Cambodian highlanders deep in the forests of neighboring Oyadav district.

A February 1993 moratorium on the commercial extraction and export of minerals still stands but - like the ban on timber exports - in theory only. Moves are underway to make mining in Ratanakiri legal - at the expense of the entrepreneurs currently there.

Nhep Bunchin, the Undersecretary of State in charge of mining, said exploitation rights would be given to a company once a mining law was enacted. Interest had come from Australia, Malaysia and Canada, he said.

Ratanakiri's Second Deputy Governor, Bunhom Ounmany, said a United States company had been in contact about the prospects of gold mining.

Some foreign business people are apparently already getting an illicit slice of what's up for offer. On a recent trip to the provincial capital of Ban Lung, a small group of non-Cambodian Asians were seen at the airport carrying sifters and a metal detector - in an area generally free from land mines but hiding unknown reserves of coal and base metals along with the gems and gold.

Provincial authorities tend to turn a blind eye to the mining and at Borkeo the district authorities even collect a small fee, according to gem buyer Kim San.

He said the quality of gems in Ratanakiri could not match those unearthed at Pailin in the northwest.

"If you find a gem the size of a thumbnail in Pailin, you're a millionaire," said San.

The deputy governor, Bunhom Ounmany, said that zircon, a semi-precious stone, sold for about $100 a kilo, more if the quality was good.

A trip to one of the mining sites revealed more than a dozen people working in zircon pits.

A hoist operator, Soeung, explained that there were "less people than before because it's the harvest season".

The Tampuan hill tribesman lowered and raised the hoist above a deep meter-wide hole in the ground, with a creeper acting as the line and a wicker basket as the hook for hauling out the earth.

A colleague worked at the bottom of the hole, digging out earth until he found something interesting. Soeung said he had been working on this particular pit for three days without joy.

It seemed like a lot of hard work for little return - he said he earned anything between 2,000 and 20,000 riels (75 cents and $7.5) for a nine-hour shift to help support his wife and three children.

Nhep Bunchin said that when a suitable investor was found to exploit the province's gold and gem resources the miners - and above all the Vietnamese - "will have to stop".

Officials in Oyadav district town said a bigger gold mine had already been put off limits.

Men like San, Soeung and Nay Keo may soon have to return to the fields full time or try to get employment with the company that wins the right to work the mines.

In the meantime, they keep chipping away hoping to strike it rich.