Check out the documentary Bomb Hunters. Their site has more information. The documentary is about the Lives of people that hunt unexploded ordnance (UXO) for a living. Their only interest is to separate the scrap metal from the detonator and TNT (or other explosive chemicals) and sell it to a middle man.
Farmers in north and eastern parts of Cambodia resort to the dangerous profession of collecting scrap metal from UXO in spite of the low pay (USD 9 to 15 cents per hour) that it attracts. They sell it to a local middle-man who in turn ships it to a massive scrap metal yard in Poipet (nearby the Thai border). The scrap metal yard then sells it to its Thai buyers at about USD 100 to 250 profit per truck load depending on the price of Steel in markets. These scrap metals are then smelted and casted in to construction rods. Irony is, in spite of this dangerous practice, the industrial owners in Thailand deny that they get scrap metals that originally came from UXOs. This trade also flourishes along the Vietnamese border. Barges transport scrap metal on the Mekong river.
FYI, about half a million tonnes of explosives were dropped during the period 1968 and 1973 as a part of the wretched Nixon and Kissinger secret bombing raid approvals. Cambodia was neutral at that time of Vietnam War. These bombings were on the pretext that the north and eastern parts of Cambodia might be abetting the North Vietnam Communists (Commies). As a result of the bombings, it is claimed that the Democratic Government of Cambodia lost its credibility and the Khmer Rouge eventually took control over the situation.
During Khmer Rouge’s brutal reign (1975 - 1979), about 1 to 3 million Cambodians were executed in secret prisons and killing fields. I would recommend interested people to watch movies like Killing Fields and Salvador (based on the military coup in El Salvador). Salvador is a film by Oliver Stone (Man, I’m becoming a big fan of Oliver Stone - known to invite Controversies).
Disclosure: I try to take an independent stance on socio-political issues. I love the American Constitution as much as I hate their foreign policies that lean to the interest of their Corporations in the pretext of bringing Democracy.