Aki Ra thinks the bomb could have been lying in rural Siem Reap, Cambodia, for 40 years. If it hadn't been found, it may have added another death to the approximately 20,000 people killed by explosives laid in the country from the late 1960s to the 1990s. Ra, founder of Cambodian Self Help Demining (CSHD), and his team have found about 100 explosives in the two months they've been sweeping this 23-acre (9.5-hectare) site in Chi Kraeng district. Despite handling the devices every day since 2008, when the CSHD was formed, none of its workers have been injured by them. Ra's mine-clearing team offers basic medical help to poor villagers they work near, as an extra service to those who can't afford to travel to hospitals or buy medical equipment and medicine. With 40 employees working across 10 provinces, the CSHD, which says it has cleared 175 minefields in the country since forming in 2008, targets villages overlooked by larger NGOs and the government's Cambodian Mine Action Authority. "Another village needs us soon," says Ra, as his team breaks for a quick meal of rice and fish. "If we stay too long, other villagers aren't happy. So we have to move." Ra cleared mines with the UN when it sent peacekeeping forces to Cambodia in the early 1990s. "The UN showed me that the outside world has schools, hospitals, food. Then I understood. I threw out the bad things of the past. I wanted to make my country safe." With funding from US charity Landmine Relief Fund, Ra founded the CSHD.