Careful where you dig!

Improved excavation techniques help contractors at former nuclear weapons site avoid digging up the past. The Department of Energy's Hanford Site is an excavator's nightmare. It's one of the country's oldest nuclear sites, with facilities that were built in the rush to win a world war and then a decades-long arms race. During World War II the reactors and process facilities at Hanford were constructed with utmost secrecy. For instance, the site was divided up into various, distinct processing areas -- each with its own separate survey coordinate system to confuse an invading enemy. In 1989 when the Cold War ended, Hanford began its metamorphosis from top secret defense site to the nation's largest and most complex nuclear waste cleanup project. National defense urgency and past environmental and as-built standards of the time left a legacy of chemical discharges and semi-hidden utilities. Also, the new cleanup mission included a new interest in privatization and outsourcing for engineering and services. This brought an influx of new contractors and personnel with no work experience of the Hanford Site. In the 50-year history of Hanford, various government agencies, contractors and their policies have come and gone. As federal budgets rose and fell, so did the accuracy of as-built documentation. At one point, jobs below $150,000 in value were not even documented as they were built because it wasn't considered cost-effective. Many utilities were field-routed, leaving no dependable as-built drawings. To be cost-effective, adjacent construction projects often shared a common excavation, both adding underground lines to the same trench. This 1ed to mixed confidence levels in the accuracy of the as-builts