Fact of the day: Moles can dig 15 feet per hour in good soils

Robert "Red" Robinson, senior vice president of Shannon & Wilson Inc., of Seattle. He was asked to compare the capabilities of moles and "moles," as tunnel-boring machines are affectionately known in the underground construction industry.

He sized up a typical 4-ounce mole versus the 642-ton Emerald Mole, the tunneling machine that recently completed the Beacon Hill light-rail tunnels for Sound Transit.

It turns out that, pound-for-pound, the tiny mole is an astounding 336 times mightier than the behometh Emerald Mole.

"It's all in the weight ratio of the two critters," Robinson wrote. "Anyone for nuclear-enhanced 600-ton, 20-foot-diameter, flesh-and-blood moles?"

Annie Kolb-Nelson at King County's Wastewater Treatment Division — several machines have been digging a tunnel for the Brightwater sewage-system at the rate of about 5 feet per hour on a good day — was similarly awed at the mighty mole, which can dig 15 feet per hour in good soils. Read more at seattletimes.nwsource.com