Just a few months after starting operations last January, M6 Cutting and Coring, Wichita, Kan., rose to new heights when refurbishing the world's largest grain elevator facility, located near its hometown. The jobsite was at the top of the silos--120 feet above ground.

"We had to use a crane to hoist the 1800-pound walkbehind saw, generator, water, and other supplies to the roof of the elevators," says Jamey Johnston, sales manager for M6 Cutting and Coring, a division of M6 Concrete Accessories Co. Inc. The 1/2-milelong facility, owned and operated by DeBruce Companies, Kansas City, contains 246 concrete silos and a capacity of 22.4 million bushels.

Two Concrete Sawing & Drilling Association-certified saw operators, Jake Myers and Casey Gobel, cut 125 holes in the 7-inch-thick reinforced concrete roof. They used a Husqvarna FS 6600 walk-behind saw with a 66-hp diesel engine and a 17 1/2-inch cutting depth, a machine typically used for roadwork. For corners, the operators used Husqvarna K 960 16- inch handheld power cutters.

"With 60 hp at the blade shaft, the power of the FS 6600 allowed us to make 20 to 25 openings per day," says Johnston. "The cutters on the previous phase of this project averaged three to four openings per day." Another plus, he adds, was the blade clutch feature that allows the blade to be stopped between cuts rather than turning off the saw after each cut.

Most of the holes were rectangular conveyor dump openings for depositing grain transported from the head house into the silos. These holes were premarked on the slab. For each hole, the saw operator made three cuts and then attached a bracket to the cut section to prevent the piece from dropping 120 feet into the elevator cavity. The bracket was hooked to a chain hanging from a portable pulley system positioned over the slab. This device supported the slab as a fourth cut was made. The pulley lifted each 1000- pound piece, which was placed on a cart for removal and lowered by crane for transport to disposal.

About 30 of the openings were 8-inch cores that serve as vents to release flammable gases. "The challenge with these holes was to keep the core from falling into the silo," says Johnston. "We set the saw depth one inch less than the slab thickness and popped the core."

M6 Cutting and Coring also performed work underneath the silos. "Grain is loaded at the top and conveyors below the silo remove the grain to load train cars," Johnston explains. Installation of a new conveyor required removal of portions of the 13- inch-thick concrete from the sides of two silos to accommodate the motor section of the new system.

Various phases of the cutting work, which represented about $30,000 of the $2 million upgrade, took place between June and September.