Vermont granite cut with fire
They are using fire to slice open the Green Mountains. Deep in the Rock of Ages quarry, roaring lik a jet fighter, a flame is splitting tough Vermont stone into blocks the size of a garage.
The process uses a giant neddle called a jet piercer. Heat does not pass easily through granite -- it is a dense material, formed by the slow cooling of a mass of minerals -- so the white-hot tip of a piercer will cause small bits of the rock to expand and flake off. The needle moves up and down, chipping a crack across a piece of gray granite that will soon be part of a bank building.
A net of wires and poles laces over the 15-acre hole. Next to me, the man wearing orange gloves beckons a derrick, which bends to pluck stone from the quarry floor. On the other side, John Corrigan adjusts his hard hat and points to a far corner.
"There," he says, "that's where the stone for the Houston Commerce Bank Tower is coming from."
From a distance, the indicated area seems quite small, only a few chunks taken from the cubed face of the quarry, but eventually enough blocks will be removed to cover a 75-story skyscraper with rock -- one of the tallest stone-skinned buildings in the world.
In the fashion show of modern architecture, granite is stylish once again.
"The market for structural granite is booming," says Dorothy Kender, executive vice-president of the Building Stone Institute. "Quarries can barely keep up with the demand."
Part of the reason is efficiency. A granite building is cheaper to heat and cool than a giant glass box because of the rock's resistance to temperature change. And maintenance costs are almost nonexistent.
If you build with a granite exterior," says Mr. Corrigan, vice-president of Rock of Ages' building division, "you don't have to maintain it, you don't have to paint it, and you don't have to clean it. It's there, and it's there forever."
"Forever" is a word you hear often in Barre. The town is on the east slope of the Green Mountains, the stone backbone of Vermont. It has been a quarrying center for a hundred years, and signs of the industry are everywhere. The post office is granite. The banks are granite. Part of the high school is granite.Granite blocks edge driveways and form planters. There are stone houses , and the carving in the cemeteries must be seen to be believed.
About 2,200 people (from a population of 11,000) work at granite-related jobs. the greatest concentration of skilled stonecutters in the world lives in Barre.
Up in the mountains, there are five quarries owned by Rock of Ages. The stone produced is a fine-grained, high-quality kind named Barre Gray, in the past used mostly for memorials and statues. In fact, Rock of Ages, the largest granite operation in the area, had abandoned its buildingstone operations until several years ago. But now it is busily courting architects -- the key figures in any construction materials decision. I. M. Pei will use 750,000 square feet of Barre Gray, shipped to Italy for finishing, on his Texas Commerce Bank building. And Rock of Ages is curretnly quarrying stone for three other skyscrapers.
"One of the reasons granite is coming into vogue is that famous architects like Pei are specifying it for their new work. It becomes stylish then," says Philip Marshall, a building-material historian at the University of Vermont.
Like house paint and yard goods, granite comes in many colors. Besides Barre Gray, the 11 Rock of Ages quarries yield, among other colors, red and black stone from Oklahoma, gray and rose from Quebec, pink from New Hampshire, and a greenish stone from Maine. Color is determined by feldspar, as hardness is determined by quartz content and sparkle comes from the rock's percentage of mica. These three minerals are the main ingredients of the molten batter mixing underground. When the batter cools, it forms granite.
If, as in the Barre stone, the raw material cools fairy quickly, the ingredients stay relatively blended and the stone is fine grained. But if the batter cools more slowly, the feldspar, quartz, and mica have time to grow crystals, and the stone is speckled with large grains. Only the finest-grained stone is used for memorials. The coarsest is used for curbs, and the many medium grades are utilized in buildings.
The most recent Bureau of Mines figures show 82 companies in 18 states cutting block granite three years ago. Georgia is the leading producer. Vermont is second, with New Hampshire and Massachusetts close behind.
But Barre bills itself as "The Granite Capital of the World." John Corrigan says the stone itself earns the title.
"It has a unique grain structure. And it's consistent. You can put a building up today, and if you want to raise an addition in 20 years you can go back to the source and get the same color stone."
The town is rich in the tradition of stonecutting. Over the years, hundreds of immigrant artisans have turned this corner of Vermont into a European enclave: Italian carvers, Scots from the Aberdeen stone pits, and French cutters have all mixed in with the population at one time or another. In the '20s the town could boast 23 ethnic clubs.
While much of the finishing work has been automated, many crucial parts are still done by hand. In the hangar-size Rock of Ages Craftsman Center, where assembly lines for stone-shaping stretch the length of the building, giant saws rip the raw granite into slabs with wire blades and an abrasive slurry of silicon carbide. The slabs are cut to rough size with the "guillotine," a pneumatic steel knife, and polished with buffing wheels the size of truck tires.
Then each stone is treated according to its destiny. Large, thin slabs are cut into building panels with diamond-tipped saws. Smaller sizes become memorials, with sand-blasted designs and hand-carved figures. Massive blocks, polished almost perfectly flat, become bases for machine tools and optical equipment.
Frederick DeMasi, chunking away at a piece of stone near the side of the building, has been shaping granite for 25 years. His hands move quickly, raising splinters of stone and dust.
"I started down at Jones Brothers, picking up chips. Everybody starts that way. I asked to move to the cutting machine, and I did rough work for a while. Then I was an apprentice carver for 4 years. And the 4 years after that, when I was a journeyman, I learned even more."
He turns to his box of tools, where pneumatic chisel handles dangle like heavy-duty dentist's drills. He has dozens of carbide-tipped steel bits, in every imaginable shape. Inserted in the handles, they are used to chip rough granite into moldings and capitals for buildings, to carve flowers, faces, and letters. He hefts one with a tip that looks like six razor blades bolted together.
"This is a brush chisel. It's used to close up the stone's grain."
He chooses another, finer one.
"This is a fantail. You can use it to smooth large areas and close up the grain even more."
With several other tools, he demonstrates how the piece of granite at an adjacent work station will be rippled to resemble the pages of an open book.
"There's tremendous variety in this job. And when you're done, you feel like you've accomplished something. I like that."
DeMasi pats his piece of stone; it is a proprietary gesture. In Barre, granite is not inert. Everyone from company vice-presidents to sweepers treats the material with respect. Just as farmers live with their fields, granite men live with their quarries: They know how the rock splits along a pronounced grain , how it freezes in the winter and becomes harder to cut, and what happens when a derrick topples over and 50 tons of stone falls free to the floor. They know a drill bit left overnight in a hole will be stuck in the morning, trapped by the downward pressure of the quarry walls.
Despite the decades of work, the quarries are a mere scratch on a vein of rock that runs 10 miles deep. People say the stone will last forever (in this case an easy thing to believe).
It is beautiful country -- rolling hills covered with the thick green foliage of New England. From Barre's tallest point, one can see piles of scrap boulders scattered for miles. From a distance they look like giant seeds which may yet sprout mountains.