Re-emerging U.S. Stone Industry
A proud heritage of slate production
Sheldon Slate Products was formed in 1917, and Tatko Bros. was formed in 1925. The two companies were tied together by John Tatko, Sr., who bought Sheldon in the late 1940s. Today, the companies are owned by Joseph Tatko, Edna Tatko and John Tatko, Jr., who still works in the quarries. But although the companies have the same ownership, they have always run independently and continue to do so today.
Unlike many slate producers in the region, the company focuses on floor tiles and structural work such as countertops rather than solely relying on roofing products. "The company decided to focus on this type of work a long time ago because the market for slate roofing 40 years ago went up and down a lot," explained Peter J. Tatko, great-grandson of the company's founder. "With tiles and structural work, we're not completely tied into new construction. A lot of renovation work continues when new construction falls off."
Between the quarries, mills and offices, Sheldon Slate Products and Tatko Brothers employ a total of 75 workers, some of which have been with the company as long as 25 to 30 years. To maintain an experienced work force, the company offers its employees 100% company-paid health insurance, a company-funded pension plan and production and loyalty bonuses. "It's hard work, so we have to be competitive with the other local industries," Tatko said.
The company operates three quarries in Vermont for green and purple slate varieties as well as a quarry for red slate located on the premises of its main office and factory in Middle Granville, NY. In addition to its own quarries along the New York/Vermont slate belt, the company operates a quarry for black slate and fabricating plant in Maine. Run by John Tatko, III, (Peter's older brother), the plant fabricates specializes in kitchen countertops, and it also produces headstones, slate sinks and slate electrical panels for mounting switches and control panels.
Although the company primarily fabricates material from its own quarries, it also brings in black slate from Pennsylvania as well as some Brazilian green slate varieties and Portuguese black slate.
Quarrying operationsThe company's quarries supply fabricating plants for both Tatko Brothers and Sheldon Slate products. The quarry in Poultney, VT, which is 54 years old, holds four different varieties of slate - gray, green, purple and dark green. The latest investment in this quarry was a Caterpillar 345B excavator, which has a 42-foot reach, weighs 105,000 pounds and can lift 30,000 pounds.
As much as 40 to 70 feet of overburden must be removed to reach the "pillars" of good slate underneath. Overburden is blasted using "delay blasting" techniques to take better advantage of the explosives while minimizing ground vibration and air blast. When useable slate is reached, a "softer hit" of black powder occurs to loosen the blocks. Even during busy periods, however, blasting is infrequent - taking place less than once a week.
After the excess stone is removed with an excavator, a jackhammer run by an air compressor is used to drill and loosen large pieces of slate. The slate is then cleaved with a hammer and chisel, which splits the stone along its natural veining.
According to Tatko, the quarrying operations must follow the natural seams formed by the slate within the earth, and the quarry bed is pitched at a 45-degree angle. Also, the overburden for Vermont slate can be a challenge, as crews often have to work through as much as 80 feet of earth before reaching useable stone. Also, because the nature of the quarry can be unpredictable, the company is constantly in a "development stage" where it is looking for new areas to extract high-quality stone. "It's not like a virgin bed of granite, where you can just saw it out," Tatko said. "The pillars may last for months, but they don't last forever."
The quarry operates 12 months per year, but due to the natural characteristics of the slate, care must be taken to ensure that the stone does not freeze (once frozen, the slate cannot be split). When faced with temperatures below 15 degrees, exposed faces of stone within the quarry must be covered, and any stone that has been extracted must be taken directly inside the mill or a heated storage area.
Once slabs of stone are freed from the quarry face, an air hammer is used to split the larger pieces of slate. The stone is then loaded onto the trucks, and they are transported to the mill. Pieces of stone are graded in the pit, and they are delivered to one of several mills - depending on what final product they are suited for. For larger stones, the company looks to fabricate high-value products such as countertops or other structural work, while smaller pieces are used for tiles or flagstone.
Tile fabricationPieces designated for tile production are delivered to a primary sawing mill adjacent to the quarry site. Here, the blocks are loaded onto a conveyor, and they are cut with diamond saws into "cutting stock" for slate tiles, and they are hand-split to the proper thickness. At this point in the process, the pieces are evaluated once again, and the ones that are too small or have too much veining for tile production are processed into flagstone. The smaller waste material is also saved, as it can be used for fill or crushed for driveways
Once processed into cutting stock, the material is shipped via truck from the quarry location to one of two tile finishing plants. Large pallets of slate are moved to the saw with a forklift, and vacuum lifters from Anver and an overhead jib crane are used to move the pieces of slate to a conveyor belt. From here, the material is cut into blocks of the desired tile sizes, and the blocks are then hand-split into tiles with a hammer and chisel.
The split slate is then loaded onto a pallet and moved to one of 11 gaugers, which grind the tiles to the required thickness. Once gauged, the material is delivered to packaging via forklift, and a quality control expert inspects the tiles before they are packaged in cartons, placed on pallets, marked for color and size.
In addition to standard tiles and flagstone pavers, the company also manufacturers tumbled slate tiles. For this product, gauged tiles as large as 6 x 6 inches with thicknesses ranging from 1/4 to 3/4 inch are placed in a drum tumbler designed and built by the company. The material is then tumbled for two hours in a mixture of crushed stone and water to achieve the desired effect.
Structural/countertop fabricationWhen larger blocks of slate are quarried, they are typically destined for countertop production. An air hammer is used to split the slate within the quarry, followed by a forklift to complete the process. Because of the nature of the material, the slate must be split into much thicker pieces and then machined to the desired countertop thickness. A 7-foot, 6-inch-blade saw from Park Industries is used to square large blocks of slate and produce 1-inch-thick slabs for countertops. Additionally, the company has a bridge saw from Cemar, which is fully computerized and cuts to depth of up to 10 inches. A second Cemar saw is in operation at the Maine plant, and both saws were supplied by Pyramid Supply of Barre, VT.
After being split and cut to the proper size, the slabs are then delivered to the gaugers, which grind the countertops on both sides. The material is also processed on a polishing machine from Ducharme's, which gives a honed finish to the slate. From the polisher, the slabs are carried with Anver lifters onto an edge-polishing bed, where workers process the edges of the counter by hand using a flexible diamond pad.
Sink cut-outs are created with an automated machine from L-Tec, which uses a diamond router bit. The machine can also cut oval and round tabletops, and it is used for the ogee edge work on slate sills. In addition to the L-Tec in operation in Middle Granville, the company operates a second L-Tec in Maine.
One of the latest developments in production has been the design and manufacturing of decorative slate tiles. For this production, a company artist creates drawings of various designs, and they are scanned into a computer. A plotter then cuts the design into vinyl, which is attached to the front of a stone, and the pieces are then sandblasted to achieve the desired effect.
The company sells its products throughout North America, and it also ships overseas. Customers for kitchen countertops have included television/publishing personality Martha Stewart as well as "60 Minutes" correspondent Ed Bradley, and the company's Monson Black slate from Maine was used for the headstones of President John F. Kennedy and Jacqueline Kennedy Onasis. Additionally, the company has fabricated floor tile for projects such as PSInet Stadium in Baltimore, MD, which houses the NFL's Ravens, the Foxwoods Casino in Connecticut, and the Norman Rockwell Museum in Massachusetts.