Tools and Machinery of the Granite Industry
This article, the first in a series of four on granite working, deals with granite as a material, an industry, and a product and begins the description of the granite quarrying process. The second article will complete the account of granite quarrying. The final two articles concern the process of finishing granite and will conclude with a discussion of power sources, toolmaking, patents, granite workers, labor unions, and safety and health issues. The four articles will appear in consecutive issues of The Chronicle.
Granite is a very common stone found world-wide. Granite has been commercially quarried in the United States, Canada, Scotland, Finland, Italy, Ukraine, India, China, and Africa. Granite is found throughout the United States and has been commercially exploited in every New England state (Figure 1). Granite is composed primarily of quartz and feldspar with smaller amounts of mica. Quartz contributes to granite’s strength, hardness, and luster, and acts as a cement binding all the elements together. Feldspar, granite’s principal ingredient, occurs in a number of forms, mostly sodium/aluminum/silicon-rich plagioclase and potassium-rich microcline. In addition to contributing to strength and hardness, feldspar primarily determines granite’s color, resistance to discoloration and decay, and ability to receive a polish. Mica (mostly white muscovite and black biotite) is present in much smaller amounts. The relative amounts of white and black mica are an important factor in both the color and commercial value of the granite. If white mica predominates, the granite will be light-colored, and if the black predominates, the granite will be dark, often approaching black. If the white and black occur in roughly equal amounts, the granite will be speckled. Since mica does not polish well nor does it retain its luster, excessive amounts of mica decrease the commercial value of granite. As an example, granite of the Barre, Vermont, area contains 31.7 percent plagioclase feldspar, 26.4 percent microcline feldspar, 23.3 percent quartz, 6.4 percent muscovite mica, 4.5 percent biotite mica, 2.7 percent orthoclase, 2.1 percent chlorite, and 1.6 percent calcite.
Granite is an igneous rock, formed by high heat and pressure from molten rock called magma. Deep magma over time forced its way up through fissures and cracks toward the surface where it cooled into columns of granite called plutons. Over millions of years, erosion, especially glaciation, exposed the tops of the plutons. In Barre, Vermont, it is estimated that the pluton is ten miles deep-plenty of granite for the future. If the cooling was slow, it produced coarse-grained, building-grade granite with large crystals, up to the size of a large pea. Monumental granite must be fine grained, with crystals the size of a pin head, to allow fine carved details and to accept a mirror-like polish. Fine monumental granite occurs, for example, at Barre, Vermont, Quincy, Massachusetts, and Westerly, Rhode Island, while building granite occurs at Woodbury and Bethel, Vermont. Only granite, certain marbles and a few dolomites can be polished. Limestone, soft marbles, and sandstones can be rubbed and honed but not polished. Monument designers exploit the marked contrast between darkpolished and light-hammered granite surfaces (Figure 2). Different quarries not only yield a range of grain sizes but also a wide variety of colors, including deep red, light pink, white, light gray, gray with blue tints, dark gray, and black. The white granite of Bethel, Vermont, is the whitest known granite, having almost the appearance of a fine white marble, and this white stone made the quarry so bright that many of the quarry workers wore dark glasses (Figure 3). Quarries also differ in the maximum size blocks that can be quarried without including a seam or defect. Most granite deposits are laminated by horizontal joints or cleavage. The distance between these joints typically increases with the depth of the quarry; hence, the deeper the quarry the larger the defect-free blocks that can be extracted.
Marble, limestone, and slate are granite’s chief competitors. Marble is easy to rough out but difficult to finish. It carves beautifully and takes a sharp carved edge. However, marble does not stand up well out of doors since it dissolves, pits, and discolors in polluted air. Limestone is easy to work when freshly quarried, takes a sharp carved edge and weathers well outdoors. Slate is easy to work but due to its strong lines of cleavage is subject to flaking both while being worked and as it ages. Brownstone and sandstone were used for buildings in the nineteenth century, but these stones are very soft and subject to flaking and pitting. Granite is the hardest and most durable of the building and monumental stones and is the most difficult to quarry and to finish. The development of the granite business into a large-scale industry had to wait on the invention of more powerful and more efficient tools and machinery to deal with this obdurate stone.
A Brief History of America’s Granite Industry
Often farmers who lived where granite was found cut stone from boulders on the “back 40” as a part-time activity and used a corner of their barns as stone sheds. Some towns had common lands strewn with granite boulders. Boulders on the Braintree, Massachusetts, commons were the chief source of stone for local area building projects. People helped themselves until 1715, when the Braintree town fathers became concerned that the supply of stones would become exhausted, and they declared that from then on permission would be required to remove any stone.
The early stoneworker might have used any one of a number of historic splitting methods. This included heating by fire and then splitting by dousing with cold water, heating by fire and splitting by impact with an iron ball, heating by fire and splitting by impact with a large sledge, use of expanding ice in holes or cracks, use of expanding wet wooden wedges in cracks, and grooving and then hammering along the groove. The use of flat wedge and flat shims in holes made by a cape chisel (Figure 4) was a great improvement, providing better control over splitting. The invention of this technique is attributed both to John Park of Scotland (circa 1770) and to Josiah Bemis, George Stearns, and Michael Wild of Groton, Massachusetts (circa 1803). At this time, granite was commonly used for retaining walls, house foundations, well linings, posts, steps, sills, lentils, hearthstones, wharves, and jetties. A few large granite structures were built in Boston in the eighteenth century including, Hancock House and King’s Chapel (Figure 5)-both of which were built of granite boulders from the Braintree commons-as well as the Old Powder House and the lighthouse on Beacon Island.
The granite industry in the United States first developed along coastal New England, where the quarries yielded different colored granite. In Maine, there was pink from Deer Island and light gray, almost white from Hallowell, and in Massachusetts blue gray or greenish from Cape Ann and dark gray in Quincy. Westerly, Rhode Island, granite, was gray and pink and Stony Brook, Connecticut, granite red.
Since granite is heavy and has a low value per pound, it was important that low-cost transportation be available. The sloops and schooners that plied New England’s coast filled this need. One early 1800s exception was the inland quarry at Chelmsford, Massachusetts. Barges on Middlesex Canal (built from 1795 to 1803) allowed the early development of the Chelmsford quarries (actually in Westford and Tyngsboro, Massachusetts) by making available low-cost shipment from Chelmsford to Boston’s Charles River. Some early nineteenth-century granite buildings erected in Boston, including some built from Chelmsford granite, were the Boston Courthouse, New South Church, Congregational House, Parkman House, and University Hall.
Solomon Willard is considered the father of commercial granite in the United States. He was a man of many talents-carpenter, carver in wood and stone, draftsman, architect, quarry operator, building contractor, and inventor of the central heating furnace and quarrying tools and machines. In 1825, Willard was chosen superintendent and architect for the Bunker Hill Monument (built from 1825 to 1843), a 220-foot high granite obelisk with a thirty-foot square base (Figure 6). For this pioneering granite structure, Willard searched throughout coastal New England for granite and concluded by purchasing a quarry in Quincy, Massachusetts, forever after known as the Bunker Hill Quarry. To facilitate the quarrying operation, Willard invented a boom derrick, lifting jack, pulling jack, and hoisting jack. These inventions, in addition to the early 1800s introduction of a new and better method of splitting using the plug drill and wedge and shims (described later in this article), put quarrying on a commercial footing. He was probably the first quarry operator to do detailed costing calculations and, much to the consternation of other quarry owners, quoted prices just barely above the quarrying cost.
Essential for the delivery of granite to the Bunker Hill Monument site was a railroad, designed by the master mason and engineer Gridley Bryant, that ran on a gradual downhill slope for a little over three miles from the quarry to a wharf on the Neponset River. From there, a schooner took the stone to the foot of Breed’s Hill. Bryant had designed a special car under which blocks of granite could be suspended and also a four-truck railway car with a capacity of sixty-four tons. The granite cars ran on iron-capped wooden rails with granite sleepers and could be pulled by a single horse. Bryant also designed a cable-operated inclined plane that transported the granite down a steep slope from the quarry to the beginning of the railroad. Other outstanding structures built from Bunker Hill Quarry granite were the Boston Custom House (completed in 1847) (Figure 7) and Minot’s Ledge Lighthouse (completed in 1860).
Following the example set by Willard, New England quarry operators invented new ways of quarrying, shaping, handling, and transporting granite that resulted in much lower prices and in the availability of large blocks. The classical Greek revival style promoted by architects such as Charles Bullfinch, Alexander Parris, Solomon Willard, Ammi Burnham Young, and Gridley Bryant soon led to the design of many buildings utilizing the large granite blocks that had simplicity of design and resulted in a massive but clean effect. The 1870s through the 1890s was a period of active memorialization of the Civil War dead with large public memorials appearing in towns and cities across the nation. By 1900, architects were preoccupied with monumentality, volume, and formality. Great fortunes had been made by American businessmen and granite-faced, high-rise office buildings were erected as monuments to their owner’s business success. Large and elaborate granite mausoleums were purchased as memorials to themselves and their families (Figure 8). Granite mansions, the size of small hotels, were built in the fashionable sections of America’s major cities. Indeed, granite had become a manifestation of conspicuous consumption.
As the railroads reached North America’s interior, granite quarries were developed along the Appalachian Mountains, including Quebec, Canada (pink/rose); Woodbury, Vermont (gray); Barre, Vermont (gray); Bethel, Vermont (white); Concord, New Hampshire (blue-gray); Cooperstown, Pennsylvania (black); Mt. Airy, North Carolina (light gray); Salisbury, North Carolina (purplish pink); and Elberton, Georgia (blue). Also, a cluster of red granite quarries were developed in the Great Lakes region, including St. Cloud, Minnesota; Wassau, Wisconsin; Graniteville, Missouri; and Milbank, South Dakota. Rock of Ages Corporation, currently the nation’s largest quarrier of granite, owns and operates nine quarries in the U.S., Canada and Ukraine and its quarries yield a variety of stone-Barre gray (Barre, Vermont), Bethel white (Bethel, Vermont), Salisbury pink (Salisbury, North Carolina), Gardenia white (Rockwell, North Carolina), American black (Morgantown, Pennsylvania), Kershaw pink (Kershaw, South Carolina), Coral gray (Kershaw, South Carolina), Laurentian pink (Guenette, Quebec), Stanstead gray (Stanstead, Quebec), and Galactic blue (Zhitomir, Ukraine).
Granite has a remarkably wide range of uses, including monuments, buildings, skyscrapers, landscape products, precision products, and some unusual products not so easily categorized. By the late 1880s, granite monuments began to replace marble monuments that had earlier displaced slate monuments. Monuments include private gravestones and mausoleums, public memorials (mostly war memorials), and cemetery vaults. The market has changed for monuments. In the early part of the twentieth century, it was not uncommon for a significant portion of the deceased’s estate to be spent on a memorial. The result was impressive monuments and mausoleums on which skilled carvers and sculptors worked for weeks or months. Today, retailers, for the most part, emphasize low price, and few of the more impressive and more expensive monuments are sold. A four-foot wide monument with a five-foot wide base is now a rarity.
Granite facing was used for a wide variety of buildings, including federal, state, and local governments (federal buildings, state capitols, post offices, city halls, court houses), businesses (banks, railroad stations, office buildings, department stores, hotels, theaters, garages), non-profit organizations (libraries, schools, museums, churches, hospitals), and private residences.
Of all the buildings, the skyscraper was the most dramatic. Initially, high-rise buildings were constructed using load bearing masonry walls in which the weight of the entire building was supported by the masonry wall. There are two historically important existing examples of buildings with load bearing walls. The Monadnock Building in Chicago was designed by Burnham & Root and built in 1889-91. The building has sixteen floors, the north half of which uses bearing wall construction-the tallest in the world. The building is supported by masonry walls, six-foot thick at the base. It was the last building designed by the noted architect John Wellborn Root. The other example is the Ames Building in Boston designed by Shepley, Rutan, & Coolidge and built in 1889 (Figure 9). It has thirteen floors and is the second tallest building with bearing wall construction. This building is supported by masonry walls, nine-feet thick at the base.
Since load bearing walls limited a building’s height, a new design approach for high-rise buildings was invented using a steel framework with “curtain walls” of granite ashlars-four-to twelve-inch thick blocks with bed joints and end joints carefully and accurately cut so the blocks fit tightly together-supported at each floor by the steel frame. This new approach was pioneered in three Chicago buildings. The Home Insurance Building in Chicago, designed by William LaBaron Jenney, is ten stories high and was built in 1884-85. It was the first iron and steel frame building. It has iron columns, wrought iron and steel beams, and iron angle connecting brackets and a foundation consisting of stone and cement pyramid-shaped piers. The Rookery Building in Chicago, designed by Burnham & Root, has twelve stories and was built in 1886. It is the first building to use a steel-grillage foundation. The Tacoma Building in Chicago, designed by Holibird & Roche, is fourteen stories high and was built in 1887. It was the first building to use curtain walls (in this case made of brick and terra-cotta) supported at each floor by the spandrel beams. A key motivation for the use of granite in skyscrapers was the pride of ownership of a building with a stone façade from sidewalk to the building’s top. In the early twentieth century, the Woodbury Granite Co. of Hardwick, Vermont, using Woodbury, Vermont, granite, became the world’s largest building granite company-supplying granite for, among other buildings, the impressive state capitols at Madison, Wisconsin (Figure 10), and in Harrisburg, Pennsylvania (Figure 11), the magnificent Pro Cathedral in Minneapolis, Minnesota, the Chicago City Hall and Cook County Courthouse, and the forty-six-story Bankers Trust Co. building in New York City (Figure 12).
Granite has been used for a variety of precision products including surface plates (a base for testing precision manufactured products), testing gauges, gauge blocks, press rolls (for the manufacture of newspaper), and chocolate rolls (for the milling of chocolate). Landscaping was another large granite market and included posts, steps, terrace paving, benches, stands, basins, birdbaths, fountains for gardens, curbstones for roads, and paving blocks for roads and sidewalks.
The utilization of grout (waste granite) was one of the most difficult problems for granite companies to solve-the large pieces of quarry grout could not be economically crushed and if used at all would only be appropriate for such uses as piers, breakwaters, rip rap, or fill. Currently, Swenson Granite Co. reports only 15 percent waste in its building granite quarrying operations at the Fletcher Quarry in Woodbury, Vermont. Rock of Ages Corp. reports that the E.L. Smith monumental quarry in Barre, Vermont, which has homogeneous defect-free granite, is its highest recovery rate quarry with only 25 percent waste. Its other quarries have considerably higher percentages of waste. The Barre Granite Association (circa 1954) estimated an average of 75 percent waste for the Barre granite quarries. The higher percentage of waste, compared to building granite quarries, is due to the more discriminating selection of granite for monuments. Crushed granite-in sizes from a few inches to sand-for railroad ballast and road bases provided most of the market for grout. It is estimated that one mile of a two-lane highway requires forty thousand tons of aggregate, which consists of sand, gravel, and crushed stone. Some other miscellaneous products made from waste granite included poultry grit (crushed, graded, and bagged), fertilizer (perhaps due to its potassium content), soil conditioner, additive for artificial stone, additive for bituminous concrete, and ship’s ballast.
Quarry configurations have evolved along with the available quarrying technology. At first, fields of granite boulders, often glacial erratics scattered across a farmer’s field, would be exploited for local consumption as house foundations, posts, hearths, and steps. Next, hillside quarries (Figure 13), consisting of exposed granite outcroppings on the sides of hills, would be exploited using small manual or horse-powered boom derricks. Also, sheet quarries of exposed horizontal sheets of granite crossed by wide-spaced steep joints might be developed, following the natural fault lines. For both hillside and sheet quarries, the granite was loaded by derrick onto ox- or horse-drawn wagons or sleds. In some quarries, boulder quarries, the joints were so closely spaced that only small blocks “boulders” could be quarried. With the advent of large steam, compressed air or electric-powered derricks, it became possible to develop pit quarries (Figure 14) which extended quarrying hundreds of feet down into the granite plutons. Some pit quarries are as deep as five hundred feet with stepped-back quarry working faces. The stone is lifted out with derricks and loaded on railroad flatcars. Since the best stone is found at the lower layers of the quarry, the pit quarry allowed the extraction of large quantities of high-quality, defect-free granite. Finally, the use of the large-capacity, diesel-powered forklift truck led to the current development of drive-in quarries in which a vehicle can be driven directly to the quarry working face. Drive-in quarries can extract large amounts of granite with fewer quarrymen, the forklift trucks hauling the quarry blocks directly from the working faces and loading them on flatbed trucks.
Removal of Overburden
The first task in the development of most quarries is the removal of the overburden or waste materials that usually cover at least a part of a proposed quarry site. These waste materials might include soil, boulders, and low-quality granite. Blasting with dynamite might be required to free some of the waste and to reduce it to manageable size. At first, removal was a manual operation assisted by ox or horse. An ox shovel would be used to drag waste to the edges of the quarry site. A manually loaded ox cart might be used to carry the waste greater distances. The waste removal operation reached a new level of efficiency with the introduction of the stripping cableway with self-filling bucket (Figure 15). The cable extended across the quarry site and beyond. The scoop filled with waste as it was dragged across the surface and was automatically dumped at one side, out of the way of future quarry operations. Piling of grout on top of good granite was a costly lack of foresight. The cableway with skip, or grout box, was also used for the removal of overburden. The skip was filled with waste and automatically dumped onto waste piles at the quarry edge (Figure 16). Often, the cableway that was initially used for stripping was later used during quarrying operations for the removal of grout and small quarry blocks. Today, grout is usually not piled but rather backfilled on marginal land not likely to be used for future quarrying.
Drilling Deep Holes and Lift Holes
Slate splits easily into sheets along cleavage planes. Marble and limestone can also be split relatively easily by the use of wedges. Granite is the hardest stone and the most difficult to split, but these two characteristics vary among the granites. For example, Barre, Vermont, granite is a harder stone and more difficult to split than Woodbury, Vermont, granite. Bethel, Vermont, granite drills harder and breaks harder than Barre granite. Even though granite is a much more difficult stone to split, it does have an easiest plane of splitting called the rift. Perpendicular to the rift is a plane of” next easiest splitting called the lift or grain. Perpendicular to both these planes is a third plane of most difficult splitting called the hard way or head grain. Typically, the quarry block face (the front) and back are the hard way, the sides are the rift, and the top and bottom are the lift. Granite quarries are configured as a staircase of benches (the “steps”), each bench being typically twenty feet high and twenty feet deep and hundreds of feet in length. The first block extracted from the bench is called the keyway block (see Figure 14) and is often difficult to remove due to the sideways compressive forces that build up in granite deposits. After the keyway block is removed, the two adjacent blocks with three exposed surfaces are removed and so forth in both directions down the bench.
Two types of holes were drilled-vertical deep holes forming the sides and back of the quarry block to be extracted and horizontal lift holes forming the bottom of the block. These lines of holes were indicated with marking chalk, which was usually blue or red in half-globe cakes or square blocks, by the head quarryman. The holes were typically one and one-quarter inches in diameter, twenty feet deep, and spaced six inches on center. This resulted in a cube-shaped quarry block twenty feet on a side weighing about 680 tons (Figure 17). Initially, quarry drilling was a manual operation using a hand drill and drilling hammer (Figures 18 and 19). For the deep holes, one quarryman held the drill and one (called single jacking) or two (double jacking) quarrymen swung the drilling hammers with the drill-holding quarryman rotating the drill slightly after each blow (Figure 20). It is believed that the terms single and double jacking came from “Cousin Jack,” a nickname for a Cornish miner. The drilling hammer had two beveled-edge striking faces and weighed three to four-and-a-half pounds. Hand drills came in graduated lengths and had either a star-shaped or flattened cutting head. Periodically, a deep hole mud spoon (Figure 21) was used to clean the powdered granite from the hole. For the lift holes, either a granite surface was available for the quarryman to stand on or scaffolding was erected on the face just below the intended line of drilled holes (Figure 22). The quarryman held and rotated the drill as well as swung the drilling hammer. In a Michigan hand drilling contest, a double jacking team drilled a fifty-nine-and-one-half-inch deep hole in Vermont granite in fifteen minutes. In a Colorado contest, a quarryman single-handedly drilled a twentysix and five-eighths-inch deep hole in Colorado granite in fifteen minutes.
Steel granite-working hammers came in three basic varieties. Some hammers, like the drilling hammer, were designed to be swung and to strike steel graniteworking tools of various kinds; other hammers were designed to be swung and to strike the granite directly, and finally, some hammers were designed to be held in place against the granite and to be struck by another hammer. In any situation where steel strikes steel, the hammer striking face is both tempered to provide impact resistance and beveled to reduce the chance of splintering. Granite workers are now required to wear protective glasses or goggles to prevent steel splinters from flying into their eyes. Repeated use causes striking faces to “swell” and thus need to be periodically ground back into their original shape. Hammer handles were usually made of hickory and were of various lengths, cross-sections, and shapes depending on the hammer size and use. Today, the buyer can order fiberglass handles as an option for most granite-working hammers.
Joseph Couch of North Bridgewater, Massachusetts, was issued the first patent for a steam-powered rock drill in 1849 (Figure 23). The patent describes a reciprocating percussion steam-powered rock drill. The drill, which weighed several thousand pounds, was mounted on a portable wheeled frame and could be adjusted to any angle from horizontal to vertical. Power was imparted to the drill bit from a steam cylinder by a gear and crank mechanism. A cam and wedge device grasped the drill bit during its forward motion and released it at its moment of impact with the stone. This was the first drilling mechanism that did not depend solely on gravity for the drilling stroke, and therefore, the first one that could be applied to other than vertical drilling. The drill bit was rotated after each impact. In 1852, Joseph Fowle of Boston, Massachusetts, was issued a patent for a less cumbersome version of the Couch drill. Fowle’s design included the important innovation of the drill bit as an extension of the piston rod.
Charles Burleigh of Fitchburg, Massachusetts, and others were issued an 1866 patent for a number of improvements to the basic Couch/Fowle design-resuiting in the first practical and reliable steam drill (Figure 24). It was successfully used to drill the Hoosac Tunnel, the first mechanically bored American tunnel. Later, Burleigh bought the Fowle patent, which his drill infringed, and organized the Burleigh Rock Drill Co. In 1871, Simon Ingersoll of Brooklyn, New York, was issued patents for a feed rod/plunger/ratchet/wheel-nut combination that produced an automatic feed, for a supporting tripod drill stand with independently adjustable legs, and for a spiral bar to rotate the drill bit during operation (Figure 25). Henry Sergeant of New York City was issued an 1873 patent for a steam or pneumatic drill in which the drill bit was an extension of the piston rod. Sergeant claimed the improvements-rotating valves, cushioning piston stop, a new mechanism for revolving the drill bit, and automatic feed.
The widespread introduction (circa 1870s) of the steam quarry drills revolutionized the quarrying operation. Although steam drills were used up to the 1920s, pneumatic quarry drills began replacing steam drills by the early 1900s. The heart of the mechanical quarry drill is a mechanism called the valve, which directs the steam or compressed air alternately to the back and front of the drill piston. There were many valve designs, including unbalanced spool, tappet, auxiliary, butterfly, and ball and disc. Charles Burleigh had the first really successful drill that was manufactured in quantity. The Burleigh design had a piston with a slight hourglass-shaped curvature and piston rings at each end. It had a rod attached to the front of the piston that projected through a packing gland. The end of the rod was coke-bottle shaped and bored out at the end to accept the drill bit (or drill steel) (Figure 26). A chuck with a U-bolt clamped the drill bit onto the piston rod. It also included a rifle bar device with a series of pawls to rotate the drill bit after each blow. This drill, in which the drill bit is connected directly to the piston, is called a piston-type drill and can achieve about six hundred blows per minute. Drill bits were sold in sets of increasing lengths. When the hole depth reached the length of the drill bit, the next longer drill bit was used. A drill bit set advertised for the Rand no. 5 steam drill consisted of a dozen octagonal shank, cruciform head drill bits in two-and-one-half-foot increments from two and one-half feet to thirty feet.
In 1898, John Leyner of Denver, Colorado, made two important improvements to the quarry drill, a drill bit that was no longer connected to the piston and a hollow drill bit to allow air or water to flush out the cuttings (Figure 27). The piston rotated with each blow and an attached chuck held and rotated the drill bit. Called a hammer-type drill, it could achieve fifteen hundred blows per minute since it did not have to overcome the mass and friction of a long drill bit. With this drill, the bits could be easily removed and sent away for sharpening without taking the drill out of service. A blow tube, that carried air or water, ran through the center of the drill piston and its hammer head projection and into the hollow drill bit. Thus, the air or water was carried to the bottom of the drill hole where it flushed out the stone cuttings. Piston drills produced a pumping action of the drill bit that moved the cuttings out of the drill hole. Hammer drills could not do this since the drill bit did not move with the piston, and so cuttings would build up in the hole. Therefore, until sufficiently strong hollow drill bits could be manufactured, the hammer drill was primarily used for mine ceiling stopeing where the cuttings would fall out of the hole by gravity. Rock drills, which emit a thunderous roar and produce large quantities of airborne dust are, without protection, hazardous to human health. Today, quarry drillers normally wear double ear protection. Wet drilling, made possible by Leyner’s invention, greatly reduced the amount of airborne granite dust and saved the lives of thousands of quarrymen and miners. Before this time, mechanical quarry drills were called “widow makers” since many quarry workers succumbed to early deaths from silicosis induced tuberculosis.
Before the advent of carbide tips, drill bits had to be resharpened after about every two feet of drilling. Each drill operator had an assistant who mostly dealt with the drill bits. The drill bits were lifted and placed by the derrick, in front of the bench for the lift holes or on top of the bench for the deep holes. Some of the larger quarry operations used specialized drill-sharpening machines. The large drills used for lift and deep holes were mounted on a channel bar frame (Figure 28) or a tripod drill stand (see Figure 25). The channel bar frame was patented by Henry Sergeant of New York City in 1887. The frame was called a “channel bar” since it facilitated the drilling of a series of holes along a straight channel line. The bar was typically twenty feet long with two legs on each end. This design had a carriage that was driven along the bar by rack and pinion gearing and a circular journal that attached the drill to the carriage and allowed the drill to rotate to different angles-vertical for deep holes and horizontal for lift holes. The carriage location and the drill angle could each be changed without disturbing the other. This design was very popular and seen in many quarries. The most successful of the later pneumatic rock drills were valve-less. One of the all-time best drills, the Joy/Sullivan 360 drifter drill, was valve-less. It had a five- to six-inch diameter cylinder bore and is still manufactured. In the mid-19OOs, using pneumatic drills, it took about two months of drilling to free a thirty-foot by thirty-foot by fifteen-foot-high quarry block. Currently, deep holes are drilled two inches in diameter and spaced three to four inches on center and the quarry blocks are typically thirty to forty feet long by forty feet wide by fifteen-feet high. A pneumatic, double, deep-hole rotary drill capable of drilling two holes simultaneously is used.
Channeling is the removal of all the granite along the side and back faces of the quarry block before the block is shot. In the 1860s, a carriage-mounted, steam-driven channeling machine with a linear array of chisels was developed for and successfully used on marble. It was briefly tried on granite but proved less effective for the much harder granite. George Wardwell of Rutland, Vermont (Figure 29), and Ebenezer Lamson of Windsor, Vermont, each applied for patents for channeling machines. Both were issued patents for channeling machines, and between the two, they held thirteen patents for the machine. The two men had an agreement to jointly produce a channeling machine, but Wardwell later backed out. Lamson then designed, patented, and built his own channeling machine. This situation lead to a long, expensive, and acrimonious infringement lawsuit by Wardwell against Lamson, and the court eventually ruled that Lamson had infringed Wardwell’s earlier patents.
For granite, the drilling of deep holes and channeling by removal of the granite between the holes (called the core) proved much more effective. A quarry drill with broaching bit (or core cutter) (Figure 30) was used to break out the cores. The broaching bit had a four-inch-wide by one-inch-thick blade with a series of blunt teeth.
In the mid 1900s, the jet piercing (or torch cutting) technology was developed. It burned fuel oil and oxygen at a temperature of 4,000 degrees F, causing spalling (flaking off) of the granite due to the stresses set up by the differential heating of the granite. (This same spalling causes the destruction of granite exposed to the intense heat of building fires.) Jet piercing created the necessary twenty-foot-deep channels without the need of drilling deep holes. The burner was a complex tool, requiring water, electricity, compressed air, oil, and oxygen. The burner itself consisted of a long “pole” carrying fuel oil, pure oxygen, and cooling water. At the end of the pole was a copper tip where the oil and oxygen were mixed and burned. The initial design was manual, requiring two operators. Later, an automatic design was introduced requiring only a single operator.
In the late 1880s, M. Paulin Gay of Marseilles, France, designed and manufactured a wire saw that was used in quarries of France, Germany, Spain, Italy, and other European countries. The saw used three-strand twisted wire with a sand and water abrasive. The wire moved at a speed of sixteen feet per second and could cut about five hundred square feet of stone before wearing out. The wire was held in a pulley carrier and was forced down onto the stone by a screw feed mechanism. Two-and-a-half-foot diameter starter holes were required to accommodate the pulley carrier. Diamond-encrusted wire saws are now used for cutting the side faces. A one-and-one-quarter-inch diameter deep hole and lift hole joined at their bottoms are drilled for each side face. The saw wire is threaded through the holes, soldered into a loop, and driven by an electric motor mounted on a track. A set of gears moves the motor back an adjustable distance from the stone for every revolution of the wire. A diamond wire saw makes a very narrow cut-approximately one-half inch wide-and leaves spiral cut marks on the rock face. If a wire has to be replaced, it is a costly event since the wire costs approximately three dollars per foot.
Another currently used channeling technique employs a slot drill. First, two-and-one-half-inch diameter deep holes are drilled about four and one-halfinches on center and then the cores are drilled out using a core drill with a three-inch diameter drill bit. A bit guide, inserted into an adjacent deep hole, is used to center the drill bit on the core. An experimental technology, water jet channeling, cuts channels at a rate of forty square feet per hour with high pressure (40,000 psi) water. This is a costly technology -a water jet power pack is valued at a hundred thousand dollars.
Black powder is used where less explosive force is desired, as is the case with quarrying dimension granite, which is used for building stones or monuments. Black powder consists of the granular ingredients sulphur, charcoal, which provides carbon to the reaction), and saltpetre (potassium nitrate), which provides oxygen to the reaction. It deflagrates at five hundred meters per second if contained and is termed a low explosive. Dynamite is a high explosive with a shattering and somewhat unpredictable effect and is often used to blast waste granite. Initially, loose black powder was loaded into the drilled holes and tamped in with a sparkless brass tamper. A sparkless pricker, also called a priming needle (Figure 31) was then used to make a hole in the compressed powder for insertion of a fuse. The fuse was typically a one-quarter-inch diameter cloth fiber wrapping a black powder core. Finally, loose sand was tamped into the hole to contain the blast and direct the blast forces perpendicular to the sides of the hole.
Later, black powder was manufactured in paper tubes (or sticks) that could be easily placed in the drilled holes. Some quarries “rolled their own” black powder in paper cartridges. Also, DuPont made cylindrical cakes of compressed black powder. For the first hole, a whole stick was placed in the back of the hole, a half stick in the middle, and a whole stick near the front. The next hole loaded was six or eight holes over and had a half stick in the back, a whole stick in the middle, and a half stick near the front. This process would be repeated until the end of the line of holes was reached. Sand in cylindrical bags was tamped in behind each stick (Figure 32). Today, electrically-fired primer cord explosive is loaded into every other lift hole.
Blasting caps were introduced as a much more reliable way to fire the charge. Blasting caps were initially non-electric with a fuse. Electrical detonation was a great improvement since it was safer and more holes could be shot at the same time. An electric blasting cap is fired by a blasting machine (Figure 33). There are a number of types of blasting machines, but all strive to produce every time a sufficient amplitude electric pulse. When there is an insufficient or marginal electrical pulse and blasting caps in series, the most sensitive caps detonate first and the remaining caps do not fire causing a misfire. The powderman must then deal with the remaining and dangerous unexploded powder-not knowing exactly where it is located. With the pushdown plunger type blasting machine, the handle is pushed down as hard as possible-spinning a dynamo. When handle reaches the bottom, a switch made of a strip of brass under the handle is closed and an electric pulse is sent to the blasting caps. The pull-up plunger type works similarly, except that the handle is pulled up to spin the dynamo. The condenser discharge type blasting machine consistently produces a sufficient electrical pulse. A crank is turned to build up an electric charge on condensers and when a red light comes on the condensers are fully charged. The condensers can be discharged, by pushing a button, only after the red light comes on. Blasting caps can be wired in series, in parallel, or in series-parallel. For series-parallel wiring, the blasting caps are divided into groups in series with wires coming back to the blasting machine from each serial group. For example, there may be ten groups each with one hundred caps in series. Some blasting machines can handle up to a thousand blasting caps in series-parallel, which is an order of magnitude greater than was possible with non-electric blasting caps.
Splitting Out Saw Blocks
At the same time the deep holes forming the back and sides of the block were drilled, three lines of vertical deep holes spaced about four inches apart were drilled along the hardway parallel to and at five-foot intervals back from the front face of the quarry block. These holes were used to blast or split off smaller twenty-foot by twenty-foot by five-foot blocks. After the powderman shot the quarry block, lifting and releasing it, he loaded and shot the first line of deep holes nearest and parallel to the front face. The explosion moved the smaller block forward and left a gap between it and the stone behind. If the stone was splitting easily, deep hole wedges and shims (Figure 34) could be used to split oft’ these smaller blocks instead of the more expensive blasting. A pair of shims fit down either side of the hole with ears at the top to hold them in position at the top of the hole. Their outside surface was curved to fit the hole curvature and their inside surface was flat. A flat wedge was inserted between the shims and, as it was driven, slid along and pushed against the shims causing the shims to exert an outward force uniformly along their entire length against the sides of the hole. Deep hole wedges and shims could be up to ninety-six inches long and weigh sixty pounds per set. Splitters usually worked in two-man teams. One man drilled, and the other broke. The breaking quarryman tapped the wedges with a drilling hammer in sequence down the line of holes and then paused to let the stone work. Normally, three passes down the line were enough to split off the block. An alternative procedure might be employed using a jackhammer-a hand-held pneumatic hammer that can either drill or pound-(Figure 35) and short, heavy wedges known as steel gluts. When the first block was removed, the next line of deep holes was shot or split with wedges and so on.
Once a smaller twenty-foot by twenty-foot by five-foot block had been freed from the quarry block, it was tipped over onto wooden beams or old tires, and was further reduced in size by splitting with wedges. Drill hole lines were drawn on one of the twenty-foot by twentyfoot faces with marking chalk by the head quarryman and typically yielded eight blocks, each five feet by five feet by ten feet, that were small enough (about twentyone tons) to be removed by derrick or forklift truck. These were called saw blocks since they were just the right size to fit under a gang saw at the finishing shed. Lines of six-inch-deep, three-quarter-inch-diameter plug holes were drilled at three-inch intervals with a plug drill. Plug holes were just deep enough (about six inches) to accommodate the plug hole wedges and round shims. These wedges and shims, similar to but shorter than those used for deep holes, were sufficient since the splits were along the easy-splitting rift and lift planes and the stone was only five feet thick (Figure 36). Initially, plug holes were drilled manually using a hand plug drill (Figure 37) that was rotated after each blow by a drilling hammer. The plug drill has a flattened head with a blunt central point. Periodically, a plug hole mud spoon was used to clean the powdered granite from the hole. This is similar to but shorter than the mud spoon used for deep holes that has a socket for a long handle (see Figure 21). Later (circa 1902), the pneumatic plug drill (or sink drill) (Figure 38) was introduced. It was hand held and much smaller than the deep hole quarry drill, but at fourteen to twenty-five pounds, was larger than the stonecutter’s pneumatic hammer (described in a later article). Some suppliers sold a small plug drill, called the “baby plugger,” for shallow plug hole drilling. Drill rotation was done manually by a plug drill bit wrench that fit over the shank of the plug drill bit (Figure 39).
The second article in this series, which will be published in September 2006, will complete the account of granite quarrying.
Books and Journals
Allen, Donald G. Barre Granite Heritage with Guide to the Cemeteries. The Friends of the Aldrich Public Library, 1997.
Brayley, Arthur W. History of the Granite Industry of New England, vol. 1 and 2. The National Association of Granite Industries of the United States, 1913.
Clarke, Rod. Carved In Stone, A History of the Barre Granite Industry. Rock of Ages Corp., 1989.
Dale, T. Nelson. “The Granites of Vermont,” United States Geological Survey, Bulletin 404, 1909.
Dale, T. Nelson and Gregory, Herbert E. “The Granites of Connecticut? United States Geological Survey, Bulletin 484, 1911.
Deborah Deford, ed. Flesh and Stone, Stony Creek and the Age of Granite. Stony Creek Granite Quarry Workers Celebration, 2000.
Dickenson, E. H. “Rock Drill Data” Compressed Air Magazine Co., 1960.
Erkkila, Barbara H. Hammers on Stone, The History of Cape Ann Granite. Peter Smith, 1987.
Gage, Mary and James. The Art of Splitting Stone, Powwow River Books, 2002.
Garvin, Donna-Belle. “The Granite Quarries of Rattlesnake Hill,” Industrial Archeology 20, no. 1-2, 1994.
Granite Railway Company. The First Railroad in America, The Granite Railway Company, 1926.
Hunt, Marjorie. The Stone Carvers, Master Craftsmen of Washington National Cathedral. Washington: Smithsonian Institution Press, 1999.
John Fyfe Limited. John Fyfe, One Hundred and Fifty Tears, 1846-1996. Time Pieces Publications, 1996 .
Jones, Robert C. et al. Vermont’s Granite Railroads. Boulder, Colo.: Pruett Publishing Co., 1985.
King, Ross. Brunelleshi’s Dome. New York: Walker & Co., 2000.
Macomber, Stephen W The Story of Westerly Granite. Westerly (Rhode Island) Historical Society, 1958.
McKee, Harley J. Introduction to Early American Masonry; Stone, Brick, Mortar and Plaster. National Trust for Historical Preservation, 1973.
McGarvey, G.A. and H.H. Sherman. Granite Cutting, An Analysis of the Granite Cutter’s Trade, U.S. Department of the Interior, 1938 .
Paton, Todd The Rock of Ages Story. Rock of Ages Corp., 2003.
Poitras, Gregory B. Stone Slabs and Iron Men, The Deer Isle Granite Industry. Deer Island Granite Museum, 1997.
Richardson, Eleanor M. Hurricane Island-The Town that Disappeared. Rockland, Maine: Island Institute, 1989.
Rosner, David and Gerald Markowitz. Deadly Dust, Silicosis and the Politics of Occupational Disease in Twentieth-Century America. Princeton University Press, 1991.
Sample, O.H. ed., Monument Dealer’s Manual. Allied Arts Publishing Co., 1919.
Starrett, W.A. Skyscrapers. Charles Scribner’s Sons, 1928.
Wheildon, William W. Memoir of Solomon Willard. Bunker Hill Monument Association, 1865.
H.H. Harvey, Pulsometer Steam Pump Co., Lincoln Iron Works, ER. Patch Mfg. Co., Lidgerwood Mfg. Co., Thos. H. Dallett Co., Trow & Holden Co., Granite City Tool Co., Miles Supply Co., Bicknell Mfg. Co., Lima Locomotive & Machine Co.
Barre Life, Monumental News, Memorial Merchandising, Monument Builder News, Elberton Graniteer, American Art In Stone, The Memorial Builder, The American Architect
EAIA member Paul Wood is a retired electrical engineer, who worked his entire career in the computer industry. He is interested in the tools, implements and machinery of the granite industry and of nineteenth- and early-twentieth-century farming in New England.
Copyright Early American Industries Association Jun 2006
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