Yule Marble
Yule Marble is a marble of metamorphosed Leadville Limestone found only in the Yule Creek Valley, in the West Elk Mountains of Colorado, 2.8 miles (4.5 km) southeast of the town of Marble, Colorado. First discovered in 1873, it is quarried underground at an elevation of 9,300 feet (2,800 m) above sea level—in contrast to most marble, which is quarried from an open pit and at much lower elevations.
The localized geology created a marble that is 99.5% pure calcite, with a grain structure that gives a smooth texture, a homogeneous look, and a luminous surface. It is these qualities for which it was selected to clad the exterior of the Lincoln Memorial and a variety of other buildings throughout the United States, in spite of being more expensive than other marbles. The size of the deposits enables large blocks to be quarried, which is why the marble for the Tomb of the Unknown Soldier at Arlington National Cemetery, with its 56-long-ton (57 t) die block, was quarried from Yule Marble.
Yule's quality comes at a high price due to the cost of quarrying in a high-altitude mountain environment. This challenge has caused the industry and the town of Marble to undergo many boom-and-bust periods since quarrying started in the mid-1880s, making the town emblematic of the economic fluctuations that beset a single-industry economy. Technology advancements in quarrying machinery and transportation have reduced, but not solved, the cost problem that afflicts the operation through the present.
Geology
Development
The forces that created Yule Marble make it distinct from all other American marbles. It was formed by contact metamorphism, unlike Vermont marble and Georgia marble, which are the result of regional metamorphism, a process more associated with the orogeny and erosion of mountain ranges on a regional scale. Geologists still debate over Tennessee marble which did not undergo the same type of metamorphism, leaving it in a very unique property somewhere between metamorphic marble and sedimentary limestone.
In evaluating the marble cross-section, the United States Geological Survey found the marble is bounded above and below by unconformities. This lack of conformable contact resulted in the early dating of the limestone as Silurian rather than the currently accepted Mississippian. The lack of conformable boundaries in exposures along the Treasure Mountain dome explains the variation in reported thicknesses in the quarry area west of Yule Creek of 166–239 feet (51–73 m) about 2,000 feet (610 m) southeast of the quarry. The overlying Pennsylvanian Molas Formation was an argillite unit which was converted to hornfels and quartzite. Stratigraphically below the Leadville, the chert bearing Devonian Dyer Dolomite Member of the Chaffee Formation was altered by the metamorphism to impure silica-rich marble and occasional serpentine-bearing marble.
The Yule Marble is a metamorphic facies of the regionally distributed Leadville Limestone of Mississippian age deposited 350 million to 324 million years ago. The Leadville within the Yule area was transformed by contact metamorphism that occurred during the latest Eocene and Oligocene epochs (34 to 28 million years ago) associated with the intrusion and uplift of the nearby granitic Treasure Mountain Dome. The uplift of the Treasure Mountain Dome tilted the limestone away from the intrusion resulting in the marble bed dipping at an angle into the mountain. The marble unit along with older and younger adjacent units in the Yule Valley have a north-northwest strike paralleling the valley and variable dips of 35 to 50 degrees to the west-southwest. This local contact with the heat and pressure from the intrusion of hot granitic magma recrystallized the Leadville Limestone into a distinctive white marble. Although the Leadville Limestone covered hundreds of square miles and was the ore host at the Leadville mining district, the Yule Creek Valley is the only known location of marble in the region. When the magma cooled, it crystallized into granite.
This local geological activity resulted in a type of marble that is 99.5% pure calcite, with trace amounts of non-calcite inclusions (mainly quartz), and has a density of 170 pounds per cubic foot (2,700 kg/m). The non-calcite inclusions were caused through penetrations along the seams created by the dome uplift rather than through metamorphic contact with the uplifted dome. Though marble is on both sides of the creek, the only visible marble is the 1-mile-long (1.6 km) seam of the present-day quarry on the west side of Yule Creek.
Timeline
Development of Yule Marble is put into context with Colorado geology by showing the passage of time from earliest rock units to the present with "Ga" = billions of years ago and "Ma" = millions of years ago.
Start | End | Geologic activity |
---|---|---|
1.78Ga | 1.65Ga | Colorado forms (age of oldest exposed rocks found to date). |
350Ma | 324Ma | Leadville Limestone formed in a shallow, warm sea that covered Central Colorado through the accumulation of calcite from the remains of marine life. Today that limestone, which became Yule Marble, is 9,300 feet (2,800 m) above sea level. |
300Ma | 248Ma | Ancestral Rockies start and eroded away. The town of Marble was located at the edge of the Ancestral Rockies. Limestone was stripped away by erosion leaving the rest buried until 72 million years ago. |
248Ma | 70Ma | Area was a flat coastal plain over which dinosaurs roamed and during the later part was covered by another shallow sea. |
72Ma | 40Ma | 1st of 3 uplifts (Laramide orogeny) of present-day Rockies but partially erodes. |
34Ma | 28Ma | 2nd of 3 uplifts of the present-day Rockies. Volcanic activity with magma intrusions pushing up from below crystallized the limestone into marble. When the magma cooled it crystallized turning into granite. The upward push of the magma against the limestone resulted in the marble being tilted upward and way from the intrusion, creating the 7-mile diameter Treasure Mountain Dome. The town of Marble lies at the edge of the dome. |
25Ma | 5Ma | Colorado Mineral Belt forms |
10Ma | Present | 3rd of 3 uplifts of the Rockies – Colorado |
Characteristics
It is the grain of Yule Marble that gives an appearance of smooth texture, a homogeneous look, and a luminous surface that polishes well. These qualities are why it has been chosen for a number of major national and state landmarks, most notably the Lincoln Memorial. Because of its aesthetic value, architect Henry Bacon successfully urged that it be used to clad the whole exterior of the Memorial, even though it was the most expensive material.
The overall configuration of the grain is small, irregularly shaped, generally equidimensional to slightly elongated with irregular edges and does not vary significantly among the different grades (in 1992). The edges of the calcite grains are deeply crenulated (irregularly and minutely notched and scalloped). Grain sizes range primarily from 0.1 mm (0.00393 in) to 0.6 mm (0.0236 in), as determined by scanning electron microscope images. There are 2,000–3,000 grains to the square centimeter (0.1550 square inches). Where the marble is in direct contact with the intrusive granite, the most consistent change in the marble is that it becomes extremely coarse-grained, with the grain size in the contact zone being 10 mm to 20 mm (0.3937–0.7874 inches). The grains in turn are tightly bonded in the shape of a jigsaw puzzle, forming crystals which are aligned so that the long axes of the grains are essentially perpendicular to the principal veining in the deposit.
When marble does break down, the cause is weak boundaries between the grains that permit water or solutions to penetrate into the marble. As water enters, the calcite grains dissolve slightly, and the opening between the grains widens. With time, as the grain openings widen, the edges become smooth, and the grains become rounded. As the surface grains become round, they loosen and fall off the surface of the stone. Because Yule Marble is finely grained with tight bonding, water is not likely to react as quickly as with a coarse-grained, loose-textured marble. Also the crenulated boundaries of Yule Marble crystals may account for the weathering resistance, because the spaces between grains must be widened enough to free adjoining crystals.
Included in the grains are intrusions (non-calcite material) which does not vary significantly among the four grades; tests in the late 1990s confirm the 1910 amount of 0.5%. Constant inclusions in all Yules are magnesium oxide (MgO), manganese oxide (MnO), iron oxide (FeO), and strontium oxide (SrO) while other inclusions vary by quarry location. Inclusions are in four groups: quartz (the most abundant and gray in color); muscovite (mica, occurs as thin gold lines and streaks, and also occurs with quartz in clouds of gray mixed with brown); feldspar (with larger grain size 0.591 inches (15 mm) to 1.379 inches (35 mm) and gray in color but less translucent than quartz inclusions); and pyrite. Other minor inclusions are sphene, apatite, rutile, zircon, and sphalerite. An example of inclusion affect is gold veining, the result of iron or manganese, that is still quarried today.
When the physical characteristics of Yule Marble are compared to the other US marble, the results are about the same for general characteristics of weight, hardness, specific gravity, porosity, absorption, and coefficient of thermal expansion. In strength characteristics, the properties of Yule Marble are lower than most of the other marbles for compressive strength and transverse strength, but they are not unreasonably low. For ordinary uses, stone having a compressive strength of 5,000 lb per square inch is satisfactory. Test results from 1913 to 1937 ranged from 6,694 to 10,195 pounds per square inch (471 to 717 kg per square cm); in 1996, results were 14,874 (1,046 kg per square cm).
Quarry
The same geology that created the marble also created a host of problems in quarrying the stone. Quarrying in this high altitude environment with steep slopes, deep snow, and snow-mud slides is so expensive that advances in technology have not been able to overcome the challenges. These factors limit periods of operation and the amount of marble that can be brought down from the quarry. In the early years a lack of transportation to move enough of the stone out of Marble added to the difficulties. The transportation problem was largely mitigated by the advent of a railroad (1906 through 1941) and by road and truck since 1990. The cutting rates of today's equipment are much faster than the 1911 technology.
Located along and above the east and west side of Yule Creek, from an elevation of 9,000 feet (2,700 m) to 9,500 feet (2,900 m) were five quarries, of which only one on the west side is in operation today. Those on the west were the most productive being the John Osgood quarry (pit-type started in the early 1890s) and the present-day quarry started in 1905 by the Colorado-Yule Marble Company inside the mountain. The east side quarry, started in 1904 by the Strauss brothers, was quarried inside Whitehouse Mountain. Most marble quarries in the world today are pit-type operations, such as Carrara, Italy. The amount of Yule Marble remaining for quarrying should last for hundreds of years.
Use of Yule Marble has grown through several periods of boom and bust from local to national, and today is international. The first major use was in the Colorado State Capitol building in 1895. Yule Marble quarried between 1907 and 1941 can be found in banks, mausoleums, libraries, schools, hotels, and government buildings from the west coast (Seattle south to Los Angeles) to the east coast, including the Equitable Building skyscraper in New York City. The dimension of the deposit enables large blocks to be quarried, which is why Yule Marble was selected for the Tomb of the Unknowns (Tomb of the Unknown Soldier) in Arlington National Cemetery. In 1931, the 56-ton (55.86 metric ton) block for the die section (on which six wreaths, three Greek figures, and the inscription were carved) was the largest single piece of marble ever quarried at that time. Today, the marble is primarily shipped to Italy to supply fabricators throughout Europe. Blocks also go to Saudi Arabia, Peru, and other developing international markets. Finished marble is used for tile and slabs (walls, countertops, etc.).
As the marble industry cycled, the town's economy, being based on a single industry, also fluctuated. At the same time, had Marble not made the transition from its origins as a mining town to quarrying Yule Marble, the town would have died, as did other Colorado mining towns such as nearby Crystal and Schofield.
State rock
On 9 March 2004, Yule Marble became the official state rock of Colorado. The designation was the result of petitioning by Girl Scout Troop 357 of Lakewood, Colorado of the Colorado General Assembly, who in turn passed a bill that was signed by Governor Bill Owens (R).
Discovered: 1873 to mid-1880s
Yule Marble was discovered in the Crystal River Valley in the spring of 1873 by geologist Sylvester Richardson. George Yule (for whom the marble was later named) was the prospector who "rediscovered" the marble in 1874. In the same year, an unknown person took some marble—from which polished samples were made—and appeared in Denver but failed to generate interest. The marble became lost again, and was rediscovered 10 years later, yet again by accident. By this time, prospectors were digging into Whitehouse Mountain for silver and gold when they encountered the Treasure Mountain Dome and thick marble. This time a transition started that moved the town away from mining to one of quarrying marble, although some locals were still involved with mining in 1910. The transition enabled the town to survive while nearby towns such as Crystal and Schofield became ghost towns. The town was still a one-industry economy, and its future followed that of the marble operation.
First quarries come and go: 1884 to 1905
The local miners never had the capital to develop marble quarries and in the 1890s they started selling marble claims:
- Colorado Marble and Mining was formed in 1891, by Steven Keene with capital stock of $1,000,000. In 1909 the lease was transferred to Monarch Marble, in 1921 to Colorado White Marble Company (by the Morman Church of Missouri) and out of business in 1926. Attempted to restart in 1937 but were unable to so.
- Crystal Land and Development was formed in 1892, by John C. Osgood and started quarrying the same year with an open-pit quarry on west side of Yule Creek. Osgood was also the president of Colorado Fuel and Iron, with major coal and coke operations in Redstone, Colorado, 12 miles (19 km) from the town of Marble. In the late 1890s, he formed Yule Creek White Marble Company, then reorganized in 1905 as Redstone Marble. The reorganization did not result in any quarrying and the company was out of business on 5 September 1917.
- Marble City Quarry Company was formed on 29 September 1893, by Dr. R.H. Kline. The marble deposit was sold to Channing Meek, 28 February 1905 and the company was dissolved.
- Crystal River Marble Company was formed on 12 April 1904, by the Strauss brothers. The quarry was on the east side of Yule Creek inside Treasure Mountain. In support of their operation they completed the Treasury Mountain Railway in August 1910. They had little marble production with no major contracts and were bankrupt in 1917.
Though better financed, the new companies had little success in spite of growing interest in Yule Marble generated by glowing test results from London (1887), the St Louis Exposition (1890) and the Chicago Exposition (1893). The companies had different degrees of development and success with the quarry of John Osgood obtaining a major contract in 1895 to supply 140,000 square feet (13,000 m) of marble for the new state capitol in Denver, Colorado. After this initial success, little production has accomplished by Osgood or the other two companies. The Osgood operation was well financed but even he was afflicted by the problems associated with developing and operating a quarry in the Yule Creek Valley. Also the lack of transportation to move enough of the stone out of Marble added to the difficulties. Taken together, these factors resulted in high operating costs that could not be covered by marble revenue. The high cost problems would also affect the next quarry and its operators up to the present time.
In 1905, another major transfer of leases took place with acquisitions by the newly formed Colorado-Yule Marble Company (CYMC). First was Channing Meek purchasing the marble deposits of the Marble City Quarry Company on 28 February 1905. He in turn sold the deposits to the newly formed CYMC on 11 April 1905 and subsequently became the CYMC president. The marble deposit that became the quarry of the CYMC was acquired on 14 November 1905 from Osgood. (Osgood never quarried the marble because of financial problems.) Because the three remaining quarries had no more production to speak of this leaves only the quarry started by the CYMC in 1905.
Primary quarry: 1905 to today
When the Colorado-Yule Marble Company (CYMC) arrived in Marble in 1905 they developed the last Yule Marble quarry, which is still in production today. The operation showed the unrealized promise of the previous 20 years with a 10-year boom in which marble was shipped to the east and west coasts with contracts reaching one million dollars. The marble boom also resulted in one for the town of Marble. While the CYMC overcame some quarry problems of the previous 20 years, other difficulties ultimately led to their bankruptcy in April 1917. Subsequent operations from 1922 through 1941 were on a much smaller scale with several different operators and dramatic fluctuations in quarrying until the next bust at the end of 1941 After almost 50 years the quarry reopened in September 1990. The 1905 problems of transporting marble out of the town have been largely solved (by road and trucks) but the high costs of working in a mountain environment still exist today, and there have been several operator changes with the last one in 2010.
Integrated operation: 1905 to 1941
The quarry was part of the integrated operation created by the CYMC during 1905 into 1907, and was retained by subsequent operators until the quarry shut down in 1941. Once marble was out of the quarry, it was lowered onto CYMC transport for movement down to Marble, a descent of 1,300 feet (400 m) over 3.9 miles (6.3 km) with grades up to 54% (17% starting in 1910). In Marble, the stone entered an enormous CYMC mill site and was transformed into a variety of finished objects. The site was 150 feet (46 m) feet at its widest point and almost 1,400 feet (430 m) long under one roof, totaling 108,000 square feet (10,000 m). (It was the largest operation of its kind in the world.) Finished marble was moved into railroad cars of the CYMC-built Crystal River & San Juan Railway (CR&SJ) for shipment throughout the country.
Building the CR&SJ solved a major problem of no viable transportation to move large quantities of the stone out of Marble. In November 1906, the CR&SJ completed a 6-mile (10 km) railway line from Marble to Placita, where it connected to the Crystal River Railway (CRR). (To support his coal and coke operations in the Redstone area, Osgood started building the CRR line in the late 1890s from Carbondale, Colorado southward reaching Redstone in June 1900. By the early 1900s, the line reached its final destination of Placita.) In 1910, the CR&SJ obtained a right-of-way to operate on the CRR line to Carbondale, 28 miles (45 km) from Marble. The railway also increased the efficiency of getting supplies to the operation from outside the Crystal River Valley. The town's residents benefited by the railroad for transportation with the depot on the grounds of the mill site. In later years, livestock was transported out of the Crystal River Valley by the railroad.
Development of the integrated operation also created a large debt that led directly to receivership in July 1916 and bankruptcy in April 1917. Although the spending created an operation using the best equipment and was technically efficient, the company was unable to repay the debt with marble revenue because of high operating costs. By 1913 CYMC was in financial trouble when a loan of $1,868,000 was approved early in 1913 and used to refinance the debt.
Configuration
Exterior
1905 development started the first of three quarry openings with #2 in 1905. When Quarry 2 cutting started, none of the workers wanted to hang off the edge of the cliff sitting on a wooden bench attached to an overhead derrick. So the company president, Channing Meek, came up to the quarry, sat on the wooden bench, was lowered over the mountainside, and started cutting marble. After that no worker refused to go over the side and cut marble. Quarry 2 was followed by #3 in 1907 and #1 in 1912. A fourth opening to the left of #3 (out of view) was started but did not become a producing quarry.
To operate the quarries, structures for various functions were built around the quarry exterior. Wooden derricks were located by and above the openings to lift blocks out of the quarries. The boiler house (providing steam power for quarrying equipment) was the last major addition (second building to the right of opening 2). In front of the boiler house is a 50-ton (49.875 metric ton) electric hoist and the hoist electric power house is to the right of the boiler house. Below the boiler house area near the bottom of the photo is the Pea Vine (winch-cable powered carts on rails) used to move marble from the quarry to the loading station several hundred feet away, where it was placed on wagons for transport to the mill site. There are other facilities to the right of opening 1; compressor house, machine shop, and bunk house. To provide the needed electricity, the company built a hydro-electric plant with the generators located just east of the town limits and completed in July 1907.
By 1914 the quarry configuration had gone through several changes but from then on remained largely unchanged until the shut down in 1941. Several buildings located to the right of opening 1 had been relocated to opening 3, such as the machine shop (first building to the left of opening 2), offices (to the left of the machine shop), and the compressor house (first building on the right of opening 2 and left of the boiler house). The boarding house (not visible to the right of opening 1) was also relocated. In 1910, a new system was finished to get the stone from the quarry down to the finishing mill in the town of Marble. Two tall wooden derricks (one to the left opening 2 and another on the east side of Yule Creek) suspended an 880 feet (270 m) long cable. The 50-ton (49.875 metric ton) electric hoist attached a block to the cable for lowering marble 225 feet (69 m) to the new loading station and onto a railroad car (on standard gauge track) towed by the new electric tram finished in 1910. The electric tram replaced the Pea Vine. After closing in October 1941, the equipment inside was removed and the wood structures fell apart.
When the quarry reopened in 1990, the functions of the previous structures that were needed were located inside the quarry. The only structures remaining from prior to 1942 are the two cable derricks. One major 1990 alteration to the cliff was the blasting of a 16-by-16-foot (4.9 by 4.9 m) tunnel for access to the quarry interior. Today the marble is loaded onto a truck inside the mountain and driven out.