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Laramie Formation
The Laramie Formation is a geologic formation of Late Cretaceous (Maastrichtian) age, named by Clarence King in 1876 for exposures in northeastern Colorado, in the United States.King, C. 1876. Report of the Geological Exploration of the Fortieth Parallel. U.S.Geographical and Geological Survey. It was deposited on a coastal plain and in coastal swamps that flanked the Western Interior Seaway. It contains coal, clay and uranium deposits, as well as plant and animal fossils, including dinosaur remains. Stratigraphy and Lithology The Laramie Formation is exposed around the edges of the Denver Basin and ranges from 400–500 feet (120–150 m) on the western side of the basin, and 200–300 feet (60–90 m) thick on the eastern side. It rests conformably on the Fox Hills Sandstone and unconformably underlies the Arapahoe Conglomerate. The formation can be divided into an unnamed lower member containing bedded sandstone, clay and coal; and an unnamed upper member composed predominatel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outcrop
An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. Features Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficial deposits are covered by soil and vegetation and cannot be seen or examined closely. However, in places where the overlying cover is removed through erosion or tectonic uplift, the rock may be exposed, or ''crop out''. Such exposure will happen most frequently in areas where erosion is rapid and exceeds the weathering rate such as on steep hillsides, mountain ridges and tops, river banks, and tectonically active areas. In Finland, glacial erosion during the last glacial maximum (ca. 11000 BC), followed by scouring by sea waves, followed by isostatic uplift has produced many smooth coastal and littoral outcrops. Bedrock and superficial deposits may also be exposed at the Earth's surface due to human excavations such as quarrying and build ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unconformity
An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger layer, but the term is used to describe any break in the sedimentary geologic record. The significance of angular unconformity (see below) was shown by James Hutton, who found examples of Hutton's Unconformity at Jedburgh in 1787 and at Siccar Point in 1788. The rocks above an unconformity are younger than the rocks beneath (unless the sequence has been overturned). An unconformity represents time during which no sediments were preserved in a region or were subsequently eroded before the next deposition. The local record for that time interval is missing and geologists must use other clues to discover that part of the geologic history of that area. The interval of geologic time not represented is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranium Mining In Colorado
Uranium mining in Colorado, United States, goes back to 1872, when pitchblende ore was taken from gold mines near Central City, Colorado. The Colorado uranium industry has seen booms and busts, but continues to this day. Not counting byproduct uranium from phosphate, Colorado is considered to have the third largest uranium reserves of any US state, behind Wyoming and New Mexico. Uranium price increases from 2001 to 2007 prompted a number of companies to revive uranium mining in Colorado. However, price drops and financing problems in late 2008 have forced some companies to cancel or scale back uranium-mining projects. There are no currently producing uranium mines in Colorado. Front Range province Hydrothermal uranium deposits are present through a widely spaced area in the Front Range of the Rocky Mountains, in Larimer, Boulder, Gilpin, Clear Creek, and Jefferson counties. The first uranium identified in the USA was pitchblende from the Wood gold mine at Central City, Colo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grover, Colorado
The Town of Grover is a Statutory Town located in Weld County, Colorado, United States. The town population was 157 at the 2020 United States Census, a 14.60% increase since the 2010 United States Census. Grover is a part of the Greeley, CO Metropolitan Statistical Area and the Front Range Urban Corridor. Geography Grover is located at (40.868393, -104.226126). At the 2020 United States Census, the town had a total area of , all of it land. Demographics As of the census of 2000, there were 153 people, 78 households, and 32 families residing in the town. The population density was . There were 85 housing units at an average density of . The racial makeup of the town was 96.08% White, 1.96% African American, 1.31% Native American, 0.65% from other races. Hispanic or Latino of any race were 1.96% of the population. There were 78 households, out of which 23.1% had children under the age of 18 living with them, 39.7% were married couples living together, 2.6% had a female hous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weld County, Colorado
Weld County is a county located in the U.S. state of Colorado. As of the 2020 census, the population was 328,981. The county seat is Greeley. Weld County comprises the Greeley, CO Metropolitan Statistical Area, which is included in the Denver–Aurora, CO Combined Statistical Area. History On May 30, 1854, the Kansas–Nebraska Act created the Nebraska Territory and the Kansas Territory, divided by the Parallel 40° North (Baseline Road or County Line Road or Weld County Road 2 in the future Weld County). Present-day Weld County, Colorado, lay in the southwestern portion of the Nebraska Territory, bordering the Kansas Territory. In July 1858, gold was discovered along the South Platte River in Arapahoe County, Kansas Territory. This discovery precipitated the Pike's Peak Gold Rush. Many residents of the mining region felt disconnected from the remote territorial governments of Kansas and Nebraska, so they voted to form their own Territory of Jefferson on October 24, 185 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leyden, Colorado
Leyden, Colorado, elevation is a small unincorporated community in Jefferson County, Colorado west of Arvada at the junction of West 82nd Avenue and Quaker Street. It is a historic company town established by the Leyden Coal Company in 1902 to house the miners of the Leyden Coal Mine nearby to the west. History The town of Leyden consists of a collection of square frame homes with pyramidal roofs that were originally red trimmed in white. It was named for pioneer miner brothers Michael, Martin and John Leyden, who discovered the original Leyden mine in the hogback ridge to the west, where Michael and Martin died in 1866 and 1870, respectively. At its height, the town of Leyden included these homes as well as the company store, school, boarding house, saloon, and Presbyterian chapel. The store still stands at the southeast corner of 82nd and Quaker, while the school is the easternmost house on the hillside to the north, and the foreman's house stands next door to its west. The to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Mining
Surface mining, including strip mining, open-pit mining and mountaintop removal mining, is a broad category of mining in which soil and rock overlying the mineral deposit (the overburden) are removed, in contrast to underground mining, in which the overlying rock is left in place, and the mineral is removed through shafts or tunnels. In North America, where the majority of surface coal mining occurs, this method began to be used in the mid-16th century and is practiced throughout the world in the mining of many different minerals. In North America, surface mining gained popularity throughout the 20th century, and surface mines now produce most of the coal mined in the United States. In most forms of surface mining, heavy equipment, such as earthmovers, first remove the overburden. Next, large machines, such as dragline excavators or bucket-wheel excavators, extract the mineral. The pros of surface mining are that it has a lower financial cost and is a lot safer than undergrou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stoping
Stoping is the process of extracting the desired ore or other mineral from an underground mine, leaving behind an open space known as a stope. Stoping is used when the country rock is sufficiently strong not to collapse into the stope, although in most cases artificial support is also provided. The earliest forms of stoping were conducted with hand tools or by fire-setting; later gunpowder was introduced. From the 19th century onward, various other explosives, power-tools, and machines came into use. As mining progresses the stope is often backfilled with tailings, or when needed for strength, a mixture of tailings and cement. In old mines, stopes frequently collapse at a later time, leaving craters at the surface. They are an unexpected danger when records of underground mining have been lost with the passage of time. Stoping is considered "productive work", and is contrasted with "deadwork", the work required merely to access the mineral deposit, such as sinking shafts and winz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Room And Pillar
Room and pillar or pillar and stall is a variant of breast stoping. It is a mining system in which the mined material is extracted across a horizontal plane, creating horizontal arrays of rooms and pillars. To do this, "rooms" of ore are dug out while "pillars" of untouched material are left to support the roof overburden. Calculating the size, shape, and position of pillars is a complicated procedure, and is an area of active research. The technique is usually used for relatively flat-lying deposits, such as those that follow a particular stratum. Room and pillar mining can be advantageous because it reduces the risk of surface subsidence compared to other underground mining techniques. It is also advantageous because it can be mechanized, and is relatively simple. However, because significant portions of ore may have to be left behind, recovery and profits can be low. Room and pillar mining was one of the earliest methods used, although with significantly more man-power. The room ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sub-bituminous Coal
Sub-bituminous coal is a lower grade of coal that contains 35–45% carbon. The properties of this type are between those of lignite, the lowest grade of coal, and those of bituminous coal, the second-highest grade of coal. Sub-bituminous coal is primarily used as a fuel for steam-electric power generation. Properties Sub-bituminous coals may be dull, dark brown to black, soft and crumbly at the lower end of the range, to bright jet-black, hard, and relatively strong at the upper end. They contain 15-30% inherent moisture by weight and are non-coking (undergo little swelling upon heating). The heat content of sub-bituminous coals range from 8300 to 11,500 BTu/ lb or 19.3 to 26.7 M J/ kg. Their relatively low density and high water content renders some types of sub-bituminous coals susceptible to spontaneous combustion if not packed densely during storage in order to exclude free air flow. Reserves A major source of sub-bituminous coal in the United States is the Powder R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Golden, Colorado
Golden is a List of municipalities in Colorado#Home rule municipality, home rule city that is the county seat of Jefferson County, Colorado, Jefferson County, Colorado, United States. The city population was 20,399 at the 2020 United States Census. Golden lies along Clear Creek (Colorado), Clear Creek at the base of the Front Range of the Rocky Mountains. Founded during the Pike's Peak Gold Rush on June 16, 1859, the mining camp was originally named Golden City in honor of Thomas L. Golden. Golden City served as the capital of the provisional Territory of Jefferson from 1860 to 1861, and capital of the official Territory of Colorado from 1862 to 1867. In 1867, the territorial capital was moved about east to Denver#History, Denver City. Golden is now a part of the Denver–Aurora–Lakewood, CO Metropolitan Statistical Area and the Front Range Urban Corridor. The Colorado School of Mines, offering programs in engineering and science, is located in Golden. In addition, it is also h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concretions
A concretion is a hard, compact mass of matter formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary rock or soil. Concretions are often ovoid or spherical in shape, although irregular shapes also occur. The word 'concretion' is derived from the Latin "(act of) compacting, condensing, congealing, uniting", itself from ''con'' meaning 'together' and ''crescere'' meaning "to grow". Concretions form within layers of sedimentary strata that have already been deposited. They usually form early in the burial history of the sediment, before the rest of the sediment is hardened into rock. This concretionary cement often makes the concretion harder and more resistant to weathering than the host stratum. There is an important distinction to draw between concretions and nodules. Concretions are formed from mineral precipitation around some kind of nucleus while a nodule is a replacement body. Descriptions dating from the 18th ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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