The Kayenta mine was a surface coal mine operated by Peabody Western Coal Company, a subsidiary of Peabody Energy ) on the Navajo Nation in northern Arizona from 1973 to 2019. About 400 acres were mined and reclaimed each year, providing about 8 million tons of coal annually to the Navajo Generating Station .
34-538: The Kayenta mine was located near the northern edge of Black Mesa , a 5,400 square mile highland plateau in northeast Arizona that contains extensive coal deposits in several geologic formations . Since about 1300 AD, the Hopi had extracted coal from the area for pottery firing and domestic heating. In the early 1900s, limited surveying of the coal field was made and a number of small underground mines were put into production, supplying local reservation schools and communities in
68-415: A boom , dipper (or stick), bucket , and cab on a rotating platform known as the "house" . The modern excavator's house sits atop an undercarriage with tracks or wheels , being an evolution of the steam shovel (which itself evolved into the power shovel when steam was replaced by diesel and electric power). All excavation-related movement and functions of a hydraulic excavator are accomplished through
102-401: A tiltrotator which allows attachments rotate 360 degrees and tilt +/- 45 degrees, in order to increase the flexibility and precision of the excavator. Before the 1990s, all excavators had a long or conventional counterweight that hung off the rear of the machine to provide more digging force and lifting capacity. This became a nuisance when working in confined areas. In 1993 Yanmar launched
136-446: A boom, stick and bucket with three joints between them and the house. The boom attaches to the house and provides the up-and-down movement. It can be one of several different configurations: Attached to the end of the boom is the stick (or dipper arm). The stick provides the digging movement needed to pull the bucket through the ground. The stick length is optional depending whether reach (longer stick) or break-out power (shorter stick)
170-451: A concentration that is about 1/10th that of average shale rock and among the lowest concentrations in US coals. Coal is removed by the open cut or strip mining method. Topsoil is first removed and placed on previously mined and re-contoured areas or stored separately for later reclamation. Overburden is then blasted to loosen the materials and is removed primarily by electric dragline to expose
204-595: A four-foot-thick root zone. The land is then seeded and restored for grazing, wildlife habitat, and cultural plant cultivation. Replanted areas are monitored for a minimum of 10 years to correct any erosion problems, control invasive weeds, and insure the plant systems are fully established before being released for grazing. As of 2012, more than 15,000 acres had been restored on the Black Mesa Complex and 39 permanent ponds had been created for livestock watering and wildlife habitat. Reclamation efforts were recognized by
238-415: A number of locations identified as sacred or ceremonial sites. Measures to protect air quality include water sprays and sprinklers to control dust on dirt roads and disturbed areas, enclosures and water sprays at belt conveyor transfer points, baghouses on coal storage silos, and other requirements of the mine's Clean Air Act operating permit NN-OP 08-010. The permit is administered, monitored and enforced by
272-514: A skilled operator to control all four functions simultaneously. The most popular configuration in the US is the SAE controls configuration while in other parts of the world, the ISO control configuration is more common. Some manufacturers such as Takeuchi have switches that allow the operator to select which control configuration to use. Hydraulic excavators now perform tasks well beyond bucket excavation. With
306-576: A subsidiary of Peabody Coal Company , was issued drilling and exploration permits on the Mesa to determine areas where coal could be economically recovered. In 1964 and 1966, Sentry entered into mining lease agreements with the tribes for 64,848 acres. The first lease was made in 1964 for 24,858 acres of land held exclusively by the Navajo Tribe, designated Navajo Coal Lease No. 14-20-0603-8580, or N-8580 for short. The additional 40,000 acres were leased in 1966 in
340-531: Is generally smaller, stronger, and has hardened side cutters and teeth used to break through hard ground and rocks. Buckets have numerous shapes and sizes for various applications. There are also many other attachments that are available to be attached to the excavator for boring, ripping, crushing, cutting, lifting, etc. Attachments can be attached with pins similar to other parts of the arm or with some variety of quick coupler . Excavators in Scandinavia often feature
374-545: Is regulated through the US EPA's National Pollutant Discharge Elimination System under NPDES permit No. NN0022179, and Multi-Sector General Permit No. AZR05000I. The mine pumps about 1,240 acre-feet (1.5 million cubic meters ) of ground water per year from the Navajo aquifer (aka N-aquifer). The water is used primarily for dust control, with about 60 acre-feet (74,000 m) made available to area residents. Up until December 2005,
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#1732858510423408-458: Is required. Most common is mono stick but there are also, for example, telescopic sticks. The largest form ever of an excavator, the dragline excavator , eliminated the dipper in favor of a line and winch . On the end of the stick is usually a bucket . A wide, large capacity (mud) bucket with a straight cutting edge is used for cleanup and levelling or where the material to be dug is soft, and teeth are not required. A general purpose (GP) bucket
442-505: The arms , swing motor, track motors and accessories while the third is a lower pressure (≈700 psi , 48 bar) pump for pilot control of the spool valves ; this third circuit allows for reduced physical effort when operating the controls. Generally, the 3 pumps used in excavators consist of 2 variable displacement piston pumps and a gear pump. The arrangement of the pumps in the excavator unit changes with different manufacturers using different formats. The three main sections of an excavator are
476-476: The backhoe . In the UK , wheeled excavators are sometimes known as "rubber ducks". Excavators are used in many ways: Modern hydraulic excavators come in a wide variety of sizes. The smaller ones are called mini or compact excavators . For example, Caterpillar's smallest mini-excavator weighs 2,060 pounds (930 kg) and has 13 hp ; their largest model is the largest excavator available (developed and produced by
510-427: The undercarriage , the house and the arm. The boom, the front part that is attached to the cab itself and holds the arm, is also used. The undercarriage includes tracks, track frame, and final drives, which have a hydraulic motor and gearing providing the drive to the individual tracks. The undercarriage, especially frequently for a mini-excavator, can also have blade similar to that of a bulldozer. The house includes
544-640: The Black Mesa Complex. In 1982, the U.S. Office of Surface Mining Reclamation and Enforcement (OSM) issued permit AZ-0001 for surface mining and reclamation operations on the Black Mesa and Kayenta mines. The permit was most recently renewed in 2012 for the Kayenta Mine as permit No. AZ-0001E. In 2005, the Black Mesa Mine ceased production when the Mohave Generating Station was shut down, leaving
578-437: The Black Mesa mine had used ground water to slurry coal through a 273-mile-long (439 km) pipeline to the Mohave Generating Station. Until the station was shut down, the combined water usage by both mines had been 4,450 acre⋅ft (5.5 million m) per year. Once a section has been mined out, it is backfilled and graded to the approximate previous contour and topped with suitable spoil, subsoil, and topsoil to create
612-629: The Kayenta Mine as the only active mine in the leasehold area. As of June, 2019, the mine staff was being reduced in anticipation of the closure of the Navajo Generating Station . The mine delivered its last load of coal to the station in August 2019, and the station closed in November 2019. The closures reduced the Hopi budget by $ 12 million, or 80% of the total budget. The coal that is mined comes from
646-613: The Navajo Generating Station near Page, Arizona. Mine locations were set relative to conveying transfer points, natural divisions between recoverable sections of coal (called coal resource areas), and projected quantities to be supplied to the respective power plants, such that each mine had portions on both the Navajo Reservation and in the Joint Use Area. The leased areas, mines, and facilities were collectively termed
680-550: The Navajo Nation Environmental Protection Agency (NNEPA), as authorized by the US EPA. Peabody maintains a network of PM10 particulate monitors to assess the effectiveness of fugitive dust control measures and ensure compliance with national ambient air quality standards ( NAAQS ). Monitoring data are reported quarterly to the OSM and NNEPA. Two main washes – Moenkopi Wash and Dinnebito Wash – pass through
714-492: The Navajo-Hopi Joint Use Area, leases being entered into with each of the two tribes – Joint Mineral Lease No. 14-20-0450-5743, aka J-5743, with the Hopi tribe, and 14-20-0603-9910, aka J-9910, with the Navajo Tribe. When the Joint Use Area was later partitioned between the tribes in 1974, much of the mine lease area and surface rights ended up with Navajo Nation, but the two tribes retained joint and equal interest in
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#1732858510423748-527: The Orenstein & Koppel, Germany, until the takeover 2011 by Caterpillar, named »RH400«), the CAT 6090, which weighs in excess of 2,160,510 pounds (979,990 kg), has 4500 hp, and a bucket as large as 52.0 m . Hydraulic excavators usually couple engine power to (commonly) three hydraulic pumps rather than to mechanical drivetrains . The two main pumps supply oil at high pressure (up to 5000 psi , 345 bar) for
782-734: The U.S. Office of Surface Mining for reclamation excellence in 1998; for cultural, historic and archaeological preservation in 2002; good neighbor award in 2003, and reclamation excellence and good neighbor awards in 2005. Black Mesa (Apache-Navajo Counties, Arizona) Too Many Requests If you report this error to the Wikimedia System Administrators, please include the details below. Request from 172.68.168.226 via cp1108 cp1108, Varnish XID 761612308 Upstream caches: cp1108 int Error: 429, Too Many Requests at Fri, 29 Nov 2024 05:35:10 GMT Excavator Excavators are heavy construction equipment primarily consisting of
816-467: The Wepo formation, the uppermost coal-bearing formation on the Mesa, and is removed from multiple seams that are typically 3 to 15 feet thick and lie within about 130 feet of the surface. It is classified as low-sulfur, high volatile C bituminous , having a heat content of 10,820 Btu/lb, ash content of 10.4%, and sulfur content of 0.63%. Average mercury content is 0.04 ppm , or about 4 lb/trillion Btu,
850-494: The advent of hydraulic-powered attachments such as a breaker , a cutter, a grapple or an auger ,a crusher and screening buckets the excavator is frequently used in many applications other than excavation. Many excavators feature a quick coupler for simplified attachment mounting, increasing the machine's utilization on the jobsite. Excavators are usually employed together with loaders and bulldozers . Most wheeled, compact and some medium-sized (11 to 18-tonne) excavators have
884-585: The coal and other minerals under the partitioned lands. Peabody developed two separate mines within the leasehold area – the Black Mesa mine and Kayenta mine. The Black Mesa mine, located on 20,775 acres in the southwestern section of the leasehold area, began operation in 1970 supplying the Mohave Generating Station in Laughlin, Nevada via a pipeline . The Kayenta mine, on 44,073 acres in the northern and eastern sections, began operation in 1973 supplying
918-407: The coal seams. Excavators , loaders and haul trucks then remove the exposed coal to a collection point, where it is crushed and loaded on a 17-mile-long (27 km) overland belt conveyor. The conveyor carries the coal to rail load-out silos, where the coal is loaded into BM&LP rail cars bound for the Navajo Generating Station . Areas disturbed by mine activities cover less than half of
952-417: The leasehold area, and traditional land use and occupancy are allowed to continue within the leased area where safely removed from active mining operations. As of 2010, approximately 83 households were located within the leasehold area, four of them in an area planned for future mining operations. For those households that must be moved, Peabody provides for relocation to an agreed-upon area within or adjacent to
986-684: The leasehold area, as well as compensation for acreage removed from customary grazing as a result of mining activities. From 1967 to 1986, one of the largest and longest-running archaeological projects in North America, the Black Mesa Archaeological Project, was conducted with the assistance of Peabody Coal Company to record, preserve or relocate archaeological artifacts within the leasehold area. Since 1986, Peabody has continued archaeological testing and mitigation ahead of mine activities. Mining operations have also been adjusted to avoid
1020-580: The mine permit area and eventually run into the Little Colorado River . Although mining does not occur in these washes, storm water runoff from areas disturbed by mining activities could potentially degrade the quality of water going into them. To prevent degradation of surface waters, sedimentation ponds are constructed under the mine's surface water protection program. Water quality is monitored and controlled at these ponds, as well as at livestock watering ponds, seeps and storm water runoff. The program
1054-457: The operator cab, counterweight , engine, fuel and hydraulic oil tanks. The house attaches to the undercarriage by way of a center pin. High-pressure oil is supplied to the tracks' hydraulic motors through a hydraulic swivel at the axis of the pin, allowing the machine to slew 360° unhindered and thus provides the left-and-right movement. The arm provides the up-and-down and closer-and-further (or digging movement) movements. Arms typically consist of
Kayenta Mine - Misplaced Pages Continue
1088-529: The region. The coal field received increased attention beginning in 1950 when the Navajo-Hopi Long Range Rehabilitation Act was enacted in response to dire economic conditions on the reservations. The Act intended to promote economic development and better utilization of the reservations’ natural resources. As a result, the strata and coal deposits of Black Mesa were more extensively studied; and in 1961 and 1964 Sentry Royalty Company,
1122-555: The use of hydraulic fluid , with hydraulic cylinders and hydraulic motors , which replaced winches, chains, and steel ropes . Another principle change was the direction of the digging action, with modern excavators pulling their buckets toward them like a dragline rather than pushing them away to fill them the way the first powered shovels did. Excavators are also called diggers, scoopers, mechanical shovels, or 360-degree excavators (sometimes abbreviated simply to "360"). Tracked excavators are sometimes called "trackhoes" by analogy to
1156-455: The world's first Zero Tail Swing excavator, which allows the counterweight to stay inside the width of the tracks as it slews, thus being safer and more user friendly when used in a confined space. This type of machine is now widely used throughout the world. There are two main types of control configuration used in excavators to control the boom and bucket, each distributing the four primary digging functions across two x-y joysticks. This allows
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