Fergana Valley
Fergana Valley or Ferghana Valley, region, 8,494 sq mi (22,000 sq km), divided among Uzbekistan, Tajikistan, and Kyrgyzstan. The Fergana Range (part of the Tian Shan system) rises in the northeast and the Pamir in the south. The narrow Khudjand Pass in the west has historically served as an invasion route into the valley. The Xinjiang region of China borders the valley in the southeast. The Fergana Valley, consisting partly of the very fertile Karakalpak steppe and partly of desert land, is drained by the Syr Darya River and by numerous mountain streams, which are fed by snowfields and glaciers in the mountains. A dense irrigation network is linked by the Great Fergana and South Fergana canals. Major cities of the valley include Fergana, Kokand, Andijan, and Namangan, in Uzbekistan; Khudjand, in Tajikistan; and Osh, in Kyrgyzstan; many of them are connected by a circular rail line, which also has spurs serving the mining settlements on the valley's periphery.
The Fergana Valley is one of Central Asia's most densely populated agricultural and industrial areas. Cotton fields, orchards, vineyards, walnut groves, and mulberry tree plantations (for silk) cover the region, which is one of the world's oldest cultivated areas. Along the fringes of the valley are deposits of oil, natural gas, and iron ore. The region's natural resources contributed to the industrialization of all Soviet Central Asia. Cotton and silk milling and the manufacture of chemicals and cement are among the valley's important industries.
According to ancient Chinese sources, the Fergana Valley was a major center of Central Asia as early as the 4th cent. BC The introduction of silk raising from China, the development of cotton cultivation, and its favorable location astride the silk route between China and the Mediterranean stimulated the valley's growth. The Arabs, following the path of earlier invaders, occupied the valley in the 8th cent. and introduced Islam. The region was held in the 9th and 10th cent. by the Persian Samanid dynasty, in the 12th cent. by the Seljuk Turks of Khwarazm, and in the 14th cent. by the Mongols under Jenghiz Khan. The valley later belonged to the empire of Timur and his successors, the Timurids.
Early in the 16th cent., it was overrun by the Uzbeks, who established the khanate of Kokand. The opening of the sea route to East Asia around that time led to the decline of the prosperous caravan trade through the valley. Russian conquest of the Fergana Valley was completed in 1876; the region was then made part of a much larger unit called Fergana, which was a province of Russian Turkistan. During the Russian civil war, the valley was the center of the anti-Bolshevik Autonomous Turkistan Government, with Kokand as its capital. The crowded conditions in the valley contributed to ethnic violence in 1989-90, and Fergana has been one of the hot spots of post-USSR Central Asia.
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Pumice and pumicite
Magazine article from: Mining Engineering; 6/1/2003; ; 700+ words
; The estimated domestic production of pumice and pumicite in 2002 was 950 kt (1...Geological Survey (USGS). The amount of pumice and pumicite sold or used in the United...came from 16 producers in six states. Pumice and pumicite was mined in Arizona, California...
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Pumice and Pumicite
Magazine article from: Mining Engineering; 6/1/1999; ; 700+ words
; Estimated domestic production of pumice and pumicite in 1998 increased by 39 kt...1996. The USGS estimated the value of pumice and pumicite sold or used in the United...An estimated 616 kt (679,000 st) of pumice was produced during 1998, according to...
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PUMICE AND PUMICITE
Magazine article from: Mining Engineering; 6/1/2004; ; 700+ words
; Estimated domestic production of pumice and pumicite during 2003 decreased by...production. The USGS estimated the value of pumice and pumicite sold or used in the United...The USGS estimated that the amount of pumice and pumicite exported during 2003 was...
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Industrial minerals 1997: Pumice and pumicite
Magazine article from: Mining Engineering; 6/1/1998; ; 700+ words
; Estimated domestic production of pumice and pumicite in 1997 decreased by 74 kt...1991. The USGS estimated the value of pumice and pumicite sold or used in the United...caused by a decrease in the demand for pumice in construction, building and laundry...
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The effects of pumice aggregate/cement ratios on the low-strength concrete properties.
Magazine article from: Construction and Building Materials; 5/1/2008; ; 700+ words
; ...The present study covers the use of pumice lightweight aggregate (PLA) to produce...load bearing elements. In this study, pumice aggregate lightweight concrete (PALWC...different sizes of 8-16 mm as coarse pumice aggregate (CPA), of 4-8 mm as medium...
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Mixture Design, Strength, Durability, and Fire Resistance of Lightweight Pumice Concrete
Magazine article from: ACI Materials Journal; 9/1/2007; ; 700+ words
; ...presents the development of lightweight volcanic pumice concrete (VPC) using pumice as aggregate illustrating 21 concrete mixtures...Natural lightweight aggregates include diatomite, pumice, volcanic scoria, sawdust, oil palm shells...
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Bond characteristics of plain and deformed bars in lightweight pumice concrete.
Magazine article from: Construction and Building Materials; 7/1/2008; ; 700+ words
; ...reinforcing bars in lightweight volcanic pumice concrete (VPC) and normal concrete...manufactured by incorporating crushed lightweight pumice and gravel aggregates, respectively...Bond strength; Lightweight concrete; Pumice; Reinforcing bar; Pullout test; Code...
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Pumice-stone powder assures a smooth finish for your wood
Newspaper article from: Chicago Sun-Times; 7/15/1988; ; 591 words
; Pumice stone in the form of powder is a material...have no trouble achieving good results with pumice powder even if you have only a limited amount...finishes. One thing you will discover is that pumice powder does not leave scratches and is...
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Santa Fe, N.M., Developer Plans for Pumice-Processing Plant.
Newspaper article from: Knight Ridder/Tribune Business News; 11/21/2003; 700+ words
; ...Nov. 21--SANTA FE, N.M.--The pumice-processing plant at St. Francis Drive...s General Plan zone designation at the pumice plant site. SF Brown Inc. representatives...a change in zoning of the eight-acre pumice plant property from open space to mixed...
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Stones help keep jean sales afloat; company goes from rocks to riches. (Ashco Industries, pumice stones for denim finishing)
PR Newswire; 11/10/1988; 700+ words
; ...are all applied with tennis ball sized pumice stones. One company that has gone from...and commonly known as "The Prince of Pumice," has proven what many spelunkers have...is a major source for the specialized pumice rock that jean manufacturers and commercial...
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Pumice
Book article from: World of Earth Science
Pumice Pumice is a vesicular volcanic rock that is commonly light enough to float in...counterpart, granite ), although magma of virtually any composition can form pumice. The term vesicular refers to the presence of vesicles, or irregularly...
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pumice
Book article from: The Columbia Encyclopedia, Sixth Edition
pumice , volcanic glass formed by the solidification...rocks of diorite or gabbro composition. Pumice is used chiefly as an abrasive and is included in many scouring preparations. Ground pumice is also used in finishing furniture. Deposits...
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ignimbrite
Book article from: A Dictionary of Earth Sciences
...and flattening of groundmass shards and pumice clasts can occur in the lower part of...between the loosely packed shards and pumice in the upper parts of the flow, creating...sillar horizon in which the glass of the pumice and shards is devitrified. Ignimbrites...
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pyroclastic and volcaniclastic rocks
Book article from: The Oxford Companion to the Earth
...substances known as Pelée's hair and pumice are also grouped with pyroclastic and volcaniclastic...volcanic glass spun out like candy-floss. Pumice is a foam of volcanic gas bubbles volcanic glass. Some pumice is so filled with gas that it will float...
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Caldera
Book article from: World of Earth Science
...subside in two ways. First, eruptions of large volumes of pumice or magma , or subterranean drainage of the latter to other areas...material — in some cases, thousands of cubic miles of pumice and ash — excavate very wide underground chambers...
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