paragraph_text: As part of the Unification of China, Qin Shi Huang (Chinese: 秦始皇; pinyin: Qín Shǐ Huáng, 260 BC – 210 BC) introduced a uniform copper coin with the inscription "Ban Liang" based on the coins previously used by Qin. All other forms of local currency were abolished. The coins were round with a square hole in the middle which was the common design for most Chinese copper coins until the 20th century. Due to the low value of an individual coin, the Chinese have traditionally strung a nominal thousand copper coins onto a piece of string. Government taxes were levied on both coins and products such as rolls of silk. Salaries were paid in "stones" (石, dàn) of grain during the Qin and Han dynasties.

paragraph_text: Sichuan came under the firm control of a Chinese central government during the Sui dynasty, but it was during the subsequent Tang dynasty where Sichuan regained its previous political and cultural prominence for which it was known during the Han. Chengdu became nationally known as a supplier of armies and the home of Du Fu, who is sometimes called China's greatest poet. During the An Lushan Rebellion (755-763), Emperor Xuanzong of Tang fled from Chang'an to Sichuan. The region was torn by constant warfare and economic distress as it was besieged by the Tibetan Empire.

paragraph_text: There are 29 isotopes of copper. 63Cu and 65Cu are stable, with 63Cu comprising approximately 69% of naturally occurring copper; they both have a spin of 3⁄2. The other isotopes are radioactive, with the most stable being 67Cu with a half-life of 61.83 hours. Seven metastable isotopes have been characterized, with 68mCu the longest-lived with a half-life of 3.8 minutes. Isotopes with a mass number above 64 decay by β−, whereas those with a mass number below 64 decay by β+. 64Cu, which has a half-life of 12.7 hours, decays both ways.

paragraph_text: Years Material Weight (grains) Weight (grams) 1793 -- 1795 ~ 100% copper 208 grains 13.48 1795 -- 1857 ~ 100% copper 168 grains 10.89 1856 -- 1864 88% copper, 12% nickel (also known as NS - 12) 72 grains 4.67 1864 -- 1942 bronze (95% copper, 5% tin and zinc) 48 grains 3.11 1943 zinc - coated steel (also known as 1943 steel cent) 42 grains 2.72 1944 -- 1946 brass (shell case copper) (95% copper, 5% zinc) 48 grains 3.11 1947 -- 1962 bronze (95% copper, 5% tin and zinc) 48 grains 3.11 1962 -- 1981 brass (95% copper, 5% zinc) 48 grains 3.11 1982 brass (95% copper, 5% zinc) 48 grains 3.11 copper - plated zinc (97.5% zinc, 2.5% copper) 38.6 grains 2.5 1983 -- present copper - plated zinc (97.5% zinc, 2.5% copper) 38.6 grains 2.5

paragraph_text: The Beutong mine is a large copper mine located in the west of Indonesia in Sumatra. Beutong represents one of the largest copper reserve in Indonesia and in the world having estimated reserves of 505 million tonnes of ore grading 0.59% copper, 2.1 million oz of gold and 20 million oz of silver.

paragraph_text: Copper is a former community in Jackson County, Oregon, United States. Copper was located about north of the Oregon–California border, near the mouth of Carberry Creek. Copper was named for the copper mining in the region, including at the Blue Ledge mine just over the state line in California. The town had a post office from 1924 until 1932.The elevation of Copper is 1,949 feet.

paragraph_text: Britain's first use of brass occurred around the 3rd–2nd century BC. In North America, copper mining began with marginal workings by Native Americans. Native copper is known to have been extracted from sites on Isle Royale with primitive stone tools between 800 and 1600. Copper metallurgy was flourishing in South America, particularly in Peru around 1000 AD; it proceeded at a much slower rate on other continents. Copper burial ornamentals from the 15th century have been uncovered, but the metal's commercial production did not start until the early 20th century.

paragraph_text: Conchas Chinas is an affluent colonia directly south of Puerto Vallarta in the state of Jalisco, on the Pacific coast of Mexico. The term Conchas Chinas means "Chinese Shells" referring to the type of shell found only on the beaches of Conchas Chinas. Locals in Puerto Vallarta refer to Conchas Chinas as "The Hills" (as in 'the Beverly Hills of Puerto Vallarta'). There are many gated communities perched high on the mountainsides directly on the bay, with many million-dollar homes owned by internationally-known celebrities and politicians.

paragraph_text: In December 2004, PalmSource announced a new OS strategy. With the acquisition of the mobile phone software company China Mobilesoft, PalmSource planned to port Palm OS on top of a Linux kernel, while still offering both Palm OS Garnet and Palm OS Cobalt. This strategy was revised in June 2005, when still no device with Palm OS Cobalt was announced. PalmSource announced it was halting all development efforts on any product not directly related to its future Linux based platform.With the acquisition of PalmSource by ACCESS, Palm OS for Linux was changed to become the Access Linux Platform which was first announced in February 2006. The initial versions of the platform and software development kits for the Access Linux Platform were officially released in February 2007. As of January 2011, the Access Linux Platform had then yet to ship on any devices, however development kits then existed and public demonstrations had been showcased.

paragraph_text: The Nuclear Science Department at EPN is the only one in Ecuador and has the large infrastructure, related to irrradiation factilities like cobalt-60 source and Electron beam processing.

paragraph_text: The United Copper Company was a short-lived United States copper mining business in the early 20th century that played a pivotal role in the Panic of 1907.

paragraph_text: Sichuan has been historically known as the "Province of Abundance". It is one of the major agricultural production bases of China. Grain, including rice and wheat, is the major product with output that ranked first in China in 1999. Commercial crops include citrus fruits, sugar cane, sweet potatoes, peaches and grapes. Sichuan also had the largest output of pork among all the provinces and the second largest output of silkworm cocoons in 1999. Sichuan is rich in mineral resources. It has more than 132 kinds of proven underground mineral resources including vanadium, titanium, and lithium being the largest in China. The Panxi region alone possesses 13.3% of the reserves of iron, 93% of titanium, 69% of vanadium, and 83% of the cobalt of the whole country. Sichuan also possesses China's largest proven natural gas reserves, the majority of which is transported to more developed eastern regions.

paragraph_text: Late Imperial China maintained both a silver and a copper currency system. The copper system was based on the copper cash (wen). The silver system had several units which by the Qing Dynasty were: 1 tael = 10 mace = 100 candareens = 1000 lí (silver cash).

paragraph_text: Before the 1997 war, about 9,000 Europeans and other non-Africans lived in Congo, most of whom were French; only a fraction of this number remains. Around 300 American expatriates reside in the Congo.

paragraph_text: Copper is synthesized in massive stars and is present in the Earth's crust at a concentration of about 50 parts per million (ppm), where it occurs as native copper or in minerals such as the copper sulfides chalcopyrite and chalcocite, the copper carbonates azurite and malachite, and the copper(I) oxide mineral cuprite. The largest mass of elemental copper discovered weighed 420 tonnes and was found in 1857 on the Keweenaw Peninsula in Michigan, US. Native copper is a polycrystal, with the largest described single crystal measuring 4.4×3.2×3.2 cm.

paragraph_text: Cobalt (II) chloride is an inorganic compound of cobalt and chlorine, with the formula CoCl. It is usually supplied as the hexahydrate CoCl 6H O, which is one of the most commonly used cobalt compounds in the lab.

paragraph_text: Years Material Weight (grains) Weight (grams) 1793 -- 1795 ~ 100% copper 208 grains 13.48 1795 -- 1857 ~ 100% copper 168 grains 10.89 1856 -- 1864 88% copper, 12% nickel (also known as NS - 12) 72 grains 4.67 1864 -- 1942 bronze (95% copper, 5% tin and zinc) 48 grains 3.11 1943 zinc - coated steel (also known as 1943 steel cent) 42 grains 2.72 1944 -- 1946 brass (shell case copper) (95% copper, 5% zinc) 48 grains 3.11 1947 -- 1962 bronze (95% copper, 5% tin and zinc) 48 grains 3.11 1962 -- 1981 brass (95% copper, 5% zinc) 48 grains 3.11 1982 brass (95% copper, 5% zinc) 48 grains 3.11 copper - plated zinc (97.5% zinc, 2.5% copper) 38.6 grains 2.5 1983 - present copper - plated zinc (97.5% zinc, 2.5% copper) 38.6 grains 2.5

paragraph_text: In 2008, Bloomberg claimed child labour in copper and cobalt mines that supplied Chinese companies in Congo. The children are creuseurs, that is they dig the ore by hand, carry sacks of ores on their backs, and these are then purchased by these companies. Over 60 of Katanga's 75 processing plants are owned by Chinese companies and 90 percent of the region's minerals go to China. An African NGO report claimed 80,000 child labourers under the age of 15, or about 40% of all miners, were supplying ore to Chinese companies in this African region. Amnesty International alleged in 2016 that some cobalt sold by Congo Dongfang Mining was produced by child labor, and that it was being used in lithium-ion batteries powering electric cars and mobile devices worldwide.

paragraph_text: Copper Creek is a ghost town in Pinal County, Arizona, United States. Copper Creek is located in a canyon in the Galiuro Mountains.

paragraph_text: Georg Brandt (26 June 1694 – 29 April 1768) was a Swedish chemist and mineralogist who discovered cobalt (c.1735). He was the first person to discover a metal unknown in ancient times.

Question: How many Americans live in the country that supplied copper and cobalt to China?
Answer: Around 300