Editing Codelco (section)

===Codelco Norte===
Codelco Norte is a division of Codelco that is made of the Chuquicamata and Radomiro Tomic mining areas.<ref name="divisions">{{cite web|url=http://www.codelco.cl/english/la_corporacion/division_norte.asp|title=Divisions|publisher=Codelco|access-date=2009-04-22|archive-date=2008-06-18|archive-url=https://web.archive.org/web/20080618001051/http://www.codelco.cl/english/la_corporacion/division_norte.asp|url-status=dead}}</ref>

====Chuquicamata====
[[File:Mina de Chuquicamata, Calama, Chile, 2016-02-01, DD 110-112 PAN.JPG|thumb|Chuquicamata mine in 2016]]
{{main|Chuquicamata}}
Copper has been mined for centuries at Chuquicamata as was shown by the discovery in 1898 of "Copper Man", a mummy dated at about 550 A.D. which was found trapped in an ancient mine shaft by a fall of rock.<ref>{{cite journal | url=https://doi.org/10.1007%2Fs11837-004-0256-6 | doi=10.1007/s11837-004-0256-6 | title=The production of copper in 6th century Chile's chuquicamata mine | year=2004 | last1=Fuller | first1=David R. | journal=JOM | volume=56 | issue=11 | pages=62–66 | bibcode=2004JOM....56k..62F | s2cid=137666853 | url-access=subscription }}</ref>  However mining on any scale did not start until the later years of the 19th century and these early operations mined the high grade veins (10-15% copper) and disregarded the low grade disseminated ore.<ref name="closure">[https://codnorte.codelco.cl/cierrecampamento ''Closure of Chuquicamata camp ''] {{webarchive|url=https://web.archive.org/web/20071022120700/https://codnorte.codelco.cl/cierrecampamento/ |date=2007-10-22 }}</ref> One attempt was made to process the low grade ore in 1899-1900 by Norman Walker, a partner in La Compañia de Cobre de Antofagasta, but it failed leaving the company deeply in debt.<ref name="lucha">[http://www.scielo.cl/scielo.php?pid=S0717-71942004000100006&script=sci_arttext ''La Lucha de los Mineros Contra la Leyes: Chuquicamata (1900-1915) Luis Orellana Retamales'']</ref>

The modern era started when the American engineer Bradley finally developed a method of working low grade oxidised copper ores.  In 1910 he approached the lawyer and industrialist [[Albert Burrage|Albert C Burrage]] who sent engineers to examine Chuquicamata.  Their reports were good and in April 1911 he started to buy up mines and claims in association with Duncan Fox y Cia., an English entrepreneur.<ref name=closure/><ref name=lucha/>
 
Unfortunately, Burrage did not have the capital to develop a mine so he approached the Guggenheim Brothers.  They examined his claims and estimated reserves at 690 million tonnes grading 2.58% copper.<ref name = closure/>  The Guggenheims also had a process for treating the low grade ores developed by [[Elias Anton Cappelen Smith| E A Cappelen Smith]]<ref name="decline">{{cite book | url=https://books.google.com/books?id=Xn5jSP46ZNQC&dq=chile+copper+history&pg=PP1 | title=The Decline of the Copper Industry in Chile and the Entrance of North American Capital, 1870-1916 | isbn=9780405133794 | last1=Przeworski | first1=Joanne Fox | date=January 1980 | publisher=Arno Press }}</ref> and were immediately interested, organised the Chile Exploration Company (Chilex) in January 1912 and eventually bought out Burrage for US$25 million in Chilex stock.<ref>[http://www.referenceforbusiness.com/history2/16/Corporacion-Nacional-del-Cobre-de-Chile.html ''History of Corporacion Nacional del Cobre de Chile'']</ref>

=====The modern mine=====
Chilex then went ahead with the development and construction of a mine on the eastern section of the Chuquicamata field - it acquired the remainder gradually over the next 15 years - and a 10,000 tons per day leaching plant which was planned to produce 50,000 tons of electrolytic copper annually.  Amongst the equipment purchased were steam shovels from the Panama Canal.<ref name=closure/><ref>[https://www.nytimes.com/1914/03/19/archives/copper-mountain-site-of-model-city-american-capital-is-transforming.html ''New York Times article on Chuquicamata '']</ref>  A port and oil-fired power plant were built at Tocopilla, 90 miles to the west and an aqueduct was constructed to bring water in from the Andes.<ref>[http://www.referenceforbusiness.com/history2/16/Corporacion-Nacional-del-Cobre-de-Chile.html ''History of Codelco'']</ref>  Production started on May 18, 1915.  Actual production rose from 4345 tonnes in the first year to 50,400 tonnes in 1920 and 135,890 tonnes in 1929 before the Depression hit and demand fell.<ref name=decline/>  The Guggenheims gave up control of the mine in 1923 when they sold 51% to [[Anaconda Copper]], which acquired most of the remainder in 1929.  Anaconda ran the mine until the 1960s when the Chilean state acquired a 51% holding in the "Chilenization" of the copper industry.  In 1971 the mine was nationalised and in 1976 was incorporated into Codelco.

Production from the capping of oxidised minerals, which required mere leaching in sulphuric acid to dissolve the copper and the recovery of the copper by electrolysis was the sole means of production until the 1950s.  However their gradual depletion forced the construction of a mill and flotation plant in 1961 to treat the underlying secondary sulphides.  These have been steadily expanded until recently the pit was producing over 600,000 tonnes of copper annually, though this has now fallen with the lower grades as the richer secondary mineralisation is also depleted in the three porphyries that make up the orebody.

The present mine is a conventional truck and shovel operation, with a large proportion of the ore crushed in-pit and transported by underground conveyors to the mill bins.  The 182,000 tonnes p.a. concentrator is also conventional and is primary crushing followed by SAG mills and ball mills with cyclone classification.  The flotation section produces both copper and molybdenum concentrates.<ref>[http://findarticles.com/p/articles/mi_qa5382/is_200211/ai_n21322102 ''Outokumpu delivers flotation cells to Chuquicamata, Engineering and Mining Journal,  Nov 2002 '']</ref>  The 1.65 million tonnes p.a. of concentrate are smelted in one [[Outokumpu]] flash smelter and one Teniente converter with electric furnace and cylindrical slag cleaning followed by four Pierce Smith converters.  The blister copper goes to six anode furnaces which feed three anode casting wheels.  The anodes go on to the 855,000 tonnes p.a. electrolytic refinery.<ref name="smelter">[https://www.u-cursos.cl/ingenieria/2007/1/MI51A/1/material_docente/ ''Tick Fundiciones Chilenas for details '']</ref>

=====The future of Chuquicamata=====
{{update|section|date=March 2025}}
Plans to go underground and mine the rest of the Chuquicamata orebody by block caving are now well advanced.  At the SIMIN conference in 2007 in Santiago<ref>[http://www.simin.cl/PDF-Viernes-24-08/Proyecto_Chuquicamata_Subterranea.pdf ''Proyecto_Chuquicamata_Subterranea '']{{dead link|date=May 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>{{broken link|date=March 2025}} Codelco engineers detailed a possible future mining plan.  The open pit is becoming gradually uneconomic and it was estimated that mining would slow down and stop by 2020.  In the meantime the mill will be kept up to its 182,000 tonnes per day capacity with sulphides from Radomiro Tomic and Alejandro Hales.  The underground mine will start up in 2018 and when it reaches full capacity of 120,000 tonnes per day in 2030, the balance of the tonnage will come from the Alejandro Hales underground mine.  It is estimated that extractable underground reserves below the present pit total 1,150 million tonnes of ore grading 0.76% copper and 0.052% molybdenum.

This remarkable mine was for many years the world's largest annual producer until overtaken recently by [[Escondida]] and it is one of the largest ever copper mining excavation.  It has produced over 29 million tonnes of copper in total, far more than any other mine
.<ref name="yaci">''Yacimientos Metaliferos De Chile, Carlos Ruiz Fuller & Federico Peebles, page 54.''</ref><ref>[http://www.cochilco.cl/cochilcoswf.htm ''Cochilco Yearbook 1986-2005''] {{webarchive|url=https://web.archive.org/web/20080206074751/http://www.cochilco.cl/cochilcoswf.htm |date=2008-02-06 }}</ref>

====Radomiro Tomic====
The Radomiro Tomic deposit, 5&nbsp;km north of the main pit, was discovered in 1952 when Anaconda conducted an extensive churn drilling programme to explore for oxidised ore to the north of the Chuquicamata pit.  It was named Chuqui Norte but they did not develop it, largely because the technology had not been developed, particularly SX/EW.  Two smaller areas of interest were found and the overall results showed that the Chuquicamata complex of mineralised porphyries is no less than 14&nbsp;km long.<ref name=yaci/>

The deposit is covered with some 100 metres of alluvium and in 1993/94 Codelco estimated a resource base for the operation of 802 million tonnes of oxide ore grading 0.59% copper and 1,600 million tonnes of refractory (sulphide) ore.  The deposit covers an area of 5&nbsp;km x 1.5&nbsp;km.<ref>[http://www.mining-technology.com/projects/radomiro/ ''Radomiro Tomic Copper Mine, Chile '']</ref>

Mining started in 1997 and is again a conventional truck and shovel operation followed by crushing, pre treatment and stacking before acid leaching.  Copper is extracted by SX/EW.  Leached ore is removed by bucket wheel excavator followed by secondary leaching.  It is likely that the 'refractory' sulphide ore will be mined and used to keep the Chuquicamata mill full during the changeover to underground mining.  The last published production by Radomiro Tomic, from Cochilco, was 379,600 tonnes in 2013.

====Northern expansion of Mina Sur====
Between the main pit and Mina Sur there remains a substantial tonnage of so-called exotic copper in the channel of paleogravels (ancient gravels) between the two and which were mined in Mina Sur.  The minerals, thought to be deposited by colloidal copper solutions leached from the main deposit, included manganese bearing copper pitch and copper wad, along with other impurities which made the ore difficult to leach in the original vats and produced a substandard cathode.  The 'exotic' ore is now being heap leached and the copper extracted by SX/EW which leaves the impurities behind in the leach solution.  It is expected that this operation will produce 129,000 tonnes of good quality copper cathode annually.

====Secondary waste dump leach====
This is the leaching of certain copper bearing waste dumps and is expected to produce 26,000 tonnes of copper annually.

====Ministro Alejandro Hales (formerly Mansa Mina)====
This is a major discovery that was made between Chuquicamata and Calama.  It was initially estimated to have reserves of over 500 million tonnes grading over 1% copper,<ref name="Rep2000">[http://www.codelco.cl/english/la_corporacion/memorias/memoria_00.pdf ''Codelco 2000 Annual Report '']</ref> but was found to be geologically complex and have a high arsenic content and work was stopped on it for some years.  Work resumed in 2000, as a result of the development of a process to treat high arsenic ores, the need for sulphide ore feed to the mill when Chuquicamata's mining goes underground and to test bioleaching technology.  It is also possible that it may enable an expansion of the sulphide mill's capacity.<ref name="Rep2006">[http://www.codelco.cl/english/la_corporacion/memorias/memoria2006/pdf/memoria.pdf ''Codelco 2006 Annual report ''] {{webarchive|url=https://web.archive.org/web/20090226130938/http://www.codelco.cl/english/la_corporacion/memorias/memoria2006/pdf/memoria.pdf |date=2009-02-26 }}</ref>

====Pollution====
For many years Chuquicamata, particularly its smelter, was a byword for pollution and the inhabitants of the Chuquicamata camp and Calama had serious amounts of arsenic in their blood.  This has changed drastically.  The camp at Chuquicamata has been closed and the inhabitants moved to Calama, away from the dust and general pollution close to the mine.

The off gasses from the flash smelter, Teniente converter and Pierce-Smith converters have a high enough sulphur dioxide content to allow sulphuric acid production in a single absorption sulphuric acid  plant which has improved sulphur capture to 98%.<ref name=Rep2006/>  The corporation also planned some years ago to reduce arsenic emissions by 97% but there have been no recent reports.   Pollution of the River Loa, which flows through Calama is a problem which is being addressed but little has been reported.