bulk-online, the Powder/Bulk Portal

(From the archive of ”bulk solids handling", article published in Vol. 32 (2012) No. 1 , ©2012 bulk-online.com)Located at over 4000 metres above sea level in the Altiplano of the Andes Mountains, the San Cristobal Mine is the largest mine in Bolivia. The open-pit silver, lead and zinc mine's production process requires the transportation of 150,000 tonnes of rock, and the processing of 40,000 tonnes of mineral daily.In early 2010, Bolivian contractor Carlos Caballero responded to a bid request for a stockpile containment solution. Minera San Cristobal, in accordance with its principles regarding worker protection and protection of the environment and neighbouring communities, sought to prevent the release of dust from its stockpile into the environment, and protect the material awaiting transport to the mine's ore processing facility.

Caballero teamed with global storage company Geometrica to propose a customized containment solution for the mine. Following review of the proposal and visits to other bulk storage domes in South America by San Cristobal engineers, the project was awarded to the Caballero-Geometrica team. Caballero served as the main contractor and installer of the dome, while Geometrica, as a subcontractor, engineered, manufactured and supplied the dome. Key factors in the decision to employ this type of dome solution for the site included the team's extensive experience, the capability to build around an operating stockpile, and the capability to follow an irregular shape for the supports.

South American Record

Fig. 1: The 140 metre diameter dome at the San Cristobal Mine in Bolivia was constructed without interrupting the stockpiling operation. (Pictures: Geometrica)

The finished stockpile containment structure is a dome 140 metres in diameter and 59 metres in height anchored by concrete foundation – the largest dome of its kind inƒ South ƒAmerica. ƒThe ƒfoundation, ƒwhichƒ accommodatesƒ a ƒnine ƒmetre ƒchangeƒ in ƒelevationƒ overƒ 140ƒ metres, ƒ isƒ fittedƒ toƒ theƒ terrain. ƒ Theƒ domeƒ isƒ designedƒ toƒ withstandƒ windƒ speeds ƒofƒ upƒ toƒ 150 kilometresƒ perƒ hourƒ andƒ anƒ iceƒ loadƒ ofƒ 110 kilogrammes ƒperƒ squareƒmetre.The ƒGeometrica ƒdomeƒ at ƒSan ƒCristobalƒ Mine ƒis ƒmade ƒup ƒof ƒmore ƒthanƒ 88,ƒ000 ƒgalvanizedƒ steel tubesƒ organizedƒ andƒ insertedƒ intoƒ aluminiumƒ hubsƒ toƒ formƒ theƒ structure. ƒ Localƒ crewsƒ recruitedƒ byƒ Caballeroƒ builtƒ theƒ domeƒ asƒ deliveriesƒ arrivedƒ onƒ site. ƒShipments ƒconsistedƒ of ƒcontainerisedƒ cratesƒ ofƒ parts, ƒ eachƒ holdingƒ twoƒ tonnesƒ ofƒ structure, ƒ andƒ organizedƒ byƒ construction ƒphase. ƒTheƒ system ƒrequires ƒno ƒwelding, ƒasƒ theƒ prefabricated ƒtubes ƒslideƒ easilyƒ intoƒ theƒ aluminiumƒ hubsƒ andƒ holdƒ fast. ƒ Theƒ preciseƒ yetƒ simpleƒ assemblyƒ processƒ allowed ƒthe ƒmineƒ toƒ continueƒ toƒ operateƒ inƒ theƒ midstƒ ofƒ domeƒ constructionƒ andƒ made ƒit ƒeasier ƒtoƒ assemble ƒthe ƒbuildingƒ inƒ anƒ environment ƒsubjectƒ to ƒhigh ƒwinds.

Technical Details

Fig. 2: The dome was build by local crews from more than 88000 tubes and 25000 connectors without welding.

Aƒ ventilation ƒlantern ƒisƒ locatedƒ at ƒthe ƒtopƒ ofƒ the ƒdome ƒandƒ additionalƒ armatureƒ onƒ the ƒsideƒ of the ƒdomeƒ canƒ supportƒ dustƒ removalƒ equipment. ƒThe ƒinteriorƒ includesƒ aƒ system ƒforƒ loweringƒ the ƒmaterial-conveyorƒ pulley ƒfor ƒmaintenance, ƒand ƒaƒ catwalk ƒcirclingƒ theƒ dome ƒinterior. ƒThreeƒ 13ƒ×ƒ10 metre ƒdoors ƒallowƒ simultaneousƒ access ƒby ƒupƒ toƒ two ƒoff-road ƒvehicles ƒto ƒtheƒ interiorƒ ofƒ the ƒdome. ƒTheƒ finishedƒ building ƒisƒ cladƒ inƒ galvanizedƒ andƒ paintedƒ metalƒ sheetsƒ andƒ translucent ƒskylights ƒprovideƒ natural ƒlight. ƒ Materialƒ is transportedƒ from ƒtheƒ dome toƒ the ƒmine's ƒoreƒ processing ƒplant ƒviaƒ an ƒexisting ƒundergroundƒ tunnel.Geometrical ƒandƒ technicalƒ details ƒofƒ theƒ storageƒ solutionƒ include:

• ƒCovered area: 15,493 square metres
• ƒSurface area: 25,340 square metres
• ƒBase diameter: 143 metres
• ƒHeight from base to apex: 59 metres
• ƒWeight of structural dome elements: 523,400 kilogrammes
• ƒStructural material: galvanized steel and aluminium
• ƒNumber of tubes: 88,329 pieces
• ƒNumber of connectors: 25,295 pieces
• ƒCladding: galvanized steel, painted steel and translucent panels

Worldwide Applications

Inƒ additionƒ toƒ creatingƒ theƒ largestƒ bulk storageƒ domeƒ inƒ Southƒ Americaƒ at ƒthe ƒSanƒ Cristobal ƒMine, ƒGeometrica ƒhas ƒdesignedƒ moreƒ thanƒ 15 ƒbulk ƒstorage ƒdomesƒ for ƒmining ƒprojectsƒ locatedƒ in ƒthe ƒAndes, ƒwhereƒ constructionƒ challengesƒ includeƒ ruggedƒ terrain, ƒremoteƒ job sites ƒandƒ insanely ƒhighƒ snowƒ loads. ƒ Examplesƒ ofƒ recentƒ projectsƒ includeƒ theƒ Barrickƒ Zaldivarƒ Mine, ƒ theƒ Mantos ƒBlancos ƒcopperƒmine, ƒboth ƒlocatedƒ in ƒneighboringƒ Chile, ƒasƒ well ƒas ƒMineraƒ Aguas ƒTenidasƒ inƒ Spain. ƒHundredsƒ of ƒGeometrica ƒstructuresƒ haveƒ beenƒ built ƒfor ƒclientsƒ andƒ endƒusersƒ aroundƒ theƒ worldƒ includingƒ BHPƒ Billiton, ƒ Anglo-American, ƒ Barrick, ƒ Codelco, ƒ Firstƒ Quantum, ƒFluor, ƒ Sumitomo, ƒ andƒ otherƒ miningƒ companiesƒ inƒ locationsƒ rangingƒ fromƒ theƒ Saharaƒ desertƒ toƒ theƒ jungles ƒof ƒBorneo.Apartƒ fromƒ theƒ solutionsƒ forƒ irregularƒ shapes, ƒtheƒ companyƒ offersƒ containmentƒ solutionsƒ forƒ automated, ring-shapedƒ stockpilesƒ and forƒ spans ƒof ƒupƒ toƒ 300 ƒmetres. Aƒ preciseƒ designƒ process, ƒ theƒ abilityƒ to ƒpackageƒ andƒ shipƒ a completeƒ structureƒ byƒ constructionƒ phase, ƒ andƒ mechanicalƒ jointsƒ thatƒ doƒ notƒ require ƒweldingƒ result ƒinƒ aƒ durable ƒstructure ƒthat ƒis ƒeasily ƒbuiltƒ inƒ aƒ wideƒ rangeƒ ofƒ environments. 

A Note from the Editor

For all statements in this article that refer – directly or indirectly – to the time of publication (for example “new”, “now”, “present”, but also expressions such as “patent pending”), please keep in mind that this article was originally published in 2012.

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