Orocobre Limited Tincalayu Upgraded to JORC Compliant Resource

Perth, Australia (ABN Newswire) - Orocobre Ltd. (ASX:ORE) (TSE:ORL) ("Orocobre" or "the Company") is pleased to announce the upgrade of a historical estimate to an Indicated and Inferred Resource for the Tincalayu borate mine in Salta Province, Argentina. This mine is located on the Tincalayu Peninsula, adjacent to the Hombre Muerto salar, within 17 mining leases owned by the 100% Orocobre subsidiary Borax Argentina.

Independent, Qualified/Competent Person, Murray Brooker has estimated an Indicated and Inferred resource of 6.5 million tonnes at 13.9% B2O3 at the a marginal cut-off of 5.6% B2O3, which increases to 17.8 million tons of 11.0% B2O3, at a marginal cut-off grade of 2.8% B2O3. Details are given below:

These cut-offs have been generated by undertaking Whittle pit modelling and reflect the breakeven grade for a tonne of ore at the point of exit from the open pit assuming no throughput limitations in ore processing. Further studies are likely to result in a higher cut-off being applied in an optimised mining operation and in a reserves estimate.

This compares to a superseded historical estimate of 1.85 million tonnes at 17.2% B2O3 estimated at a 12% B2O3 cut-off and adjusted for mining depletion to 2011.The superseded historical estimate was originally reported on the 21st of August 2012, at the time of the announcement of the Company's purchase of Borax Argentina. The majority of the mineral tincal (also referred to as borax) is hosted within a sand matrix, from which is separated in the processing plant to produce the Borax Decahydrate mineral product.

The company is in the process of upgrading the historical estimates (refer to Appendix 1 in link below) of the different Borax Argentina mining properties to JORC/NI43-101 compliant mineral resources. The first of these, the Porvenir resource estimate, was announced on the 29th April, 2014 in accordance with the requirements of JORC 2012. Geological interpretation is currently underway for the Sijes mine, where Borax Argentina has extensive properties that contain a number of different borate minerals. The historical estimate (now superseded) of the Tincalayu deposit was at the time of purchase only a small part of the overall quantity of borates. However with the lower cut-off grade applied in this resource estimate the Tincalayu resource is considerably larger and the strategic importance has therefore increased for the Company.


Background

Borax Argentina SA, including the Tincalayu mine, was acquired by Orocobre from Rio Tinto Minerals in August 2012. Borax Argentina has been in operation for over 50 years and operates open pit mines in Tincalayu, Sijes, and Porvenir. There are concentration plants in Tincalayu, Sijes and Porvenir (not currently used) and refinery facilities in Tincalayu and Campo Quijano. Additionally, the ulexite deposit at Diablillos is essentially undeveloped.

There are presently three product streams. Firstly, at the Tincalayu mine the mineral tincal is mined and concentrated and then processed onsite to produce the Borax Decahydrate and Pentahydrate products. Secondly, ulexite is mined, mainly at Porvenir, and transported to Campo Quijano to produce Boric Acid. The third product stream, hydroboracite and colemanite are mined at Sijes and concentrated to produce mineral concentrates for direct sale.

At Tincalayu, following the relocation of the borax decahydrate plant from Campo Quijano, ore is currently being mined at a 17% B2O3 headgrade during the ramp up period but this will be reduced to 15% B2O3 once the operation is in a steady state condition based on a 10% B2O3 cut-off. Material between the marginal cut-off of 5.6% B2O3 and the 10% B2O3 mining cut-off will be stockpiled as low grade ore for potential later processing. Ore is transported to the processing plant and then processed into borax decahydrate (36.5% B2O3). This material is currently dispatched from site in 1 tonne bulk bags for packaging and sale from Campo Quijano which is 300kms to the south-east of Tincalayu, or for conversion into Pentahydrate (47.8% B2O3) and anhydrous borax.

The production capacity at Tincalayu is currently a nominal 30,000tpa of borax decahydrate and the Company is evaluating expansion options based on the much larger resource base than expected. Based on preliminary work, a possible expansion to 100,000tpa borax decahydrate equivalent would seem sensible from a resource utilisation perspective and this has been used to report a resource at the related lower cut-off.


Location and Properties

Tincalayu is located near the southern end of the Tincalayu Peninsula (Figure 1 link below) in Salta province, immediately north of the boundary with the province of Catamarca. The project is in the Puna geographical region, at an altitude of ~4000m above sea level, 175km west-southwest of the province capital, Salta.

Tincalayu lies approximately 200km south of the paved highway (Figure 1 in link below) that passes through the international border with Chile, approximately 80 kilometres by road to the west (Jama Pass). That road continues on to the major mining centre of Calama and the port of Mejillones in northern Chile, a major port for the export of mineral commodities and import of mining equipment.

Orocobre, through its 100% owned subsidiary Borax Argentina, owns seventeen mining properties on the Tincalayu Peninsula that include and surround the Tincalayu mine (Figure 2 in link below). Borax Argentina also owns properties covering the majority of the Diablillos salar, 33km east of Tincalayu, where there is a large historically defined ulexite resource (refer to Orocobre announcement 21 August, 2012). Twenty seven kilometres east-northeast of Tincalayu, Borax Argentina also owns properties in the Ratones salar which host ulexite mineralisation.


About Borate Mineralisation

Borates are the group of minerals which consist of boron bonded with oxygen and cations such as Ca, Mg and Na. Economic borate mineralisation largely consists of minerals such as ulexite (NaCaB5O9-8(H2O)) and tincal (Na2B4O7-10(H2O)) which were deposited in salar (salt lake) and playa-lake environments. Tincal is also often referred to as borax. The most significant borate deposits are located in Turkey, the USA and Argentina. These natural minerals and refined industrial chemicals produced from them have a wide range of uses. These include use in insulation fibre glass, fertilisers, ceramics, wood preservatives, glass additives, fluxes as well as many other minor uses.

At Tincalayu the sodium borate tincal (borax) is the most important borate mineral. Tincal is used to produce Borax Decahydrate (Na2B4O7-10(H2O)) from the plant that was relocated to Tincalayu from Campo Quijano during the first part of 2014. Conversion to Borax Pentahydrate (Na2B4O7-5(H2O)) and anhydrous borax (Na2B4O7) continues at this time at Campo Quijano.


Deposit Geology

The Tincalayu mine (Figure 3) is hosted in the Miocene age Sijes Formation, which consists of thick sequences of continental evaporites and alluvial clastic rocks, with lesser tuffaceous deposits.

For figures and complete geology report, please visit:
http://media.abnnewswire.net/media/en/docs/ASX-ORE-829503.pdf


About Orocobre Limited:

Orocobre Ltd. is listed on the Australian Securities Exchange and Toronto Stock Exchange (ASX:ORE) (TSE:ORL), and is building a substantial Argentinian-based industrial minerals company through the construction and operation of its portfolio of lithium, potash and boron projects and facilities in the Puna region of northern Argentina. The Company is building in partnership with Toyota Tsusho Corporation the first large-scale, "greenfield" brine based lithium project in 20 years at its flagship Salar de Olaroz resource, with projected production of 17,500 tonnes per annum of low-cost battery grade lithium carbonate scheduled to commence at the end of Q2, 2014. The Company also wholly-owns Borax Argentina, an important regional borate producer. Orocobre is included in the S&P/ASX 300 Index and was named 2012 Mining Company of the Year by Argentine mining magazine Panorama Minero and the Fundacion para el Desarrollo de la Mineria Argentina ("Fundamin" or Foundation for Development of Argentina Mining).<



Contact:

Australia and Asia
David Hall, Business Development Manager
Orocobre Ltd.
T: +61 7 3871 3985
M: +61 407 845 052
E: dhall@orocobre.com

North America
James Calaway, Chairman
Orocobre Ltd.
M: +1 (713) 818 1457
E: jcalaway@orocobre.com