Inferred Resource at Bunder diamond project, Madhya Pradesh, India

Inferred Resource at Bunder diamond project, Madhya Pradesh, India

Following the previously announced Exploration Target for the 17 hectare Atri lamproite pipe, Rio Tinto has completed an Order of Magnitude study which has identified an Inferred Resource.
Classification Million tonnes Carats per tonnes Million carats
Inferred Resource 37 0.7 27.4



Location and Title

The Bunder diamond project, located 500 kilometres southeast of Delhi, is wholly owned and operated by Rio Tinto through Rio Tinto Exploration India Limited. The Bunder pipes were discovered in 2004 as part of a reconnaissance exploration programme. A Prospecting License was granted in September 2006 allowing the start of an Order of Magnitude study. Rio Tinto announced the lodging of mining lease applications over the project in 2008.

Inferred Resource at Bunder diamond project, Madhya Pradesh, India

Following the previously announced Exploration Target for the 17 hectare Atri lamproite pipe, Rio Tinto has completed an Order of Magnitude study which has identified an Inferred Resource.
Classification Million tonnes Carats per tonnes Million carats
Inferred Resource 37 0.7 27.4



Location and Title

The Bunder diamond project, located 500 kilometres southeast of Delhi, is wholly owned and operated by Rio Tinto through Rio Tinto Exploration India Limited. The Bunder pipes were discovered in 2004 as part of a reconnaissance exploration programme. A Prospecting License was granted in September 2006 allowing the start of an Order of Magnitude study. Rio Tinto announced the lodging of mining lease applications over the project in 2008.


Location Map

Summary of Exploration Results

Rio Tinto has been actively exploring for diamonds in India since 2001 and has so far discovered over 40 lamproites and kimberlites in India.

The Bunder project includes a cluster of eight lamproite pipes hosted by flat-lying Proterozoic sedimentary rocks. Drilling and sampling has so far focussed on the Atri lamproite, two coalesced pipes with a surface area of 17 hectares. The pipe is exposed along its south-western margin but elsewhere is covered by up to 23 metres of colluvium.

The Order of Magnitude study indicated that the Atri pipe is amenable to conventional open pit mining and diamond processing technology. Capital and operating costs were estimated for a nominal production rate of 5 million tonnes per annum and support the classification of an Inferred Resource.

The geometry of the lamproite has been constrained by HQ and NQ drilling to depths of 400 metres below surface. Diamond grade is based on eleven large diameter (8 inch) core holes at 50 to 75 metre spacing up to 250m depth. Diamond price evaluation was from 320 carats recovered from a surface bulk sample and from an additional 90 carats recovered from large diameter drilling. Samples were processed using standard dense media separation techniques to recover commercially-sized stones (>0.85mm). The northern pipe at Atri does not currently contribute to the reported diamond resource.

CP Statement

The information in this press release that relates to Mineral Resources is based on information compiled by Richard Platell who is a member of the Australasian Institute of Mining and Metallurgy (AusIMM). Richard Platell is a full-time employee of Rio Tinto and has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which they are undertaking to qualify as a Competent Person as defined in the 2004 Edition of the 'Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves'. Richard Platell consents to the inclusion in the press release of the matters based on his information in the form and context in which it appears.