Koidu Limited

Koidu Limited is a locally registered Sierra Leonean diamond-mining company and a subsidiary of OCTÉA Limited. Its principal asset is the Koidu Kimberlite Project, located in Tankoro Chiefdom in the Kono District of eastern Sierra Leone. The project covers approximately 4.9 square kilometres and contains two principal kimberlite pipes, known as No. 1 Pipe or K1 and No. 2 Pipe or K2, together with several kimberlite dyke zones and associated blows. The company emerged during the post-civil-war reconstruction of Sierra Leone's extractive sector. A joint venture formed on 1 June 2002 acquired the remaining term of a 20-year mining lease originally granted in 1995. Koidu Limited was formed in 2003 and became the first commercial diamond-mining company to invest in the development of Sierra Leone's resource sector after the civil war. The company's early operations were enabled by Sierra Leone's participation in the Kimberley Process Certification Scheme from 2003, an international system intended to reduce the trade in conflict diamonds. Development of the Koidu operation began in 2003. The initial project included mining infrastructure, bulk sampling and a 50-tonne-per-hour dense-media-separation plant. Processing of K1 kimberlite started in January 2004, followed by work at K2 while the company stripped waste and installed the headgear, hoist and winder needed for a planned vertical excavation at K1. From August 2005 through December 2007, mining concentrated on the K1 pit. The excavation was described in the company's historical project material as exceptionally large and deep for its type, while the operator sought to manage the mine's effects on the adjacent Koidu community. Exploration drilling between 2003 and 2008 expanded knowledge of the resource and supported studies for a longer-term mine plan. Further bulk sampling and large-diameter drilling took place in 2009 and 2010 at K2, the dyke zones and several blows. An independently signed-off resource statement reported indicated resources of 4.2 million tonnes at an average grade of 0.45 carats per tonne at K1, K2 and Blow B3, plus inferred resources of 10.12 million tonnes at an average grade of 0.54 carats per tonne across additional identified areas. These figures are historical mineral-resource estimates rather than current reserves or production data. A feasibility plan proposed expanding the operation from the original plant to an 180-tonne-per-hour facility, with open-pit mining of both pipes followed by underground extraction. The plan envisaged open-pit work at K2 through 2015 and at K1 through 2016, with underground access and production then becoming increasingly important. The plan also contemplated mining the dyke zones and blows underground. The company's mining lease was renegotiated during Sierra Leone's national mining-agreement review and replaced by a new agreement dated 6 September 2010. That lease extended the term to 22 July 2030, with a possible further 15-year renewal. Koidu Limited's business is therefore centered on the extraction and processing of rough diamonds from kimberlite ore, rather than on consumer-facing jewelry or branded diamond retail. Publicly available reference material identifies the Koidu Kimberlite Project as its sole mining lease, but does not provide reliable current information on production, workforce, revenue, ownership percentages, executive leadership or the present operating condition of the mine. Those aspects remain unconfirmed in this dossier.

Koidu Limited's origins are associated with the redevelopment of Sierra Leone's diamond industry after the country's civil war. On 1 June 2002, a joint venture was formed and acquired the remainder of a 20-year mining lease that had originally been signed in 1995. The company was formed in 2003 and became the first commercial diamond-mining company to invest in Sierra Leone's resource sector after the conflict. Sierra Leone's entry into the Kimberley Process Certification Scheme in 2003 provided an important regulatory context for renewed formal diamond production. The company's initial focus was the Koidu Kimberlite Project in Tankoro Chiefdom, Kono District. Development work began in 2003 with the construction of a 50-tonne-per-hour dense-media-separation plant and related mining infrastructure. Processing of K1 kimberlite began in January 2004. Operations later shifted toward K2 while waste was removed and a headgear, hoist and winder were installed at K1 for vertical-pit development. Between August 2005 and December 2007, the company concentrated on extracting ore from K1. Historical company material characterized the resulting excavation as one of the largest and deepest of its type, while also noting the need to limit impacts on the nearby Koidu community. Because the initial vertical-pit design had a limited operating life, Koidu Limited initiated core-drilling programs to identify enough resources to support mining over the remaining lease period. Four phases of drilling were completed from 2003 to 2008. As the geological potential became clearer, the company commissioned studies covering resource estimation, hydrology, mine design and possible expansion scenarios. In 2009 and 2010, additional bulk sampling was carried out through surface excavations and large-diameter drilling at K2, Dyke Zones A and B, and several blows intended to form part of the longer-term mine plan. The resulting historical resource statement, independently signed off by Mineral Services Canada in the role of competent-person advisers, identified indicated resources of 4.2 million tonnes at an average grade of 0.45 carats per tonne in K1, K2 and Blow B3. It also identified inferred resources of 10.12 million tonnes at an average grade of 0.54 carats per tonne across K1, K2, Blow A, Blow B1 and Dyke Zones A and B. These estimates describe the resource knowledge available at the time and should not be treated as current reserves or evidence of present production. Following feasibility work, the proposed expansion plan called for mining both pipes by open-pit methods before transitioning to underground operations. The plan contemplated a pit at K1 reaching approximately 310 metres below surface and a pit at K2 reaching approximately 244 metres, followed by underground mining of both pipes, the dyke zones and the blows. The proposed processing capacity was 180 tonnes per hour, replacing the original 50-tonne-per-hour plant after commissioning and ramp-up of the expanded facility. Underground access construction was expected to begin in 2012, with underground ore production planned for 2016. Sierra Leone reviewed mining agreements after the country's second post-war democratic election in 2007. Koidu Limited's lease was among the first agreements examined in the review process, which began in July 2008. A new mining lease agreement was signed by the Republic of Sierra Leone and Koidu Limited on 6 September 2010. It extended the lease to 22 July 2030 and provided for a possible additional 15-year renewal. The Koidu Kimberlite Project is identified in the available reference material as the company's sole mining lease. Current operational, ownership and leadership information is not established by the supplied sources.

• 2010

  New mining lease

  [1]Koidu Limiteden.wikipedia.org

  A new lease agreement was signed on 6 September, extending the Koidu lease to 22 July 2030 with a possible further 15-year renewal.

• 2008

  Mining agreement review

  [1]Koidu Limiteden.wikipedia.org

  Sierra Leone's national mining-agreement review began in July, and the Koidu lease was among the first agreements assessed.

• 2005

  K1-focused mining phase

  [1]Koidu Limiteden.wikipedia.org

  The operation entered a period focused on extracting ore from the K1 pit, continuing through December 2007.

• 2004

  First K1 kimberlite processing

  [1]Koidu Limiteden.wikipedia.org

  Processing of kimberlite from the K1 pipe began in January.

• 2003

  Company formation and mine development

  [1]Koidu Limiteden.wikipedia.org

  Koidu Limited was formed and began developing the Koidu Kimberlite Project, including mining infrastructure and a dense-media-separation plant.

• 2002

  Joint venture and lease acquisition

  [1]Koidu Limiteden.wikipedia.org

  A joint venture formed on 1 June acquired the remaining term of the original Koidu mining lease.

• 1995

  Original mining lease

  [1]Koidu Limiteden.wikipedia.org

  A 20-year mining lease covering the Koidu area was originally signed.

A locally registered Sierra Leonean kimberlite-diamond operator focused on developing and mining the Koidu deposits in the post-war resource sector.

• Gemstone mining output

  Rough diamonds

  Koidu Limited's principal output is rough diamond recovered from kimberlite ore at the Koidu Kimberlite Project. The operation is based on two kimberlite pipes, K1 and K2, with additional potential from dyke zones and associated blows. The available sources describe extraction and dense-media separation, but do not provide current information on diamond volumes, quality mix, sales channels or downstream branding.

1. 1Koidu Limiteden.wikipedia.org