Location and Site Description


The Koidu Kimberlite Project is situated within the Tankoro Chiefdom of the Kono District in the Eastern Province of Sierra Leone, approximately 2 km south of the district capital, Koidu and approximately 360 km east of Freetown, the capital city.

Location of Koidu on the African continent
Satellite view of the Koidu Kimberlite Project
(click to enlarge)

Mining Lease

Location of dykes, pipes & blows (click to enlarge)

The Company inherited the initial 25-year mining lease agreement signed in 1995 from the previous mineral right holders. After the second successful post-war democratic election in 2007, the new government undertook to review all mining agreements in the country.

The Mining Review Process commenced in July 2008 and Koidu Limited' mining lease for the Koidu Kimberlite Project was tackled first. A new mining lease agreement was entered into between the Republic of Sierra Leone and Koidu Limited on 6 September 2010. The term of the mining lease was extended to 22 July 2030 and may be renewed for a further period of 15 years.

The mining lease measures approximately 4.9 km2 and hosts two small  kimberlite pipes, No. 1 Pipe ("K1") and No. 2 Pipe ("K2"), and four kimberlite dyke zones, along which four small blows or enlargements have been discovered.  A feature known as the Ring Structure is located to the west of K2 but has not yet been evaluated.


The primary means of access to the Koidu Kimberlite Project is by motor vehicle. The road linking Freetown and Koidu has been upgraded since 2007 and is currently in good condition for approximately 200 km from Freetown. The final 160 km between Makeni and Koidu is in very poor condition, but work has begun on upgrading this section as well.


Although fixed landline communications are not well developed or maintained in Sierra Leone, communications have improved substantially over the past few years with the introduction of cellular communication. At present several cellphone providers are operating in Sierra Leone, offering both voice and data services.


The climate in the region is described as wet tropical monsoon, with a single wet season each year between mid-May and mid-November. The average rainfall is approximately 2,540 mm, with the wettest month usually in August and rivers attaining maximum discharge in mid-September.

Normal temperature range is 20°C to 33°C, although it can drop as low as 10°C at night during the Harmattan season in January. Day temperatures average 31°C in the dry season and 28°C in the wet season.

Topography & Drainage

Topographically, the diamond fields consist of the undulating coastal plains and the dissected margins of the inland plateau, which are embayed by the broad valleys of the major rivers.

Approximately 0.36 km2 of the mining lease area is occupied by Monkey Hill, which reaches a height of just over 500 m amsl, surrounded by gently undulating topography (between 365 m and 391 m amsl) where the kimberlites occur. Monkey Hill forms a watershed, with the northern tributaries draining into the Woyie River and those to the south joining up with the Meya River.

Social context

An Environmental and Social Impact Assessment (“ESIA”) was completed by Digby Wells and an EIA Licence was issued by the Environment Protection Department prior to the commencement of operations in 2003. The ESIA identified certain areas that would be affected by the relatively small-scale operation envisaged at the time.

Within the project area there are five main settlements, namely New Sembehun, Saquee Town, Sokogbe, Swarray Town and Yormandu.

Over the seven years following the completion of the initial ESIA and commencement of the resettlement programme, the mine experienced various difficulties in managing the impacts of the operation on these communities. This was compounded by the need to accommodate a national road that passes between the two kimberlite pipes, while at the same time maintaining security, access control and a safe working environment in line with international norms for the diamond industry.

In December 2007, mining operations were suspended for several months after a demonstration by the community. After extensive consultation between stakeholders, all parties agreed on a management solution which involved the relocation of all settlements located within the mining lease area. A formal agreement was entered into between the mine, affected parties and certain non-governmental organisations (NGOs).

With the increase of the blast safety envelope to 500m beyond the final pit perimeter, the community within the Extended Affected Area will now also be resettled, in line with the blueprint established for the resettlement of those within the mining lease area.