Murowa

Overview

Murowa diamond mine is located some 40 km southwest of Zvishavane in central Zimbabwe, Africa.

The diamond deposit was discovered in 1997 by Rio Tinto and a small open pit mine was commissioned in 2004. The owner of the mine, Murowa Diamonds Private Limited, is incorporated in Zimbabwe.  Rio Tinto plc has a 78 per cent interest in the company and the remaining 22 per cent interest is owned by Riozim Limited, an independent Zimbabwean owned and listed company.

The truck and shovel mining operations produced 367,000 carats of diamonds in 2011and had a mineral reserve of 7.1 million carats.

There is potential to expand the mine’s resources so at current production levels the mine would be able to operate another 50 years. The expansion is estimated to cost $200 million and would expand mining and processing capacity to two million tonnes of ore per year.

Location 

Murowa diamond mine is located some 40 km southwest of Zvishavane in the Midlands Province of central Zimbabwe, Africa.

Zimbabwe (formerly known as Rhodesia) is a landlocked country located in southern Africa. Mining agriculture and tourism are the country's largest exports. The country has three official languages: English, Shona and Ndebele.

Midlands is a province of Zimbabwe and its capital city is Gweru. Zvishavane is a mining town on the main Bulawayo-Masvingo road.

Geology & Mineralization

Three diamondiferous kimberlite pipes were discovered by Rio Tinto in 1997. The three kimberlite pipes are intruded into the Chivi suite granites of the Zimbabwean Craton and are 500 million years old. Two of the pipes (K1 & K2) are of sizes that warrant exploitation.

The kimberlite pipes geology is complicated because they are heterogenous, made of material that originated at different depths. The pipes also have different geology and grade.

As of December 2011, Murowa diamond reserves were estimated at 7.1 million carats. A total mining reserve covering all three kimberlite pipes was estimated at 16.5 million tonnes grading 0.9 carats per tonne.

Mining & Operation

Murowa is a small open pit mining operation. The waste is drilled and blasted then loaded on haul trucks and disposed at the dumps. Ore is also blasted and broken ore is transported to the processing plant.

A feasibility study was underway to determine the best way to expand mining operations to 2 million tonnes of ore per year at a capita cost of $200 million.

Processing 

Ore sourced from the pit is crushed by a combination of crushers (gyratory, cone and high pressure roll crushers) then scrubbed and sent to the heavy-medium separation circuit where a diamond concentrate is separated. Finally, X-ray fluorescence sorters are used to extract diamonds from the HMS concentrate.

Environment & Community

Although the Murowa diamond mine is a small-scale operation, the impact of the mine on the community was recognised at the outset and consultation and community engagement have been key factors in this project. Rio Tinto's commitment to sustainable development at Murowa meant ensuring that the footprint of the mine was kept to a minimum.

Resettlement Recognising that the area of the mine was already populated, Murowa collaborated with local communities to resettle 141 families.

Working with local leaders, Murowa developed the five-year Communities Action Plan to support and develop local communities over the life of the mine.

Looking ahead Murowa continues to work towards the sustainable development of its operations, to ensure that the rights of the surrounding community are protected and that the mine's impact on the environment is minimised.

In 2011, Murowa achieved the best safety performance in the Rio Tinto’s product group.