Diamond Protection Force

The Diamond Protection Force was a private army established by De Beers to defend its diamond interests in Sierra Leone. Created under a colonial monopoly over alluvial diamonds, it grew larger than the colonial government’s own force, but the spread of small-scale mining overwhelmed it. Its history illustrates the limits and consequences of enforcing exclusive control over a resource that many people could mine.

Formation and purpose

Diamonds were discovered in Kono, in eastern Sierra Leone, in January 1930. Because they were alluvial rather than deep underground, they could be gathered by panning in rivers, a method that made mining potentially accessible to many people. The British government instead granted the Sierra Leone Selection Trust a monopoly over diamond mining throughout the protectorate and awarded the trust to De Beers.

In 1936, De Beers was authorized to establish the Diamond Protection Force. The private force was intended to support the company’s control of the diamond fields, but its scale also reflected the reach of the monopoly: it eventually became larger than Sierra Leone’s colonial government force.

Enforcement and its limits

The geographic availability of alluvial diamonds made exclusive control difficult to enforce. By the 1950s, thousands of illegal miners were working the fields, and the Diamond Protection Force was overwhelmed. Their presence became a major source of conflict and disorder, exposing the gap between the formal monopoly and the government and company’s ability to make it effective.

In 1955, the British government opened some diamond fields to licensed diggers outside the Sierra Leone Selection Trust. The concession did not end the trust’s dominance: it retained the richest areas, including Yengema, Koidu, and Tongo Fields. The arrangement thus widened access only partially, leaving the most valuable deposits under monopoly control.

After independence and significance

The political management of the diamond industry changed after independence. In 1970, Siaka Stevens effectively nationalized the Sierra Leone Selection Trust, replacing it with the National Diamond Mining Company of Sierra Leone, in which the government held a 51 percent stake. The book describes this as the opening phase of Stevens’s plan to take over diamond mining; it does not describe a later role for the Diamond Protection Force.

The force’s history forms part of a broader contrast between the monopoly imposed in Sierra Leone and the more open licensing system adopted for alluvial gold mining in Australia. In Sierra Leone, a resource that could support widespread participation was placed under exclusive corporate control, and a private army larger than the colonial government’s own force could not prevent extensive unauthorized mining. The episode shows how extractive institutions could restrict access while generating persistent conflict around the resource they sought to control.