Precious gemstones miner Gemfields has returned to trading on the AIM, the London Stock Exchange’s market for juniors, after delisting in 2017 following its acquisition by Pallinghurst Resources.

The company, which mines emeralds and rubies in Zambia and Mozambique, is trading under the symbol GEM, the same it had before taken private.

“We were delighted to have played our part in one of the first admissions to AIM this year and a rare listing of a mining company in what remains a challenging market for the mining and metals sector,” the company said.

Gemfields, which owns the luxury Fabergé jewellery brand, is the world’s biggest coloured gems producer. Kagem mine in Zambia provides more than one-fifth of the world’s emeralds, while the company’s 75%-owned Montepuez operation in Mozambique accounts for half of the global supply of rubies.

News of the listing came a day after 11 illegal miners died at Montepuez following a series of tunnel collapses over three days.

About 800 people had trespassed in previous days and, despite mine staff’s warnings, began undercutting the outer edge of the Maninge Nice 3 mining pit, which led to several ground collapse incidents.

The pit, which generally contains smaller, flatter, pink-coloured rubies of lower value, accounts for less than 10% of the total ruby value sold by Gemfields-controlled Montepuez Ruby Mining Limitada.

Last year, the miner chose to pay £5.8 million (about $7.6m) to community members residing near the Mozambican mine, in a “no admission of liability” move that settled a claim of human rights abuses brought against it by locals.