On 30 April, Minsur submitted a filing to the Peruvian stock exchange that mine workers had begun an unauthorized strike at its San Rafael mine in Peru. The workforce at the mine is comprised of around 550 Minsur personnel, along with nearly 1800 third party contractors. The unionized workers went against the approval of labour authorities to begin an indefinite strike in search of a higher bonus. According to Minsur, the union was unhappy with the share of profits distributed amongst workers.
The San Rafael mine produced some 18,400 tonnes of tin-in-concentrate in 2018, roughly 6% of world production. Delays to production at this globally significant mine could have seen the global tin market tighten further; the market is already tight due to falling supply from Myanmar and long-term declines in mine grades. Yet, despite the threat of lengthy negotiations and delays to production, Minsur announced that an agreement had been reached on 1 May. On 3 May, Minsur released its quarterly earnings report, detailing a 71% increase in net profit.