Gemstone group Richland Resources (LON:RLD) said its efforts were partly undermined by illegal underground activity nearby, though it was still able to report a strong second quarter performance.
Production of Tanzanite, blue and purple stones found only in Tanzania, rose strongly in the three months to 671,819 carats.
This compared with 533,400 carats in the first quarter and 641,615 carats in the same period last year. The average grade was 87 carats per tonne, which represented a 71 per cent increase the three months earlier.
Sales in the period, meanwhile, were US$6.5 million, representing the best quarterly figures in four years. Chief executive Bernard Olivier said: “During the period the company has increased the carat per tonne grade of the ore processed in order to partly offset the negative impact of the illegal mining activities.
“This carat increase represents an increase of 72 per cent on the previous quarter and 66 per cent on the comparable quarter in 2011.
“The company is firmly focused on working with the Government, various bodies and the police to resolve the illegal mining issues at the mine site and whilst there is likely to be a negative impact on the forthcoming interim results, is hopeful that the issue will be concluded without further affecting the company's continued delivery of value for shareholders.”
Separately, the group’s listing on the Dar es Salaam Stock Exchange has been delayed pending clarification of rules governing Richland’s primary listing on AIM.