Jubilee Platinum (LON:JLP) said it knows of no reason for the sharp increase in the recent share price.
Shares in the group are over 21% higher today at 2.4p and have risen around 33.3% since June 10.
In a brief statement the firm drew shareholders attention to the announcement of May 26, in which it said its platinum surface processing projects were gaining momentum and had raised £600,000 via a placing to maintain momentum on its development projects.
It added there had been "no new announceable events since that time and consequently the board knows of no reason for the sudden increase in the share price".
The group's platinum surface projects are targeting an estimated 4.4 million tons of platinum containing surface material and it wants to build two chrome and platinum group metals (PGM's) processing plants to process the material at a combined rate of 80 000 tons per month.
The design phase, as reported in February, has been executed and principal engineering firms have been appointed.