Proxima in a stock market statement said it is currently in the very early stages of considering a potential offer for JKX.
The Moscow based firm added it now intends to approach the JKX board to discuss its proposal.
The regulated announcement came with the customary warning that “there can be no certainty that a firm offer will be made nor as to the terms on which any offer might be made.”
Stock exchange rules dictate that Proxima has until 5:00pm on March 5 to announce a firm intention to make an offer for the listed company.
JKX shares had gained 6.5p, 35%, trading at 25p each at 2:00pm.
The company’s principal assets are located in Ukraine and Russia, and it also has interests in Hungary and Slovakia.