Egypt-focused miner Centamin has expressed its disappointment in the way that its potential suitor, Endeavour Mining, is tackling negotiations, slamming the Toronto-listed company for “repeatedly refusing to engage in a proper manner”.

On Monday, Endeavour announced that its CEO Sébastien de Montessus met with Centamin chairperson Josef El-Raghy and that they have agreed to a reciprocal due diligence exercises.

As Endeavour made a voluntary announcement about a potential all-share transaction and it triggered an automatic “put up or shut up” (PUSU) deadline under UK takeover rules, the company only has until December 31 to announce its a firm intention to make an offer.

Centmin said that Endeavour had indicated it would only provide it with requested information, if it agreed to an extension of the PUSU deadline.

“Without Endeavour providing information that is core to the assessment of value, such as its financial model, Centamin cannot properly assess the proposed combination.

“The Centamin board is disappointed that despite its efforts at constructive engagement, Endeavour has repeatedly refused to engage in a proper manner.

"The unsolicited approach from Endeavour has created an intense period of uncertainty for all of the company's stakeholders. Therefore, the Board of Centamin believes that Endeavour should, without further delay, enter into substantive reciprocal due diligence.”

Centamin said it would decide on an extension of the PUSU deadline once it reviewed any forthcoming information from Endeavour.

On December 3, Endeavour went public with a proposed C$2.5-billion all-share merger for Centamin, having complained that the Egypt-focused company’s board did not want to entertain discussions before entering into a standtill agreement. Such an agreement would preclude Endeavour from taking the proposal directly to shareholders.

Centamin, on its part, said Endavour refused to enter into a non-disclosure agreement to allow the board to further assess the proposal.

The nondisclosure agreements signed at last week’s meeting do not include a standstill agreement. However, Endeavour has confirmed that it was prepared to execute a standstill undertaking that would preclude it from announcing a firm intention to make an offer to the shareholders of Centamin, unless the offer was recommended by the Centamin board at the time of announcement.

"The initial exchanges between Centamin and Endeavour Mining appear to have been strained and somewhat ill-tempered reinforcing our impression that a resolution may take some time," said analysts at London-based SP Angel in a note to clients.