Nigerian bourse bucked its 12-straight weeks of rally; Barrick Gold wants more gold activities in Zambia and DRC; Sinosteel pumping funds into ore mining in Cameroon; HF Group Kenya's 1Q results; MTN Nigeria round-2 share offering soon; Dangote raising two bond tranches to fund refinery; Standard Bank gets first Black woman as Board Chair-Elect; S&P Global sees inversion of Moroccan banks NPL curve and lots more in today's edition of Frontier Opening Bell.