Natural resources investment firm Polo Resources has acquired a small stake in North Africa-focused phosphate producer Celamin.Polo said it has taken up a placement by Sydney-listed Celamin, representing a 12.7% interest for an investment of A$1.2m (£0.66m)."This is an excellent opportunity for Polo Resources to add phosphate to its suite of projects through this investment in Celamin," said Michael Tang, Executive Chairman of Polo.Celamin is currently focused on the 51%-owned Chaketma Phosphate project in Tunisia and will soon be advancing a bankable feasibility study.Polo said that drilling to date has intersected thick mineralised zones averaging over 15 metres at favourable depths, outcropping at surface in places and at grades that generally exceed 20% phosphorous pentoxide."Independent metallurgical studies have verified the potential to produce marketable concentrate acceptable to international offtakers," the company said.Polo was trading 1% higher at 17.05p in early trading on Wednesday.BC