Summary:
Two types of apatite-ilmenite occurrences (nelsonite and anorthositic gabbro) are present within the Lac a Paul Project. Both are magmatic in origin and form specific facies of the Lac Saint-Jean Anorthositic complex. Although these kinds of deposits are known to be associated with various anorthosite complexes around the world, none are currently being mined for their phosphate content. However, similar deposits with dominant ilmenite are currently mined at Lac Tio (Rio Tinto Iron Titanium, Havre St-Pierre, Québec) and Tellnes (Norsk Hydro, Norway). Numerous occurrences are currently under evaluation in the Province of Québec for their iron and titanium content.
Mineralization at the Lac a Paul Project originated from magmatic sedimentation and segregation within the anorthositic complex. The main geological unit of interest is a Nelsonite consisting of apatite and ilmenite magnetite rich layers.
Many apatite mineralized zones are reported within the Arianne’s Lac a Paul Project. Zones No.1 and No. 2 are low-grade apatite-ilmenite bearing gabbros discovered by the FMSLSJ and will only be discussed briefly. Only Zone No. 2 has been explored significantly with diamond drilling. Zone No 3 is no longer part of the land package; Arianne did not renew the claims due to the low grades encountered. Most of the other zones, i.e. Manouane, Paul, Nicole, Lucie, Lise, Intersection and La Traverse have been drilled, are considered nelsonites, and show a good potential.
The Paul Zone is Arianne’s prime target. It is located in the northern part of the Property on claims no.2129818, no.2129818 and no.2167470. The Zone occupies a hillcrest adjacent to the north of Lac a Paul (UTMX: 374000; UTMY: 5529000). It is easily accessible via various logging trails connecting to the road leading to the Manouane River. Less than 10 meters of overburden has been reported.
The rocks consist of an olivine nelsonite, composed of similar proportions of apatite, ilmenite, magnetite and olivine, plus accessory pyroxene, feldspar and biotite as reported and validated by Réjean Girard from IOS. Depending on mineral proportions, this layered rock can vary between a genuine nelsonite, a troctolitic nelsonite, a troctolite (olivine-plagioclase rock), a pyroxenite, a gabbroic anorthosite, etc.
These facies are intricate or layered in a disorderly fashion. This Zone is embedded in apatite-free gabbroic to anorthositic host rock. The difference between the various facies is subtle, and detailed correlation between drill holes remains tricky. The Paul Zone is known to extend at least 2,700 meters, aligned east-southeast. Ovoid in shape, its width is not constant, between 150 and 300 meters (presumed thickness of the Zone). The Zone is open at depth (400 vertical meters) and presumed true thickness range from 150 to 300 meters.
Summary:
The beneficiation plant is designed to process an average of 55,000 tonnes per day of Run of Mine (ROM) ore to produce on average 3 million tonnes per annum of phosphate rock concentrate grading at 38.6% P2O5 with concentrate P2O5 recovery of 90%.
The ROM ore is trucked from the open pit mine to the primary crusher. The crushed product is then conveyed overland to a Coarse Ore storage Silo (COS) providing approximately 50,000 tonnes of storage for the beneficiation plant. The ore is reclaimed from the COS and conveyed to the beneficiation plant to feed a two stage grinding circuit. The grinding circuit is made up of one primary 15,000 kW SAG Mill and two secondary 11,000 kW Ball Mills operating in a closed circuit with classification hydrocyclones. The classification hydrocyclone product is fed to a Low Intensity Magnetic Separation (LIMS) circuit where magnetite rich gangue is removed ahead of the flotation circuit. The non-magnetic material is then dewatered through two stages of dewatering hydrocyclones before being fed to two parallel trains of flotation preconditioning tanks for reagentising. The magnetic material is discharged to the combined plant tailings thickener.
The beneficiation plant has been designed such that there is a turn down ratio of 50%. This means one ball mill and the associated downstream LIMS circuit and flotation circuits can be switched off for maintenance without stopping the entire plant.
The phosphate flotation circuit is designed to produce a concentrate grading at about 39% P2O5. The flotation circuit is designed to make use of an all column flotation cell arrangement. The flotation tailings are pumped to the tailings thickener prior to disposal in the plant tailings storage facility. The flotation concentrate is also thickened, filtered in pressure filters and dried in a flash dryer to obtain a product moisture content of 1.0±0.5%.
The dried concentrate from the flash dryer is fed to two 100,000 tonne dome storage silos which form part of the product load-out section. The apatite concentrate is transported via trucks from site to the future export facility at St-Fulgence on the north shore of the Saguenay River.