This report describes the crushing, grinding, and classification circuit at the Golden Quarry Mine reduction plant as it operated in 2012.
Report context
The 20 December 2012 independent technical report prepared for New Dawn Mining Corp describes the processing plant that receives run-of-mine mineralized material from the Camperdown opencast and underground operations, the Wanderer underground mine, and the Golden Quarry underground mine.
Processing route
Crushing and screening
Run-of-mine material from Camperdown and Wanderer mines is transported by dump trucks and tipped onto a stockpile near the crushing section at Golden Quarry mine, with a front-end loader feeding material onto the stockpile. Mineralized material from underground at Golden Quarry is directly fed onto the stockpile via a conveyor system. From the stockpile the material is conveyed onto a 50 mm x 50 mm primary vibrating screen. Oversize material reports to a 14 x 24 jaw crusher via conveyor No. 5a, while undersize material passes through the primary screen chute onto No. 3 conveyor belt and is fed onto the double-deck vibrating screen. The double-deck screen has a top screen of 38 mm x 38 mm and a bottom screen of 25 mm x 25 mm. Oversize ore from the double-deck screen is conveyed into a 4¼ Symons crusher through conveyor No. 4. Discharge from the jaw and cone crushers is fed onto No. 3 conveyor via conveyors No. 5b and 5c. Undersize material from the double-deck screen passes through a chute onto No. 6a conveyor, then to No. 6b conveyor, and finally reports into the fine mineralized material bins.
Grinding and classification
There are two fine mineralized material bins with a combined capacity of 600 tons. The plant treats approximately 600 to 700 tons of mineralized material per day at an average rate of 25 to 32 tons per hour. Material from No. 1 fine bin is fed onto No. 8 conveyor through a manually controlled feeder, conveyed onto No. 9 conveyor, and feeds the 7 x 12 primary rod mill. Low-grade lime is added directly on these conveyors at a rate of 3.00 kg per ton. The primary mill is charged with an average of 25 steel rods per week, each rod being 75 mm in diameter and 3400 mm in length.
The primary mill discharge is split proportionally to feed two secondary mills: an 8 x 8 ball mill and an 8 x 12 ball mill. Pulp discharge from each of the two ball mills is pumped with a 4/3 Warman pump into two separate 250 mm cyclones. The cyclone overflow from each ball mill flows onto two wedge wire screens. Sampling for assaying is conducted at various points within the plant, including feed to the rod mill, thickener discharge, profile samples in the CIP tanks, and residue samples.
Key reported parameters
| Parameter | Value | Basis |
|---|---|---|
| Plant throughput | 600–700 t/d | Historical operating data |
| Plant feed rate | 25–32 t/h | Historical operating data |
| Fine bin combined capacity | 600 t | Design |
| Lime addition rate | 3.00 kg/t | Design |
| Primary screen aperture | 50 mm x 50 mm | Design |
| Double-deck top screen aperture | 38 mm x 38 mm | Design |
| Double-deck bottom screen aperture | 25 mm x 25 mm | Design |
| Primary mill | 7 x 12 rod mill | Design |
| Secondary mill 1 | 8 x 8 ball mill | Design |
| Secondary mill 2 | 8 x 12 ball mill | Design |
| Cyclone diameter | 250 mm | Design |
| Mill rod charge | 25 rods/week (75 mm x 3400 mm each) | Historical operating data |
Project website: https://www.heraldonline.co.zw/local-company-canadian-firm-in-mining-venture/
Technical qualifications
This report is based on the processing description provided in Item 17 of an independent technical report dated 20 December 2012, prepared for New Dawn Mining Corp. No information was available in the report source regarding flowsheet performance, recoveries, economics, ownership, current operating status, or testwork results beyond the stated design and historical operating data.
Source: Independent Technical Report, Golden Quarry and Camperdown Mines, Prepared For New Dawn Mining Corp, 20 December 2012, Item 17 (Recovery Methods).
