This technical report describes the processing plant at the Turk and Angelus mine as it existed in 2012, including milling, classification, and gold recovery circuits.
Report context
This independent technical report was prepared for New Dawn Mining Corp and finalised on 20 December 2012. The processing section documents the existing plant configuration and operating practices at the Turk and Angelus mine as observed during the reporting period. All data presented are historical operating information from the current plant; no proposed design changes or testwork results are described in the recovery methods section.
Processing route
Milling
The plant contains three ball mills arranged in parallel, all operating with wet milling. Water is added at the discharge end of each mill. The mills consist of one 8x16ft unit and two 9x12ft units. All mills receive ore from a common conveyor and use steel balls as grinding media, with a consumption rate of 2.0 kg/t. The combined milling capacity is approximately 600 tonnes per day. Mill load amperes and oil pressure are recorded by the mill attendant on an hourly basis.
To monitor tonnages entering the milling circuit, mill attendants take a 1-metre belt cut sample at 30-minute intervals on the common conveyor and at hourly intervals on each mill feed conveyor. Samples are weighed on a digital scale and masses are recorded on a log sheet. All hourly belt cut samples from the common conveyor are riffle split; one duplicate sample is placed into a drum and the other sample is discarded. This process continues over an 8-hour period until a bulk sample is obtained. At the end of each shift, the mill attendant riffle splits the bulk sample into two smaller samples of approximately 400 g each. One split sample is retained in the plant as a check sample; the other is sent to the assay laboratory for gold analysis. Part of the sample is also used to determine ore moisture content.
Bulk lime is fed with the ore for milling on an hourly basis at a consumption rate of 2.5 kg/t. This addition is for pH control, maintaining a pH range of 8.5 to 9.
Classification
The plant uses hydrocyclones powered by water pressure supplied by pumps. The cyclones employ centrifugal forces to classify particles: lighter ore particles report as hydrocyclone overflow and denser particles report as hydrocyclone underflow, which returns to the mill, forming a closed circuit with the mills. The mill attendant collects a sample from each of the mill discharge, hydrocyclone overflow, and hydrocyclone underflow streams and checks their densities. These densities are maintained at ranges of 70–75%, 30–35%, and 70–85% respectively and recorded on a log sheet. Primary cyclone overflow is then pumped to cluster cyclones for secondary classification. Likewise, the cluster cyclone underflow reports back to the mill circuit.
Key reported parameters
| Parameter | Value | Basis |
|---|---|---|
| Number of ball mills | 3 (one 8x16ft, two 9x12ft) | Historical operating |
| Grinding process | Wet milling | Historical operating |
| Grinding media consumption | 2.0 kg/t | Historical operating |
| Combined milling capacity | ±600 t/day | Historical operating |
| Lime consumption | 2.5 kg/t | Historical operating |
| pH range | 8.5 – 9 | Historical operating |
| Mill discharge density range | 70–75% | Historical operating |
| Hydrocyclone overflow density range | 30–35% | Historical operating |
| Hydrocyclone underflow density range | 70–85% | Historical operating |
| Classification equipment | Hydrocyclones (primary) and cluster cyclones (secondary) | Historical operating |
Project website: https://www.newswire.ca/news-releases/new-dawn-mining-corp-reports-an-illegal-work-stoppage-at-its-turk-and-angelus-mine-in-zimbabwe-509418601.html
Technical qualifications
The report presents only the current (2012) processing plant configuration and operating data. No testwork results, proposed design modifications, or performance projections are included in Item 17 – Recovery Methods. All reported parameters are based on routine plant operations as recorded by mill attendants and do not represent locked-cycle tests, pilot plant trials, or engineering design criteria. Densities and consumptions are operator-controlled targets rather than measured optima. The report does not provide metallurgical balances, recovery efficiencies, or economic analyses for the processing circuit.
Source: Independent Technical Report, Turk and Angelus Mine, Prepared for New Dawn Mining Corp, Medusa Geo-Consulting LLC, Final Report: NDM 10-100-04, 20 December 2012, Item 17 – Recovery Methods, pages 56–57.
