Source:
p. 2
Company | Interest | Ownership |
Besra Gold Inc.
|
92.06 %
|
Indirect
|
North Borneo Gold Sdn Bhd
|
92.06 %
|
Direct
|
Besra Gold Inc. currently owns and controls 92.06% of the Bau Project JV through its subsidiary, North Borneo Gold Sdn Bhd, (“NBG”) a Malaysian incorporated company. The other minority co-ventures are a Malaysian Mining Group, Gladioli Enterprises Sdn Bhd (“Gladioli”) and Golden Celesta Sdn Bhd in which Besra has a joint venture interest.
Deposit Type
- Porphyry
- Skarn
- Vein / narrow vein
- Sediment-hosted
Summary:
The known deposits in the Bau Goldfield can be characterized by four distinctive gold mineralisation styles that exhibit both lateral and vertical geochemical and mineralogical zonation with respect to the Bau Trend intrusives. In general these styles are:
• Sediment Rock-Hosted Disseminated Gold Deposits, e.g. Jugan; Bukit Sarin;
• Silica replacement (jasperoid) and open space siliceous breccias, e.g. Tai Parit; Bukit
Young Pit, Bekajang;
• Mangano-calcite-quartz veins, e.g. Tai Ton; Pejiru, Kapor;
• Magmatic – Hydrothermal porphyry related deposits with/without calc-silicate skarn,
e.g. Sirenggok, Sey Seng, Ropih, Arong Bakit, Juala West.
Sirenggok
The Sirenggok deposit lies approximately 1.5km NE of Bau Township. The current resource modelling has outlined an Inferred Resource of 8.346 million tonnes at 1.14 g/t Au for 307,000 ounces at a lower cut-off of 0.5g/t Au.
Jugan
The Jugan Deposit is centred on Jugan Hill, approximately 7 km NE of Bau, within a kilometre of the Bau-Kuching Road. The current measured and indicated resource modelled stands at 17.91 million tonnes at 1.51 g/t Au for 870,500 ounces gold. Inferred resources are 1.77 million tonnes at 1.57 g/t Au for 89,800 ounces gold.
Pejiru Sector
The Pejiru Sector between 5 km and 8 km SW of Bau, comprises four deposits that have been modelled. These are the Pejiru-Bogag, Pejiru Extension, Kapor and Boring deposits. As a result of the current resource work these now have Inferred Resources of 25.8 million tonnes at a grade of 1.20 g/t Au for 997,800 ounces gold at a lower cut-off of 0.5 g/t Au.
Pejiru-Bogag & Pejiru Extension
The Pejiru-Bogag deposit has a main zone of mineralization that is essentially flat lying with a 1,500 m length, 50 m to 150 m wide and up to 80m thick, averaging 15 m to 20 m. It has a NESW trend and a NW-SE trend.
Boring
The Boring deposit comprises two areas that lie between 1.3 km and 2km NE of the centre of the Pejiru-Bogag deposit. The northern area covers around 150 m square and consists of several intersections of gold mineralization ranging from 3 m to 50 m in downhole intersections.
Kapor
The Kapor deposit lies 5 km SW of Bau and is adjacent to the Fairy Cave National Park. Mineralisation can be traced almost continuously to Pejiru; 2.5 km along strike to the SW. Mineralisation is hosted in limestone as is the case at Pejiru but with much higher arsenic levels recorded. Again gold is associated with arsenopyrite and records show arsenic can reach to around 30 % in isolated samples, antimony is strongly anomalous with values in the 100’s and 1000’s of ppm.
Taiton Sector
The Taiton Sector lies some 3 km to 4 km SW of Bau Township. The deposit types are dominantly mangano-calcite veins and breccias and remnants of the extensive elluvial auriferous clays that were mined historically by the Chinese miners of the late 19th Century and early 20th Century. Current modelling has defined Indicated Resources of 1.517 million tonnes at a grade of 2.75 g/t Au for 134,000 ounces and Inferred Resources of 3.419 million tonnes at a grade of 1.75 g/t Au for 192,000 ounces. This specifically excludes the mineralisation exposed in the underground workings at Taiton B as there has been insufficient work here to define a resource.
Tabai
Tabai (including the former Rumoh mine) is developed on a vein system between 4m and up to 23m wide, (observed) mostly composed of brecciated mangano-calcite vein, frequently vuggy with drusy quartz infilling and overgrowths along with patchy silicification, auriferous clay, arsenopyrite, realgar, stibnite and native arsenic.
Taiton A
Taiton A is approximately 400 m further north along strike on the Tai Parit Fault Structure. It comprises the Taiton A open pit, the NW striking Overhead Tunnel Adit above Taiton A Pit and several adits that are located at the base of the limestone bluffs.
Bungaat
The Bungaat area lies ~400 m North of Taiton A. It comprises a NW-SE trending zone of mineralisation with native arsenic, realgar and coarse calcite vein material developed in a steep dipping structure with a well developed sub-horizontal set of mineralised calcite veins peripheral to the main structure.
Taiton B & Taiton C
The Taiton-B massive mangano-calcite vein has now been mapped over a 1.5 km of strike length and includes the section known as Taiton C. It trends NW-SE and a 700 m section of this vein has historically been underground mined. Strike and depth extensions remain unexplored. From 74 vein rock chip samples, assays ranged from 0.16 to 62.0 g/t Au, with 48 % reporting above 1.0 g/t Au; the average being 7.85 g/t Au.
Bekajang Sector
Revised modeling has increased the resources in the Bekajang Sector which now stand at Indicated Resources of 1.857 million tonnes at a grade of 2.02 g/t Au for 120,400 oz Au and Inferred Resources of 7.5 million tonnes at a grade of 1.76 g/t Au for 423,700 oz Au. A further 100,400 ounces of gold has been inferred for the BYG Tailings.
Summary:
The mining method is planned as traditional open pit mining utilising hydraulic excavators and in- pit trucks for haulage to ROM, dump or TSF construction. Rock breaking will be a combination of free digging, rip and dig using dozer and drill-andblast depending upon the rock characteristics. Two ramps are designed, one carrying ore and the other waste and positioned relative to ROM and dump/TSF. A surface traffic system has been designed to handle traffic flows.
As the deposit is near surface an open pit mining method is selected. The deposit outcrops on a hill with little or no waste cover, therefore no pre-strip is applicable.
Both contract-mining and owner-operator methods investigated, with contract mining the preferred option at this stage.
Crusher / Mill Type | Model | Size | Power | Quantity |
SAG mill
|
|
|
6200 kW
|
1
|
Summary:
Primary Crusher with Grizzly Feeder
Ore is delivered by truck from the mining operation to a run of mine (ROM) storage pad. A front-end loader OR direct truck transfers ore from the ROM stockpile to a VF 561-2V,30 kW Vibratory Grizzly feeder and +130 mm will fed to a C 125, 160 kW Jaw Crusher to crush the ore to P100 = 210 mm ,P80 = 130 mm. The bottom chute and the conveyor will convey the crushed ore to the stockpile hopper or on to a concrete pad.
The crushed material is conveyed to the 12,000 tonne capacity mill stockpile.
A static belt magnet is installed along the primary feed conveyor, and is swung away from its position using a hand pulley, to enable operators to remove tramp metal.
The crushing circuit capacity is rated at 670 Mtph and is designed for fourteen (15) hours per day operation at 90% availability. This will have sufficient stock for one (1) day operation.
Dual display HMI workstation will be set up in the crusher control room (20 ft container) for operators to control and monitor crushing system. This HMI workstation will be interconnected through Ethernet IP communications networks to Main Control Rooms in Area 110.
A 20 ft container electrical room will be used to house the motor control centre, PLC system, starters, Variable Speed drive and control power systems.
The crushed material is conveyed to the 12,000 tonne capacity mill stockpile.
Grinding/Primary Cyclone
The mill stockpile has a capacity of 12,000 tonnes and contains crusher product which is sized at P100 of 210 mm. The mill stockpile sits over a concrete tunnel which contains three vibrating pan feeders and a conveyor belt which directs material into the SAG mill retractable feed chute. A single 6,200 kW SAG Mill (8.54 m dia x 4.57 m) is operating in closed circuit with a vibrating screen 1.6 m x 3.6 m which in turn returns the oversize after pebble crushing to the SAG Mill and a Cyclone classification. The SAG Mill will reduce the size F80=130 mm to P80= 150 micron.
A duty and standby mill discharge pump delivers slurry to the closed loop Primary cyclone Cavex 4 x 500 CV x 10 cyclone cluster, three (3) working and one (1) stand by. A 300 % recirculation load is considered. The under flow will flow by gravity to the Mill feed hopper and the overflow P80-150 micron at 35 % solids will report to a thrash screen then to the desliming continuous CVD 64 Knelson units/Deslime Cyclone cluster. The deslimed feed will then gravity flow to the flotation condition tank.
The design capacity of the grinding circuit is 400 tph feed rate, closed circuit operation at 95% availability with a design factor of 1.15.
Flow Sheet:
Summary:
In relation to the basecase option – namely 8,000 tpd (2,920,000 tpa) and flotation concentrate process option – the process plant will likely have the following configuration:
- Crushing
- Grinding/Primary Cyclone
- Cyclone or Continuous Knelson Desliming
- Rougher/Scavenger Flotation
- Regrinding/Secondary Cyclone
- Cleaner Flotation
- Concentrate Filter feed Thickener
- Filter Press
- Reagent mixing, storage and distribution
- Services.
- Control room & Facilities
- Support Facilities.
Concentrate will be dried and packed into bulk bags and transported by road to Kuching port facilities for export to Asian smelters.
Recoveries & Grades:
Commodity | Parameter | Avg. LOM |
Gold
|
Recovery Rate, %
| ......  |
Gold
|
Head Grade, g/t
| 1.32 |
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Projected Production:
Commodity | Units | Avg. Annual | LOM |
Gold
|
oz
| 116,000 | 463,650 |
All production numbers are expressed as metal in concentrate.
Operational Metrics:
Metrics | |
Stripping / waste ratio
| 1.7 * |
Waste tonnes, LOM
| 18,569,000 t * |
Ore tonnes mined, LOM
| 10,927,500 t * |
Daily processing capacity
| 8,000 t * |
Tonnes processed, LOM
| 10,927,500 t * |
Annual processing capacity
| 2,920,000 t * |
* According to 2013 study.
Reserves at November 16, 2018:
Category | Tonnage | Commodity | Grade |
Proven
|
3,418,650 t
|
Gold
|
1.47 g/t
|
Probable
|
7,243,920 t
|
Gold
|
1.81 g/t
|
Proven & Probable
|
10,662,570 t
|
Gold
|
1.7 g/t
|
Measured
|
3,405,600 t
|
Gold
|
1.52 g/t
|
Indicated
|
17,879,700 t
|
Gold
|
1.67 g/t
|
Measured & Indicated
|
21,285,300 t
|
Gold
|
1.64 g/t
|
Inferred
|
51,329,000 t
|
Gold
|
1.32 g/t
|
Mine Management:
Job Title | Name | Profile | Ref. Date |
.......................
|
.......................
|
|
Oct 12, 2020
|
.......................
|
.......................
|
|
Oct 12, 2020
|
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Corporate Filings & Presentations:
Document | Year |
...................................
|
2020
|
...................................
|
2018
|
...................................
|
2018
|
Feasibility Study Report
|
2013
|
- Subscription is required.
News:
- Subscription is required.