Overview
| Stage | Production |
| Mine Type | Open Pit |
| Commodities |
|
| Mining Method |
|
| Processing |
- Smelting
- Carbon re-activation kiln
- Heap leach
- Carbon in column (CIC)
- AARL elution
- Carbon adsorption-desorption-recovery (ADR)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
|
| Mine Life | 5.25 years (as of Jan 1, 2019) |
Source:
p. 15
PT Merdeka Copper Gold Tbk (“Merdeka”), a holding company with operating subsidiaries engaging in mining business activities. The subsidiaries are (i) PT Bumi Suksesindo (“BSI”) as the holder of the operation production mining business license for the Tujuh Bukit mine, (ii) PT Damai Suksesindo (“DSI”) which holds the adjacent exploration permit, (iii) PT Batutua Tembaga Raya (“BTR”) as the holder of operation production mining business license specifically for processing and refining.
Summary:
The Tujuh Bukit Oxide deposits are classified as High Sulphidation Epithermal (HSE) type containing economic accumulations of gold and silver.
Summary:
Tujuh Bukit Gold is a gold and silver mine located in Banyuwangi Regency, East Java Province and employ conventional truck and shovel mining method.
| Crusher / Mill Type | Model | Size | Power | Quantity |
|
Jaw crusher
|
|
|
|
1
|
|
Cone crusher
|
|
|
|
1
|
Summary:
Tujuh Bukit processing plant crushing circuit consists of primary jaw crushing and secondary cone crushing.
Processing
- Smelting
- Carbon re-activation kiln
- Heap leach
- Carbon in column (CIC)
- AARL elution
- Carbon adsorption-desorption-recovery (ADR)
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
Flow Sheet:
Summary:
The Tujuh Bukit plant was designed with processing rate of 4.0 million tonnes of oxide ore per annum and expanded its capacity to 8 million tonnes per annum in Q2-2019.
The ore is stacked in nominal 10m lifts, with cell widths between approximately 50m to 70m. Cells will be irrigated using a repetitive 7m x 7m irrigation pattern over a 75-day primary (oxide and transition) leach cycle using Intermediate Leach Solution (ILS), with a further 75-day (105-day for sulphide) period of secondary leaching with Barren Leach Solution (BLS) under the same irrigation pattern before the next lift is stacked over. The leachate solution is percolated through the ore before sub-grade collection and drain via flumes to either the (low gold grade) ILS pond or (high gold grade) Pregnant Leach Solution (PLS) pond. PLS solution is then pumped to the Adsorption Desorption Refining (ADR) process plant for gold and silver recovery.
Gold and silver doré is recovered from solution using co ........
Recoveries & Grades:
| Commodity | Parameter | 2020 | 2019 | 2018 | 2017 |
|
Gold
|
Recovery Rate, %
| ...... | ...... | | |
|
Gold
|
Head Grade, g/t
| ...... | ...... | ...... | 2.16 |
|
Silver
|
Recovery Rate, %
| ...... | ...... | ...... | |
Reserves at December 31, 2020:
| Category | OreType | Tonnage | Commodity | Grade | Contained Metal |
|
Proven & Probable
|
Stockpiles
|
1.4 Mt
|
Gold
|
0.45 g/t
|
20 koz
|
|
Proven & Probable
|
In-Situ (OP)
|
31.7 Mt
|
Gold
|
0.67 g/t
|
682 koz
|
|
Proven & Probable
|
Total
|
33.1 Mt
|
Gold
|
0.66 g/t
|
702 koz
|
|
Proven & Probable
|
Stockpiles
|
1.4 Mt
|
Silver
|
11 g/t
|
465 koz
|
|
Proven & Probable
|
In-Situ (OP)
|
31.7 Mt
|
Silver
|
29 g/t
|
28,887 koz
|
|
Proven & Probable
|
Total
|
33.1 Mt
|
Silver
|
27.6 g/t
|
29,352 koz
|
|
Total Resource
|
In-Situ (OP)
|
157.7 Mt
|
Gold
|
0.39 g/t
|
1,970 koz
|
|
Total Resource
|
In-Situ (OP)
|
157.7 Mt
|
Silver
|
15 g/t
|
77.8 M oz
|
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