Braúna mine
Braúna Diamond Mine, Brazil (100% Equity Interest)
The Braúna Mine property consists of five adjoining mineral licences covering 6,928 hectares, located in the Municipality of Nordestina, State of Bahia, Brazil. The Braúna licences encompass 23 kimberlite pipe and dyke occurrences. The Braúna 03 pipe is the largest of the kimberlite occurrences and is the only productive occurrence to date. The Braúna 3 Mine commenced commercial production as an open-pit mining operation in July 2016, and has produced 1,144,675 carats of natural rough diamonds from 6.15Mt of kimberlite mined from the Braúna 3 kimberlite for an average production grade of 18.6 cpht to year-end 2023. Since the start of commercial production in 2016, gross sales revenues total US$209.8M from the sale of 1,132,970 carats of rough diamond at an average unit sales price of US$185 per carat.
Open pit mining operations were suspended in May 2023 when the pit reached its planned economic limit. From May 2023 to January 2024 Lipari’s production came from the processing of a lower grade ore stockpile that was generated from mining of the central and northern lobes of the Braúna 3 kimberlite.
Transition of the open pit mine to an underground mining operation started in February 2024 with the initial blast of the mine portal that will provide underground access to allow for the continued production of diamonds from the Braúna 3 kimberlite below the bottom of the current open pit. The underground operation is expected to add an additional four years of mine life, producing an estimated 433,000 carats of diamonds from the processing of 1.85Mt of ore at a diamond grade of approximately 17 cpht. Underground mining will be conducted using the sub-level retreat (“SLR”) mining method which has been successfully implemented at the Diavik and Ekati mines in NWT, Canada, and the Koffiefontein mine in South Africa.
The kimberlite ore mined from the Braúna 3 deposit is processed through a 2,500 tonnes per day processing plant which operates on a 24 x 7 basis. The plant consists of a crushing and screening circuit that feeds a 150 tonnes per hour dense media concentrating circuit, feeding 6 X-Ray diamond recovery machines enclosed in a high-security final recovery building. The plant also has an integrated large diamond circuit featuring XRT technology. Lipari’s in-house plant maintenance team has produced exceptional plant performance with a plant availability averaging over 94%.
Lipari’s processing plant at the Braúna mine recycles 98% of the water used to process the ore. This is done by dewatering the plant “tailings”, which is the waste produced that is produced during the crushing, screening and concentration of the ore, by passing this fine waste material through a rotary centrifuge which spins the material at a high velocity to remove the water. This clean water is then recycled back to the processing circuit. In addition to water conservation, another important benefit of Lipari’s water recovery system is that the mine does not have a traditional “tailings pond”, or a wet storage system for the processing plant waste. Traditional tailings ponds can be a long-term environmental liability for mining companies and the communities in which they operate. Lipari is extremely proud of the fact that the mine recycles over 98% of the water used by the processing plant. Lipari is the only diamond producer in the world that operates without a traditional tailings pond.
Tchitengo Diamond Project
The Tchitengo Property is situated in the Lunda Province in northeastern Angola, 945 kilometres from the capital city Luanda. The Property encompasses 18 kimberlites including the Tchiuzo and Tchegi kimberlites – two advanced-stage kimberlite deposits. Tchitengo is located in the heart of Angola’s diamond rush:
- 30 km away from the world-class Luele (Luaxe) kimberlite owned by Sociedade Mineira do Luele which was inaugurated in November 2023 and is expected to produce between 3 to 4Mcts/annum by the end of 2024;
- 15 km north of the Chiri kimberlite currently being drilled and bulk sampled by Rio Tinto;
- 15 km north of the Catoca Mine, owned by Sociedade Mineira de Catoca (“SMC”), Angola’s largest diamond producer at Mcts/annum; and
- 5km south of the Camatchia mine which produces ~100kcts/annum.
The Tchitengo Property encompasses 30 kimberlites. Between 2006 and 2013, SMC explored the southern part of the Tchitengo Property and discovered the 10.6-hectare Tchiuzo kimberlite, ultimately spending US$32M on exploration and development work. During 2006 and 2011, a joint venture between BHP Billiton and Banco Espírito Santo explored the northern part of the Tchitengo Property area and discovered 29 of the kimberlites, spending a reported US$25M on exploration within the concession area. In total, over US$57M has been spent on exploration and development on the Tchitengo Property resulting in the discovery of 30 kimberlite deposits, advancing one to the pre-feasibility stage of development.
Tchiuzo Kimberlite
- The 10.6-hectare Tchiuzo kimberlite is the most advanced stage deposit on the Property. SMC developed the kimberlite to the pre-feasibility stage of development. In 2009 SMC reported resources for the Tchiuzo kimberlite, stated to NAEN standards which has been summarized by SRK Consulting (Canada) Inc. as follows:
| Resource Block | Russian Resource Category (NAEN Code) | Broadly Equivalent CRISCO (NI43-101) Category | Block Elevation (masl) | Kimberlite Volume (m3) | Density (t/m3) | Block Tonnage(K/t) | Diamond Grade(ct/t,+1.2mm effective) | Extractable Diamonds (kcts, +1.2mm) | |
|---|---|---|---|---|---|---|---|---|---|
| From | To | ||||||||
| 2009 Block 1 | C1 | Measured | 890 | 880 | 881,847 | 1.76 | 1,552.05 | 0.48 | 745.66 |
| 2009 Block 2 | C1 | Measured | 880 | 680 | 8,062,763 | 2.20 | 17,738.08 | 0.37 | 6,489.07 |
| 2009 Block 3 | C1 | Measured | 880 | 680 | 7,347,008 | 2.29 | 16,824.65 | 0.51 | 8,536.84 |
| Sub-total C1 | C1 | Measured | 890 | 680 | 16,291,618 | 2.22 | 36,114.78 | 0.44 | 15,771.57 |
| 2009 Block 4 | C2 | Indicated | 680 | 530 | 7,492,005 | 2.33 | 17,456.37 | 0.43 | 7,589.04 |
| Sub-total C2 | C2 | Indicated | 680 | 530 | 7,492,005 | 2.33 | 17,456.37 | 0.43 | 7,589.04 |
| Total C1+C2 | C1+C2 | M+I | 890 | 530 | 23,783,623 | 2.25 | 53,571.15 | 0.44 | 23,360.61 |
SMC completed the initial pre-feasibility study in 2009 and then updated the study in 2013. The study projected four different open-pit mining scenarios based on ore mining and processing rates ranging from 2.0 MTPA to 2.9 MTPA, and open pit mine depths ranging from 200 metres below surface to 250 metres below surface. Life of mine of these mine scenarios ranged from 13 to 22 years. Diamond sales prices used in their 2013 pre-feasibility study ranged from US$112 per carat to US$149 per carat.
| Reference | Unit | Scenario 1 | Scenario 2 | Scenario 3 | Scenario 4 |
|---|---|---|---|---|---|
| Throughput per annum | MTPA | 2.0 | 2.0 | 2.9 | 2.9 |
| Ore volume for LOM | Million tons | 42.23 | 35.81 | 42.23 | 35.81 |
| Overburden for LOM | Million m3 | 32.56 | 27.13 | 32.56 | 27.13 |
| Head feed for LOM | Million m3 | 51.48 | 43.30 | 51.48 | 43.30 |
| Ore transport for LOM | Million ton/km | 380.56 | 305.85 | 377.10 | 303.35 |
| Commercial Production | Million carats | 17.78 | 15.10 | 17.78 | 15.10 |
| Diamond value | US$/carat | 144.79 | 129.71 | 122.42 | 112.59 |
| Total revenues | US$ million | 2,574.11 | 1,958.48 | 2,176.36 | 1,699.93 |
| Operating expenses | US$ million | 1,310.38 | 1,081.50 | 1,199.93 | 1,007.66 |
| Capital expenses | US$ million | 173,743.00 | 171,568.00 | 195,523.00 | 190,88.00 |
| Return on Capital (IRR) | % | 15.25 | 14.57 | 19.24 | 18.48 |
Tchegi-38 Kimberlite
The Tchegi-38 kimberlite was one of 18 kimberlites discovered by the BHP Billiton/ESCOM joint venture within the boundaries of the Tchitengo Property. BHP Billiton advanced the Tchegi-38 kimberlite to the resource definition stage of development, completing 18 large diameter drill holes which resulted in the recovery of 834 tonnes of kimberlite for processing.
| # LLD Holes Drilled | Metres Drilled | Sample Weight (tonnes) | Diamonds Recovered | Total Weight of Diamonds (carats) | Recovered Diamond Grade (cpht) | Largest Diamond Recovered (carats) | Average Diamond Size (carats/ stone) |
|---|---|---|---|---|---|---|---|
| 18 | 2999 | 834.32 | 2516 | 214.69 | 25.7 | 3.43 | 0.09 |
The central portion of the 10 ha Tchegi-38 kimberlite comprises an open-ended ore body that is well constrained by large diameter drilling. Processing of the 834 tonnes of kimberlite recovered from the drilling program resulted in the recovery of 214.69 carats of diamonds, resulting in a recovered diamond grade of 24.7 cpht. Additional drilling is required to define the margins of the Tchegi-38 kimberlite, and large-scale bulk sampling is required to confirm the diamond grade and value.