Trial Mining Successfully Completed at TGME Gold Project
Theta's Chairman Bill Guy commented: "Successful trial mining at TGME is a critical de-risking event and major milestone for Theta as it confirms that long hole mechanized mining methods can effectively mine these large tabular shallow dipping (3-7o) narrow gold reef systems. The reef varies greatly in thickness from 0.24 metres to 6 metres. The ability to mine at 0.6m or narrower means reduced dilution and delivery of a higher ore grade to the plant."
"As the reef system is tabular, the Beta and CDM combined complex strikes over 8.2km with a downdip extension of more than 2500m (refer to Appendix A). The trial mining has assisted with confirming initial costs and mine design. The reef is relatively soft in relation to the surrounding host rock, reducing anticipated drilling and explosive costs. The competence of the host sedimentary rock was again experienced as no uncontrolled fall of ground took place during the blasting operations, as observed in other parts of the mine where excavations mined over a hundred years ago are still standing up."
"The next two quarters will deliver exciting news as the Rietfontein PFS, TGME underground DFS together with an updated JORC (2012) Resource Statement will be completed. Underground sampling, bulk gravity gold sampling and further metallurgical test work continues throughout Christmas and New Year into 2022."
The trial mining project that started in September 2021 focused on rock engineering and mine support systems, drilling, and blasting technics as well as cleaning of broken ore in support of the current definitive feasibility study being prepared by Minxcon for Q1 2022.
A systematic roof support installation was undertaken to secure a safe working environment at Frankfort Mine. The support system consisted of tendon support installed at a 90-degree angle into the hanging wall in all main access development. Aerial support in the form of timber packs was installed in large open unsupported areas and the in-stope support consisted of mechanical jacks, rock bolts, Mine poles, and timber packs. No uncontrolled fall of grounds was recorded during the trial blasting sessions and the designed rock engineering support system did perform to the expected specifications.
A total of 34 horizontal blast holes were drilled at various lengths across the span of the trial mining block. A series of holes were drilled on a staggered pattern spaced 60cm apart thereafter converting to a single horizontal line of drill holes spaced 60cm apart to complete the remainder of the holes.
Different drill hole diameters were tested ranging from 45mm to 52mm. Three different drill bits were tested during this project to understand the best-matched drill bit to the rock, evaluating rock penetration, metres drilled per drill bit, and drilling cost per metre.
Bulk emulsion explosives had been selected and supplied by Enaex Africa for trial mining due to the advantages of bulk emulsion explosives over alternative explosive technologies, both in terms of safety and blast performance. The desired outcome of advance per hole and reef contact breaking points was achieved. All blasted holes were primed up to 150 grams Trojan cast booster and the detonator inserted to the middle of the shot hole. The shot holes were pumped with Devex explosives and tamped with stemming material top and bottom to ensure proper breaking can be achieved. This was done up to the collar of the hole. This process proved that 85% of all blasted rock will be cast to the cleaning drive.
Evaluation of the blast fragmentation indicated that the burden and spacing should be increased and hole diameter reduced in future drill designs to increase the rock fragmentation size. The drilling redesign will lead to a cost reduction in both drilling and explosive costs. Figure 6*, indicates the blasted stope face, broken rock casted into the cleaning drive, and rock fragmentation.
The trial mining at Frankfort Mine was a success and proved that the planned mechanical longhole drilling applied to a narrow vein orebody will achieve the desired outcome and open endless possibilities within these goldfields.
As part of the ongoing trial mining within the project scope, investigations were undertaken in accessing suitable equipment to allow for bulk gravity gold sampling for exploration work in targeted areas across the concession. A centrifugal concentrator was procured, which will be utilized to test different ore types and attain an understanding of potential gravity gold recovery.
Both the Phase 1 underground DFS and Rietfontein PFS is ongoing and progressing well with the expected completion of the PFS by end of December 2021 and a DFS by Q1 2022 respectively.
*To view figures, please visit:
About Theta Gold Mines Limited
Theta Gold Mines Limited (ASX:TGM) (OTCMKTS:TGMGF) is a gold development company that holds a range of prospective gold assets in a world-renowned South African gold mining region. These assets include several surface and near-surface high-grade gold projects which provide cost advantages relative to other gold producers in the region.
Theta Gold Mines core project is located next to the historical gold mining town of Pilgrim's Rest, in Mpumalanga Province, some 370km northeast of Johannesburg by road or 95km north of Nelspruit (Capital City of Mpumalanga Province). Following small scale production from 2011-2015, the Company is currently focussing on the construction of a new gold processing plant within its approved footprint at the TGME plant, and for the processing of the Theta Open Pit oxide gold ore. Nearby surface and underground mines and prospects are expected to be further evaluated in the future.
The Company aims to build a solid production platform to over 100Kozpa based primarily around shallow, open-cut or adit-entry hard rock mining sources. Theta Gold Mines has access to over 43 historical mines and prospect areas that can be accessed and explored, with over 6.7Moz of historical production recorded.
Theta Gold Mines Limited