Past year: ▲ 68%(65.0c – 1.20 CAD)
Each one in plain English, with the numbers worked through for a shareholder.
29 Apr 2022drilling result▲ GoodMajor
Eight holes from the 720 level found the Fortuna zone next to existing Yauricocha workings, with 27.22% zinc over 4.90 metres and 12.94% zinc over 2.85 metres in ECF 10 22 02, and 6.41% copper with 3.51% zinc over 4.80 metres in ECF 10 22 05; true widths are not yet determined. It is the last exploration success reported before the mine's September 2022 collapse.
4 Mar 2022resource reserve update● Neutral
Filed the updated Yauricocha expansion report with no material differences from the January announcement.
3 Mar 2022resource reserve update● Neutral
The updated Yauricocha study as filed, effective 31 March 2021 and dated 25 February 2022, prepared by SRK Consulting (Canada) with Redco Global Peru responsible for reserves and mining.
20 Jan 2022resource reserve update● NeutralMajor
Reworked the Yauricocha expansion case on the March 2021 resource and with prefeasibility-level cost estimates: after-tax net present value of US$273.1 million at 8%, down from the US$359 million filed in December 2020, on US$102.2 million of development capital in the first three years, US$312.1 million of total capital and an operating cost of US$44.01 a tonne. Better costings made the same project worth less, and the mine plan now leans on inferred resources.
29 Sept 2021resource reserve update● Neutral
Filed the updated Bolivar study including iron ore, with no material differences from the August announcement. Its effective date is still 31 December 2019, so the resource base behind the US$361 million figure is nearly two years old.
29 Sept 2021resource reserve update● Neutral
The updated Bolivar study as filed - the October 2020 report reissued on 21 September 2021 with iron ore production added, still effective 31 December 2019.
16 Aug 2021resource reserve update▲ GoodMajor
Reworked the 10,000 tonne-a-day Bolivar study to include iron ore concentrate as a saleable product, lifting the after-tax net present value from US$283 million to US$361 million at 8%. The incremental value of going from 5,000 to 10,000 tonnes a day rises from US$57.4 million to US$78.2 million, so most of the improvement comes from selling the magnetite rather than from the extra throughput.
13 Apr 2021drilling result▲ Good
Found a new high-grade oxide zone along the Yauricocha fault between the Cachi Cachi and Esperanza areas, inside the existing mine footprint. The intercepts are narrow but exceptionally rich: 29.05% zinc over 1.0 metre in hole 17-21-13, 28.64% zinc over 2.0 metres in 17-21-03, and 571 g/t silver with 22.58% lead over 0.9 metres in 17-21-01. Oxide material is a different processing problem from the sulphides the mill was built for.
6 Jan 2021resource reserve update● Neutral
Filed the technical report for the 2,400 tonne-a-day Cusi expansion study, unchanged from the December announcement at an after-tax net present value of US$81 million.
6 Jan 2021resource reserve update● Neutral
The Cusi expansion study as filed, effective 31 August 2020 and dated 13 November 2020, prepared by SRK Consulting (Canada).
22 Dec 2020resource reserve update● Neutral
The Cusi resource report as filed, prepared by SRK Consulting (Canada), effective 31 August 2020 and dated 13 November 2020.
22 Dec 2020resource reserve update▲ Good
Filed the Cusi resource report, effective 31 August 2020: measured and indicated up 18% to 5,356,000 tonnes from 4,557,000, reflecting the new high-grade vein system found during 2020 development.
10 Dec 2020resource reserve update▲ GoodMajor
The third expansion study of the season, doubling Cusi to 2,400 tonnes a day for an after-tax net present value of US$81 million at 8%, assuming US$20 an ounce silver long term, and US$134 million of net after-tax cash flow. The step from 1,200 to 2,400 tonnes contributes US$28.1 million of that at a 46.8% return.
8 Dec 2020resource reserve update● Neutral
The Yauricocha expansion study as filed, effective 30 June 2020 and dated 19 November 2020, prepared by SRK Consulting (Canada).
8 Dec 2020resource reserve update▲ GoodMajor
Filing the Yauricocha report improved the headline: the after-tax net present value in the final document is US$359 million, 7.8% above the US$333 million announced three weeks earlier. Unusually for these filings, the report does differ from the press release, and in the company's favour.
18 Nov 2020resource reserve update▲ GoodMajor
Yauricocha's measured and indicated resource tonnage rose 26% and inferred 79%, to 16 million and 12 million tonnes - the largest in the mine's history and, as management notes, achieved after mining 9.1 million tonnes since the 2011 acquisition, when indicated resources were 5 million tonnes. The accompanying study puts an after-tax net present value of US$333 million at 8% on expanding from the permitted 3,150 tonnes a day to 5,500, having tested cases up to 7,500 and settled on 5,500 as the optimum for the resource base.
6 Nov 2020resource reserve update● Neutral
The Bolivar expansion study as filed, effective 31 December 2019 and dated 19 October 2020, prepared by SRK Consulting (Canada) with Sierra's own VP Corporate Planning as one of the qualified persons.
5 Nov 2020resource reserve update● Neutral
Filed the technical report for the 10,000 tonne-a-day Bolivar study, with no material differences from the October announcement.
20 Oct 2020resource reserve update▲ GoodMajor
A fresh Bolivar study, this time for 10,000 tonnes a day rather than the 5,000 assumed two years earlier: after-tax net present value of US$283 million at 8%, US$521 million of net cash flow, US$317 million of life-of-mine and sustaining capital and an operating cost of US$19.77 a tonne. The incremental step from 5,000 to 10,000 tonnes is worth only US$57.4 million of that at a 27.9% return, so most of the value is in the first doubling, not the second.
18 June 2020drilling result▲ GoodMajor
A genuinely high-grade silver find at Cusi in a northeast-southwest epithermal vein system: 17.45 metres true width at 428 g/t silver, plus 4.90 metres at 1,140 g/t, 9.35 metres at 304 g/t and 8.75 metres at 303 g/t. It builds on the 40-metre stockwork announced in June 2018 and, like that, matters because width allows bulk mining at a mine that has struggled with narrow veins.
14 May 2020resource reserve update● Neutral
Filed SRK's Bolivar technical report, effective 31 December 2019, supporting the March reserve and resource update with no material differences.
14 May 2020resource reserve update● Neutral
The Bolivar technical report as filed, prepared by SRK Consulting (Canada) and dated 8 May 2020.
31 Mar 2020resource reserve update● NeutralMajor
With the litho-structural model and the fourth-quarter drilling added, Bolivar's indicated resource rebounded 68% from the December figure to 19.5 million tonnes at 0.78% copper, and inferred rose 29% to 21.5 million tonnes - but at lower grades again. Reserves are 7.5 million tonnes at 0.69% copper, 13.4 g/t silver and 0.22 g/t gold, 5% less tonnage than the 2017 estimate after two years of mining about 2.5 million tonnes, with contained silver down 34%. Bolivar is getting bigger and poorer at the same time.
3 Feb 2020resource reserve update● Neutral
The Yauricocha technical report itself, prepared by SRK Consulting (Canada) with an effective date of 31 October 2019.
3 Feb 2020resource reserve update● Neutral
Filed SRK's Yauricocha technical report, effective 31 October 2019, supporting the December 2019 reserve and resource announcement with no material differences.
31 Dec 2019resource reserve update▼ BadMajor
A rare downgrade after two years of increases: Bolivar's indicated resource fell 12% by tonnage to 11.63 million tonnes, with copper grade down 9%, silver down 20% and gold down 17%, to 0.95% copper, 18.1 g/t silver and 0.24 g/t gold. Inferred more than doubled to 16.69 million tonnes but at similarly reduced grades. Lowering the net smelter return cut-off pulled in lower-value material, which is the mirror image of the cut-off changes that had inflated earlier updates.
27 June 2019drilling result▲ GoodMajor
Received the construction permit for the next lift of the Yauricocha tailings dam, following the earlier environmental approval, plus a permit for surface drilling of four Titan 24 targets. Tailings capacity is the practical constraint on any throughput expansion, so this is the permitting step the 5,500 tonne-a-day study depends on.
3 Apr 2019drilling result▲ Good
Four holes testing Titan 24 geophysical anomalies extended the Bolivar West zone about 500 metres, averaging 1.15% copper (2.09% copper-equivalent) over 7.7 metres true width. Best intercepts were 2.29% copper with 7.56% zinc and 140 g/t silver over 4 metres in DB18B666, and 1.32% copper with 1.16 g/t gold over 20 metres in DB18B669 - more gold than the mine has historically carried.
4 Oct 2018drilling result▲ GoodMajor
A hole driven from the 720 level to 1,394.6 metres depth confirmed copper-molybdenum porphyry mineralisation in the quartz monzonite between the Cuye and Esperanza zones - 0.46% copper with 134 ppm molybdenum over 22 metres, and 0.54% copper over 18 metres. Grades are low against the polymetallic ore Yauricocha mines, but a porphyry is a different scale of target and it sits under an operating mine.
24 Aug 2018resource reserve update● Neutral
Filed the technical report for the Bolivar 5,000 tonne-a-day expansion study, completing the set of three; again no material differences from what was announced.
