Mineral reserve growth replaces close to 100% of 2021 mining depletion and extends the mine life at each of Constancia and Snow Lake by one year to 2038
Annual copper production from Constancia is expected to average approximately 105,000 tonnes over the next seven years, a 35% increase from 2021 levels
Annual gold production from Snow Lake is expected to average over 180,000 ounces over the next six years, a more than 55% increase from 2021 levels
Positive scoping study on underground mining potential at Constancia Norte results in an initial inferred mineral resource estimate of 6.5 million tonnes at 1.2% copper, adding potential to increase copper production at Constancia after 2028
Successful exploration at Lalor and the 1901 deposit in Snow Lake further increases the size of the base metal and gold zones at these deposits; contained gold in Snow Lake’s mineral reserve estimates increases by 218,000 ounces to 2.4 million ounces
Ongoing exploration drilling at Copper World in Arizona has the potential to extend known mineralization on private mining claims; preliminary economic assessment remains on track for completion in the first half of 2022
TORONTO, March 28, 2022 (GLOBE NEWSWIRE) -- Hudbay Minerals Inc. (“Hudbay” or the “company”) (TSX, NYSE:HBM) today released its annual mineral reserve and resource update. All amounts are in U.S. dollars, unless otherwise noted.

“We have continued to grow our copper and gold mineral reserves and resources through successful exploration in Peru, Snow Lake and Arizona,” said Peter Kukielski, Hudbay’s President and Chief Executive Officer. “While we already have a solid production growth profile for many years to come, our exploration efforts over the past year have been successful in replacing what we have mined, adding reserves to our life of mine plans and expanding our resource base to position us for additional long-term reserves growth. This is another example of our proven track record of delivering value through exploration, and we look forward to continuing to advance our leading organic pipeline of copper exploration and development assets for the next stage of growth at Hudbay.”

Constancia Operations

Mine planning gains and economic re-evaluations have resulted in additional mineral reserves at Constancia which have largely offset 2021 mining depletion. Current mineral reserve estimates at Constancia total 521 million tonnes at 0.31% copper with over 1.6 million tonnes in contained copper. As a result, Constancia’s expected mine life has been extended one year to 2038. The copper contained in inferred mineral resources has also increased in 2022 due to the inclusion of the Constancia Norte underground mineral resource estimates.

In 2021, Hudbay completed a positive scoping study which resulted in an inferred mineral resource estimate of 6.5 million tonnes at 1.2% copper in two high grade skarn lenses located below the open pit in the Constancia Norte area. The study concluded these two lenses could be mined by underground methods starting in 2029 to supplement the open pit production. Please refer to Figure 1 for a cross-section of the conceptual underground mine design at Constancia Norte. The company intends to conduct infill drilling and an internal pre-feasibility study in hopes of converting the underground mineral resources to mineral reserves for inclusion in the mine plan for the Constancia operations.

Hudbay released an updated mine plan for Constancia in 2021 that reflected an increase in copper and gold production from 2022 to 2025 as the higher grades from the Pampacancha deposit enter the mine plan. The updated mine plan incorporates higher-grade reserves including the Constancia Norte pit extension. With the incorporation of Pampacancha and the Constancia Norte pit extension, annual production at Constancia is expected to average approximately 105,000 tonnes of copper and 60,000 ounces of gold over the next seven years, an increase of approximately 35% and 20%, respectively, from 2021 levels.

Current mineral reserves and resources (exclusive of reserves) for Constancia and Pampacancha as of January 1, 2022 are summarized below.

Constancia Operations
Mineral Reserve and Resource Estimates 1 ,2,3,4,5 Tonnes Cu Grade
(%) Mo Grade (g/t) Au Grade (g/t) Ag Grade (g/t)
Constancia Reserves
Proven 426,200,000 0.29 82 0.042 2.90
Probable 56,800,000 0.24 69 0.043 3.06
Total Proven and Probable - Constancia 483,000,000 0.28 80 0.042 2.92
Pampacancha Reserves
Proven 36,400,000 0.65 177 0.368 5.26
Probable 1,600,000 0.52 234 0.259 6.33
Total Proven and Probable - Pampacancha 38,000,000 0.65 179 0.364 5.30
Total Proven and Probable 521,000,000 0.31 87 0.065 3.09
Constancia Resources
Measured 123,800,000 0.22 64 0.038 2.07
Indicated 118,200,000 0.22 65 0.037 2.08
Inferred – Open Pit 51,000,000 0.30 77 0.054 2.69
Inferred – Underground 6,490,000 1.20 69 0.137 8.62
Pampacancha Resources
Measured 9,200,000 0.37 63 0.293 5.71
Indicated 1,500,000 0.39 152 0.223 6.63
Inferred 6,800,000 0.33 102 0.286 5.01
Total Measured and Indicated 252,700,000 0.23 65 0.048 2.23
Total Inferred 64,300,000 0.40 79 0.087 3.53
Note: totals may not add up correctly due to rounding.
1 Mineral resources are exclusive of mineral reserves and do not have demonstrated economic viability.
2 Mineral resources do not include factors for mining recovery or dilution.
3 The open pit mineral reserves and resources are estimated using a minimum NSR cut-off of $6.40 per tonne and assuming metallurgical recoveries (applied by ore type) of 86% for copper on average for the life of mine, while the underground inferred resources at Constancia Norte are based on a 0.65% copper cut-off grade.
4 Long-term metal prices of $3.45 per pound copper, $11.00 per pound molybdenum, $1,500 per ounce gold, and $20.00 per ounce silver were used to estimate mineral reserves and resources.
5 Mineral resources are based on resource pit designs containing measured, indicated, and inferred mineral resources.

Peru Regional Exploration

Hudbay controls a large, contiguous block of mineral rights with the potential to hold mineable deposits within trucking distance of the Constancia processing facility, including the past producing Caballito property and the highly prospective Maria Reyna and Kusiorcco properties. Exploration agreement discussions with the communities of Uchucarcco and Anahuichi on the Maria Reyna, Kusiorcco and Caballito properties are in progress.

Drilling continues at the Llaguen copper porphyry target in northern Peru with a total of 9,250 metres in 21 holes completed to-date. Assays have been received for eight holes and all holes have intersected mineralization. Based on the positive results from the initial drilling, a second phase of drilling has been initiated aimed at defining an initial inferred mineral resource estimate for Llaguen in the third quarter of 2022.

Other Constancia Updates

In March 2022, Hudbay obtained approval from Peru’s National Environmental Certification Service for Sustainable Investments (SENACE) of a third amendment to the Environmental and Social Impact Assessment (“ESIA MOD III”) for Constancia. The ESIA MOD III will allow for the optimization of the water balance and management plan, an alternate road for concentrate transportation, improvements to the tailings management facility dam design criteria and other operational benefits. This approval was obtained with technical input from the National Water Authority, the Ministry of Agrarian Development and Irrigation, and the Ministry of Culture.

The company also signed an addendum to its framework agreement with the province of Chumbivilcas in March 2022. Under the agreement, Hudbay will contribute to the district municipalities, assist with the return to classes in the education sector and continue to provide employment opportunities within the province.

Snow Lake Operations

As a result of exploration success in 2021, additional mineral reserves were identified at Lalor and the 1901 deposit, which are expected to extend the mine life of the Snow Lake operations by one year until 2038, maintaining the 17-year mine life. Resource to reserve conversion has more than offset 2021 mining depletion with a net gain for all metals, including an additional 218,000 ounces of gold contained in reserves after adjusting for 2021 mining depletion.

Refurbishment and commissioning activities at the New Britannia gold mill were completed in July 2021 and the construction of the new copper flotation facility at New Britannia was completed in October 2021, ahead of the original schedule. The copper facility consists of an innovative and first-of-its-kind flotation circuit based entirely on Jameson cells, a modern pneumatic flotation design that offers a compact layout, low-cost process and flexible flowsheet. Following a brief commissioning period, the New Britannia mill achieved commercial production on November 30, 2021. Full design throughput rates and recoveries are expected to be achieved in the second quarter of 2022, a mere six months after commissioning.

Hudbay released an updated mine plan for the Snow Lake operations in 2021 that reflected an increase in annual gold production to over 180,000 ounces on average during the next six years due to the incorporation of the New Britannia mill, which represents an increase of more than 55% from 2021 levels. The updated mine plan reflects the third phase of the company’s Snow Lake gold strategy focused on expanding and further optimizing operations. These expansion and optimization initiatives include increasing the production rate at Lalor to 5,300 tonnes per day by the end of 2022 following the closure of the 777 mine, increasing the throughput rate at the Stall mill to 3,800 tonnes per day, incorporating mineral reserves from the 1901 deposit into the mine plan, and implementing a recovery improvement project at the Stall mill to increase copper and precious metal recoveries. There also remains potential to further enhance the Snow Lake operations through exploration opportunities and additional mill processing projects.

Current mineral reserves and resources (exclusive of reserves) for Lalor, 1901 and other Snow Lake satellite deposits as of January 1, 2022 are summarized below.

Lalor Mine and 1901 Deposit
Mineral Reserve and Resource Estimates 1 ,2,3,4 ,5,6,7 Tonnes Zn Grade
(%) Au Grade (g/t) Cu Grade (%) Ag Grade (g/t)
Base Metal Zone Reserves
Proven – Lalor 6,420,000 5.57 2.6 0.47 29.5
Proven – 1901 1,260,000 8.00 2.2 0.32 24.7
Probable – Lalor 1,300,000 4.02 3.2 0.50 32.4
Probable – 1901 380,000 10.01 0.7 0.29 31.0
Total Proven and Probable - Base Metal 9,360,000 5.86 2.6 0.45 29.3
Gold Zone Reserves
Proven – Lalor 3,590,000 0.82 5.9 0.62 28.5
Proven – 1901 50,000 1.22 3.8 0.78 18.7
Probable – Lalor 4,190,000 0.53 5.1 1.05 27.9
Probable – 1901 20,000 0.51 1.6 1.89 5.3
Total Proven and Probable - Gold 7,850,000 0.67 5.4 0.85 28.1
Total Proven and Probable (Base Metal and Gold) 17,200,000 3.50 3.9 0.64 28.7
Base Metal Zone Resources
Inferred – Lalor 1,960,000 5.72 1.5 0.31 30.4
Inferred – 1901 670,000 6.04 1.4 0.22 27.8
Total Inferred - Base Metal 2,630,000 5.80 1.5 0.29 29.7
Gold Zone Resources
Inferred – Lalor 4,170,000 0.28 5.1 1.56 29.0
Inferred – 1901 1,260,000 0.39 4.9 1.49 20.8
Total Inferred - Gold 5,430,000 0.31 5.1 1.54 27.1
Total Inferred (Base Metal and Gold) 8,060,000 2.10 3.9 1.13 28.0
Note: totals may not add up correctly due to rounding.
1 Mineral resources are exclusive of mineral reserves and do not have demonstrated economic viability.
2 Mineral resources do not include factors for mining recovery or dilution.
3 Base metal mineral resources are estimated based on the assumption that they would be processed at the Stall concentrator while gold mineral resources are estimated based on the assumption that they would be processed at the New Britannia concentrator.
4 Long-term metal prices of $1.15 per pound zinc, $1,500 per ounce gold, $3.45 per pound copper, and $20.00 per ounce silver with an exchange rate of 1.30 C$/US$ were used to estimate mineral reserves and resources.
5 Lalor mineral reserves and resources are estimated using a minimum NSR cut-off of C$117 per tonne for waste filled mining areas and a minimum of C$127 per tonne for paste filled mining areas.
6 Individual stope gold grades at Lalor were capped at 10 grams per tonne as a prudent estimate until reserves-to-mill reconciliations can be developed to support the recovery of higher-grade gold. This capping method resulted in an approximate 3% reduction in the overall gold reserve grade at Lalor.
7 1901 mineral reserves and resources are estimated using a minimum NSR cut-off of C$110 per tonne. see & read more on
https://www.hudbayminerals.com/news-media/default.aspx#2022#Hudbay-Provides-Annual-Reserve-and-Resource-Update