Nouveau Monde Graphite Inc. press release
SILVERCORP REPORTS MINERAL RESERVES AND RESOURCES AND EXTENDS LIFE OF MINE TO 2037 AT THE YING MINING DISTRICT
TSX - Toronto Stock Exchange · Graphite · Canada
Canada NewsWire
Trading Symbol: TSX/NYSE American: SVM
VANCOUVER, BC , Sept. 21, 2022 /CNW/ - Silvercorp Metals Inc. ("Silvercorp" or the "Company") (TSX: SVM) (NYSE American: SVM) is pleased to report the results of an updated National Instrument ("NI") 43-101 Technical Report on Mineral Resources and Mineral Reserves for the Ying Property ("The Ying 2022 Technical Report") (Mineral Resources and Mineral Reserves effective December 31, 2021 ), prepared by AMC Mining Consultants ( Canada ) Ltd. ("AMC"). The Ying 2022 Technical Report covers all the mines in the Ying Property (also referenced as the "Ying Mining District") in Henan Province , China , namely the SGX, HZG, HPG, TLP, LME, LMW and DCG underground mines.
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Six of the seven authors of the Ying 2022 Technical Report qualify as independent Qualified Persons ("QPs"). Three of the independent authors have visited the Ying Mining District (latest visit in July 2016 ), with a more recent planned visit postponed because of the COVID-19 pandemic. The non-independent author, Mr. Guoliang Ma of Silvercorp, has visited the Ying Mining District on numerous occasions, the most recent being June 24 to July 22, 2021 . The QPs have examined all aspects of the project, including drill core, underground workings, processing plant and surface infrastructure. The Ying 2022 Technical Report will be made available for review on the SEDAR system and on the Company's website at www.silvercorpmetals.com within 45 days of this news release.
Based on Proven and Probable Mineral Reserves, annual production of silver is projected to average approximately 7.0 million ounces between fiscal 2023 and 2025, 8.0 million ounces between 2026 and 2029, 7.1 million ounces between 2030 and 2032, and 4.0 million ounces between 2033 and 2037, to have a life of mine (LOM) at 15 years. There is also the potential to extend the LOM beyond 2037 via further exploration and development, particularly in areas with identified Inferred Resources.
Summary of the Ying 2022 Technical Report
Estimated Mineral Resources of 18.7 million tonnes (inclusive of Mineral Reserves) in the Measured and Indicated categories grading 242 grams per tonne (g/t) silver (Ag), 0.27 g/t gold (Au), 3.51% lead (Pb), and 1.03% zinc (Zn), containing 146 million ounces (oz) silver, 161 thousand oz gold, 657 thousand tonnes lead, and 193 thousand tonnes zinc. In comparison with the 2020 Technical Report (Mineral Resources as of December 31, 2019 ), Measured and Indicated Resource tonnes have decreased by 7%, and contained metal has increased by 64% for gold and decreased by 3% for silver, 10% for lead and 16% for zinc. Estimated Mineral Reserves of 12.3 million tonnes in the Proven and Probable categories grading 241 g/t silver, 0.26 g/t gold, 3.36% lead, and 1.03% zinc, containing 96 million oz silver, 105 thousand oz gold, 414 thousand tonnes lead, and 127 thousand tonnes zinc. In comparison with the 2020 Technical Report (Mineral Reserves as of December 31, 2019 ), there has been a 3% increase in total Proven and Probable Mineral Reserves. The changes in total contained metal for silver, gold, lead, and zinc are -3%, +110%, -9% and -24% respectively. These Mineral Reserves are on top of approximately 11 million ounces of silver produced between January 2020 and December 2021 . In comparison with the 2020 Technical Report, Inferred Resource tonnes have decreased by 30%, and contained metal has decreased by 20% for gold, 23% for silver, 27% for lead and 20% for zinc. The Ying Mining District is reporting Mineral Reserves at the DCG mine for the first time. Also for the first time, the Ying Mining District as a whole is reporting over 100,000 ounces of gold Mineral Reserves. The results of the 2020-2021 underground drilling program at the Ying Mining District show that most of the major mineralized vein structures are still open at depth and laterally. Based on Proven and Probable Mineral Reserves only, an annual production rate increase is planned from the current level of around 650,000 tonnes per annum (tpa) to approximately 950,000 tpa by 2026, with that level being sustained through to 2032 and a full LOM to 2037. Annual production of silver is projected to be approximately 7.0 million ounces between fiscal 2023 and 2025, 8.0 million ounces between 2026 and 2029, 7.1 million ounces between 2030 and 2032, and 4.0 million ounces between 2033 and 2037. There is also the potential to extend the LOM beyond 2037 via further exploration and development, particularly in areas with identified Inferred Resources.
Mineral Resources:
The Mineral Resource estimates for the SGX, HPG, HZG, LMW, and DCG mines were carried out by Silvercorp and reviewed by independent Qualified Person, Rod Webster , MAIG of AMC, who takes responsibility for these estimates.
The Mineral Resource estimates for the TLP mine were carried out by Silvercorp and reviewed by independent Qualified Person, Simeon Robinson , P.Geo., MAIG of AMC, who takes responsibility for these estimates.
The Mineral Resource estimates for the LME mine were carried out by Silvercorp and reviewed by independent Qualified Person, Dr. Genoa Vartell, P.Geo. of AMC, who takes responsibility for these estimates.
The December 2021 Mineral Resources were estimated using a block modelling approach in Micromine. All grade estimation was completed using inverse distance squared.
Resource estimates were made for a total of 356 mineralized vein structures for the seven active mines in the Ying Mining District.
Additional geological sections in the Ying 2022 Technical Report were prepared by independent Qualified Persons Dr. Genoa Vartell, P.Geo. and Simeon Robinson , P.Geo., MAIG, both of AMC, who take responsibility for those sections.
The Mineral Resources are reported above cut-offs after applying a minimum practical extraction width of 0.4 m . Diluted grades were estimated for blocks with mineralization widths less than 0.4 m by adding a waste envelope with zero grade. Cut-off grades are based on in situ values in silver equivalent (AgEq) terms in grams per tonne and incorporate mining, trucking and processing costs, with metallurgical recoveries and payable values provided by Silvercorp for each mine and reviewed by the QPs. AgEq formulas by mine are shown in the footnotes of the table below.
The estimated Mineral Resources and metal content for the Ying Mining District as of December 31, 2021 are detailed in Table 1 below.
| MINE | Resource Category | Tonnes
(Mt) | Au
grade
(g/t) | Ag
grade
(g/t) | Pb
grade
(%) | Zn
grade
(%) | Au
metal
(koz) | Ag
metal
(Moz) | Pb
metal
(kt) | Zn
metal
(kt) | | SGX | Measured | 3.51 | 0.05 | 290 | 5.56 | 2.75 | 5.48 | 32.81 | 195.38 | 96.62 | | SGX | Indicated | 3.13 | 0.01 | 247 | 4.67 | 2.17 | 0.57 | 24.86 | 146.14 | 68.04 | | SGX | Measured + Indicated | 6.64 | 0.03 | 270 | 5.14 | 2.48 | 6.05 | 57.66 | 341.52 | 164.66 | | SGX | Inferred | 3.98 | 0.01 | 232 | 4.63 | 1.93 | 0.70 | 29.75 | 184.30 | 76.79 | | HZG | Measured | 0.51 | - | 372 | 1.20 | - | - | 6.15 | 6.18 | - | | HZG | Indicated | 0.51 | - | 358 | 0.91 | - | - | 5.91 | 4.68 | - | | HZG | Measured + Indicated | 1.03 | - | 365 | 1.06 | - | - | 12.06 | 10.86 | - | | HZG | Inferred | 0.55 | - | 326 | 0.83 | - | - | 5.75 | 4.55 | - | | HPG | Measured | 0.77 | 1.37 | 94 | 3.87 | 1.40 | 33.91 | 2.31 | 29.73 | 10.72 | | HPG | Indicated | 0.92 | 1.60 | 68 | 3.17 | 1.22 | 47.36 | 2.01 | 29.22 | 11.26 | | HPG | Measured + Indicated | 1.69 | 1.50 | 80 | 3.49 | 1.30 | 81.27 | 4.32 | 58.95 | 21.98 | | HPG | Inferred | 1.45 | 2.61 | 91 | 3.43 | 1.20 | 121.87 | 4.26 | 49.78 | 17.43 | | TLP | Measured | 2.45 | - | 221 | 3.43 | - | - | 17.41 | 83.93 | - | | TLP | Indicated | 2.01 | - | 189 | 3.08 | - | - | 12.16 | 61.84 | - | | TLP | Measured + Indicated | 4.46 | - | 206 | 3.27 | - | - | 29.58 | 145.77 | - | | TLP | Inferred | 3.76 | - | 180 | 2.86 | - | - | 21.78 | 107.46 | - | | LME | Measured | 0.45 | 0.10 | 357 | 1.73 | 0.35 | 1.45 | 5.11 | 7.71 | 1.54 | | LME | Indicated | 1.02 | 0.22 | 315 | 1.67 | 0.42 | 7.17 | 10.35 | 17.06 | 4.30 | | LME | Measured + Indicated | 1.47 | 0.18 | 327 | 1.69 | 0.40 | 8.62 | 15.46 | 24.77 | 5.85 | | LME | Inferred | 1.49 | 0.65 | 221 | 1.45 | 0.41 | 30.86 | 10.55 | 21.58 | 6.03 | | LMW | Measured | 0.94 | 0.21 | 325 | 2.63 | - | 6.45 | 9.78 | 24.65 | - | | LMW | Indicated | 2.16 | 0.36 | 232 | 2.04 | - | 24.84 | 16.12 | 43.91 | - | | LMW | Measured + Indicated | 3.09 | 0.31 | 260 | 2.22 | - | 31.28 | 25.90 | 68.56 | - | | LMW | Inferred | 1.51 | 0.07 | 235 | 2.36 | - | 3.63 | 11.39 | 35.52 | - | | DCG | Measured | 0.15 | 2.57 | 75 | 1.19 | 0.30 | 12.67 | 0.37 | 1.82 | 0.46 | | DCG | Indicated | 0.20 | 3.33 | 101 | 2.26 | 0.20 | 21.50 | 0.65 | 4.54 | 0.39 | | DCG | Measured + Indicated | 0.35 | 3.00 | 90 | 1.80 | 0.24 | 34.17 | 1.02 | 6.36 | 0.85 | | DCG | Inferred | 0.32 | 1.44 | 98 | 2.70 | 0.21 | 14.77 | 1.00 | 8.58 | 0.67 | | All Mines | Measured | 8.78 | 0.21 | 262 | 3.98 | 1.25 | 59.96 | 73.94 | 349.40 | 109.34 | | All Mines | Indicated | 9.95 | 0.32 | 225 | 3.09 | 0.84 | 101.44 | 72.06 | 307.39 | 83.99 | | All Mines | Measured + Indicated | 18.73 | 0.27 | 242 | 3.51 | 1.03 | 161.40 | 146.01 | 656.79 | 193.34 | | All Mines | Inferred | 13.05 | 0.41 | 201 | 3.15 | 0.77 | 171.83 | 84.46 | 411.77 | 100.92 |
| Notes: | | | | • | Measured and Indicated Mineral Resources are inclusive of Mineral Resources from which Mineral Reserves are estimated. | | | • | Metal prices: gold US$1450/troy oz, silver US$18.60/troy oz, lead US$0.95/lb, zinc US$1.10/lb. | | | • | Exchange rate: RMB 6.50 : US$1.00. | | | • | Mineral Resource reported 5 m below surface. | | | • | Veins factored to minimum extraction width of 0.4 m after estimation. | | | • | Cut-off grades: SGX 170 g/t AgEq; HZG 170 g/t AgEq; HPG 180 g/t AgEq; TLP 155 g/t AgEq; LME 180 g/t AgEq; LMW 160 g/t AgEq; DCG 155 g/t AgEq. | | | • | AgEq equivalent formulas by mine: | | | | - | SGX = Ag g/t+37.79*Pb%+20.76*Zn% | | | - | HZG = Ag g/t+36.31*Pb% | | | - | HPG = Ag g/t+69.41*Au g/t+36.84*Pb%+24.73*Zn% | | | - | TLP = Ag g/t+36.65*Pb% | | | - | LME = Ag g/t+35.84*Pb%+10.44*Zn% | | | - | LMW = Ag g/t+36.88*Pb% | | | - | DCG = Ag g/t+36.84*Pb%+24.73*Zn% | | • | AgEq formulas used for significant gold bearing veins: | | | | - | SGX (Veins S16W_Au, S18E and S74) = Ag g/t+66.25*Au g/t+37.79*Pb%+20.76*Zn% | | | - | LME (Vein LM4E2) = Ag g/t+66.70*Au g/t+35.84*Pb%+10.44*Zn% | | | - | LMW (Veins LM22, LM26, LM50 and LM51) = Ag g/t+65.78*Au g/t+36.88*Pb% | | | - | DCG (Veins C9, C76) = Ag g/t+69.41*Au g/t+36.84*Pb%+24.73*Zn% | | • | Exclusive of mine production to December 31, 2021. | | | • | Rounding of some figures may lead to minor discrepancies in totals. | |
The previous Mineral Resource estimates for the Ying Mining District only reported gold values for the HPG mine. Recently, Silvercorp has identified and targeted gold rich veins at SGX, LME, LMW and DCG. Table 2 is a Mineral Resource subset for the silver lead zinc veins and exclusive of HPG. Table 3 is a Mineral Resource subset for the significant gold-bearing veins, and inclusive of HPG.
| Mine | Resource Category | Tonnes
(Mt) | Au
grade
(g/t) | Ag
grade
(g/t) | Pb
grade
(%) | Zn
grade
(%) | Au
metal
(koz) | Ag
metal
(Moz) | Pb
metal
(kt) | Zn
metal
(kt) | | SGX | Measured | 3.40 | - | 297 | 5.69 | 2.80 | - | 32.41 | 193.40 | 94.95 | | SGX | Indicated | 3.10 | - | 249 | 4.69 | 2.17 | - | 24.80 | 145.48 | 67.32 | | SGX | Measured + Indicated | 6.50 | - | 274 | 5.22 | 2.50 | - | 57.21 | 338.89 | 162.28 | | SGX | Inferred | 3.97 | - | 233 | 4.64 | 1.93 | - | 29.72 | 184.22 | 76.69 | | HZG | Measured | 0.51 | - | 372 | 1.20 | - | - | 6.15 | 6.18 | - | | HZG | Indicated | 0.51 | - | 358 | 0.91 | - | - | 5.91 | 4.68 | - | | HZG | Measured + Indicated | 1.03 | - | 365 | 1.06 | - | - | 12.06 | 10.86 | - | | HZG | Inferred | 0.55 | - | 326 | 0.83 | - | - | 5.75 | 4.55 | - | | TLP | Measured | 2.45 | - | 221 | 3.43 | - | - | 17.41 | 83.93 | - | | TLP | Indicated | 2.01 | - | 189 | 3.08 | - | - | 12.16 | 61.84 | - | | TLP | Measured + Indicated | 4.46 | - | 206 | 3.27 | - | - | 29.58 | 145.77 | - | | TLP | Inferred | 3.76 | - | 180 | 2.86 | - | - | 21.78 | 107.46 | - | | LME | Measured | 0.43 | - | 360 | 1.75 | 0.35 | - | 4.98 | 7.52 | 1.48 | | LME | Indicated | 0.93 | - | 327 | 1.73 | 0.43 | - | 9.77 | 16.09 | 3.98 | | LME | Measured + Indicated | 1.36 | - | 337 | 1.74 | 0.40 | - | 14.75 | 23.61 | 5.47 | | LME | Inferred | 1.10 | - | 275 | 1.79 | 0.41 | - | 9.73 | 19.70 | 4.54 | | LMW | Measured | 0.90 | - | 335 | 2.72 | - | - | 9.70 | 24.55 | - | | LMW | Indicated | 1.95 | - | 247 | 2.19 | - | - | 15.49 | 42.80 | - | | LMW | Measured + Indicated | 2.85 | - | 275 | 2.36 | - | - | 25.20 | 67.34 | - | | LMW | Inferred | 1.49 | - | 237 | 2.38 | - | - | 11.32 | 35.41 | - | | DCG | Measured | 0.02 | - | 50 | 6.56 | 0.19 | - | 0.03 | 1.28 | 0.04 | | DCG | Indicated | 0.07 | - | 76 | 5.14 | 0.15 | - | 0.18 | 3.82 | 0.11 | | DCG | Measured + Indicated | 0.09 | - | 71 | 5.44 | 0.16 | - | 0.21 | 5.09 | 0.15 | | DCG | Inferred | 0.21 | - | 87 | 3.74 | 0.18 | - | 0.59 | 7.91 | 0.38 | | ALL MINES | Measured | 7.71 | - | 285 | 4.11 | 1.25 | - | 70.69 | 316.86 | 96.47 | | ALL MINES | Indicated | 8.57 | - | 248 | 3.20 | 0.83 | - | 68.32 | 274.71 | 71.41 | | ALL MINES | Measured + Indicated | 16.29 | - | 265 | 3.63 | 1.03 | - | 139.01 | 591.57 | 167.89 | | ALL MINES | Inferred | 11.08 | - | 222 | 3.24 | 0.74 | - | 78.89 | 359.25 | 81.61 |
| Notes: | | | | | • | Measured and Indicated Mineral Resources are inclusive of Mineral Resources from which Mineral Reserves are estimated. | | | | • | Metal prices: silver US$18.60/troy oz, lead US$0.95/lb, zinc US$1.10/lb. | | | | • | Exchange rate: RMB 6.50 : US$1.00. | | | | • | Mineral Resource reported 5 m below surface. | | | | • | Veins factored to minimum extraction width of 0.4 m after estimation. | | | | • | Cut-off grades: SGX 170 g/t AgEq; HZG 170 g/t AgEq; TLP 155 g/t AgEq; LME 180 g/t AgEq; LMW 160 g/t AgEq; DCG 155 g/t AgEq. | | | | • | Silver equivalent formulas by mine: | | | | | | - | SGX = Ag g/t+37.79*Pb%+20.76*Zn% | | | | - | HZG = Ag g/t+36.31*Pb% | | | | - | TLP = Ag g/t+36.65*Pb% | | | | - | LME = Ag g/t+35.84*Pb%+10.44*Zn% | | | | - | LMW = Ag g/t+36.88*Pb% | | | | - | DCG = Ag g/t+36.84*Pb%+24.73*Zn% | | • | Exclusive of mine production to December 31, 2021. | | | | • | Rounding of some figures may lead to minor discrepancies in totals. | | | | | | | |
| Mine | Resource Category | Tonnes
(Mt) | Au
grade
(g/t) | Ag
grade
(g/t) | Pb
grade
(%) | Zn
grade
(%) | Au
metal
(koz) | Ag
metal
(Moz) | Pb
metal
(kt) | Zn
metal
(kt) | | SGX | Measured | 0.12 | 1.47 | 106 | 1.70 | 1.43 | 5.48 | 0.40 | 1.98 | 1.67 | | SGX | Indicated | 0.03 | 0.57 | 61 | 2.13 | 2.32 | 0.57 | 0.06 | 0.66 | 0.71 | | SGX | Measured + Indicated | 0.15 | 1.28 | 97 | 1.79 | 1.62 | 6.05 | 0.46 | 2.63 | 2.38 | | SGX | Inferred | 0.01 | 1.94 | 73 | 0.70 | 0.89 | 0.70 | 0.03 | 0.08 | 0.10 | | HPG | Measured | 0.77 | 1.37 | 94 | 3.87 | 1.40 | 33.91 | 2.31 | 29.73 | 10.72 | | HPG | Indicated | 0.92 | 1.60 | 68 | 3.17 | 1.22 | 47.36 | 2.01 | 29.22 | 11.26 | | HPG | Measured + Indicated | 1.69 | 1.50 | 80 | 3.49 | 1.30 | 81.27 | 4.32 | 58.95 | 21.98 | | HPG | Inferred | 1.45 | 2.61 | 91 | 3.43 | 1.20 | 121.87 | 4.26 | 49.78 | 17.43 | | LME | Measured | 0.02 | 2.97 | 255 | 1.26 | 0.39 | 1.45 | 0.12 | 0.19 | 0.06 | | LME | Indicated | 0.09 | 2.38 | 195 | 1.03 | 0.34 | 7.17 | 0.59 | 0.97 | 0.32 | | LME | Measured + Indicated | 0.11 | 2.47 | 204 | 1.06 | 0.35 | 8.62 | 0.71 | 1.16 | 0.38 | | LME | Inferred | 0.39 | 2.47 | 65 | 0.48 | 0.38 | 30.86 | 0.81 | 1.87 | 1.49 | | LMW | Measured | 0.04 | 5.48 | 69 | 0.29 | - | 6.45 | 0.08 | 0.11 | - | | LMW | Indicated | 0.21 | 3.74 | 94 | 0.54 | - | 24.84 | 0.62 | 1.11 | - | | LMW | Measured + Indicated | 0.24 | 4.00 | 90 | 0.50 | - | 31.28 | 0.70 | 1.22 | - | | LMW | Inferred | 0.02 | 5.77 | 108 | 0.56 | - | 3.63 | 0.07 | 0.11 | - | | DCG | Measured | 0.13 | 2.95 | 79 | 0.41 | 0.31 | 12.67 | 0.34 | 0.54 | 0.42 | | DCG | Indicated | 0.13 | 5.29 | 115 | 0.57 | 0.23 | 21.50 | 0.47 | 0.72 | 0.28 | | DCG | Measured + Indicated | 0.26 | 4.09 | 97 | 0.49 | 0.27 | 34.17 | 0.81 | 1.26 | 0.70 | | DCG | Inferred | 0.11 | 4.31 | 120 | 0.63 | 0.27 | 14.77 | 0.41 | 0.67 | 0.29 | | ALL MINES | Measured | 1.07 | 1.74 | 95 | 3.04 | 1.20 | 59.96 | 3.25 | 32.54 | 12.87 | | ALL MINES | Indicated | 1.38 | 2.29 | 84 | 2.37 | 0.91 | 101.44 | 3.75 | 32.68 | 12.58 | | ALL MINES | Measured + Indicated | 2.45 | 2.05 | 89 | 2.66 | 1.04 | 161.40 | 7.00 | 65.22 | 25.45 | | ALL MINES | Inferred | 1.98 | 2.70 | 88 | 2.65 | 0.98 | 171.83 | 5.57 | 52.52 | 19.31 |
| Notes: | | | | • | Measured and Indicated Mineral Resources are inclusive of Mineral Resources from which Mineral Reserves are estimated. | | | • | Metal prices: gold US$1450/troy oz, silver US$18.60/troy oz, lead US$0.95/lb, zinc US$1.10/lb. | | | • | Exchange rate: RMB 6.50 : US$1.00. | | | • | Mineral Resource reported 5 m below surface. | | | • | Veins factored to minimum extraction width of 0.4 m after estimation. | | | • | Cut-off grades: SGX 170 g/t AgEq; HPG 180 g/t AgEq; LME 180 g/t AgEq; LMW 160 g/t AgEq; DCG 155 g/t AgEq. | | | • | AgEq formulas used for significant gold bearing veins: | | | | - | SGX (Veins S16W_Au, S18E and S74) = Ag g/t+66.25*Au g/t+37.79*Pb%+20.76*Zn% | | | - | HPG = Ag g/t+69.41*Au g/t+36.84*Pb%+24.73*Zn% | | | - | LME (Vein LM4E2) = Ag g/t+66.70*Au g/t+35.84*Pb%+10.44*Zn% | | | - | LMW (Veins LM22, LM26, LM50 and LM51) = Ag g/t+65.78*Au g/t+36.88*Pb% | | | - | DCG (Veins C9, C76) = Ag g/t+69.41*Au g/t+36.84*Pb%+24.73*Zn% | | • | Exclusive of mine production to December 31, 2021. | | | • | Rounding of some figures may lead to minor discrepancies in totals. | | | | | |
A comparison of Mineral Resource estimates between December 31, 2019 and December 31, 2021 for payable metals indicates the following:
Measured and Indicated tonnes have decreased by 7% overall. The Inferred tonnes have decreased by 30%. Measured and Indicated grades have increased for gold and silver by 79% and 4% respectively. Measured and Indicated grades have decreased for lead by 4% and zinc by 10%. Inferred grades increased for all metals: gold by 14%, silver by 9%, lead by 4% and zinc by 13%. The net result in the Measured and Indicated categories has been an increase in the contained gold of 64% and decreases in the contained silver, lead and zinc of 3%, 10% and 16% respectively. The net result in the Inferred category has been a decrease in the contained gold, silver, lead and zinc of 20%, 23%, 27% and 20% respectively.
Reasons for the differences in grade, tonnes, and contained metal include conversion to higher categories arising from drilling and level development, generally higher cut-off grades due to inflation, and depletion due to mining.
Mineral Reserves
The Mineral Reserve estimation is based on the assumption that current stoping practices will continue to be predominant at the Ying Mining District, namely cut and fill resuing and shrinkage stoping, using hand-held drills and hand-mucking within stopes, and loading to mine cars by rocker-shovel or by hand. The largely sub-vertical veins, generally competent ground, reasonably regular vein width, and hand-mining techniques using short rounds, allows a significant degree of selectivity and control in the stoping process. Minimum mining widths of 0.5 m for resuing and 1.0 m for shrinkage are assumed. The QP has observed the mining methods at the Ying Mining District and considers the minimum extraction and mining width assumptions to be reasonable. Minimum dilution assumptions are 0.10 m of total overbreak for a resuing cut and 0.2 m of total overbreak for a shrinkage stope.
Mining dilution and recovery factors vary somewhat from mine to mine and with mining method. Average dilution factors have been estimated as 15.5% for resuing and 19.5% for shrinkage, while assumed mining recovery factors are 95% for resuing stopes and 92% for shrinkage stopes.