Pulacayo Project Feasibility Study - Apogee Silver

More documents

Recommendations

Info

Pulacayo 1 000 t/d Phase I Feasibility Study - NI 43-101 Technical Report 090644-3-0000-20-IFI-100 boreholes, it was found that 8 boreholes did not intersect or plot close to the proposed stopes. These boreholes were excluded from the database and were not used in the design of the underground workings. Two rock mass rating systems were used, namely Laubscher’s Mining Rock Mass (RMRL) System (1990) and Barton’s Q System (1974). The ore body and country rock were found to be generally in the poor to fair range of rock mass quality. The average RMRL values were estimated to be 44 (fair) for the hangingwall and 42 (fair) for the footwall. The average Q values were estimated to be 2.3 (poor) and 1.8 (poor) for the hangingwall and footwall, respectively. The results of the mapping exercise that was completed in one of the tunnels (drift OB7) show similar rockmass conditions in the country rock. The Q values average 2.6 (poor) with a minimum of 1.3 (poor) and a maximum of 4.2 (fair). These values translate to equivalent RMR values of minimum of 47 (fair), average of 53 (fair) and maximum of 57 (fair). An effort was made to demarcate the different sections of the mine into different geotechnical zones based on rock mass characterization. This would have enabled design of different stope dimensions for the different geotechnical zones based on rock mass quality. This analysis was not conclusive due the limited number of boreholes in some of these areas. It is therefore recommended that additional geotechnical logging of boreholes that intersect the proposed stopes should be carried out to increase the database of rock mass quality. For design purposes, a single geotechnical zone was assumed. 16.5.2 Mining Spans Analysis of the geotechnical data described above indicate that the recommended stope dimensions of maximum 30 m (height) by maximum 10 m (length) and maximum 6 m (width) will be stable. Stopes are expected to remain free standing for a reasonable time with possible sidewall slabbing issues for stopes that plot in the transition zone on Potvin’s Stability Graph. The slabbing material will generally come from the mineralized zones thus the dilution of ore should be minimized, as the diluting material will have some grade in it. Cemented backfill placed after the broken ore has been drawn out will provide permanent support to the stope back. 16.5.3 Support of Excavations 16.5.3.1 Pillars A sill pillar will be required below zero level to protect the San Leon tunnel from the proposed underground workings and a crown pillar will be required to protect the underground workings from the planned future open pit mine. The study proposes a crown/sill pillar thickness of 15 m. This was determined based on a Safety Factor of 1.8 and an average Q value of 2.6. The possibility of having voids in the pillars was also taken into consideration. The design and stability of the proposed pillar width was assessed using empirical formulae and deemed sufficient. Crosscut protection pillars will also be required to support crosscuts during mining. Once all the stopes being serviced by the crosscut have been mined out, the crosscut pillar will be recovered on retreat. A 15 m wide crosscut protection pillar is deemed sufficient. This dimension was checked using numerical modeling code Map3D. TWP Sudamérica S.A. Av. Encalada 1257 Of. 801, Santiago de Surco Lima 33, Perú (51-1) 4377473 Page 153
Pulacayo 1 000 t/d Phase I Feasibility Study - NI 43-101 Technical Report 090644-3-0000-20-IFI-100 16.5.3.2 Other Support Types Tendons and Other Support Types: Support tendons will be in form of 20 mm diameter rock bolts except where specified otherwise. The tendons will be full column resin grouted with a fast setting capsule installed in the back of the hole. The rest of the hole will be filled with medium setting resin and the tendons will be spun to stall. The lengths of the tendons are tabulated below. The spacing of the tendons will vary depending on ground conditions. In good ground conditions (as per Rock Engineer’s assessment) support spacing can be opened up to 1.5 m x 1.5 m while in poor ground conditions, support spacing can be reduced to 1.0 m x 1.0 m. Weld mesh or chain link wire mesh or shotcrete should be used to support excavations and keep loose rocks intact in poor ground conditions as per the Rock Engineer’s assessment. The mesh should be galvanized to minimize the rate of corrosion, and its aperture size should be 100 mm x 100 mm with wire strand diameter of 4 mm. In exceptionally poor ground conditions (as per Rock Engineer’s assessment), timber sets should be used for both the hangingwall and sidewalls. Excavation dimensions 2.5 m (w) x 2.5 m (h) 3.0 m (w) x 3.0 m (h) Table 16.2: Tendon Support Requirements for Different Excavations Excavations Ore and waste drives for shrinkage stopes Waste pass, vent raise and RAW 4.0m (w) x 4.0m (h) Ramp, access ramp, haulage, crosscuts for the longhole stopes, mucking bays, orepass access, vent raise access Tendon length Comment 2.1 m Weld mesh or 50 mm thick plain shotcrete will be required in poor ground conditions 2.1 m Weld mesh or 50 mm thick plain shotcrete will be required in poor ground conditions 2.1 m Weld mesh or 50 mm thick plain shotcrete will be required in poor ground conditions 4.0m (w) x 6.0m (h) Loading bay 2.1 m Weld mesh or 50 mm thick plain shotcrete will be required in poor ground conditions 5.0m (w) x 6.0m (h) Workshop 2.4 m Locate workshop in good ground and avoid poor areas. 5 m long, 18 mm diameter 38 ton cable anchors will be required at 2 m x 2 m spacing. 6.0m (w) x 4.0m (h) Long hole stope ore drives 2.4 m Rock bolts will be 2.4 m long and 20 mm diameter at 1.2 m x 1.2 m spacing. 50 mm thick plain shotcrete should be used in poor ground conditions. 16.6 Mine Development The decline ramp system will be developed from surface (at an inclination of 8 degrees from the horizontal) using conventional drill and blast techniques. Broken rock from the ramp development will be mucked out using the 3.1 m 3 LHD that the mine already owns. Mucking bays will be developed every 100 m along the decline ramp. These will serve as temporary TWP Sudamérica S.A. Av. Encalada 1257 Of. 801, Santiago de Surco Lima 33, Perú (51-1) 4377473 Page 154
Page 1 and 2:
NI 43 — 101 TECHNICAL REPORT PULA
Page 3 and 4:
Pulacayo 1 000 t/d Phase I Feasibil
Page 5 and 6:
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116: Pulacayo 1 000 t/d Phase I Feasibil
Page 165: Pulacayo 1 000 t/d Phase I Feasibil
Page 217 and 218:
Page 219 and 220:
Page 221 and 222:
Page 223 and 224:
Page 225 and 226:
Page 227 and 228:
Page 229 and 230:
Page 231 and 232:
Page 233 and 234:
Page 235 and 236:
Page 237 and 238:
Page 239 and 240:
Page 241 and 242:
Page 243 and 244:
Page 245 and 246:
Page 247 and 248:
Page 249 and 250:
Page 251 and 252:
Page 253 and 254:
Page 255 and 256:
Page 257 and 258:
Page 259 and 260:
Page 261 and 262:
Page 263 and 264:
Page 265 and 266:
Page 267 and 268:
Page 269 and 270:
Page 271 and 272:
Page 273 and 274:
Page 275 and 276:
Page 277 and 278:
Page 279 and 280:
Page 281 and 282:
Page 283 and 284:
Page 285 and 286:
Page 287 and 288:
Page 289 and 290:
Page 291 and 292:
Page 293 and 294:
Page 295 and 296:
Page 297 and 298:
Page 299 and 300:
Page 301 and 302:
Page 303 and 304:
Page 305 and 306:
Page 307 and 308:
Page 309 and 310:
show all

Pulacayo Project Feasibility Study - Apogee Silver

Create successful ePaper yourself

Delete template?

Save as template?