Mining, Technology Management in Mining - Essay Example

CHAPTER I INTRODUCTION The Santa Rosa Gold Project has been in existence as other individual mine works, even before the 1700s when the Spanish conquistadors first arrived, and is currently 100% owned by the Red Eagle Mining Corporation, which in 2011, also purchased the San Ramon Gold Deposit. There are over 1,700 adits (horizontal entrances to underground mines), over 60 areas of sluice mining that have been mapped to date. Santa Rosa Gold Mining Project (Fig. 1, Santa Rosa, 2014) The Santa Rosa Project lies within the Cajamarca-Valdivia which encompasses a Palaeozoic metamorphic basement complex and the Cretaceous Antioquia batholith (Red Eagle, 2014a). The project covers 320 square kilometres, and the latest gold mining project at San Ramon, is located 70 km north of Medellin, in the Department of Antioquia, Colombia (Red Eagle, 2014b). The elevated area is 2,400 metres high, resting on a plateau. Historically, the Tumaco people on the Pacific coast side, are considered to be the earliest miners in gold and gold works, dating back to around 325 B.C. Santa Rosa Phase I Drill Hole Plan (Fig.2, CNW, 2012a) Gold mineralization occurs in a multitude of high-grade mesothermal quartz vein within a ductile-brittle shear zone in the Antioquia batholith. The shear zone trends east to west, is 50 millimetres wide and 2 kilometres long. The zone occurs from a dilation between two regional-scale NW-striking faults, and high-grade gold mineralization has been delineated within that shear zone through drilling to depths of over 600 millimetres (Red Eagle, 2014b). Currently, the San Ramon deposit presents measured and indicated resources of 2,721,658 t grading 5.10 g/t Au and an inferred resources of 831,370 t grading 4.16 g/t Au. Initial San Ramon Shear Zone Schematic Long Section (2012) (Fig. 3, CNW, 2012b) The San Ramon shear zone is represented in the above figure by intercepts SR-003 - 39.7m at 1.59 g/t Au incl. 5.2m at 4.93 g/t Au, SR-011 - 58.9m at 1.00 g/t Au incl. 5.1m at 5.37 g/t Au, SR-015 - 15.1m at 2.51 g/t Au incl. 3.7m at 6.62 g/t Au, and SR-016 - 54.0m at 1.01 g/t Au incl. 7.8m at 5.25 g/t Au (CNW, 2012).. Preliminary economic assessment (PEA) shows an NPV (5%) of $152 million, IRR of 47%, a pay back of 1.4 years, and cash costs of $540 per ounce, according to company headquarters (Red Eagle, 2014b). One of the biggest issues for mining in this area is the lack of suitable roads for transporting large equipment and loads. In San Ramon, as of this year (2014), several roads have been built close by the mining operation, but more are required in order to speed up transportation efficiently. 1.1 Report Objectives The key objectives for this research is to determine the mining operations in place and what technologies are currently being used, including what might be proposed for implementation in the future. These objectives are: Determining current practices in load intake and output, and making suggestions of how to speed up the process for more efficiency; Regulations currently in place to avoid risks and hazards in mining operations, and on the environment; Reviewing personnel safety procedures (regulations) currently in place, including training practices of local workers by management; Outlining three current technologies and making suggestions for more efficient up-to-date advances, including processes; Determine ability to set up efficient communications headquarters, including a software management process to oversee projects and parts of projects. With this particular area of Columbia, there are challenges that must be faced and examined, such as the location, how mining operations affect the crew, how it affects any nearby towns and villages in terms of environmental impact, and viability over long term operations. The San Ramon mining project is fairly new and, therefore, it is experiencing all the birthing pains of any new mining infrastructure, including the initial mapping procedure for where drilling can be established to ensure the most efficient return. The latest 2014 Feasibility Assessment is soon to be published in late September, 2014, but already it is looking at being a very profitable mining operation (Red Eagle, 2014c). CHAPTER II 2. INDENTIFYING THREE TECHNOLOGIES In the initial phases of the Santa Rosa and San Ramon gold assessments, core drill holes were conducted using diamond drill rigs at one metre sample intervals, using the standard industry practice (See Appendix A). Samples were then prepped and screened by Acme Analytical Laboratories in Medellin, and then sent on to Santiago, Chile, for metallic fire assay and multi-element IC-MS analysis (CNW, 2012). In the fire assay, gold value was determined at a charge of 30g with an AA finish, and, if over 10 g/t Au, samples were re-assayed with a gravimetric finish (CNW, 2012). In the newly completed Feasibility Study of 2014, the San Ramon Gold project is described as an underground mining operation, which uses conventional shrinkage methods, with delayed backfill that uses dry filtercake process tailings and developmental waste. Ore processing is conducted through single-stage crushing, SAG milling and floatation with concentrate re-grinding, followed by a conventional carbon-in-leach (CIL) process, which combines float tails and reground concentrate to produce onsite gold doré (Red Eagle, 2014c). Mine backfill and surface dry stacking will be created with detoxed and filtered leached tailings. What should be noted here is that San Ramon is similar to a number of other small deposits across the Santa Rosa landscape and, as there are plans to expand into these small deposits, much of the major equipment and project design was initially built to accommodate further expansion without disrupting production. However, it would take just under $15 million to add on a ball mill, tower mill, a filter press, and three more leach tanks to keep production output at a steady pace (Red Eagle, 2014c). 2.1 Mobile Metal Ion (MMI) Geochemistry Technology In determining the precise places to make first incursions into the soil to locate viable ore and gold deposits, a MMI geochemistry tool was used over the Santa Rosa project area, including San Ramon, to find the most probable locations for completing first drillings in core samples (Hicks, 2012). So far, it has proven to be very accurate for the team at the Santa Rosa project, providing a nearly 100% accuracy. Using the MMI geochemistry technology provides an innovative process of analysing metals in soils, along with other related materials. Samples of about 200 to 250 grams, are extracted by using solutions of organic and inorganic compounds rather than stringent conventional acid or cyanide-based digests. Metal ions are detached from their loosely bound home base soil particles, by strong ligands in the MMI solutions, which then causes the ions to move up to the surface. The ions are then collected and put through careful soil sampling strategies, high-level chemical ligands and the use of ultra-sensitive instruments. This provides a clear interpretation of anomalous areas, ripe for conducting first level drilling operations (SGS, 2014). The benefits of using MMI technology in soil geochemistry, over any other in the market is: there are very few false anomalies; results are sharp and focused; definition of metal zones and associations; low background values (low noise); low limits of detection; and good detection of deeply buried mineralization (SGS, 2014). In essence, this process most likely, does not need to be upgraded at the Santa Rosa/San Ramon sites, because it is currently the most efficient process on the market in this area. 2.2 Delayed Backfill Using Dry Filtercake Process Tailings and Developmental Waste In first examining this operation, understanding what dry filtercake process tailings, combined with developmental waste, is important in how backfill is created. Tailings are the materials left over when the valuable section of ore is separated out from the main body, and can be very small. Developmental waste is then combined and, in this case, is transported by conveyor or truck, to be deposited in a layered effect in a designated area (Engels, 2012). Example of Dry Stacking of Tailings from a Conveyor at La Coipa, Chile (Fig. 4, Engels, 2012) Backfilling is uses to fill up stopes (open areas) during the mining process. Therefore, in delayed backfilling, the stopes are filled up with the product created by combining dry filtercakes tailings and developmental wastes. This also prevents any future cave-ins that might leave depressions in the ground above. Backfilling is used most commonly in Canadian metal mines and is a good passive hard rock mine support (Emad et al., 2014). In the case of the Santa Rosa/San Ramon mines, the backfill is most likely a paste fill application, as the ore is chemically processed, and the non-valued materials are then mixed with the developmental wastes. 2.3 Conventional Carbon-In-Leach (CIL) Technique The San Ramon project uses a single-stage crushing process in ore mining which crushes large-sized ores down to about 5mm, replacing two and three-stage crushing methods used in the past (Lindgarden, 2014). SAG milling and floatation with concentrate re-grinding is part of the processing and finally, is followed by a conventional carbon-in-leach. This activity, generally, is the recovery process where a slurry of gold ore, cyanide and carbon granules are mixed together, the gold content is dissolved and absorbed, finally, on the carbon. The carbon is separated from the slurry to remove the gold (Zanbak, 2012). Sulphuric acid and cyanide salts are used in most conventional dissolution processes. Reducing the ore down to at least 5 mm, is one of the main contributors to successfully separating as much gold as possible from the ore. With smaller pieces, there may be a more advanced degree of natural liberation whereby the gold separates from the ore easily. The San Ramon project uses tanks for the leaching process, which means that crushed/milled ores or floatation concentrates are chemically treated in open tanks. Metal salts are extracted, under atmospheric pressure conditions, at an accelerated rate. This is most commonly known as a “semi-closed system.” Three types of tank leaching techniques are shown in the figure below. Leaching Processes in Mining Operations (Fig. 5, Zanbak, 2012) Nearly 60 to 65% of mined gold production uses tank leaching and other supplementary processes to recover any accompanying silver, which is currently under consideration for the San Ramon mine. Activated carbon is used in carbon-in-pulp (CIP) and in carbon-in-leach (CIL), which has already been described. Heap leaching is another process which is more appropriate for larger loads of low-grade ore (about 0.5 to 1 gr/ton), which would not work well in tank leaching. Currently, 20% of mined copper and gold production uses the heap leaching techniques (Zanbak, 2012). Primary factors for determining the best applicable leaching technique, along with lixiviant chemicals are, first, the mineralogical ore composition and, secondly, the economic feasibility of the ore deposit, which is based on head grade and reserve, environmental management costs, market price forecasts, and magnitude of required capital investment anticipated. In total, a typical mining operation, using leaching technologies and processes, will move through the following management infrastructure: Ore excavation (San Ramon is underground); Ore staging and waste rock storage; Ore crushing and/or milling, ore concentration by flotation; Ore Leaching (CIP, CIL, or Heap); Leach Solution Processing and electrowinning; Tailings Disposal (Tank/Pressure leaching); and Mine closure and site rehabilitation (Zanbak, 2012). Operational Units in a Mine Utilizing Ore leaching Technologies (Fig. 6, Zanbak, 2012) Chapter III 3. Analysis of the Technologies Chapter IV 4. Economic Model Appendix A: Intercepts and Drill Hole Specifications for San Ramon Shear Zone (2012) San Ramon Shear Zone Gold Intercepts (2012) Hole ID From (m) To (m) Length (m) Au (g/t) SR-001* 343.8 363.3 19.5 1.11 incl. 343.8 346.5 2.6 3.78 SR-002* 166.0 182.0 16.0 0.87 incl. 166.0 168.0 2.0 4.49 SR-003* 297.3 337.0 39.7 1.59 incl. 317.0 322.2 5.2 4.93 incl. 332.0 333.0 1.0 29.40 SR-004* 87.9 96.0 8.1 1.17 incl. 87.9 90.3 2.3 2.75 SR-005* 213.0 219.1 6.1 1.33 incl. 218.3 219.1 0.8 7.64 and 238.0 252.5 14.5 1.07 incl. 238.0 242.3 4.3 2.48 SR-009 109.0 121.5 12.5 1.09 incl. 115.4 115.8 0.4 13.10 SR-010 141.0 161.3 20.3 0.40 and 172.5 176.1 3.6 0.66 SR-011 80.2 139.1 58.9 1.00 incl. 112.0 117.1 5.1 5.37 incl. 138.0 139.1 1.1 8.75 SR-012 191.0 207.0 16.0 0.25 SR-013 119.8 155.0 35.2 0.79 incl. 139.0 139.5 0.5 18.90 SR-015 179.0 194.1 15.1 2.51 incl. 181.9 185.0 3.2 3.69 incl. 190.5 194.1 3.7 6.62 SR-016 56.0 110.0 54.0 1.01 incl. 83.1 90.8 7.8 5.25 SR-017 85.0 96.4 11.4 2.19 incl. 94.0 94.9 0.9 20.30 SR-018 104.5 109.5 5.0 0.79 and 120.0 124.5 4.5 0.65 and 228.0 231.0 3.0 19.11 incl. 229.2 230.2 1.0 57.30 SR-019 78.9 83.0 4.1 2.62 incl. 80.8 81.3 0.5 17.40 (Table 1, CNW, 2012) Drill Hole Specifications (2012) Hole Easting Northing Elevation (m) Azimuth Dip EOH (m) SR-001 857600 1223488 2468 180 -50 636 SR-002 856520 1223365 2453 220 -50 409 SR-003 857792 1223457 2450 180 -45 472 SR-004 856514 1223311 2469 180 -45 302 SR-005 857405 1223383 2491 180 -45 310 SR-006 856629 1223214 2467 180 -45 250 SR-007 857416 1223112 2495 180 -45 209 SR-008 856767 1223165 2490 180 -45 315 SR-009 856960 1223267 2520 180 -45 241 SR-010 857227 1223330 2472 180 -45 242 SR-011 857692 1223252 2463 180 -45 353 SR-012 857227 1223330 2472 215 -45 246 SR-013 857602 1223300 2464 180 -45 280 SR-014 856237 1222866 2534 90 -55 401 SR-015 857909 1223295 2481 180 -45 210 SR-016 857434 1223251 2481 180 -45 202 SR-017 856721 1223291 2461 180 -45 167 SR-018 857498 1223281 2500 180 -45 329 SR-019 856285 1223336 2465 180 -45 184 SR-020 856004 1223542 2500 320 -70 443 SR-021 857313 1223269 2510 180 -45 122 SR-022 856004 1223542 2510 180 -45 296 SR-023 857313 1223269 2510 187 -45 194 (Table 2, CNW, 2012) Read More