Open pit mining
It is recommended that the following aspects are examined in the next study stage:
| ● | Review of drillhole records and geological data for improved conceptual understanding of the shallow groundwater system. |
| ● | Sampling of the springs and wetland to the north and west of the Main Pit. |
| ● | Shallow drilling (auger or diamond drilling) to install shallow piezometers and prove the depth of the colluvial system, and whether it supports a water table upstream of the springs and within the wetland area. |
| ● | Permeability testing of the existing standpipe piezometers. |
| ● | Construction of a trial dewatering borehole in the alluvial deposits of the main river channel to investigate its hydrogeological properties and allow for a targeted dewatering strategy, if required. |
| ● | Construction of at least one trial dewatering borehole into a major fault structure and surrounding piezometer array to investigate fault properties and surrounding fracture connectivity. |
| ● | The installation of multi-level vibrating wire piezometers is recommended to improve the understanding of the hydrogeological system. The following targets are recommended: |
| o | At least one major and one local fault structure. |
| o | The shallow aquifer system in hill-slope colluvium (further to positive results from exploratory drilling). |
| o | The Tarapaya Formation (where saturated). |
| o | UH3 orthogonal to the existing standpipe piezometers for triangulation of groundwater pressure. |
| o | UH3 north and south of the river. |
| ● | It is recommended to develop a weathering horizon model and collect additional geotechnical data as per Section 16.3.4 of the Silver Sand PFS Technical Report to increase the geotechnical model reliability. Geotechnical slope design criteria should be updated when further information is available and pit slope stability should be assessed under static and seismic conditions. |
| ● | The ongoing geotechnical program should be continued to collect additional data for pit wall angle stability analysis. |
| ● | Soil and weathered core samples should be collected for lab testing. |
| ● | It is recommended to undertake a detailed bench height and dilution study. The study should consider lateral block extents, flitch / bench heights, equipment specifications, drill and blast, mining rates, dilution and grade control strategies, and geotechnical implications. Grade control strategies, such as grade control drilling and blast movement monitoring should also be further evaluated. |
| ● | It is recommended that quotes from multiple Bolivian mining contractors are collected to firm up the mining costs estimates for the open pit operations. New Pacific is recommended to acquire binding (or “firm”) quotes for the primary mining contractor to achieve a higher level of accuracy for the FS. |
| ● | Further work should be conducted to identify alternative dump locations, i.e., in the creek gully, to reduce haul distance. |
| ● | The amount of time required for site development and construction will significantly influence the value of the Silver Sand Project. As part of the FS, New Pacific is recommended to prepare an operational readiness assessment and create a detailed development schedule to ensure the Silver Sand Project is fully prepared for operation. |
Infrastructure
| ● | Location and placement of accommodation camp, waste dump, crusher, and process plant to be confirmed following civil geotechnical and condemnation drilling. |
| ● | Continue to negotiate with power authorities to confirm the cost estimate, and that sufficient grid capacity can be provided. |
| ● | The site requires significant earthworks to construct the supporting infrastructure. New Pacific to investigate the potential for engaging contractors who are familiar with this type of work to obtain an accurate and dependable estimate of costs. |
