Drill and Blast

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  • Topic: Rock, BLAST, Particle size distribution
  • Pages : 5 (1366 words )
  • Download(s) : 256
  • Published : September 1, 2012
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Executive Summary

We have completed a Drill and Blast review of the current and expanded ore resource with intentions of increasing from 50k tonnes ore production to 200k tonnes ore production in the lower domain ore body. Current drill and blasting methodology will cause operational and production inefficiencies in the expansion and is recommended to change. These changes are based on the expansion tonnage requirements, and the change in the rock type to a harder more competent rock mass which requires additional considerations and resources to successfully transition through the expansion. Key points of the current and expansion drill and blast program are as follows:

1. Current drilling and blasting practice produces a blasted size distribution that is optimal for the material handling systems (P20: 55mm, P50: 200mm, P80: 400mm). Existing drill and blast configurations are not recommended to be used in the expansion due to the increased strength and competency of the rock. Modification will be required to the drill and blasting program. 2. Due to the wet regime in the expansion the explosive will need to change from Heavy ANFO to Emulsion (1.25). Drilling metrics predominantly the burdens and spacing are recommended to be lowered. Due to the strength of the rock blast damage to the pit walls will need to be managed with buffer blasting. Additional opportunities that are recommended further study include Pre Split Blasting, and Electronic Detonators (IKON etc.). 3. The cost of drilling and blasting in the expansion is estimated to almost double due to the strong rockmass. 4. Drill and blast designs in the waste have been optimized for quick vertical advance in these zones. As waste does not go through the material handling systems optimization was possible by increasing the size distribution of the blasted material. 5. Using a low density explosive is endorsed to reduce AN contents and will work in the poor Waste rockmass. With any low density explosive segregation of the dilatants will need to be monitored. 6. Basic site storage and delivery was reviewed Bins, tanks, and explosive delivery vehicles are recommended. 7. Drilling requirements in the expansion will increase 8 fold due to increase in rock strength effective penetration rates, and the additional required ore tonnes. Sandvik’s drills for production and buffer blasting are recommended.

Table of Contents

1.0 Current and Proposed Future Size Distribution Practices……………..3

2.0 Drill and Blast Redesign for the Lower Ore Domain…………………...6

2.1 Drill and Blast Design Production Blast……………………………………6 2.2 Peak Particle Velocity (PPV)……………………………………………….8 2.3 Drill and Blast Design Buffer Blast………………………………………...8 2.4 Recommended Drill and Blast Design……………………………………...9

3.0 Cost Comparison Existing versus Future Ore…………………………..9

3.1 Costs for Existing Ore……………………………………………………...9 3.2 Drill and Blast Costs for the Lower Domain………………………………10

4.0 Rapid Access through Waste……………………………………………..11

5.0 Low Shock Explosive……………………………………………………..11

6.0 Basic Site Storage, Transportation, and Explosive Delivery to the Blast Site ………………………………………………………………………………….12 6.1 Heavy ANFO Loading Truck………………………………………………………………14

7.0 Drill Rig Requirements……………………………………………………15

7.1 Drill Requirements Upper Ore Domain…………………………………….15 7.2 Drill Requirements Lower Ore Domain…………………………………….15 7.3 Drill Selection……………………………………………………………….15

Attachments:
“Q1 Current Practice.pdf”
“Q1 Deeper Ore.pdf”
“Buffer Blast Design.pdf”
“Deep Ore Blast Design Production Holes.pdf”

1.0 Current and Proposed Future Size Distribution Practices

Based on the current blasting in the ore with existing rock properties it is estimated that the cumulative size distribution of the blasted materials profile is P20: 55mm, P50: 200mm, P80: 400mm. A more detailed view of the size distribution curve can be...
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