Drilling is the creation of Artificial cavity into rock for the placement of Explosive.
Drilling can be done for different purpose ranging from:
1. Rock Blasting
2. Oil and gas production
3.rock stability and Safety purpose
4. Exploration purpose
5. Water and borehole drilling
6. Among others.
Drilling for rock Blasting is done for the loading of Explosive into the rock formation so as to generate the shock and gas energy require to fragment the rock mass.
Planning for an event makes the event or operation more perfect and productive.
The condition of the drill holes and arrangements in place of pattern design of the hole drilled for Blasting has great impact on the effectiveness of the blasting.
Some of the parameters that explains the status of blast holes are:
1. Burden: the perpendicular distance between the first drill holes row to the nearest free face. Or in others way, the distance between two adjacent
Hole rows.this affect distribution of energy within the holes during initiation.
2. Spacing: the distance between two adjacent holes on thesame row.
3. Hole diameter: the circumferential size of the Drilling bit
4. Hole depth: the vertical depth of the drill hole.
5. Hole drill angle, and others
The accuracy of all this drill parameters have great effect on the functionality of the Explosive energy.
To avoid any form of deviation in drill hole angle, error in spacing, burden and other possible mistake we must ensure all planing is perfected, drilling team are aware of the drill plan and purpose, the rock properties and location conditions are studied and account for.
During drilling, the supervisor should ensure drilled holes are checked, count and measured to avoid any form of oversight in depth, design.
Some effect of oversight during drilling:
1. Hole closure with drill cuttings resulting into depth shortage. Depth shortage directly result into reduction in tonnage. The volume of material blasted is a function of hole depth, decrease in hole depth result into decrease in tonnage.
2. Unexpected site Accident: drilling in an unknown geographical so or unknown rock mass formation may result into unexpected accident during drilling. Just as the condition of each rock layers are study during oil and gas drilling to understand the bottom pressure and fluid static condition. Thesame during drilling operation for Blasting, rock been a heterogeneity material it varies in strength and characteristics with depth. Pre-planning before drilling operation proceed will help to avoid any form of drilling Accident. It will also give sufficient information to Blasting team on the required energy needed to fragment the rock mass productively.
3. Poor Blasting output: poor drilling plan (PDP) and poor drilling supervision (PDS) makes blasting team to be stranded of information about the rock formation. Detailed information about the rock mass can best be optained from drill cuttings. Proper supervision of drilling makes the blasting teams to have sufficient information to plan for the blasting operation. The availability of enough information about the rock mass help the blasting team to plan for the charge distribution and density needed to fragment the needed rock mass. It also help blast team to account for possible blast accident. Having understanding of the rock strength, variation in composition, rock structure (dyke,sill among others) help to control charge distribution within the holes column to prevent improper use of charge energy which can result into flyrock, ground vibration among other blasting impact.
In general, drilling operation should be well planed and supervise to avoid any oversight and ensure enough information is provided on the drill log for blasting team to rely on.
Let Blasting been done safely in accordance to National, global and state laws and regulations.
Say no to illegal mining and use of Explosive and Blasting material as it deadly and bad.
Let Blast safe and relate safely with the ecosystem and earth lithosphere, this is our home.....
Thanks for reading...
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