MT/T 702-2020 in English
VALIDTechnical specification of fire fighting by grouting in coal mines
- Issued on:2020-07-09
- Implemented on:-
- File Format:PDF
- Delivery:Via email within 1~3 business days
$194.00
Introduction
Background of Standard Revision and Technological Evolution
This standard replaces the 1997 version of MT/T 702. The main technical updates include: expansion of grouting material types to 7 categories, deletion of grouting coefficient index, optimization of soil-water ratio calculation formula, and addition of slurry pipeline head calculation and other 15 key technical improvements.
Comparative analysis of core parameters
| Parameters | Requirements of the 1997 version | Requirements of the 2020 version | Explanation of changes |
|---|---|---|---|
| Soil-water ratio | 1:2~1:5 | 1:1~1:5 | Expand the scope of application |
| Slurry coverage thickness | Not specified | 0.05~0.25m | New quantitative indicators |
| Grouting volume calculation | Single formula | Calculation by working face/mine | Increase accuracy |
Key technical indicators of grouting materials
The specification requires that grouting materials must meet the following requirements:
- Settling velocity: 1~10mm/min
- Plasticity index: 7~14 (the limit can be relaxed for fly ash)
- Colloid content≥60%
When using a wet ball mill to process gangue, the particle size must be ≤5mm and the proportion of particles below 0.1mm must be greater than 60%.
Key points of project implementation
Pipeline design specifications
The critical diameter calculation formula is updated to:
D1=3√[Q2×αλρs/3600π2g(ρm-ρ)]
The pipeline is required to adopt a "low in the middle and high at both ends" layout, and flushing is required immediately after grouting each shift.
Effectiveness inspection system
Establish a three-level monitoring mechanism:
- Gas analysis once a week in the fire prevention area
- Sampling once a day in the fire extinguishing area
- Inspection of the ignition working face every shift
Implementation suggestions
Case: After a mine adopted the automatic pulping system, the slurry ratio error was reduced from ±15% to ±3%, and the fire extinguishing efficiency was increased by 40%.
It is recommended to give priority to the mechanical stirring pulping method, and to establish a grouting ledger to record 6 types of data.
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