Summary of Energy Exchange Blasting Test for Conch Water Medium in a Certain Area of Central Hunan

Water medium energy exchange blasting is an analysis of the blasting mechanism from the perspectives of thermodynamics and chemistry. If a "certain amount" of water is added to an "explosive thermodynamic system", according to the laws of thermodynamics and the law of conservation of mass, the "energy" released by the explosion of explosives will be converted into the internal energy of water in an adiabatic "explosive thermodynamic system". It is well known that water is the substance that is most likely to absorb or release energy. At normal pressure, when the temperature reaches 2000 ℃, it begins to decompose into hydrogen and oxygen, accumulating the explosive energy of water and coexisting explosive gas substances. Under the high pressure conditions of 10 × 104MPa at 3000 ℃ during explosive explosion, further chemical reactions will occur to generate new substances such as H2, O2, CO2, NO2, etc.
Calculations show that the volume of these high-temperature and high-pressure explosive gaseous substances has increased by 1100 times under standard conditions. Due to the high compression of these gaseous substances, they accumulate enormous potential energy, which will follow the principle of instantaneous detonation theory that "the dispersion of detonation products follows the law of equidistant interfacial groups". It mainly compresses the explosive medium through rapid expansion and work, causing it to break and complete the blasting operation.
According to the ideal gas state equation, the explosive pressure on the hole wall during the "water medium energy exchange blasting" can reach 330 Mpa under quasi-static conditions after the explosion is completed. According to the blasting theory, the peak pressure of the explosive can be increased by 10 times. Therefore, the peak pressure of the explosive on the hole wall during the explosion can reach 3300 Mpa, which is 6.6 times the pressure of the carbon dioxide explosion on the hole wall. According to the engineering blasting peak pressure theory, it can even reach 4661 Mpa. Therefore, theoretical calculations indicate that "water medium energy exchange blasting" mainly relies on the mixture of water medium and explosives to produce gaseous substances that rapidly expand and work, squeezing the blasting medium to break it up and complete the blasting operation.
The test area is located in the middle of the West Mountain 195 platform. The geological conditions are excellent, with the rocks mainly consisting of medium-thick layered blocky limestone. The joint and fissure development is slight. The rock's explosiveness is of medium to upper quality throughout the entire mining area. The slope surface is flat without any depression. There are no significant deviations in the resistance lines of the front row. The test conditions are favorable. Drilling was carried out using the CM30 drilling machine with a diameter of 168mm. 80° inclined blast holes were used. The on-site drilling was normal. No karst caves or fissure holes were found. The actual hole depth was basically within the deviation range of the designed hole depth. The surface loose material was 3-5 meters thick. For some blast holes, the hole opening and the hole wall were poor. 1) Construction Process
Selection of test area - Preparation of blasting design - On-site hole placement - Drilling operation with drilling machine - Hole acceptance - Preparation of blasting materials - Pre-blasting meeting - Blasting operation - Post-blasting inspection - Blasting summary
2) Loading Process
Loading of explosives at the bottom to a distance of 8.5 meters from the hole opening - Foam application of explosives to a height of 7.5 meters (if the foam height is insufficient, emulsified explosives can be used to complete the filling) - Water bags filled to a distance of 5 meters from the hole opening (three water bags are bundled and lifted at a time) - Upward filling of rock debris.

Hole Depth	Step height	Aperture	Perforation angle	Number of Holes	Rank	Total footage	Water bag height
16.5 Rice	14 Rice	168mm	80°	20	2 Arrange	330 Rice	2.5 Rice
Front resistance line	Hole spacing	Row spacing	Design unit consumption	Design dosage	Number of detonators	Explosive ore quantity	Design filling
6 Rice	7 Rice	5 Rice	0.144	4200	60 Post	29110 Ton	5 Rice

Hole number	Hole Depth	Distance from medication to orifice	Number of water bags	Filling height	Water bag height (calculation)	Charge height (Calculation)	Single hole charge quantity (estimated)
101	16.4	7.5	6*3	5	2.5	8.9	224
102	16.7	7.5	5*3	5.2	2.3	9.2	232
103	16.5	7.5	5*3	4.8	2.7	9	227
104	16.5	7	5*3	5	2	9.5	240
105	16.7	7.5	5*3	5	2.5	9.2	232
106	16.5	7.5	5*3	5.2	2.3	9	227
107	16.7	7.2	5*3	5.1	2.1	9.5	239
108	16.7	7.5	5*3	5	2.5	9.2	232
109	16.4	7.5	5*3+2	4.9	2.6	8.9	224
110	16.6	7.5	5*3	5.2	2.3	9.1	230
201	16.7	7.5	3*3	6.5	1	9.2	232
202	16.6	7.5	5*3	4.8	2.7	9.1	230
203	16.2	7.5	5*3	5	2.5	8.7	219
204	16.2	7.2	5*3	5	2.2	9	227
205	16.6	7.2	4*3+1	5	2.2	9.4	237
206	16.6	7.5	5*3	5.1	2.4	9.1	230
207	16.2	7.4	5*3	5.1	2.3	8.8	222
208	16.4	7.2	5*3	4.9	2.3	9.2	232
209	16.3	7.5	5*3	5.2	2.3	8.8	222
210	16.5	7.5	5*3	5	2.5	9	227
总计			297个		46.2米	181.8米	4585kg

The diameter of the water bag is 75mm and the length is 60cm. They are bundled and lifted on-site in groups of 3, and after being placed in the hole, the actual measurement is approximately 50cm. Due to the mismatch between the water bag specifications and the diameter of the blast hole, the difficulty of on-site operation and the operation time have increased, and the blasting operation time has approximately increased by 1/3. A large number of water bags have the phenomenon of insufficient water filling, and some water bags have leakage during on-site operations. All detonators are of Aurokai high-strength type. There are 2 detonators per hole in the hole, and 1 detonator per hole outside the hole for initiation. 9 detonators are connected in series between the holes, and 10 detonators are connected in parallel between the rows. In total, there are 60 detonators.
According to Professor Qin's suggestion, it is hoped to increase the delay time between holes, and the network connection has changed compared to before, increasing the delay time between the two holes in the row.
On-site connection diagram and delay time
The total amount of explosives used in this blasting was 4585 kg (bulk 4528 kg, 90% emulsion 57 kg). The single-unit consumption of explosives was 0.158 kg/t, and the amount of explosives used per hole was approximately 229.25 kg. No collapse cavities or fractures were observed during this blasting. There was no abnormal consumption of explosives.
Based on the total height of the actual charge (181.8 meters), the charge per meter was calculated to be 25.22 kg. The total height of the water bags was 46.2 meters. It was calculated that this blasting saved 1165.16 kg of explosives, and the blasted ore volume was 29,110 t. The single-unit consumption of explosives decreased by 0.04 kg/t.。 After on-site inspection and analysis after the blasting, the overall blasting effect was good. The blasting pile was compactly piled up, the blasting pile was loose, and the throwing was obvious. The throwing distance was about 30 meters, and the settling height of the blasting pile was about 2-3 meters, which was higher than before. No obvious large blocks were seen on the surface layer. The overall ore block size was larger than before. After the blasting, there was a slight aftershock cracking phenomenon, and the lateral shaking cracking was obvious.
The west side of this blasting pile was chiseled using R984, and the east side was chiseled using CAT988. The looseness of the blast pile was slightly lower than that of the previous normal blasting, but it did not affect the chiseled efficiency. The chiseled work on both sides was not thorough, and there was no obvious foundation after chiseled.
In terms of harmful effects of blasting, no flying rocks or blasting guns were generated after blasting. The blasting vibration was significantly reduced, and there was no noticeable vibration sensation 300 meters away. The blasting noise was small. The dust rate (dust) generated during the blasting operation decreased (due to the dust raised by the blasting of the ore to the ground during the blasting), but the dust did not significantly improve after blasting.

Diesel engine
				Model number	D10.36T20	Operating speed	1850rpm
Manufacturing Plant	Steyr	Fuel tank capacity	480L
Rated power	266kw
Screw air compressor
				Manufacturing Plant	Zhigao	Exhaust air volume	18 m3/min
Head manufacturing factory	GHH	Maximum wind pressure	17bar
Function parameters
				Aperture range	110-152 mm	Supporting impactor	4inch、5inch
Automatic change of drill hole depth	28m	Rotation speed	0-105 r/min
Drill pipe diameter	89mm /102mm	Rotational torque	4310N.M
Number of stored drill rods	6+1	Drill rod length	4m
Recommended aperture	138mm
Drill arm function
				Drilling arm form	Single straight arm	Promotion method	Oil cylinder wire method
Total length of thruster	8100 mm	Advance the itinerary	4600mm
Promote compensation	1200 mm	Maximum propulsion speed	0.88 m/s
Maximum propulsion force	34.5 KN	Maximum pulling force	67.6 KN
Chassis
				Walking speed	High speed: 3 km/h	Maximum driving force	117.7 KN
Low speed: 1.5 km/h
Climbing ability	25°	Track frame swing angle	± 10°
Ground clearance	420 mm
Weight and dimensions
				Width	2500 mm	Transportation height	3280 mm

1. The single consumption of explosives decreased by 0.04 kg/t this time, with a reduction rate of about 20%, saving approximately 6,701 yuan in explosives costs, and eliminating the cost of water bags of 594 yuan. The total savings amount to 6,107 yuan.
2. The blasting vibration has decreased somewhat, but due to the lack of specialized instruments for detection, the extent of the vibration reduction cannot be compared and analyzed through data.
3. The height of the explosive pile after blasting is high, and the compactness has decreased, resulting in a reduction in the proportion of fine ore.
4. The operation is cumbersome. Before the operation, water bags need to be filled with water, and during the operation, the water bags need to be lifted. This adds about one hour to the blasting operation time.
5. This time, the water bag specification is 75mm (the hole diameter is 168mm), and three water bags need to be tied below to ensure the tightness between the water bag and the hole wall. This increases the operational difficulty. Later, custom-made water bags that match the hole diameter can be used.
6. This blasting experiment adopts a two-row blasting method using a 7*5 grid parameter. The loading height of the explosives and the height of the water bags are in a ratio of M = 9:2.5. This section has good explosibility, and the large block rate after blasting is within the controllable range. In the future, different M values will be selected based on the geological conditions of different sections, and experiments will be continuously conducted to obtain the optimal M value suitable for the Shuangfeng Mine, ensuring the blasting effect while reducing the consumption of explosives.
12. Blast Photos

Post-explosion frontal shot

Shot from the top platform (from west to east)

Shot from above on the platform (from east to west)

The posterior commissure is clearly split.

The looseness at the top of the gun pile has decreased.

After loading, there is no solid base and the loading on both sides is not thorough.