AU745079B2 - Water spraying dust suppression system for shearer - Google Patents

Description

Our Ref:7463640 P/00/011 Regulation 3:2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT 4 4* Applicant(s): Address for Service: Yankuang Group Corporation No. 40 Fushan Road Zoucheng City Shandong 273500 People's Republic of China DAVIES COLLISON CAVE Patent Trade Mark Attorneys Level 10, 10 Barrack Street SYDNEY NSW 2000 Water spraying dust suppression system for shearer 4* Invention Title: The following statement is a full description of this invention, including the best method of performing it known to me:- 5020 P:\WPDOCS\YSpspie\746364o5i 00 3 .nuary 2002 -1- WATER SPRAYING DUST SUPPRESSION SYSTEM FOR SHEARER The present invention relates to a water-spraying dust suppression system located in a shearer, especially to a high pressure water-spraying dust suppression system located in a shearer used at a fully mechanized coal mining face.

Dust concentration raised by a shearer amounts to about 3000 6000 mg/m 3 at a fully mechanized coal mining face of an underground coal mine. To suppress coal dust is a key and long-standing problem in China.

Inner or outer water spraying dust suppression system is generally used in the prior art.

However, the dust suppression systems are not satisfactory because nozzles are blocked .i.

frequently so that the systems can not work normally. Practices at home and abroad prove that pressurized and atomized water is an effective way for suppressing coal dust.

However, this way has the following defects: Forexample, in the prior art system a pump for a water spraying dust suppression system is located in a gate. Therefore, high pressure water has to be supplied from the gate to the shearer through a high pressure hose. In general the hose is laid in a cable clamp from the gate to the shearer. The arrangement has Sthe following defects: When the shearer reciprocates along the working face, the high pressure hose is worn by the cable clamp and the cable. The pressure hose is easily damaged, because it moves together with the shearer and has a smaller bend radius. Since the pressure in the hose is very high, operators may be injured by high pressure water spraying from the damaged portions of the hose once the hose is damaged. Since a structure of an outer spraying water system generally occupies a larger space as well as a region covered by sprayed water and structures of nozzles are designed poorly, the nozzles are blocked frequently and a large amount of water is expended by this system. For the above reasons, the effects of the spray water and dust suppression of this kind system are unsatisfactory and the spray system can not normally work within the predetermined lifttime.

S, S T--he object of present invention is to provide a water spraying dust suppression system for I I~ III I- I P:\WPDOCS\DYS\pccic\7463640spc.dom.3 l =uL 2002 -2a shearer. According to the system, lower pressure water is pressurized in the shearer, then high-pressure water can form a water fog curtain at two ends of the shearer to separate the operation space of the operators from the working space of the shearer, and form a water fog for suppressing the dust raised by the shearer during cutting coal.

According to one aspect of the present invention there is provided a high pressure water spray dust suppression system for use with a shearer for use at a fully mechanised coal mining face, the shearer including an elongated body having opposed end portions, a housing between said end portions and an electric motor, the water spray dust suppression system including a high pressure pump operatively disposed within the housing, transmission means operatively connecting the electric motor to the high pressure pump a relief valve assembly and a hydraulic control valve assembly associated with said high 1 pressure pump, said hydraulic control valve assembly being mounted externally of said Shousing in a position such that when the shearer is in use, the control valve assembly faces generally in the direction of a shearer operator, the dust suppression system further including upper and lower arms each being mounted: in the region of a respective one of said opposed end portions of said shearer, a plurality of nozzle assemblies operatively mounted on each of the upper and lower arms and being operatively connected to the high pressure pump via a liquid transfer line, each nozzle assembly including a nozzle, at least 20 some of the nozzle assemblies on each of the upper and lower arms being adjustable so that the liquid spray direction from each said nozzle can be adjusted so that the spray can be directed in any one of three dimensions.

In one preferred form, the high-pressure pump comprises a horizontal-type ram pump; the transmission device includes a clutch and a gearbox; the horizontal-type ram pump and the gearbox being mounted on an upper base section with a lower base section being fixed on a bottom section of the intermediate housing; the upper and lower base sections operatively engaging with each other for relative sliding movement therebetween.

A remote control orifice K' of a remote control pilot valve of the relief valve may, in one form be connected with a remote control orifice K of the relief valve such that when an P:\WPDOCS\DYS\specic\7463640spc.doc-3 anuay 2002 -3incoming gauge indicates that the incoming pressure is lower than a predetermined pressure, contacts of a pressure relay will be in a normal position so that the shearer and the high-pressure pump do not work.

Preferably, each of the nozzle assemblies includes a nozzle base operatively mounted to a nozzle mounting support on the upper and lower arms, each nozzle being operatively mounted to a respective nozzle base so that it can be adjusted about a generally horizontal axis, each base being adjustable about a generally vertical axis.

The upper arm may include a base section which is movably connected at one end of the shearer so that the upper arm can be moved up and down.

Preferably, some of the nozzle assemblies are disposed at a lower side of said upper arm there being a spill plate associated with each .of these assemblies being disposed adjacent to the assembly with which it is associated.

In one preferred form, two filtering meshes are provided in each nozzle, and said nozzles are of different sizes and include at least two relatively small-size nozzles, a middle-sizenozzle and a large-size nozzle; the small-size nozzles having one orifice with a diameter 20 0.8mm and the spraying direction thereof being downward at an angle of 10-20° to the wall oof the coal face; the middle-size nozzle having one orifice with a diameter 1mm and the spraying direction thereof following essentially the airflow direction at an angle of 60-90°; the large-size nozzle having a diameter 1mm and the spraying direction thereof following essentially the airflow direction at an angle of 60-90°.

According to a preferred form of the present invention, the arms for distributing the highpressure water are respectively provided at the upper airflow side clean airflow side) and the lower airflow side dirty airflow side). The arm located at the upper airflow side (hereinafter referred as the upper arm) is longer than that located at the lower airflow side (hereinafter referred as the lower arm). There are nozzle mounting supports for mounting the nozzle sockets on both the upper and lower arms. The spraying direction of <1l/ P:\WPDOCS\DYSpecie746364[spe.doc-3 nuary 2002 -4the nozzle is adjustable in three dimensions freely. For instance, a nozzle socket can be rotated or vibrated around an axis of a horizontal fastening bolt to adjust the horizontal spraying direction of the nozzle. After adjusting the horizontal spraying direction of the nozzle to a necessary direction, the nozzle is relatively fixed on the nozzle socket by the horizontal fastening bolt. The nozzle socket carried with the nozzle can be rotated around an axis of a vertical fastening bolt to adjust the spraying direction in the vertical direction.

The arm base for supporting the upper or lower arm is hinged to the end of the cutting unit by pivot pins to move mounting supports in the vertical direction, so that the system according to the present invention is adapted to the undulating floor at the coal face. A protection plate for protecting the nozzle socket is provided on the lower side of the upper arm before each nozzle socket, which is mounted on the lower arm, of each small size nozzle with a single orifice.

The nozzles mounted'on the upper side of the nozzle mounting supports are used to guide the airflow so as to be called guiding nozzles. The nozzles mounted on' the lower side of :mounting supports are-mainly used to spray water to form a water fog curtain for separating the space in which the operators work from that in which dust is produced by the shearer. These nozzles are called fog curtain nozzles. The diameter of the orifice of the guiding nozzle is greater than 1 mm. The guiding nozzles include a large-size nozzle with 20 multiple orifices and a middle-size nozzle with a single orifice. The spraying direction of the nozzle essentially follows the airflow direction at an angle of 60 90' to the wall of the coal face. The arrangement results in a longer jetting distance, a higher negative pressure and an effective induction.

The nozzle for forming a water fog curtain has a single orifice, the diameter thereof is less than 0.8 mm. This nozzle is hereafter called the small-size nozzle with a single orifice.

According to the present invention, two or more nozzles for forming a water fog curtain are provided. The nozzles for forming a water fog curtain direct downward to the floor and to the wall of the coal face at an angle of 10 200. The friction between pressurized water and the wall of the orifice of the nozzle produces a lot of electrostatic charge, the electrostatically charged and sprayed water can effectively attract coal dust. It is possible 'U"2 P: WPDOCS\DYSscj\e?463.4spe.dm-3 Joo.0y 2002 to form a water fog curtain by means of installing many small-size nozzles.

Compared to the prior water spraying dust suppression system, the present invention in its various aspects and/or preferred forms provides a number of advantages: 1. Because the torque of the output shaft of the electric motor located in the shearer can be transmitted to a high-pressure pump located in the shearer by means of a clutch and a gearbox, it is possible to arrange the high-pressure pump in the shearer. This avoids transmitting high-pressure water for suppressing coal dust from a gate to the shearer.

2. The friction between the jetted water and the wall of the orifice of the nozzle causes the water to be electrostatically charged, so that the jetted water can absorb more airborne respirable dust.

3. Because the structure of the nozzle is specially designed and two filtering meshes are arranged therein, blocking the nozzle has been essentially avoided..

i.

4. The dust suppression system according to the present invention can absorb the airborne dust and guide the airflow with the airborne dust, so that it is efficient in 20 preventing the airflow with the airborne dust from spreading to the space where the operators work.

The present invention will be described in detail as accompanying with the preferred embodiment illustrated in the figures, wherein: FIG. 1 is a schematic view of a shearer including the dust suppression system according to the present invention.

FIG. 2 is a schematic view illustrating the mounting position of a high-pressure pump, a clutch and a gearbox in an intermediate housing.

OFF\C

P:\WPDOCS'SkVpcc\7463640spe.dc.3 J~luary 2002 -6- FIG. 3 is a schematic view of the upper arm located at the upper airflow side according to the present invention.

FIG. 4 is a schematic view of the lower arm located at the lower airflow side according to the present invention.

FIG. 5 is a hydraulic system drawing of the dust suppression system according to the present invention.

FIG. 6 is a structure schematic view of a hydraulic control valve assembly.

AM 500 Type shearer and TQB 80/12.5 Type horizontal three ram high-pressure pump made in Wuxi City, used as the built-in high-pressure water pump 14, are used in the embodiment.

15 FIG. 1. shows a shearer and parts or assemblies of the dust suppression system according to 00.0.

0 the present invention. The shearer mainly consists of a left drum 1, a left ranging arm 2, a 0 left cutting unit 4, a left electrical motor 6, an intermediate housing 13, a right electrical motor 17, a pump unit 18, a right cutting unit 19, a right ranging arm 20 and a right drum a.o.

20 21 etc. According to the present invention, the water spraying dust suppression system for a shearer comprises a built-in high-pressure pump 14, a clutch 9 and a gearbox 11 which are disposed in the intermediate housing 13, a relief valve block 12 of the built-in highpressure pump 14, a hydraulic control valve assembly 15, a high-pressure hose 16, upper and lower arms 22, 3 and the high-pressure nozzles 23 mounted on the upper and lower arms 22, 3.

Arrow F shown in FIG. 1 indicates the airflow direction at the coal face. Excavated coal is transported in the airflow direction. The right side in FIG. 1, namely, near the arrow F, is the upstream of the airflow, and the left side is the downstream of the airflow. The upper and lower arms 22, 3 are respectively installed on the ends of the right and left cutting units 19, 4. According to the present invention the length of the upper arm 22 located at the Fi P:\WPDOCSkDYSspV!e.74664Osp d.d- 3 J-vy 2002 -7upstream of the airflow is longer than that of the lower arm 3 located at the downstream of the airflow, as shown FIG. 1. Because the dust concentration at the upstream of the airflow is higher than that at the downstream of the airflow, the number of nozzles arranged on the upper arm 22 should be greater than that on the lower arm 3.

As shown in FIG. 1. lower-pressure water Iw is supplied from the gate to the built-in highpressure pump 14 by a hose. An incoming pressure gauge 8 for indicating the incoming water pressure is provided in the incoming water pipeline. When the incoming water pressure is less than 1 MPa, the pressure relay 7 will be actuated so as to cut off the power supplied to the shearer and to shut down the high-pressure pump 14. This ensures that the shearer will not work when the incoming water pressure is too low to suppress dust normally.

i The built-in pressure pump 14 supplies the- high-pressure water Ow, to the high-pressure nozzles 23 mounted on the upper and lower arms 22, 3 through the high-pressure hoses, 0 'and then the high-pressure water is sprayed from:the high-pressure nozzles 23 to suppress the coal dust.

Cooling water from the electrical motor of the shearer cools the high-pressure pump 14 of 20 said dust suppression system. The water flow Ic shown in FIG. 1 enters into the cooling o pipe of the crankshaft housing of the high-pressure pump 14. Outcoming water flow Oc shown in FIG. 1 is the cooling water out of the high-pressure pump 14. The shutoff valve controls the cooling water supplied to the high-pressure pump 14.

FIG. 2 shows an arrangement of the high-pressure pump 14, the clutch 9 and the gearbox 11 of the dust suppression system according to the present invention in the intermediate housing 13. As shown in FIG. 2, the right output shaft 24 of the left electrical motor 6 with two output shafts is connected with the input shaft of the gearbox 11 by the clutch 9. In this embodiment, the clutch 9 is a jaw clutch with a shear pin (not shown) for overload protection. The clutch 9 can be manually operated between an open and close position to transmit or cut off torque to the high-pressure pump 14. The high-pressure pump 14 is P:\WPDOCS\DYSspccic746364sp.doc-3 JImay 2002 -8installed on the upper sliding base 27. The lower sliding base 28 is fixed on the bottom of the intermediate housing. Both the upper and lower sliding bases 27, 28 are engaged with each other by sliding grooves so that the upper sliding base 27 can slide relatively to the lower sliding base 28. The structure of the sliding bases facilitates installing and maintaining of the equipment. Reference numeral 25 in FIG. 2 indicates an outlet of the high-pressure pump 14. The outlet 25 is connected with an end of the high-pressure hose 16 to supply the nozzles 23 with high-pressure water. The high-pressure pump 14 has the inlet 26. Low-pressure water Iw is supplied from the gate of the coal face to the highpressure pump 14 by a hose.

.FIG. 3 illustrates the structure of the upper arm 22 located at the upstream of the airflow.

The upper arm 22 includes the nozzle mounting support 30, which consists of a long arm and an arm base for connecting with the end of the cutting unit 19 of the shearer.

S: Reinforcement plates connect the long arm with the arm base to strengthen the connection strength therebetween. The arm base is connected with the end of the cutting ,unit of the shearer by pivot pins 29. On the arm base there are openings for inserting, the pivot pins.,.

The openings and the pivot pins 29 can buffer an impact of falling coal on the nozzle mounting support 30 and prevent the nozzle mounting support 30 from being damaged by large pieces of waste coming in the direction of the coal flow.

In this embodiment, each high-pressure nozzle 23 comprises 3 different kinds of nozzles.

The orifice of the large-size nozzle 35 with multiple orifices is 1 mm in diameter; the orifice of the middle-size nozzle 34 with a single orifice is also 1 mm in diameter; but the orifice of the small-size nozzle 33 with a single orifice is 0.8 mm in diameter.

According to the embodiment shown in FIG. 3, two large-size nozzles 35 are provided on the upper side of the nozzle mounting support 30. A middle-size nozzle 34 is installed between the two large-size nozzles 35. Four small-size nozzles 33 are spaced with each other on the lower side of the nozzle mounting support 30. Before each small-size nozzle 33 in the coal flow direction, a spill plate 31 is provided to protect the small-size nozzle.

The spill plate 31 is fixed on the nozzle mounting support 30 by a reinforcement plate to L7A P:\WPDOCS\DYS\~IcX\7463640spe.doc-3 1aary 2002 -9prevent the small-size nozzle 30 from being damaged by large pieces of the waste.

All the nozzles 33, 34 and 35 are supported on the nozzle bases 32 by the horizontal fastening bolts. For the clarification, the horizontal fastening bolts are not illustrated in detail in FIG. 1 but only shown with a horizontal central line. The large-size nozzle with the multiple orifices and the middle-size nozzle 34 with the single orifice can be rotated 1800 around the axes of horizontal fastening bolts to adjust the direction of the spraying water. After the spraying direction being determined, the horizontal fastening bolts are tightened up so that the nozzles 34 and 35 are fixed in the predetermined vertical direction. The nozzle bases 32 are mounted on the nozzle mounting supports 30 by the vertical fastening bolts. For the same reason, the vertical fastening bolts are also not illustrated in detail in FIG. 1, but shown with a vertical central line only. Before tightened up a vertical fastening bolt, the nozzle bases 32 can be rotated about the axis of the vertical fastening bolt to adjustthe spraying direction of.the nozzles 34,and 35 in horizontal direction. As a result, the spraying water follows essentially in the airflow direction at an angle of 60 900 to the, wall of the, coal face. Directions of spraying water both the large- "size nozzle 35 can be adjusted in 3 dimensions by means of adjusting the horizontal direction and the vertical direction. Said adjustments result a long spraying distance, a high S 2 negative pressure which is possible to guide the airflow with the airborne dust efficiently.

20 Therefore, the two kinds of the nozzles are called as the guiding nozzles.

Four small-size nozzles 33 with the single orifice are installed on the lower side of the nozzle mounting support 30. An adjustment to the small-size nozzle is similar to the procedure for adjusting both large-size nozzle 35 and middle-size nozzle 34. However, the spraying direction of the small-size nozzles 33 is essentially downward at an angle of 10 200 to the wall of the coal face. The main function of the small-size nozzle 33 with the single orifice is to form a water spraying curtain under the ranging arm of the shearer.

The water spraying curtain can separate an excavating space filled by the airborne dust from a working space in which the operators work in order to prevent the airborne dust from coming into the working space. Four small-size nozzles 33 are provided in the embodiment, as shown in FIG. 3.

P

6e P.\WPDOCS\DYSpccic\'463640spe doc-3 Janu y 002 The nozzles 33, 34 and 35 are high-pressure water nozzles. When the high-pressure water is jetted out from these nozzles, the friction between the sprayed water and the wall of the orifice of the nozzle produces electrostatic charges. Because of the special design of the nozzles, a water fog can be formed efficiently and a lot of electrostatic charges which can effectively suppress the airborne dust. The body of the nozzle is made of stainless steel, having a thick wall and a high strength. Two filtering meshes are provided in a nozzle so that the problem of easily blocking the nozzle has essentially been solved. The filtering meshes in the nozzle are changeable.

In order to clearly illustrate the arrangement of the large-size nozzle 35 with the multiple orifices and the middle-size nozzle 34 with the single orifice, the nozzles are rotated 180' in FIG. 3 and 4, namely, the spraying direction of the nozzles is facing to the working space. When cutting coal, the nozzles must face to the coal face.- .The structure of the lower arm 3 located at the downstream ofthe airflow is shown in FIG.

4. The length of the iowei arm 3 is shorter than that of the upper arm 22 located at the eeo0 upstream of the airflow, but their structures are similar to each other. The lower arm 3 a located at the downstream of the airflow is mounted on the end of the left cutting unit 6 of 20 the shearer by the bolts 37. There is no spill plate for the small-size nozzle 33 with the single orifice, because there are few coal blocks after passing under the main frame of shearer. In the present embodiment, the number of the nozzles disposed on the lower arm 3 located at the downstream of the airflow is less than that of the upper arm 22 located at the upstream of the airflow; that is there are two large-size nozzle 35 with the multiple orifices and one middle-size nozzle 34 with the single orifice on the upper side of the short arm 36; there are two small-size nozzles 33 with the single orifice located at the lower side of the short arm 36. The arrangement is, however, only a preferred embodiment.

The hydraulic system of the dust suppression spraying system for the shearer according to the present invention and the operation procedure will be described in detail accompanying with FIG. P:\WPDOCS\DYSpeci©\74636,40spe.doc-3 Januwy 2002 -11- Iw illustrates low-pressure water from the gate. The low-pressure water flows into the inlet 26 (as shown in FIG. 2) of the high-pressure pump 14. The pipeline for high-pressure water supplied by the high-pressure pump 14 is divided into three branches at the outlet (as shown in FIG. the first branch O, is connected with the nozzles 23 on the upper and lower arms 22, 3 through a high-pressure hose 16 to spray water and suppress dust; the second branch is connected with the inlet 26 of the high-pressure pump 14 by the relief valve 12 with a throttle hole, the flow of water of the hydraulic system can be controlled by the second branch so that the pressure of the hydraulic system will be constant; the third branch is connected with the cut-off valve 38, the pressure gauge 43 and the pressure-relief valve 39. The cut-off valve 38 is used to drain off water when the system does not work; the pressure gauge 43 indicates the output pressure of the high-pressure pump 14; the pressure-relief valve 39 is used to keep the normal pressure in the system. The control orifice IK of the relief valve 12 is connected with the control orifice K' of the remote pilot valve 44 so that the pressure of the system can be, adjusted by manually operating the pilot valve44: i> The pressure gauge 8 and the pressure relay 7 in the incoming pipeline are connected with the inlet 26 of the high-pressure pump 14. The pressure gauge 8 indicates the incoming pressure of the hydraulic system according to the present invention. If the pressure is lower than a predetermined pressure, for example, less than 1 MPa, the pressure relay 7 will be in the normal open position so that the shearer does not work.

The high-pressure pump 14 is cooled by the cooling water out of the shearer; Ic indicates the cooling water flowing in the cooling pipe of the crank shaft housing of the highpressure pump 14; Oc, indicates the outgoing cooling water out of the high-pressure pump 14. The cut-off valve 10 is used to control the cooling water.

The structure of the hydraulic control valve assembly 15 is shown in FIG. 6. The hydraulic control valve assembly 15 consists of the pressure-relief valve 39, the cut-off valve 38, the pressure gauge 43 and the pilot valve 44 of the relief valve. The cut-off valve 38 is a ball P:\WPDOCS\DYS\spcci\7463640spe.doc-3 January 2002 -12cut-off valve in the present embodiment. All the valves mentioned above are installed in the valve body 46. The valve body 46 is fixed on the cover of the intermediate housing 13 by the bolts 45, facing the side of the shearer operator.

In the present embodiment, the intermediate housing 13 is lengthened about 500mm as compared with all the available; the under frame of the shearer is lengthened too. The high-pressure pump 14 is TQB80/12.5, Type horizontal three-ram pump, a water pump made at Wuxi City. The relief valve 12 is YK-WYF 160/50 Type. The pressure gauges 8 and 43 are YN 60-11 Type. The ball valves 10 and 38 are QJ10 Type. The pressurerelief valve 39 is WFO101 Type. The pressure relay 7 is HED1 Type. The high-pressure hoses 16, 41, 42 and 40 are KJB Type.

The nozzle mounting supports 30 and 36 are made of I-steel and steel plate which are ,riveted and welded together. Aforesaid high-pressure nozzles making water charged electrostatic charge are products made by Chongqing Branch of Central Coal Mining Research Institute.

All the parts and assemblies only express a preferred embodiment according to the present invention. The water spraying dust suppression system for the shearer according to the 20 present invention is not limited to adopt the aforesaid type parts and assemblies.

9 9...O

Claims (3)

1. A high pressure water spray dust suppression system for use with a shearer for use at a fully mechanised coal mining face, the shearer including an elongated body having opposed end portions, a housing between said end portions and an electric motor, the water spray dust suppression system including a high pressure pump operatively disposed within the housing, transmission means operatively connecting the electric motor to the high pressure pump a relief valve assembly and a hydraulic control valve assembly associated with said high pressure pump, said hydraulic control valve assembly being mounted externally of said housing in a position such that when the shearer is in use, the control :valve assembly faces generally in the direction of a shearer operator, the dust suppression :.:system further including upper and lower arms each being mounted in the region of a respective one of said opposed end portions of said shearer, a plurality of nozzle 0@ assemblies operatively mounted on each of the upper and lower arms and being operatively 15 connected to the hiigh pressure pump via a liquid transfer'line, each nozzle' assembly including a nozzle, at least some of the nozzle assemblies on each of the upper and lower arms being adjustable so that the liquid 'spray direction from each said nozzle- can be adjusted so that the spray can be directed in any one of three dimensions. 20 2. A system according to claim 1, wherein said high-pressure pump comprises a horizontal-type ranm pump; said transmission device includes a clutch and a gearbox; said horizontal-type ram pump and the gearbox being mounted on an upper base section wvith a lower base section being fixed on a bottom section of the housing; the upper and lower base sections operatively engaging with each other for relative sliding movement therebetween.

3. A system according to claim 1, wherein a remote control orifice K' of a remote control pilot valve of the relief valve is connected with a remote control orifice K of the relief valve such that when a pressure gauge indicates that the liquid pressure to the high pressure pump is lower than a predetermined pressure, a pressure relay will adopt a 'TFqposition so that the shearer and the high-pressure pump do not work. NP _0 P:IwpDOCSIDYsdpwick763640sdoc-3 Janu 2002

14- 4. A system according to any preceding claim wherein each of said nozzle assemblies includes a nozzle base operative mounted to a nozzle mounting support on said upper and lower arms, each said nozzle being operatively mounted to a respective said nozzle base so that it can be adjusted about a generally horizontal axis, each said base being adjustable about a generally vertical axis. A system according to any preceding claim wherein the upper arm includes a base section which is movably connected at one end of the shearer so that the upper arm can be moved up and down. .1 6. A system according to claim 4 wherein some of said nozzle assemblies are disposed at a lower side of said upper arm there being a spill plate associated with each of *these assemblies being disposed adjacent to the assembly with which it is associated. 0 7. A system according to claim 1, wherein two filtering meshes, are provided in each nozzle, and said nozzles are of different sizes and include at least two relatively small-size nozzles, a middle-size- nozzle and a large-size nozzle; the small-size nozzles having one orifice with a diameter 0.8mm and the spraying direction thereof being downward at an angle of 10-20° to the wall of the coal face; the middle-size nozzle having one orifice with 20 a diameter 1mm and the spraying direction thereof following essentially the airflow direction at an angle of 60-90°; the large-size nozzle having a diameter Imm and the spraying direction thereof following essentially the airflow direction at an angle of 60-90°. 8. A high pressure water spray system substantially as hereinbefore described with reference to the accompanying drawings. Dated this 3 rd day of January, 2001 YANKUANG GROUP CORPORATION By Its Patent Attorneys DAVIES COLLISON CAVE R ~U