WO2004068060A1

WO2004068060A1 - A method of preventing uncontrolled dispersal of degraded metallic products from a bullet back stop at a shooting-range and a bullet back stop for performing the method

Info

Publication number: WO2004068060A1
Application number: PCT/SE2004/000121
Authority: WO
Inventors: Jan Kjellberg
Original assignee: Svenska Pistolskytteförbundet
Priority date: 2003-01-31
Filing date: 2004-01-30
Publication date: 2004-08-12

Abstract

In order to prevent uncontrolled discharge of metallic degradation products, especially lead, into the environment in the use of a bullet backstop (1) for a shooting range, metal-ion-enriched rainwater, which has collected in an overlying projectile-stopping layer (4) in direct contact with the atmosphere, is conducted, at least in one part of the bullet backstop, via an underlying water-permeable layer (3) of gravel or crushed stone material mixed with pH-increasing material, for example crushed limestone and a watertight bottom layer (2) to a drainage pipe (5) belonging to a collecting device. The leachate is fed to a container (10), where a check of pH/value and/or metal ion content is performed. From the container (10), leachate can be discharged, via an outflow pipe, to an infiltration bed or an open trench. Protection is also sought for a bullet backstop (1) in which the specified method is applied.

Description

A METHOD OF PREVENTING UNCONTROLLED DISPERSAL OF DEGRADED METALLIC PRODUCTS FROM A BULLET BACK STOP AT A SHOOTINGRANGE AND A BULLET BACK STOP FOR PERFORMING THE METHOD

Field of the invention

The present invention relates to a method of preventing uncontrolled discharge of metallic degradation products into the environment in the use of a bullet backstop for a shooting range and more precisely defined by the type specified in the preamble of claim 1.

The invention also relates to a bullet backstop for a shooting range designed to prevent such uncontrolled discharge and which bullet backstop is of the type specified in the preamble of claim 10.

Prior art

Various so-called anti-leaching installations in connection with the bullet backstop here under discussion have previously been proposed.

An example of such an anti-leaching installation is described in SE,C2 9503617-4 (publ . no. 505 107) under the name Moberg. In this arrangement, the bullet backstop is provided with an elastic layer constituting a water-repellent cover, which is sealed after the passage of the projectile, whereafter the projectile is stopped in an underlying projectile-stopping material which is stored in a closed space limited by a watertight layer at a distance from the elastic layer. Surface water which seeks to percolate through the projectile holes is drained by the projectile-stopping material along the inclined layer to a low point at which the water is collected by a drainage pipe. The drainage water is led off through a pipeline to closed container. A bullet backstop of this type, which enjoyed comparatively widespread use, requires regular emptying intervals and gives rise to environmental handling problems, frequent transportation of lead-containing material and destruction and/or dumping entailing very high maintenance costs, added to the comparatively high construction costs. There is therefore a need to produce a different solution which avoids the serious drawbacks specified.

Further examples of the prior art can be found in US,A, 5 441 280 (Copius) , US, , 4 475 734 (Clarke et al) and FI 108082 B (Turkki) . The first-named American document calls for large construction costs in the form of an erected concrete structure, whilst the second document describes a metal box with hinged lid, which has no direct points of contact with the problems here under discussion.

The Finnish document describes a bullet backstop comprising a water insulation, a protective layer, a drainage trench, a damping layer and a surface layer, which layers are made of a mix of carcassing materials and chemicals and in which the physical and chemical properties of the bullet protection are checked by tests on water which has been filtered through the construction layers and has been conducted to a check point. This document too has no direct points of contact with the problem to which the present invention offers a solution.

Brief description of the invention

In order to eliminate the specified drawbacks associated with the anti-leaching installation described in the abovementioned Swedish patent document under the name Moberg, the invention has the distinguishing features specified in the characterizing part of claim 1.

The bullet backstop is in this case given a pH-status which prevents the formation of metallic degradation products, so-called ions, whilst, at the same time, a simple check is granted, at low cost, on the acceptability of this pH-status.

According to the invention, nor is there an upper elastic layer of the type specified, constituting a water-repellent cover which is sealed after the passage of the projectile. Instead, the outer projectile- stopping layer is in direct contact with the atmosphere, metal-ion-enriched rainwater gathered in the projectile-stopping layer being able, in the form of leachate, to percolate into the underlying water- permeable layer of gravel or crushed stone material of coarse fraction, which is mixed with ph-increasing material, for example crushed limestone, so that pH- neutralized leachate is fed via the watertight bottom layer to the collecting member, where a check takes place at suitable intervals.

The invention eliminates the considerable costs which - in the application of the known method - are incurred in taking care of the closed container and destroying its content of lead-ion-enriched drainage water, which costs must be met as soon as the container has been filled, and in changing or repairing an upper elastic layer which has been shot to pieces. Nor do costs need to be met for the change or repair of a shot-to-pieces upper elastic layer.

A further advantage is that the method according to the invention can be applied both in the construction of new shooting ranges and in older, operating shooting ranges, or for dumps of enriched materials, for example sand or earth from shooting ranges. The invention offers the special advantage that only a part of the bullet backstop needs to be provided with a watertight bottom layer and an intercepting device, thereby considerably reducing both construction and maintenance costs in comparison with known methods. The other part of the bullet backstop, which has no watertight bottom layer and intercepting device, is provided, apart from with the projectile-stopping layer, also with said water-permeable layer of gravel or crushed stone material of coarse fraction, mixed with pH-neutralizing material, for example crushed limestone, so that pH-neutralized leachate is able to run off to underlying soil strata.

In practice, it is generally sufficient for that part of the bullet backstop which is provided . with watertight bottom layer and intercepting device to correspond approximately to the region behind 2 to 3 targets of the shooting range.

In an alternative application method, said part is constituted by the whole of the bullet backstop, in addition to which the container of the intercepting device comprises a well having an ion-absorbent material layer, for example peat, the drainage pipe of the intercepting device emerging in the region of the bottom of the well, so that, when the well is filled, the leachate passes upward through the ion-absorbent material, for example the peat.

This procedure offers extra security, since the leachate from the bullet backstop undergoes double cleaning.

The leachate filtered in the well expediently leaves this, at a higher level than the mouth of the drainage pipe in the well, via an outflow pipe from the well, which leads on to an infiltration bed or an open trench.

The outflow pipe from the well, or the infiltration bed, can herein be provided with a measuring tube for checking the presence of ions. The pH-value and the ion-absorbent material can thereby be regularly checked in a simple manner.

In addition thereto, the watertight bottom layer is preferably constituted by a watertight membrane, made of rubber material, for example, which passes the highest point of the bullet backstop surface and extends sideways beyond the particular part of the bullet backstop at which it is turned upward.

It is further preferred that the watertight membrane, in its lower part, forms a trench, in the bottom of which is placed the drainage pipe of the intercepting device.

According to another aspect, the invention also relates to a bullet backstop for a shooting range, the special characteristics of which are specified in claim 10. Such a bullet backstop according to the invention is at least partially insulated from its environment and has an environment which substantially reduces or prevents uncontrolled discharge of metallic degradation products, above all lead and copper, into the environment.

Further characteristics and advantages of the invention will be evident from the following description of preferred embodiments thereof. The description is realized in connection with the appended diagrammatic drawings . Brief description of the drawing figures

Fig. 1 is a vertical section through a specially configured part of a bullet backstop, realized according to the invention, for a shooting range.

Fig. 2 is a divided cross section, which shows the lower part of that part of bullet backstop shown in fig. 1, with associated trench and intercepting device complete with drainage pipe and container.

Fig. 3 is a cross section through the bullet backstop part according to figs. 1 and 2, laid beside the drainage pipe of the intercepting device.

Fig. 4 is a divided cross section, corresponding to fig. 2, through a modified realization of a bullet backstop according to the invention.

Description of preferred embodiments

Fig. 1 shows a cross section through a part of a bullet backstop 1 according to the invention for a shooting range, for the collection and storage of metal- containing projectiles, for example containing lead and/or copper or other metals which are undesirable from the environmental aspect .

The method according to the invention for this embodiment is based on the fact that a part of the bullet backstop, namely that region of the inclined bullet backstop 1, located behind 2 to 3 targets, in which the projectiles are collected is configured such that the bullet backstop is insulated from the surrounding ground surface and that in the bullet backstop an environment is created in which the degradation of metal, primarily lead and/or copper, into corresponding ions is prevented or reduced. To this end, the bullet backstop 1 has been provided with a watertight membrane 2, made of rubber material or reinforced plastics material, for example, which, at a distance from the surface of the bullet backstop, extends parallel thereto. The membrane 2 shall, in the upward direction, pass the highest point of the bullet backstop and, to the sides, extend beyond said part thereof. The membrane is turned up somewhat at the sides of the bullet backstop, to prevent water running out to the sides.

Approximately above the membrane, the bullet backstop 1 comprises a water-permeable layer 3 of gravel or crushed stone material of coarser fraction, mixed with pH-increasing material, for example crushed limestone. Above this layer, which runs parallel with the membrane, there is a layer 4 of bullet backstop sand, which is also mixed with a pH-increasing material. The layer 4 shall be of such thickness that projectiles cannot penetrate down into the underlying layer 3.

In its lower part, the membrane 2 forms a trench 6, in the bottom of which has been placed a drainage pipe 5. This drainage pipe, at one end of the trench, will pass through the turned-up membrane 2.

The drainage pipe 5 emerges in a container 10, in which leachate from the specified region of the bullet backstop is thus collected. For checking of the pH- value and metal ion content of the leachate, measuring members, for example a test tube for laboratory analysis, can expediently be introduced into the container through its detachable cover 10a. Such intermittent measurement or checking can take place at suitably chosen times. Another type of measuring member, which allows a continuous checking operation to be conducted, can also alternatively be used. A ventilation pipe of the container 10 is denoted by 17. On the side opposite the drainage pipe 5 of the container there is an outflow pipe 14, which can lead on, for example, to an infiltration bed or to an open trench (not shown) .

Performed checking of the leachate from the particular region of the bullet backstop - which, as specified above, can correspond, for example, to the region behind 2 to 3 targets of the shooting range - offers the chance to assess the possible presence of hazardous leachate from the bullet backstop as a whole. In most cases, however, the layer 3 described in detail above will be sufficient to prevent uncontrolled harmful discharge of metallic degradation products into the environment .

That modification of the invention which is shown in fig. 4 is intended for use in those cases in which it is feared that the checking of the leachate in the container 10 might demonstrate the presence of metal ion contents approaching a level which is deemed to be hazardous .

In this case, the bullet backstop of the whole of the shooting range is provided with a water-permeable layer 3 of the type specified, located beneath the projectile-stopping layer 4, and a watertight bottom layer 2, which conducts percolating leachate to a perforated drainage pipe 5.

Fig. 4 shows that, in this embodiment, the drainage pipe 5 emerges in the bottom region of a container in the form of a closed well 10, which, apart from a layer of crushed limestone 11 in the bottom region itself, is partially filled with a thick layer 12 of ion-absorbent material, for example peat. The well of the container 10 acts as a filter for the collection of lead or other metal ions present. On that side of the well which is opposite the drainage pipe 5 there is an outflow pipe 14, which leads on to an infiltration bed or to an open trench (not shown) . Filtered water 13 which has gathered over the peat layer 12 leaves through the outflow pipe 14 in the manner specified. Connected to the outflow pipe 14 is a measuring tube 15 for checking the possible presence of ions.

Alternatively, the well 10 can be designed as a recharge well with open bottom on a shingle bed.

A bullet backstop 1 or a dump for enriched sand or earth materials, realized in the manners described, allows continuous checking as regards possible discharges of metallic degradation products into the environment.

In the illustrated figures, 7 denotes the ground surface surrounding the bullet backstop 1 and the well 10, whilst 17 denotes a ventilation pipe on the well. It can further be seen from fig. 2 that the drainage pipe 5 is perforated to receive leachate percolating through the layer 3 of crushed limestone.

A bullet backstop according to the invention can be used both in the construction of new shooting ranges and in older, operating shooting ranges.

Unlike the previously known problem solution described above, in which it is primarily sought to limit the quantity of rainwater supplied to the bullet backstop by applying an overlying watertight layer - which thus will be shot through and damaged and will consequently shortly have to be replaced by a new one - the invention is based on the insight that such attempts to limit the supplied quantity of rainwater should be avoided and that necessary measures should instead be taken to prevent the formation of possible degradation products and that the whole or a part of the bullet backstop region is marked off or insulated from the surrounding ground surface. After this, controlled discharge of filtered leachate may take place.

The high costs associated with regular emptying intervals, environmental handling problems, transportation and destruction of the metal content of the leachate, which currently have to be applied in connection with the methods hitherto employed, can thus be avoided.

The invention can be varied within the scope of its inventive concept such as this is defined in the appended patent claims .

Claims

Patent claims

1. A method of preventing uncontrolled discharge of metallic degradation products into the environment in the use of a bullet backstop for a shooting range and a bullet backstop for implementing the method, at least a part of the bullet backstop (1) comprising three or more inclined, substantially parallel material layers

(2, 3, 4), including a watertight bottom layer (2) which conducts percolating leachate to an intercepting device located beneath the bullet backstop (1) , for example a drainage pipe (5) emerging in a container

(10) , and a projectile-stopping layer (4) , for example of sand, located above the bottom layer, which projectile-stopping layer is of sufficient thickness to intercept shot projectiles, characterized in that metal-ion-enriched rainwater collected in the projectile-stopping layer (4) , which has .preferably been provided with pH-neutralizing material and which is in direct contact with the atmosphere, is able in the form of leachate to percolate into an underlying water-permeable layer (3) of gravel or crushed stone material of coarse fraction, mixed with pH-neutralizing material, for example crushed limestone, so that pH- neutralized leachate is able to run off via the watertight bottom layer (2) and the intercepting device

(5, 10) , and in that the pH-value of the leachate in the intercepting device is checked at least intermittently by means of a measuring member (15) .

2. The method as claimed in claim 1, wherein the other part of the bullet backstop, which has no watertight bottom layer (2) and intercepting device (5, 10) , is provided, apart from with the projectile- stopping layer (4) , also with said water-permeable layer (3) of gravel or crushed stone material of coarse fraction, mixed with pH-neutralizing material, for example crushed limestone, from which water-permeable layer the pH-neutralized leachate is able to run off.

3. The method as claimed in claim 1 or 2 , characterized in that that part of the bullet backstop which is provided with the watertight bottom layer (2) and the intercepting device (5, 10) corresponds at least to the region behind 2 to 3 targets of the shooting range.

4. The method as claimed in claim 1, characterized in that said first part is constituted by the whole of the bullet backstop, in that the container of the intercepting device comprises a well (10) , in that the drainage pipe (5) of said intercepting device emerges in the region of the bottom of the well, in that the container includes an ion-absorbent material layer (12) , for example peat, so that, when the well is filled via the drainage pipe, the leachate (13) passes upward through the ion-absorbent material, for example the peat (12) , and is subsequently discharged from the container.

5. The method as claimed in claim 4, characterized in that the filtered leachate (13) leaves the container

(10) at a higher level than the mouth of the drainage pipe (5) in the well (10) via an outflow pipe (14) from the well, which leads on to an infiltration bed or an open trench.

6. The method as claimed in claim 4, characterized in that the container is constituted by a recharge well with open bottom on a shingle bed.

7. The method as claimed in claims 4-6, characterized in that the outflow pipe (14) from the well (10) , or the infiltration bed, is provided with a measuring tube (15) for checking the presence of ions.

8. The method as claimed in any one of claims 1-7, characterized in that the watertight bottom layer is constituted by a watertight membrane (2) , made of rubber material, for example, which passes the highest point of the bullet backstop (1) and extends sideways beyond the bullet backstop where this is turned upward.

9. The method as claimed in claim 8, characterized in that the watertight membrane (2) , in its lower part, forms a trench (6) , in the bottom of which is placed the drainage pipe (5) for the container (10) .

10. A bullet backstop for a shooting range designed to prevent uncontrolled discharge of metallic degradation products into the environment, at least a part of which bullet backstop comprises: a) a watertight bottom layer (2) , which conducts percolating metal-enriched leachate to a collecting device located below the bullet backstop (1) , for example a drainage pipe (5) emerging in a container

(10) , and b) a projectile-stopping layer (4) , located above the bottom layer, of sufficient thickness to intercept projectiles, characterized in that the projectile-stopping layer (1) is in direct contact with the atmosphere, and in that below the projectile-stopping layer (1) there are a layer (3) of gravel or crushed stone material of coarse fraction, for example crushed limestone, so that pH-neutralized leachate is able to run off via the watertight bottom layer (2) and the intercepting device (5, 10) , and a measuring device (15) , interacting with the collecting device (5, 10) , for at least intermittent checking of the lead content and/or pH-value of the^" collected leachate.

11. The bullet backstop as claimed in claim 10, characterized in that the other part of the bullet backstop, which has no watertight bottom layer (2) and intercepting device (5, 10) , is provided, apart from with the projectile-stopping layer (4) , also with said water-permeable layer (3) of gravel or crushed stone material of coarse fraction, mixed with pH-neutralizing material, for example crushed limestone.

12. The bullet backstop as claimed in claim 10 or 11, characterized in that that part of the bullet backstop which is provided with watertight bottom layer (2) and intercepting device (5, 10) corresponds at least to the region behind 2 to 3 targets of the shooting range.

13. The bullet backstop as claimed in claim 10, wherein the specified part corresponds to the whole of the bullet backstop, characterized in that the container of the intercepting device is constituted by a well (10) , in that the well includes an ion-absorbent material layer (12) , for example peat, in that the drainage pipe (5) of the intercepting device emerges in the region of the bottom of the well, and in that an outflow pipe (14) from the well leads on to an infiltration bed or an open trench.