Corrugated pipe with perforation protecting cover

1. An elongated pipe comprising:

a corrugated outer wall having alternating, axially-adjacent, annular crests and valleys and having an axially-extending bore, the corrugated outer wall comprising:

a fluid-impermeable valley; and

two porous valleys disposed on opposing sides of the fluid-impermeable valley, and having a plurality of through-holes disposed therein; and

a semi-cylindrical, fluid-impermeable cover comprising:

a radially, inward-extending ridge disposed near an axial midpoint of the cover; and

two uncorrugated portions extending away from opposing sides of the radially, inward-extending ridge;

wherein the radially, inward-extending ridge engages the fluid-impermeable valley of the corrugated outer wall such that the two uncorrugated portions extend over at least the two porous valleys, thereby forming an open flowpath between the plurality of through-holes disposed in the porous valleys and backfill surrounding the corrugated outer wall so as to prevent the backfill from obstructing the plurality of through-holes.

2. The pipe of claim 1 wherein the outer wall has a plurality of groups of holes, each group being disposed in a valley axially spaced from the other groups of holes, and including a plurality of covers, each sized and disposed to protect a respective group of holes.

3. The pipe of claim 1 wherein the pipe is made of plastic.

4. The pipe of claim 3 wherein the plastic is polyethylene.

5. The pipe of claim 1 wherein the cover is made of the same material as the pipe.

6. The pipe of claim 1 wherein the cover is welded to the adjacent crests of the pipe.

7. The pipe of claim 1 wherein the cover is fixed to the adjacent crests of the pipe with an adhesive.

8. A method of oxidizing mineral ore comprising the steps of:

disposing the pipe of claim 1 into a pile of such ore, and

pumping air through the pipe in a manner that permits air to pass through the hole in the pipe and into the ore pile.

9. The method of claim 8 , further comprising providing a source of air distribution, providing a first set of holes for distributing air between the pipe and the ore pile at a first air distribution rate, providing a second set of holes for distributing air between the pipe and the ore pile at a second rate that is greater than the first air distribution rate, the first set of holes being located closer to the source of air distribution than the second set of holes.

10. A distribution system comprising:

a corrugated pipe configured to be buried within a material, and having a plurality of annular crests and valleys and a passage, the corrugated pipe comprising:

a fluid-impermeable valley; and

two porous valleys disposed on opposing sides of the fluid-impermeable valley, and having a plurality of perforations for distributing a substance between the passage and the material; and

a semi-cylindrical, fluid-impermeable cover comprising:

a radially, inward-extending ridge disposed near an axial midpoint of the cover and fitted within the fluid-impermeable valley of the corrugated outer wall, and

two uncorrugated portions extending away from opposing sides of the radially, inward-extending ridge;

wherein the two uncorrugated portions extend over at least the two porous valleys, thereby forming an open flow path between the plurality of perforations and the material in which the corrugated pipe is buried so as to prevent the material from obstructing the plurality of perforations when the corrugated pipe is buried within the material.

11. The distribution system of claim 10 , wherein the material is soil and the substance is liquid drained from the soil.

12. The distribution system of claim 10 , wherein the material is landfill and the substance is leachate from the landfill.

13. The distribution system of claim 10 , wherein the material is capable of being oxidized and the substance is air.

14. The distribution system of claim 10 , wherein the material is a commodity and the substance is air.

15. The distribution system of claim 10 , wherein the cover is welded to adjacent crests of the corrugated pipe.

16. The distribution system of claim 10 , wherein the material is ore and the substance is air, said distribution system further comprising:

a source of air distribution;

a first set of holes configured to distribute air between the pipe and the ore at a first air distribution rate; and

a second set of holes configured to distribute air between the pipe and the ore at a second rate that is greater than the first air distribution rate;

wherein the first set of holes is located closer to the source of air distribution than the second set of holes.

17. A corrugated pipe assembly configured to be buried within a material, the corrugated pipe assembly comprising:

a corrugated pipe having a plurality of annular crests and valleys, and a passageway, the corrugated pipe comprising:

a plurality of fluid-impermeable valleys; and

two porous valleys disposed on opposing sides of each of the plurality of fluid-impermeable valleys, and having a group of perforations disposed in each of the porous valleys; and

a plurality of semi-cylindrical, fluid-impermeable covers, each cover comprising:

a radially, inward-extending ridge disposed near an axial midpoint of the cover; and

two uncorrugated portions extending away from opposing sides of the radially, inward-extending ridge;

wherein the ridge of each cover engages one of the plurality of fluid-impermeable valleys, thereby maintaining an open flowpath for distributing a substance between the material and the passageway via the groups of perforations.

18. The corrugated pipe assembly of claim 17 , wherein each of the semi-cylindrical, fluid-impermeable covers extends radially over a top half of the corrugated pipe, and axially over at least three valleys.

19. The corrugated pipe assembly of claim 17 , wherein the plurality of semi-cylindrical, fluid-impermeable covers are axially spaced apart from each other by about 20 feet.