Binder for mine tailings, alluvial sand and the like

Abstract

A binder for mine tailings, alluvial sand and other aggregate used as a backfill for an underground void comprises ferrous slag, cement kiln dust and/or lime kiln dust, and Portland cement and/or lime; the binder displays strength characteristics better than or comparable to those achieved with conventional binders based on Portland cement or Portland cement and slag.

Description

Claims

1. A fill material for an underground void comprising an intimate mixture of: a particulate composition comprising aggregate particles, a particulate, hydraulically solidifiable inorganic binder composition for said particulate composition and water,said binder composition comprising, in weight %, to a total of 100%, based on the weight of the binder composition:a) 49 to 95% of a ferrous slag;b) 2.5 to 35% of kiln dust selected from cement kiln dust, lime kiln dust and mixtures thereof, wherein said cement kiln dust has a free lime content of at least 2.5%, by weight, based on the weight of cement kiln dust; andc) 2.5 to 16% of a material selected from Portland cement, lime and combinations thereof.

2. A fill material according to claim 1, wherein b) is cement kiln dust, and said cement kiln dust has a total alkali content of a least 1.5%, by weight, based on the weight of cement kiln dust.

3. A fill material according to claim 1, wherein b) is cement kiln dust and further including a supplementary source of alkali effective to provide a total alkali content in said binder composition equivalent to a total alkali content of a least 1.5%, by weight, based on the weight of cement kiln dust.

4. A fill material according to claim 1, wherein b) is lime kiln dust.

5. A fill material according to claim 1, wherein said aggregate particles comprise mine tailings.

6. A fill material according to claim 1, wherein said aggregate particles comprise alluvial sand.

7. A fill material according to claim 1, wherein said mixture further comprises inert particulate aggregate.

8. A fill material according to claim 1, having a solids content of 65 to 85%, by weight.

9. A fill material according to claim 1, wherein a) is iron blast furnace slag.

10. A fill material according to claim 1, comprising said binder composition and said particulate composition in a weight ratio of 1:8 to 1:40 and a solids content of 60% to 80%.

11. A fill material according to claim 7, comprising said binder composition, mine tailings and said aggregate in a weight ratio of binder composition to mine tailings and aggregate of 1:8 to 1:50.

12. A fill material according to claim 1, wherein c) is Portland cement in an amount of 2.5 to 16%.

13. A fill material for backfilling a man-made underground void comprising an intimate mixture of: i) a particulate composition, ii) a particulate, hydraulically solidifiable inorganic binder composition, andiii) water,

14. A fill material according to claim 13, wherein said weight ratio is 1:10 to 1:35.

15. A fill material according to claim 13, wherein said weight ratio is 1:15 to 1:30.

16. A fill material according to claim 13, wherein said solids content is 65 to 75%, by weight.

17. A fill material according to claim 16, wherein said particulate composition comprises mine tailings.

18. A fill material according to claim 16, wherein said particulate composition comprises alluvial sand.

19. A method of backfilling an underground void comprising: filling said void with a fill material comprising an intimate mixture of:a particulate composition comprising aggregate particles, a particulate, hydraulically solidifiable inorganic binder composition for said particulate composition and water,said binder composition comprising, in weight %, to a total of 100%, based on the weight of the binder composition:a) 49 to 95% of a ferrous slag;b) 2.5 to 35% of kiln dust selected from cement kiln dust, lime kiln dust and mixtures thereof, wherein said cement kiln dust has a free lime content of at least 2.5%, by weight, based on the weight of cement kiln dust; andc) 2.5 to 16% of a material selected from Portland cement, lime and combinations thereof, andhydraulically solidifying said binder composition and said water to form a solid mass binding said particulate composition.

20. A method according to claim 19, wherein c) is Portland cement in an amount of 2.5 to 16%.

21. A particulate binder composition for a backfill material comprising, in weight %, to a total of 100%, based on the weight of the binder composition: a) 49 to 95% of a ferrous slag;b) 2.5 to 35% of kiln dust selected from cement kiln dust, lime kiln dust and mixtures thereof, wherein said cement kiln dust has a free lime content of at least 2.5%, by weight, based on the weight of cement kiln dust; andc) 2.5 to 16% of a material selected from Portland cement, lime and combinations thereof.

22. A particulate binder according to claim 21, wherein a) is iron blast furnace slag, b) is cement kiln dust, and said cement kiln dust has a total alkali content of a least 1.5%, by weight, based on the weight of cement kiln dust, and c) is Portland cement in an amount of 2.5 to 16%.

23. A particulate binder according to claim 21, wherein a) is iron blast furnace slag, b) is lime kiln dust, and c) is Portland cement in an amount of 2.5 to 16%.

24. A particulate binder according to claim 21, wherein a) is iron blast furnace slag in an amount of 75 to 90%, b) is cement kiln dust in an amount of 10 to 20%, and c) is Portland cement in an amount of 2.5 to 16%, to a total of 100%.