Process for applying rock dust to a mine wall

Abstract

Rock dust is applied to a coal mine wall for mine fire suppression in combination with a chemical foam containing a saturated fatty acid, preferably stearic acid, which imparts hydrophobic properties to the rock dust particles, avoiding agglomeration. The rock dust and foam containing a saturated fatty acid are combined by causing the rock dust and foam to flow through separate conduits to a combiner from which the resulting mixture is caused to flow through a nozzle for application to the mine wall.

What is claimed is: 
     
         1 . A process for applying rock dust to a mine wall comprising:
 mixing finely ground limestone powder with a foam containing a composition consisting of one or more saturated fatty acids to produce a resulting mixture of foam and limestone powder; and   applying the resulting mixture to the wall of a coal mine.   
     
     
         2 . The process according to  claim 1 , wherein the concentration of said composition in the foam and the amount of foam mixed with the limestone powder are such that the ratio of grams of said composition per kilogram of limestone powder in said mixture is in the range of approximately 1.74 to 3.48. 
     
     
         3 . The process according to  claim 1 , wherein the limestone powder and foam containing said composition are combined by causing the limestone powder and foam to flow through separate conduits to a combiner from which said resulting mixture is caused to flow through a nozzle for application to said wall of a coal mine. 
     
     
         4 . The process according to  claim 1 , wherein the concentration of said composition in the foam and the amount of foam mixed with the limestone powder are such that the ratio of grams of said composition per kilogram of limestone powder in said mixture is in the range of approximately 1.74 to 3.48, and wherein the limestone powder and foam containing said composition are combined by causing the limestone powder and foam to flow through separate conduits to a combiner from which said resulting mixture is caused to flow through a nozzle for application to said wall of a coal mine. 
     
     
         5 . The process according to  claim 1 , wherein said one or more saturated fatty acids are from the group consisting of palmitic acid, stearic acid, and arachidic acid. 
     
     
         6 . The process according to  claim 5 , wherein the concentration of said composition in the foam and the amount of foam mixed with the limestone powder are such that the ratio of grams of said composition per kilogram of limestone powder in said mixture is in the range of approximately 1.74 to 3.48. 
     
     
         7 . The process according to  claim 5 , wherein the limestone powder and foam containing said composition are combined by causing the limestone powder and foam to flow through separate conduits to a combiner from which said resulting mixture is caused to flow through a nozzle for application to said wall of a coal mine. 
     
     
         8 . The process according to  claim 5 , wherein the concentration of said composition in the foam and the amount of foam mixed with the limestone powder are such that the ratio of grams of said composition per kilogram of limestone powder in said mixture is in the range of approximately 1.74 to 3.48, and wherein the limestone powder and foam containing said composition are combined by causing the limestone powder and foam to flow through separate conduits to a combiner from which said resulting mixture is caused to flow through a nozzle for application to said wall of a coal mine. 
     
     
         9 . The process according to  claim 1 , wherein said composition is stearic acid. 
     
     
         10 . The process according to  claim 9 , wherein the concentration of said composition in the foam and the amount of foam mixed with the limestone powder are such that the ratio of grams of said composition per kilogram of limestone powder in said mixture is in the range of approximately 1.74 to 3.48. 
     
     
         11 . The process according to  claim 9 , wherein the limestone powder and foam containing said composition are combined by causing the limestone powder and foam to flow through separate conduits to a combiner from which said resulting mixture is caused to flow through a nozzle for application to said wall of a coal mine. 
     
     
         12 . The process according to  claim 9 , wherein the concentration of said composition in the foam and the amount of foam mixed with the limestone powder are such that the ratio of grams of said composition per kilogram of limestone powder in said mixture is in the range of approximately 1.74 to 3.48, and wherein the limestone powder and foam containing said composition are combined by causing the limestone powder and foam to flow through separate conduits to a combiner from which said resulting mixture is caused to flow through a nozzle for application to said wall of a coal mine.