Coal can he compacted into solid cylinders called "coal logs" to facilitate handling and transportation. It is hypothesized and proved experimentally herein that by altering the zeta potential of coal to achieve the isoelectric point, the strength and abrasion resistance of compacted coal logs can be significantly improved. Experimental data providing the evidence are reported herein. It is theorized that by zeroing the zeta potential of the coal, the charges on coal particles are neutralized, and the electrostatic repelling force between coal particles containing like charges is eliminated. This brings the particles closer together with less compaction pressure and force. This method to improve coal. agglomerate strength may be applicable to briquetting and pelletizing of fine particles of materials wetted by water.