No abstract

Acid mine drainage is acidic water that arises as a result of mining activities. Acidic water has a high acidity, which is often characterized by a low pH and contains high levels of heavy metals Fe and Mn. The purpose of this study was to determine the effect of activated carbon on the adsorption process and the effect of mass of activated carbon on eggshells. The method used in this research is the adsorption method using activated carbon of eggshell which is physically and chemically activated. This study used a mass variation of 5, 10, 15 and 20 grams with a contact time of 30 minutes and an adsorbent size of 200 mesh. The parameters studied were heavy metals iron (Fe) and manganese (Mn). The initial concentration of Fe acid mine waste was 29.179 mg/L, and Mn was 7.9692 mg/L. The results showed that the mass of activated carbon had an effect on decreasing the levels of Fe and Mn metals. On physical activation the average decrease in Fe metal was 99.50% and Mn metal was 53.21%, while on chemical activation the average decrease in Fe metal was 97.72% and Mn metal was 97.97%.Keywords: Acid mine water, Fe, Mn, Activated carbon, egg shell

Kartanegara Regency and Samarinda City East Kalimantan. From the results of the research and evaluation of the reclamation plan documents and RKTTL, as well as the reclamation implementation report, the Backfilling plan for 2017 is 35.80 Ha and is realized at 22.36 Ha, so that the percentage of success rates reaches 62,46%. The land management and land revegetation plan for 2017 is 62.12 Ha and is realized at 10.26 Ha, so that the percentage of success rate is 16.52%. Revegetation of PT BBE land for the last 3 (three) years from 2015-2017 with a plan of 165.17 Ha and realized as much as 129.05 Ha, resulting in a percentage of success rate of 78.13%, but when compared with the total realization of reclamation (land arrangement ) amounting to 109.06 Ha, realization of revegetation 129.05 Ha, then the success rate of revegetation of reclaimed land is 118.33%. This shows that PT BBE's commitment to environmental management is quite good. Based on the results of laboratory analysis, water quality at all outlet points of PT BBE compliance still meets environmental quality standards of pH 6-7 (BML 6-9). While the soil quality of top soil does not meet environmental quality standards (soil pH 3.68). Based on the overall evaluation results, the percentage of successful reclamation implementation at PT BBE is 78.43% (categorized as moderate).

Scale effect testing on rocks is carried out with the aim of knowing the strength of a rock based on different dimensions. This test was carried out using a uniaxial compressive strength test and also testing the physical properties of rocks. In the rock compressive strength test used 5 dimensions of rock samples with a H/W ratio of which are 4.5/3, 6/3, 7.5/3 for dimensions of 3 cm, 5.25/3.5, 7 /3.5, 8.75/3.5 for dimensions 3.5 cm, 6/4, 8/4, 10/4, for dimensions 4 cm, 6.75/4.5, 9/4.5, 11.25/4,5 cm for the 4.5 cm dimension and for the 5 cm dimension, namely 7.5/5, 10/5 and 12.5/5. Physical properties testing is carried out to determine the porosity value in the test rock samples, which will then be compared between the porosity values ​​and the results of the compressive strength test of rock samples. Physical properties testing carried out obtained the average value of rock porosity, namely 22.562%, 22.122%, 20.454%, 21.227%, and 22.413%. In the scale effect test, it is known that the higher the rock sample, the smaller the value of the rock strength can be seen based on the R2 value obtained in the Balikpapan Formation, which is 0.0548.

Landslide is one of the natural disasters that often occurs on natural and artificial slopes. This landslide occurs due to an imbalance of forces acting on the slope or the actuator in the slope area is greater than the resisting force on the slope. Handling needs to be done to avoid landslides, one of which is making a retaining wall. Based on the data obtained from the results of the tests and calculations that have been carried out, the value of the slope safety factor at the research location is 0.397. This value is the value of the unsafe factor of safety (Avalanche). So it is necessary to design a retaining wall with dimensions in between, namely for H = 7 m, H1 = 0.7 m, H2 = 6.3 m, H3 = 1.6 m, H4 = 0.7 m, H5 = 4.9 m, H6 = 2.6 m, H7 = 0.5 m, H8 = 2.5 m, H9 = 3.8 m, and D = 2.5 m. And the results of calculating the stability of the retaining wall that has been designed are obtained for Stability Against Overturning, namely 4.37 > 1.5 (Safe), Stability Against Shifting, namely 2.21 > 2 (Safe), and Stability Against Soil Bearing Capacity, namely 4.14 > 3 (Safe).