This paper illustrates how the Bieniawski rock mass rating geomechanics classification, within the support system used by medium-scale mining companies, allows for the development of a new anchor rock bolt selection method aimed at improving horizontal access stability in underground mines. However, this case study only seeks to select the most efficient anchor rock bolt for any given horizontal access. A proper support selection method is very important for mining companies because this decision will safeguard both miners and mining infrastructure. This selection process will ultimately prevent fatal accidents, which is critical for mining companies today, especially considering the constant operation standstills reported in Peru.