# Management System According to ISO/IEC 17025: Method Validation
## 2 Materials and Methods  
Starting from the premise that adhesion is the property of materials whereby two surfaces of different substances are held together by intermolecular forces upon contact, it becomes evident that adhesion is a fundamental phenomenon underlying the effectiveness of indoor shotrete. In mining, adhesion plays a critical role in the structural integrity of the material, particularly in the bond between mortar and steel (steel bars anchored directly into rock and submerged in mortar). Without such adhesion, steel bars would fail to withstand even minimal tensile stress, as the steel would simply slide along its entire length without encountering resistance. However, due to adhesion, when cracks occur, they distribute evenly throughout the material, enabling the steel to withstand tensile stress and maintaining the bond between the materials in cracked areas. This supports the prevention of potential rock detachment and ensures the continuity of mining operations with maximum safety. Therefore, anchors remain firmly placed in pre-drilled holes in the rock, combining rock and soil. Under these conditions, the space between the hole and the anchor is filled with mortar. In this configuration, the anchor operates passively, relying on friction, as illustrated in Figure 3.  
Figure 3: Anchoring inside the mine for illustrative purposes [9]. Both soil and rock are natural materials that exhibit a wide range of engineering properties, varying significantly from one location to another. The capacity of an anchor is influenced by its depth of placement. Rock anchors typically have medium to very high capacity, as rock can withstand higher stress concentrations. The hole typically maintains a constant cross-section. The shear strength of the anchor is generally less influenced by the depth of anchorage [10]. The anchor installation procedure typically involves three steps:  
1. Rock drilling: Holes are drilled for the anchor with diameters and depths defined by the project. Pneumatic or rotary equipment is typically used for drilling. 2. Hole cleaning: once drilling is complete, the hole is cleaned by either blowing air or washing it with water until all drilling waste material is removed. 3. Mortar placement: Subsequently, mortar is poured into the perforation using a hose of sufficient length. The mortar is deposited at the bottom of the hole first, then advanced upwards, with the hose always submerged in the mixture [11]. The installed anchor can be seen in Figure 4.  
Once the study element has been described, it is crucial to recall the requirements stipulated by the EMA for the validation of the proposed method (as outlined in Table 1). \begin{table}
\begin{tabular}{c c c} \hline ISO/IEC 17025:2017 & Description & Interpretation and Guide EMA MP-FE005-13 \\ \hline
7.2 & Selection, verification, and validation of methods & Selection, verification, and validation of methods \\ \hline
7.2.1.4 & When the client does not specify the method to be used, the laboratory should select an appropriate method and inform the client of the chosen method. It is recommended to use methods published in international, national, or regional standards; by recognized technical organizations; or in relevant scientific texts or journals. Additionally, methods specified by the equipment manufacturer are advisable. Modified or is laboratory-developed methods may also be considered. \\ \end{tabular}
\end{table} 
Table 1: Criteria for validation of test methods. Figure 4: An anchor installed inside the mine [8]. These requirements apply specifically to tests involving physical measurements:  
1. Verification of equipment performance against the method's established requirements. 2. Consistency of laboratory facilities and environmental conditions with those specified in the method. 3. Conducting repeatability and reproducibility studies to ensure compliance with acceptance criteria based on performance data. 4. Providing evidence of inter-laboratory comparisons.