by Nikola Gambiroža, Ph.D. [ Croatian Mine Action Centre ]

In order to achieve efficiency in the established humanitarian demining quality-assurance/quality-control system, acceptable quality levels have been defined for mechanical ground processing using demining machines, manual-detection methods and/or a combination of the manual method and the use of mine-detection dogs.

Quality mine and UXO clearance ensures that the beneficiaries of cleared lands can enjoy a safe livelihood in the demined area. This level of confidence requires a high degree of organization and management, maximum engagement of demining organizations and national mine-action bodies, and a quality-control system with detailed operating procedures. Such a system guarantees the best supervision and control of the suspected mined area.


The Croatian Mine Action Centre is developing a quality-assurance/quality-control system that incorporates all of the organization’s experiences, the requirements of humanitarian demining, and all of CROMAC’s functions and staff into the process of QA/QC and cancellation of areas from the suspected mined area. Based on such presumptions, CROMAC’s QA/QC system entails the following three development phases:

  1. Quality Control
  2. Quality Assurance
  3. Total Quality Management

CROMAC bases its success on the continuous improvement principle exemplified in Total Quality Management. This progress is characterized by constantly improving conditions to reach an acceptable level of quality in a demined area. Attaining TQM is a goal of all CROMAC employees.

CROMAC’s QA/QC system follows the guidelines set in the following documents: ISO 9000, ISO 2859, IMAS 09.10 and IMAS 09.20.1,2 The International Mine Action Standards are an integral part of the management process aimed at verifying demining quality and reaching sufficient confidence (with acceptable quality levels) that the demining company has removed and/or destroyed all mines and unexploded ordnance from the mined area according to specifications.

Sampling Plans (Acceptance Plans)

The basic question asked during the control by sampling is: How many samples should be taken to assure a reliable estimate of the quality level of the entire demined area?

This problem can be successfully resolved in humanitarian demining by using sampling plans or acceptance plans. Depending on the sampling plan applied, decisions about acceptance or rejection of the demined area can be made by:

Sampling plans are classified into two basic groups:

  1. Acceptance plans for attributes (control result is an attribute: proportion of “good” [acceptable] to “bad” [defective] parts of an entirety, number of defects, etc.)
  2. Acceptance plans for variable (control result is measured data)

CROMAC has made the procedures for inspection and sampling during the execution of demining operations and supervision over completed demining operations based on sampling plans for attributive char-acteristics as per standard HRN ISO 2859-1.3

Figure 1: Sampling plan scheme.
(Click image to enlarge)
Figure 1: Sampling plan scheme.

Acceptance Criteria

Acceptable Quality Level for the projected area indicates the acceptable number of nonconformities that can be present in an area without causing rejection of the entirety (an area demined under the same conditions and procedures within the span of a day or week). Several levels of nonconformity exist. The larger the mine, item of UXO, or explosive fragment and the more shallow the soil treatment depth, the lower the allowable number of defects acceptable at each nonconformity level. Once the number of defects exceeds the acceptable standard at a certain level, the area reaches “critical nonconformity,” which causes the entirety to be rejected.

The Law on Humanitarian Demining of the Republic of Croatia defines complete clearance as follows: “Complete worksite clearance is the status of an area and/or facility defined by geodetic measurement that is completely clear from all mines, UXO and their fragments to the depth specified by the project.”4 Using the term complete clearance often causes misunderstandings and is subject to various interpretations. For example, should the worksite be completely clear from all parts of mines and UXO regardless of the type and size of such fragments (metal and plastic parts, parts of explosive, pyrotechnic chain, etc.) and regardless of whether they contain explosive substances?

Prior to introduction of the AQL concept to the
quality-control system, significant demining efficiency and cost-effectiveness were lost due to the fact that every time metal was detected in the control sample during the final acceptance resulted in rejection of the demined area. This rejection of demined areas occurred frequently during the use of demining machines, especially flails.

Since the introduction of AQL, a demined area can contain certain indicators of defects such as remaining metal fragments discovered by metal detectors or remaining traces of explosives with or without metal that are found using the prescribed standard method for the detection of metal and explosives. Such cases can indicate the existence of nonconformities in demining and again create critical nonconformity. Terms for acceptance or non-acceptance of all nonconforming categories are defined by standard operating procedures for sampling. The demining contract defines the AQL that should be used.

Figure 2: The scheme of non-conformity classes and inspection levels.
(Click image to enlarge)
Figure 2: The scheme of non-conformity classes and inspection levels.

Nonconformity represents the deviation in quality that results in the demined area not meeting the specified requirements. Nonconformities are generally categorized into classes according to their level of gravity. The scheme of sampling plans (one-time sampling) and nonconformities are presented in Figures 1 and 2.

Demining methods and techniques, demining machines, and working tool types and makes, as well as the soil conditions on the demining project, are taken into consideration during the definition of critical nonconformity. Based on those factors, tables of confidence levels were made for light, medium and heavy machines as well as tables for definition of sample sizes
for inspection.2

Use of demining machines proved to be very efficient and cost-effective in combination with manual mine detection and mine-detection dogs. If demining machines that reach the depth specified by the project are used during the conduct of demining operations as a first method, following mechanical treatment, the entire area should be searched using manual methods or mine-detection dogs. In that case, the acceptability criteria for the use of MDDs should be defined as well.

Procedures of Corrections and Repetitions

Locations of control samples are selected in a partially guided way so that over 70 percent of control samples have to cover locations of minefields from the minefield records, mine- and UXO-detection sites and other risk areas (borders of minefields, road crossings, etc.) and 30 percent of control samples are selected using a random-selection method.

Acceptance plans and sampling tables are adjusted to the practical needs of demining. Sample sizes are selected in a way to inspect at least 2.5 percent of the worksite area in the case of big entireties (areas bigger than 150,000 square meters [37 acres]), or up to 35 percent in the case of smaller entireties p(areas smaller than 3,201 square meters [3,828 square yards] and bigger than 200 square meters [239 square yards]).


Mine action and demining processes in the Republic of Croatia are organized in such a way as to reduce the mines and UXO danger to an acceptable risk level. The Law on Humanitarian Demining defines the complete clearance of worksites from all mines and UXO to the depth determined by the project, meaning the acceptable risk should be zero. However, it is very difficult to reach 100-percent worksite clearance in an efficient and cost-effective way.

In order to fullfill mine-action goals and completely eliminate the mine problem from the Republic of Croatia, as specified by the National Mine Action Strategy until 2019, CROMAC will focus its future efforts primarily on landmine and UXO removal to its stated Acceptable Quality Level.

The introduction of AQL enables a demined area to contain certain indicators of nonconformity, such as individually measured depths of mechanically treated soil, remaining fragments detected by metal detector, or the remaining traces of explosive substance with or without metal that are found by approved methods for detection of metal and explosives. Such cases can indicate the existence of nonconformities in demining and again create critical nonconformity, which requires rejection of the area. Terms for acceptance or non-acceptance of all defect categories are defined by SOPs for sampling.

With CROMAC’s improved standards for humanitarian de-mining in place, the mine-action community in the Republic of Croatia hopes that the cost of demining operations will decrease as the effectiveness of demining increases. Lands will not be needlessly rejected, while areas at risk of harming its beneficiaries can be effectively targeted for demining procedures. If this model for an effective QA/QC system proves successful over time, the benefits will not only touch Croatia, but the international mine-action community as a whole.


GambirozaNikola Gambiroža, Ph.D., has worked at CROMAC since 1999. Prior to his current position as Assistant Director, which he has held since 2003, he was head of CROMAC Regional Offices in Knin and Karlovac. Gambiroža is an expert in production of explosives and powder. He is currently working on promoting the use of technical regulations, competence testing and evaluation procedures for the machines, devices and equipment used in humanitarian-demining operations. He coordinates the preparation of standard operating procedures and normative acts to develop Croatian standards relating to procedures in humanitarian demining.


  1. IMAS provides the framework of international standards and guidelines for mine clearance and has been developed to improve the effectiveness, efficiency and safety in mine action. For more information: Accessed 12 April 2010.
  2. The International Organization for Standardization is a nongovernmental organization that develops and publishes international standards to help bridge the gap between the public and private sectors. For more information: Accessed 23 April 2010.
  3. See HCR, Standard Operating Procedures. and Accessed 12 April 2010.
  4. See Law on Humanitarian Demining. Croatian Parliament 2964. Accessed 12 April 2010.
  5. Common terms and definitions may be found here:

Contact Information

Nikola Gambiroža, Ph.D.
Assistant Director
Croatian Mine Action Centre
A. Kovačića 10
44000 Sisak / Croatia
Tel: +385 44 554 103
Fax: +385 44 554 111
Web site: