Home » Optimization and Enhancement of Mine Rescue Services in Saxony

Optimization and Enhancement of Mine Rescue Services in Saxony

In recent years and decades, structural change has taken place in all German mining regions. In general, it can be said that the old-established, large-scale coal and ore mines have been closed down or have moved from an active extraction phase to rehabilitation mining, combined with a corresponding reduction in the number of employees. At the same time, we are seeing a significant rise of mechanisation at many small and medium-sized underground mining companies which is also having an impact on the number of employees and their qualifications. This development is also visible in Central Germany and Saxony. The effects of this development on the mine rescue service as well as the current challenges and approaches to restructuring the mine rescue system in the region are the subject of this article.

Authors/Autoren: Univ.-Prof. Dr.-Ing. Helmut Mischo, Dipl.-Ing. Frank Reuter und Dipl.-Ing. Stefan Pötzsch, TU Bergakademie Freiberg, Freiberg, Dipl.-Ing. Andy Tauber, Wismut GmbH, Chemnitz

The mine rescue association in Saxony

At the end of the GDR, mine rescue in the area of the Ore Mountains and its foreland was primarily organized by the large mining companies, mainly SDAG Wismut and Albert Funk Freiberg Mining and Metallurgical Combinat, who made this service also available to the smaller local mines. Up to the 2000s, this fundamental structure could be maintained due to the personnel strength of the now Wismut GmbH, Chemnitz. Due to the success of the Wismut’s mine site rehabilitation programme and the associated reduction in personnel, it has since become necessary to develop and implement new structures in order to ensure that the mine rescue system with all its specific features could be kept up throughout Saxony (1).

Thus the “Agreement on Cooperation in Mine Rescue Services” was signed in 2013 and a network was created, which, in addition to Wismut, also includes the companies GEOMIN Erz-gebirgische Kalkwerke GmbH, Pockau-Lengefeld, Erzgebirgische Fluss- und Schwerspatwerke GmbH, Kurort Oberwiesenthal, and BsS Bergsicherung Sachsen GmbH, Schneeberg.

The Freiberg Mine Rescue Department of Technical University (TU) Bergakademie Freiberg has been associated with the network right from the beginning. With the establishment of the required internal structures it became a full member in 2017. The required target strength at the Freiberg site is met – for the first time in Saxony – through a cooperation of TU Bergakademie Freiberg, the local hospital Kreiskrankenhaus Freiberg gGmbH and the Freiberg Fire Department. The Freiberg Mine Rescue Department is made up of employees of different entities at the mine site of the Research and Educational Mine and full-time members of the Freiberg Fire Department.

The Mine Rescue Association is coordinated by Wismut, who also provide the majority of the mine rescue members at the Aue and Königstein sites. In this new structure, a total of 85 mine rescue members is integrated in a joint training and alerting structure. The supervising main body according to § 131 of the Federal Mining Act (BBergG) is the Centre of Mine Rescue Services of the Prevention Office for Emergency Management by the German Social Accident Insurance Institution for the Raw Materials and Chemical Industry (BG RCI) in Leipzig.

All technical equipment is to be further harmonised throughout the association beyond the MSA AirElite 4h which is currently used as standard by default. The aim of the network is carry out the initial attack in the event of an incident at the individual sites of the member companies by on-site forces and resources, including a reserve unit, and, at the same time, to provide reinforcement in form of the neighbouring integrated mine rescue units. For this purpose, regular joint practice drills are executed together with neighbouring mine rescue teams at the majority of all mines that are part of the association. In the case of an incident, and taking into consideration the thin personnel cover at most mine sites, it is planned to proceed with mixed squads, in order to still be able to carry out a rescue operation as comprehensively as possible. Table 1 gives an overview of the association’s organization and essential equipment.

Table 1. Organization and essential equipment in the Saxon structure // Tabelle 1. Organisation und wesentliche Ausrüstung Struktur Sachsen. Source/Quelle: TUBAF

Scope of duties and requirements for underground mine rescue in Saxony

With its almost 1,000 years of mining history which continues today into the so-called “4th Berggeschrey” (4th Mining Rush) (2), the Ore Mountain region is characterized by a multitude of mining activities and several thousand historical witnesses and legacies, even beyond active mining. In the overall view, all these underground operations and facilities, which by far exceed the facilities of the alliance partners in number and size, can be classified from a (safety) legal perspective as illustrated in Figure 1.

Fig. 1. Underground operations and facilities as seen by the association (3). // Bild 1. Untertägige Betriebe und Einrichtungen aus Sicht des Verbunds (3).

All measures within the scope of assistance towards other underground structures and mining activities can only be carried out in consideration of the safeguarding of the respective own operations of the alliance partners. In concrete terms, this means that either, due to the small number of personnel in the mine rescue teams at the individual operating sites, the partners’ own underground operations must first be evacuated before the rescue teams can leave their own site, or, as in the case of Wismut, rescue teams of sufficient strength must remain at their respective home site to provide security.

According to the current legal situation in Saxony, rescue from underground structures and cavities, which are not subject to mining law, lies in the responsibility of the operating entities, if any, or, otherwise, in the responsibility of public institutions for danger prevention, e. g., local fire departments according to SächsBRKG (4, 5). However, due to inadequate equipment and non-applicable rules of engagement, especially when compared to specialized rescue forces such as a fully trained and equipped mine rescue department, such missions can either only be carried out to a very limited extent, or, more likely, cannot be carried out at all (5).

Over the past years and within the framework of practice drills and completed missions – partially in collaboration with fire departments, or within research projects – the following differences between mine rescue departments and fire departments have emerged.


In the event of an incident, the different mine rescue departments and teams of the mine rescue association, are alerted as internal rescue forces via an in-house, commercial and mobile radio-based alarm system. This system is operated by the continuously manned dispatcher service of Wismut. To date, this centralized alerting channel via the dispatcher has proved sufficiently effective for operations at the member companies and for the assumed incident scenarios at the respective mine sites. Companies and facilities outside the network that are affiliated via special assistance agreements also alert the mine rescue departments via the dispatcher service as part of their own alerting protocol.

However, in the case of incidents outside the members’ own mining operations, and particularly at underground sites outside commercial activities, e. g., visits to old and abandoned mine sites, when an emergency call is received via the general emergency call telephone number 112 at any local rescue coordination centre, it cannot be ensured that the reference to mining will be properly recognized and that thus all necessary alerting steps for a mine rescue operation are initiated. However, the Chemnitz Integrated Regional Control Center (IRLS), which is covering a large part of the Ore Mountain region, is sensitized to the possibility of underground incidents in the region and will accordingly alert the mine rescue association via the Wismut dispatcher service in the event of such an incident. At present, further-reaching, new alerting methods for the mine rescue service are being assessed and tested by the IRLS. This includes, above all, the integration of the mine rescue teams into the radio system for legal authorities and organizations with security tasks (BOS). The legal requirements for a connection to the BOS radio system were issued in 2018, and the technical implementation within the association has been carried out since 2019. BOS radio on mine rescue vehicles enables alarmed mine rescue teams to receive further information already before their arrival on site, which helps them to coordinate the selection of resources and equipment and to prepare the underground approach.

While the team structure of rural fire departments is generally composed of the forces present at the time of the alarm and it cannot be fully predetermined what skills will be available at a given time, the on-call stand-by system of the mine rescue departments ensures that the essential key functions are deployable immediately after the alarm has been raised. In addition, during regular working hours, squads are pre-assigned for different types of incidents. In the event of an emergency, these squads form the first deployment and can act largely independently.


Fig. 2. Underground facilities as seen by the association (6). // Bild 2. Untertägige Einrichtungen aus Sicht des Verbunds (6).

As illustrated in figure 2, the conceivable locations for underground rescue operations – showcased here by the location of the visitor mines in the region, the mine safety companies and the partners of the association – are spread out over the entire Ore Mountain region. The same applies to the temporary operating sites of the mining rehabilitation companies as well as to the heirlooms of the old mining activities. Putting this into relation to the locations of the operational mine rescue departments, approaching times of over 1 h, in winter considerably longer, are not uncommon. Alternatives, such as the possibility of airlifting the mine rescue teams by helicopter, as practiced e.g. in Austria, have been investigated, but do not provide any time advantage compared to the vehicle approach. This is due to the flight distances that need to be covered from the take-off points to the pickup locations of the mine rescue teams and then further on to the site of the incident. (7) Thus, the approaching time of a mine rescue team is in general significantly longer than those of the public emergency services that are required to have a maximum response time of 12 min in Saxony. (8)

In order to ensure that in the event of an incident the vehicle approach to any incident site can take place as quickly as possible, both the Freiberg and Wismut mine rescue departments were granted an exemption for the mine rescue team transport vehicle in accordance with § 46 of the German Road Traffic Regulations (StVO) for the use of special signals (blue flashing lights and emergency horn) in 2020. Thus, there are now five rescue team transport vehicles and one commando and liaison vehicle available within the association.

Incident command

During missions at mine sites of the association’s member companies, the management of the rescue operation itself and the respective responsibilities are clearly defined by the relevant regulations of the local mining law which explicitly assigns all responsibilities to the management of the company who usually delegate the execution of rescue operations and incident command to the technical management. However, during alerts and missions outside mining supervisions, such as in facilities and on underground sites under SächsHohlrVO (9), e. g., hazard control missions in old mines, the legal regulations and requirements are assessed differently. Here, incident command is incumbent on the alarmed public emergency services, in accordance with SächsBRKG. If mine rescue teams are additionally alerted to such an incident, they are integrated into the existing operational structure and provide assisting support (Figure 3). Forming an own separate task force section for the underground rescue work under the superordinate incident command has proven to be highly efficient.

Fig. 3. Exemplary operational structure of a mission in an old mine with 137 mine rescue brigade members in 2019 (10). // Bild 3. Beispielhafte Einsatzstruktur eines Einsatzes im Altbergbau im Jahr 2019 mit 137 Einsatzkräften (10).

Furthermore, for any operations that are not subject to mining law but have a specific hazard potential, section 57 of the SächsBRKG is mandatory, which lists additional requirements for the management in order to support the respective incident command – especially the obligation to provide expert advice –and to provide means of communication.

Mine mapping and knowledge of the specific mine site

Since the active mine sites of the associated member companies are regularly exercised during joint mine rescue training, knowledge of the specific location is abound to the incident command staff and quite often also to the deployed mine rescue teams from the other companies within the association. Thus, trained mine rescue members or at least trained scouts familiar with the location (according to section 3.9 in (11)) are available to the mine rescue teams in the event of an emergency. At visitor mines and caves or at temporary operating sites for rehabilitation and hazard prevention at old and abandoned mine sites the situation is, however, quite different. In addition, in the case of non-commercially managed objects and especially of abandoned old mine workings, even the existence of a comprehensive and up-to-date mine mapping cannot be assumed in the event of an incident.

Respiratory equipment

Aside from the typical risk of an underground fire and the subsequent spread of incendiary fumes within the mines, particularly the gases of geogenic origin or from putrefaction make it mandatory for the mine rescue members to be equipped with and use closed-circuit self-contained regenerating breathing apparatus (CC-SCBA), either because of the harmful impacts of these gases on the human organism or because of displacement and the subsequent lack of oxygen. Due to the spatially large extent of many mines and the resulting long operating times, only CC-SCBAs with a hold time of 4 hours can be considered. Such equipment is not used by default by the fire departments in Saxony.

Fire departments use CC-SCBAs only if there are any facilities in their area of responsibility which would require the application of such respiratory protection technology. This applies to several professional fire brigades like the Dresden Fire Department, which operated the Dräger PSS BG 4 CC-SCBA until 2012 (12), and currently the Bad Homburg Fire Department in Hesse, for incidents at their local underground water supply facilities (13).

In the larger Ore Mountain region in Saxony, radon and CO2 in particular are geogenic gases that pose a risk, although H2S and CH4 can also play a role locally. For this purpose, the AirElite 4h from MSA Safety Inc. has been introduced as the standard CC-SCBA throughout the association, with the lateral hose routing and compact design having been particularly decisive for the selection of the AirElite 4h. The mine rescue association currently holds 25 units readily available for emergencies and first advancements on three sites in Aue, Königstein and Freiberg. In addition, the association provides 19 trainer breathing apparatus, 13 of which can be quickly converted into additional operational units in the event of an incident. The advantage of having only one type of CC-SCBA for the entire mine rescue association is that, on the one hand, the trainer units can be brought together at one location at short notice for larger exercises without having to fall back on the emergency units, and, on the other hand, that mixed squads from the individual locations can be formed for exercises and operations, since everyone has been trained on the same equipment.

Gas measuring technology

As described in the previous paragraph, gases (geogenic, putrefaction or fire gases) are a key hazard in underground mines. Thus, every active mine has to have gas measuring devices for every hazardous and harmful gas that might potentially occur in the mine. Exemplary gases in the Freiberg Research and Educational Mine are O2, H2S, H2, NO2, CO2, CO, Cat-Ex and radon.

Particular attention must be paid to CO2, as it is colourless and odourless, thus making it imperceptible to the human senses. On the other hand, it can also be emitted unnoticed, e.g., from moving mine water, which is a typical hazard scenario in Saxon mining (14). Especially in old and abandoned mines, where no regular mine ventilation can be guaranteed, there is a risk of high CO2 concentrations occurring, which may lead to exhaustion, headaches, debilitation or collapse. For safety reasons, mine rescue teams must always carry CO2 and O2 measuring equipment when entering such mines. However, a scientific examination in 2020 of the structure of rescue and emergency units in the eastern Ore Mountain region by Dawin revealed that only three out of eight local fire departments had additional gas measurement devices for CO2 available. (5)

Roping technology and equipment

The special characteristics of historical mining as well as of the more recent mining of hydrothermal, steeply inclined ore bodies, as typical of the region, result in a heavily vertically structured mine, with varying working levels and sub-levels subdued by raise drifts, draw point raises, and blind shafts. Often, the original technical fixtures and historical technical installations no longer exist or can no longer be used and have only been reinstalled locally at active underground mine rehabilitation sites, so that in the event of a mine rescue operation over great vertical heights, rope technology must necessarily be used, both for the approach and for rescue and recovery. This circumstance has already been incorporated into the training and operational concept of the joint mine rescue departments in the past and is practiced regularly. The mine rescue departments at the Aue and Königstein sites therefore have appropriately trained rope rescue teams, and at the Freiberg site this competence has been implemented by the integration of the full-time members of the Freiberg Fire Department, who can be seen in figure 4 during an exercise drill at the Alte Elisabeth shaft of the Research and Educational Mine. In addition, there is a close cooperation, both during exercises and incidents, with the appropriately trained fire department unit in Annaberg-Buchholz (Mining and High-Altitude Rescue Unit Buchholz).

Fig. 4. Abscending and descending practice in the mine Alte Elisabeth (15). // Bild 4. Auf- und Abseilübung auf der Schachtanlage Alte Elisabeth (15).

Underground communication

The common lack of any communication infrastructure in old and abandoned underground mine sites generally does not permit the use of radio-based standard communication technology as used in the field of firefighting. Therefore, wire-based technologies such as the old-fashioned analogue pit phone, have always been used in mine rescue operations.

A number of unsuccessful underground tests with commercially available wireless technology from a wide variety of transmission systems and manufacturers has been conducted by the mine rescue departments. Consequently, a new tethered system has been developed at TU Bergakademie Freiberg specifically for mine rescue operations which also allows very large transmission ranges and the connection of several transmitters/receivers at reasonable investment and operating costs. The new system is now marketed under the product name of CABLECOM LR Imtradex Hör- & Sprechsysteme GmbH (Figure 5). In addition, suitable means of communication may also exist in other areas, such as speleology, e. g., the Cave-Link system, which is to be tested in Freiberg in the near future.

Fig. 5. CABLECOM LR with cable cartridge, e. g., for brigade leader (16). // Bild 5. CABLECOM LR mit Kabelkartusche, z. B. für Truppführer (16).

Reduced time delay for initial medical care

Initial medical care for casualties and victims of accidents is a serious problem in any underground operation, as well as the required medical care during the time-consuming transport back to the surface until the victim can be handed over to emergency medical services or an emergency physician. The underground area is in general outside the typical area of operation of the emergency medical services, so that the mine rescue teams also have to provide initial medical care for the whole time period until the victim has been brought back to the surface.

Whereas in the past it was sometimes possible to integrate emergency medical services into the large underground mine rescue departments of the above-mentioned but no longer existing large-scale mining operations, and sometimes even have them go underground under apparatus, such line-ups are no longer available.

According to the regulations of the professional associations, the public emergency medical service in Germany is not allowed to endanger themselves (17) and is therefore not obliged to enter an underground mine in case of an incident. Over the past years, multiple informative meetings regarding underground mining have been held at the TU Bergakademie Freiberg with senior emergency physicians in Saxony in order to sensitize medical personnel for the underground areas.

To help close this gap, a special curriculum for “Tactical Medicine in Mine Rescue” has been developed and has been implemented in Freiberg since 2019. This curriculum will be presented and discussed in detail in an upcoming medical publication as part of the official recognition process by the mining authorities.

Mining knowledge and skills

A distinctive feature of mine rescue teams in active mining operations, in addition to their extensive local knowledge of their own operations, is the mining expertise and skills available within the organization. This is probably the most important distinguishing feature compared to fire department teams. Members of the mine rescue team are qualified and trained to make operational assessments of the stability of mine workings and other looming hazards and to carry out any necessary safety measures. The knowledge about special conditions and hazards of mine operations, the technical equipment and geological peculiarities are also a regular part of their professional training. All of this serves to reduce operational risks during mine rescue missions, but requires extensive, mining-related training.

As a result of the decreasing underground mine rehabilitation projects at Wismut and the subsequent reduction in staff numbers, nowadays underground mine rescue members are recruited in part from staff whose regular professional activities are either not located, or only partially located, within the mining operations themselves. This is compensated for, on the one hand, by the skills of the teams of the association partners who are still in active mining and, on the other hand, by increased training sessions with regard to mining skills.

Synergy effects between mine rescue and fire departments

As stated in the previous paragraphs, there are some differences between mine rescue departments and fire departments in terms of equipment, but there is also potential for synergy effects. In underground operations involving a fire or gas hazard, mine rescue units have a unique selling point compared to fire departments due to their equipment with long-term CC-SCBAs, gas detection technology and special firefighting material, e. g., dam construction material. Even when providing technical assistance, e. g., with a hydraulic rescue kit, every tool must meet the special requirements of the underground space, e. g., by ensuring that the necessary hydraulic aggregates are driven electrically or by battery and not by fuel. In the area of rope technology, there are only minor differences between mine rescue departments (according to (18)) and fire departments (according to (19)), although firefighters often have a higher frequency of training, so that synergy effects can be exploited here in training and deployment. In the area of incident logistics for operations outside the mine sites of the association partners, fire departments outmatch mine rescue simply due to their shorter travel distances.

When integrating firefighters into underground mine rescue operations, special training is required in addition to the standard curricula at state firefighting schools or comparable institutions, starting with the recognition of underground hazards (wall and roof stability, gases, …) and extending to deployment tactics (squad size, means of communication and duration of deployment, …). However, the generally higher intensity and standards of training, as well as the high deployment frequency of the fire departments have a positive effect on the training level of a jointly operated mine rescue team.

Due to the recognized differences in training, mining skills and knowledge and available equipment, as well as the tactical structures and approach of fire brigades, a future comprehensive delegation of tasks from mine rescue departments to local fire departments should be refrained from in general. A recent study from the year 2020 on safeguarding of mine rescue operations in the underground facilities of the Revierwasserlaufanstalt (regional water works in the Ore Mountain region), which, out of its 70 km total length of waterways, operates a total of 39 water tunnels with a combined length of 23 km, has shown, that without the involvement of the mine rescue organisation, a comprehensive underground rescue operation cannot be carried out by the local fire departments alone due to inadequate equipment and training – including gas measuring technology, communication equipment and lack of long-term CC-SCBAs. For the future, new approaches of collaboration and coordination between local rural fire departments and mine rescue teams that must necessarily be involved at underground incidents, should be implemented. The above-mentioned integration into the BOS radio system is an important step. (5)

Conclusion and outlook

The overall structure of mining and underground operations requires a close cooperation for the individual mine rescue departments both within the Mine Rescue Association as well as with the local fire departments. Cooperation between the mine rescue teams of the partner institutions has been taking place on an operational level since 2013 in the form of the “Agreement on Cooperation in Mine Rescue Services”. Cooperation with fire departments has been implemented on two levels. On the one hand, full-time firefighters from the Freiberg Fire Department have been integrated into the Freiberg Mine Rescue structure. On the other hand, due to legal requirements and topographical conditions, cooperation with local fire brigades throughout the region is essential and necessary for mine rescue operations in those underground facilities that do not belong to any of the association partners. Some progress has been recently made in this regard, such as equipping the mine rescue teams with BOS radios and the right to use special signals during emergencies, but further potential for optimization has been identified. In this paper, various aspects of cooperation, such as equipment requirements and resulting similarities and differences have been discussed.

In other mining districts, too, mine rescue departments from different companies are diligently working together, although the collaboration regime is always geared to the regional circumstances and structures of the local mining industry and cannot simply be transferred to other districts. As an example of another association, the Central South Harz Mine Rescue Service can be mentioned. (20)



(1) Mischo, H.; Pötzsch, S.: Aktuelle Entwicklung des Grubenrettungswesens an der TU Bergakademie Freiberg und Einführung des europäischen Ausbildungsprojekts MINERS. In: Mining Report Glückauf 154 (2018) Heft 5, S. 406 – 412.

(2) Cramer, B.: Das 4. Sächsische Berggeschrey – Euphorie und Praxis. Öffentlicher Abendvortrag der Tagung Geologie und Bergbau in Sachsen, 08.04.2015, Freiberg.

(3) Bildquelle: Stefan Pötzsch, 2021, Freiberg.

(4) Sächsisches Gesetz über den Brandschutz, Rettungsdienst und Katastrophenschutz vom 24. Juni 2004 (SächsGVBl. S. 245, 647), das zuletzt durch das Gesetz vom 25. Juni 2019 (SächsGVBl. S. 521) geändert worden ist.

(5) Dawin, J.-V.: Erarbeitung eines Havariekonzepts für den Betrieb der „Revierwasserlaufanstalt Freiberg“ unter Berücksichtigung der betriebsspezifischen Gefährdungspotentiale und regional verfügbaren Rettungskräfte. Diplomarbeit am Institut für Bergbau und Spezialtiefbau der TU Bergakademie Freiberg, 2020, Freiberg.

(6) Bildquelle: Wismut GmbH, 2021, Chemnitz.

(7) Andrich, D.: Möglichkeiten und Grenzen für den Einsatz von Hubschraubern bei Grubenwehreinsätzen unter besonderer Berücksichtigung neuer Aspekte in Auswertung des Rettungswerkes in der Riesendinghöhle in Österreich. Diplomarbeit am Institut für Bergbau und Spezialtiefbau der TU Bergakademie Freiberg, 2016, Freiberg.

(8) Online: https://rettungsdienstgesetz.de/sachsen/, abgerufen am 10.02.2021.

(9) Sächsische Hohlraumverordnung vom 20. Februar 2012
(SächsGVBl. S. 191).

(10) Bildquelle: Wismut GmbH, 2020, Chemnitz.

(11) Leitlinien des Deutschen Ausschusses für das Grubenrettungswesen für Organisation, Ausstattung und Einsatz von Grubenwehren, Stand Juni 2019.

(12) Brand- und Katastrophenschutzamt der Stadt Dresden: Jahresbericht 2012. 2012, Dresden.

(13) Online: https://www.fr.de/rhein-main/hochtaunus/glueck-homburg-11267218.html, abgerufen am 10.02.2021.

(14) Weyer, J.: Grubenbewetterung. Vorlesungsunterlagen am Institut für Bergbau und Spezialtiefbau der TU Bergakademie Freiberg, 2020, Freiberg.

(15) Bildquelle: Stefan Pötzsch, 2020, Freiberg.

(16) Bildquelle: Frank Reuter, 2021, Freiberg.

(17) Neitzel, C.; Ladehof, K.: Taktische Medizin: Notfallmedizin und Einsatzmedizin. Springer, 2015, Heidelberg.

(18) Leitlinien des Deutschen Ausschusses für das Grubenrettungswesen für die Auf- und Abseiltechnik, Stand Juni 2019.

(19) Empfehlung der Arbeitsgemeinschaft der Leiter der Berufsfeuerwehren: Spezielle Rettung aus Höhen und Tiefen, Stand Juni 2019.

(20) Online: https://www.gses.de/grubenwehr.html, abgerufen am 10.02.2021.

Authors/Autoren: Univ.-Prof. Dr.-Ing. Helmut Mischo, Dipl.-Ing. Frank Reuter und Dipl.-Ing. Stefan Pötzsch, TU Bergakademie Freiberg, Freiberg, Dipl.-Ing. Andy Tauber, Wismut GmbH, Chemnitz