ATP 3-21.51 Subterranean Operations 129(0%(5 2019 DISTRIBUTION RESTRICTION: Approved for public release; distribution is unlimited. This publication supersedes ATP 3-21.51, dated 21 February 2018. Headquarters, Department of the Army This publication is available at the Army Publishing Directorate site (https://armypubs.army.mil), and the Central Army Registry site (https://atiam.train.army.mil/catalog/dashboard) *ATP 3-21.51 Army Techniques Publication Headquarters No. 3-21.51 Department of the Army Washington, DC, 1RYHPEHr 2019 Subterranean Operations Contents Page PREFACE..................................................................................................................... v INTRODUCTION ........................................................................................................ vii Chapter 1 SUBTERRANEAN ENVIRONMENT ......................................................................... 1-1 Attributes of a Subterranean System ........................................................................ 1-1 Functionality of Subterranean Structures .................................................................. 1-1 Subterranean Threats, Hazards, and Risks .............................................................. 1-2 Denial and Deception ................................................................................................ 1-6 Categories of Subterranean Systems ....................................................................... 1-9 Construction of Subterranean Spaces and Structures ............................................ 1-14 Chapter 2 THREAT .................................................................................................................... 2-1 Threat Types and Objectives..................................................................................... 2-1 Characteristics of Threat Defenses in Subterranean Systems ................................. 2-9 Chapter 3 BRIGADE COMBAT TEAM AND BATTALION OPERATIONS .............................. 3-1 Contact with Underground Facilities .......................................................................... 3-1 Defining the BCT and Battalion Fight ........................................................................ 3-1 Coordinating with Echelons Above Brigade .............................................................. 3-3 Operations Process and tactical tasks in the Subterranean Fight ............................ 3-4 Mitigating Contact with Underground Facilities ......................................................... 3-4 Conduct an Attack of an Underground Facility ........................................................ 3-24 Plan .......................................................................................................................... 3-24 Prepare .................................................................................................................... 3-42 Execute .................................................................................................................... 3-44 Assess ..................................................................................................................... 3-61 Chapter 4 COMPANY AND PLATOON SUBTERRANEAN OPERATIONS ............................ 4-1 Scope of the Company and Platoon Fight ................................................................. 4-1 Mitigating Contact with Underground Facilities ......................................................... 4-3 Plan .......................................................................................................................... 4-13 Prepare .................................................................................................................... 4-19 Execute .................................................................................................................... 4-20 Assess ..................................................................................................................... 4-45 Chapter 5 SQUAD AND INDIVIDUAL TECHNIQUES .............................................................. 5-1 Squad Order of Movement ........................................................................................ 5-1 Describe the Environment ......................................................................................... 5-3 Move Within a Subterranean System ........................................................................ 5-5 DISTRIBUTION RESTRICTION: Approved for public release; distribution is unlimited. *This publication supersedes ATP 3-21.51, dated 21 February 2018. i Contents React to Direct Fire Contact .................................................................................... 5-10 React to Contact (CBRN or Atmospheric Threat) ................................................... 5-14 Sustainment Considerations ................................................................................... 5-16 Chapter 6 ENABLING ORGANIZATIONS, OBSTACLES, AND CAPABILITIES .................... 6-1 Enabling Organizations ............................................................................................. 6-1 Mitigating Obstacles in a Subterranean Environment ............................................. 6-11 Additional Subterranean Capabilities ...................................................................... 6-13 Chapter 7 SUSTAINMENT ........................................................................................................ 7-1 Logistics Planning Considerations ............................................................................ 7-1 Army Health System Support Planning Considerations ........................................... 7-4 Organic and Area Support Medical Treatment Assets ............................................. 7-5 Casualty Evacuation ................................................................................................. 7-7 Resupply Operations................................................................................................. 7-8 Echelon of Sustainment .......................................................................................... 7-12 Maintenance and Recovery Operations ................................................................. 7-15 Appendix A SUBTERRANEAN MEDICAL CONSIDERATIONS ................................................. A-1 Appendix B TRAINING ................................................................................................................. B-1 GLOSSARY ................................................................................................ Glossary-1 REFERENCES ........................................................................................ References-1 INDEX ............................................................................................................... Index-1 Figures Figure 1-1. Attributes of a subterranean system ........................................................................... 1-1 Figure 1-2. Level 3 portals, examples ............................................................................................ 1-8 Figure 1-3. Rudimentary tunnel ................................................................................................... 1-10 Figure 1-4. Subway ...................................................................................................................... 1-11 Figure 1-5. Underground facilities portals .................................................................................... 1-12 Figure 1-6. Tactical tunnel system in jungle environment ........................................................... 1-14 Figure 1-7. Tactical tunnel system in urban environment ............................................................ 1-15 Figure 1-8. Underground facilities design features, top view ....................................................... 1-16 Figure 2-1. External view of a possible hardened artillery site ...................................................... 2-5 Figure 2-2. Internal view of a possible hardened artillery site ....................................................... 2-6 Figure 2-3. Side view to show potential complexity of a hardened artillery site ............................ 2-7 Figure 2-4. Threat passageways and barricades, examples ......................................................... 2-9 Figure 2-5. Four vent examples ................................................................................................... 2-10 Figure 3-1. Techniques for arraying combat power in different operational environments ........... 3-6 Figure 3-2. Comparison of mitigation options ................................................................................ 3-9 Figure 3-3. 3/52 Stryker brigade combat team task organization ................................................ 3-14 Figure 3-4. Enemy situation template .......................................................................................... 3-15 Figure 3-5. 3/52 Stryker brigade combat team concept of the operation .................................... 3-16 Figure 3-6. Updated 3/52 Stryker brigade combat team common operational picture ................ 3-17 Figure 3-7. 3/52 Stryker brigade combat team outer cordon established ................................... 3-19 Figure 3-8. Establishing the inner cordon .................................................................................... 3-21 ii ATP 3-21.51 1RYHPEHU Contents Figure 3-9. Isolated underground