Applied Salt-Rock Mechanics 1

Chapter 1. Introduction

Chapter 2. Geology of Evaporite Deposits


2.1 Oceanic Origin of Evaporite Deposits


2.1.1 Introduction


2.1.2 Conditions of Evaporite Formation


2.2 Mineralogy and Petrology of Evaporites


2.2.1 Evaporite Mineralogy


2.2.2 Petrology of Evaporites


2.2.3 Fluid Inclusions


2.3 Texture and Stratification of Undisturbed Deposits


2.3.1 Primary and Diagenetic Features in Shallow-Water Deposits


2.3.2 Stratification of Deep-Water Evaporites


2.4 Changes to Texture and Stratification after Consolidation


2.4.1 Relative Deformability of Salt Rocks and Interbedded Strata


2.4.2 Submarine Slumping Questioned


2.4.3 Salt Crystallization in Voids Due to Bed Separation


2.4.4 Effects of Slight Tectonic Deformations of Salt Deposits


2.4.5 Effects of Severe Deformations on Texture and Stratification


2.5 Structural Geology of Evaporite Deposits


2.5.1 Faulting and Continental Rifting


2.5.2 Folding


2.5.3 Diapirism


2.5.4 Salt Glaciers


2.6 Review of Salt Mining Methods


2.6.1 Introduction


2.6.2 History of Salt and Potash Mining


2.6.3 Room-And-Pillar Mining


2.6.4 Other Mining Methods

Chapter 3. Physical Properties and Mechanical Behavior of Evaporites


3.1 General Remarks


3.2 The Mechanism of Creep of Salt Rocks


3.2.1 Single Rock-Salt Crystals


3.2.2 Single Carnallite Crystals


3.2.3 Deformation of Polycrystalline Salt Rocks


3.3 Creep Limits of Salt Rocks


3.3.1 Rock Salt and Sylvinite


3.3.2 Carnallite and Carnallitic Salt Rocks


3.4 Strain Hardening in the Laboratory But Not in Situ


3.4.1 The Significance of Strain Hardening


3.4.2 Constant Creep Rates under Constant Loading Conditions


3.4.3 Proof by In-Situ Investigations: No Strain Hardening of Salt Rocks


3.4.4 Elasticity Parameters Insignificant in Salt Deposits


3.5 Low Tensile and Shearing Strengths of Salt Rocks


3.6 The Permeability of Evaporite Deposits


3.6.1 General Remarks


3.6.2 Salt Rocks in Situ Are Impermeable at Depths Exceeding 300 M


3.7 Plasticity of Salt Rocks—Temperature Effects


3.7.1 Equivalent Viscosity


3.7.2 Migration of Brine Inclusions


3.8 Determination of Stresses in Salt Deposits


3.8.1 Introduction and Literature Review


3.8.2 Hydraulic Measurements

Chapter 4. Deformations in Response to Stress Relief by Excavation


4.1 General Remarks—Outline of Problems


4.2 Stress-Relief Creep around Single, Isolated Openings


4.2.1 Rapid Decay of Initial Stress-Relief Creep Rates


4.2.2 The Development of Stress-Relief Creep Zones around Single Openings


4.2.3 Interrelationships between Vertical and Horizontal Stress-Relief Creep


4.3 Stress-Relief Creep Around Two Parallel Openings


4.3.1 Introduction and Outline of Design Problems


4.3.2 Stress Reduction between Two Parallel Openings


4.4 Development of Stress Gradients in Stress-Relief Creep Zones


4.4.1 Stress Gradients around Individual Openings


4.4.2 Stress Gradients around Two Parallel Openings


4.5 Elastic Deformations around Single Openings in Salt


4.5.1 Outbursts of Salt and Gas


4.5.2 Other Sudden Failure Processes Caused By Gas Pressure


4.5.3 Failure Due to Buckling


4.5.4 Shear Failure


4.6 Discharge of Fluids from Isolated Reservoirs


4.6.1 General Remarks


4.6.2 Discharge of Fluids through Boreholes


4.6.3 Discharge of Fluids through Existing Fracture Zones


4.6.4 Discharge of Fluids Due to Large-Scale Deformations

Chapter 5. Creep Deformations in Partially Extracted Salt Deposits


5.1 General Remarks


5.2 Stress-Relief Creep and Pillar Reloading in Room-And-Pillar Potash Mines


5.2.1 IMC-K1 Potash Mine, Esterhazy, Saskatchewan, Canada


5.2.2 Alwinsal Potash of Canada Mine, Lanigan, Saskatchewan, Canada


5.2.3 Other Canadian Potash Mines


5.2.4 Cane Creek Potash Mine Near Moab, Utah, U.S.A


5.2.5 Werra Potash Mining District, Germany


5.2.6 Standard Room-And-Pillar Salt Mines at Shallow Depths


5.3 Stress-Relief Creep and Pillar Reloading—Long-Pillar Mines


5.3.1 General Remarks


5.3.2 Measurements and Observations in Potash Mines, South Harz District, Germany


5.3.3 Sylvite Mine, Rocanville, Saskatchewan, Canada


5.3.4 Werra Potash Mining District, Germany


5.3.5 Horizontal Creep Deformations, Borth Rock Salt Mine, Germany


5.4 Creep Deformations in Panel-And-Pillar Mining


5.4.1 General Remarks


5.4.2 Experimental Mining at the Mine Fernand, Alsace, France


5.4.3 Panel-And-Pillar Mining in Other Potash Mining Districts


5.5 Creep Deformations Caused By Irregular Extraction Patterns


5.5.1 General Remarks


5.5.2 Lyons Mine (Project Salt Vault), Kansas, U.S.A


5.5.3 Solution Mining in Alpine Salt Diapirs, Austria

References

Subject Index