离子型稀土矿体强度弱化规律与原地浸矿临界水位计算

It is very important to determine accurately the critical water table to reclaim adequately the ion-absorpted type rare earth resources and to control the geological disasters. So, one of the core technical problems in-situ leaching is determining accurately the critical water table. In the engineering background of barefoot type ion-absorpted type rare earth deposits in-situ leaching, the relationship between micro particle migration, particle group disintegration of ore body, ion adsorption and ion desorption and hydrodynamic dispersion curve is studied. The particle group crushing effect is analyzed according to the stress-strain curve of rare earth ore body. The characteristic values of describing the grain composition and the change of pore size are extracted. The model for strength weakening of ionic type rare earth ore body in-situ leaching is established on the basis of analyzing the relationship between critical state line and consumption plastic work and the strength weakening rule of ore body in-situ leaching. The phreatic line change rule is analyzed considering the heterogeneity of osmotic coefficient of ore body under the condition of the heterogeneity of injection liquid. The seepage model in-situ leaching is established using Boussinesq equation. The methods to describe the spatial variability of strength parameters and permeability coefficient are put up. The water-soil characteristics of ore body in leaching process are studied. The slope stability is discussed under the condition of the heterogeneity of injection liquid. The study results will be useful to develop the monitoring and prevention technology of triggering slides in-situ leaching.

临界水位对于充分回收离子型稀土资源和控制地质灾害具有重要意义，也是原地浸出工艺面临的核心技术难题之一。项目以裸脚式离子型稀土矿床的原地浸矿工艺为工程背景，研究浸矿过程中的微颗粒迁移、矿体颗粒团崩解、离子吸附和解吸与水动力弥散曲线的关系，根据稀土矿体的应力应变曲线分析颗粒团破碎效应，提取表示颗粒级配和孔隙大小变化的特征值，求得临界状态线位置与消耗塑性功之间的关系，分析浸矿过程矿体强度弱化规律，建立矿体强度弱化模型；针对矿层的渗透系数具有强烈的空间变异性，分析矿体底板形状和非均匀注液条件下的浸润线变化规律，运用Boussinesq方程建立原地浸矿的渗流模型；探索描述矿体强度参数和渗透系数的空间变异性的有效方法，研究浸矿过程矿体的水土特性变化，讨论浸矿剂溶液非均匀入渗条件下边坡稳定性的变化，提出原地浸矿临界水位的计算方法。项目研究成果有助于进一步发展原地浸矿引发滑坡的监控和防治技术。

原地浸矿开采工艺现已被普遍推广应用于离子型稀土矿山稀土资源的开采，但目前原地浸矿开采工艺仅依靠经验进行工程布置，易引发滑坡等地质灾害，滑坡造成水土流失和滑坡区资源难以回收，已成为该工艺的技术瓶颈之一。与一般的滑坡相比，原地浸矿引发滑坡有4个方面的显著特征：第一，注液和收液工程多，渗流规律复杂；第二，山体含水率高，近饱和区域的体积占比大；第三，浸矿剂用量大，矿土强度参数变化显著；第四，资源赋存面积广，开采周期短。.在项目执行过程中取得了6个方面重要研究进展。（1）建立了离子型稀土矿近饱和矿体抗剪强度的计算模型，现有模型的计算相对误差31.8~51.6%，新模型的计算相对误差为10.3~12.4%。（2）揭示了水土化学作用对离子型稀土矿体抗剪强度参数的影响机理：矿体颗粒间的相互作用力发生改变，造成矿体颗粒的团聚或者分散，从而影响了矿体的抗剪强度。（3）提出了基于统计规律的离子型稀土矿体力学参数测试方法，与现有测试方法相比，采用非等间距布置测点，基于地质统计规律的测试方法测试工作量减少25%。（4）现场监测了一个生产矿块原地浸矿的渗流过程和边坡稳定性变化规律，为同类矿块提供了工程数据积累。（5）构建了渗透系数空间变异条件下临界注液强度的计算方法，为原地浸矿边坡稳定性控制提供了方法。（6）建立了原地浸矿引发滑坡的控制措施和工艺设计方法，为原地浸矿控制边坡稳定性选择工程措施提供了依据。.上述成果集成为离子型稀土矿山原地浸矿地质灾害控制集成技术，实现了强降雨天气前通过调节矿体含水量来主动控制边坡稳定性，扩大了原地浸矿工艺的适用性条件，该成果已部分应用于龙岩市稀土开发有限公司下属矿山。