Method of determining weathering characteristics of rock formations in earth moving operations

摘要

A method for producing graphic or mathematical boundary information, in the form of graphs and the like, and the use of such information, for more accurately predicting the acidity and alkalinity of water drainage from rock types which may be subjected to weathering conditions in earth moving operations. Selected rock samples of particular rock types collected from a geographic location of interest are subjected to oxidation and leaching for a predetermined period of time to simulate natural weathering conditions to which the rock types may be exposed. The leachates from each rock sample are chemically analyzed by titration with standard acid and base solutions to selected end points to obtain their acidity or alkalinity concentrations, and these concentrations are differentiated for the particular rock sample to obtain a net acidity or alkalinity value for the rock sample. Other portions of each rock sample are subjected to direct chemical analysis to determine their total acidity and alkalinity production potentials, and these total production potential values for a given rock type are plotted against each other on a suitable graph. Each sample plot is then identified as acidic or alkaline by its corresponding net acidity or alkalinity leachate value, and the so identified acid and alkaline plots are separated by a boundary line on the graph to establish areas of predicted acidity or alkalinity of the rock type to weathering conditions. The boundary information as established on the graphs for each rock type is thereafter utilized by a field operator in an on-site location with total acid and alkaline production potential values obtained by direct chemical analysis of subsequent rock samples, to more accurately predict the acid or alkaline water drainage which will be produced from a rock sample when exposed to natural weathering conditions. Such methods and data so produced are useful in mine permitting, and in mining operations to facilitate relocation of overburden materials to minimize acid water drainage therefrom.