The estimated values for the gamma-ray minimum and maximum should be as follows:
The estimated minimum GR value indicated should be approximately 38.0, as noted by the blue marker at right.
The estimated maximum GR value indicated should be approximately 92.0, as noted by the blue marker at left.
The values to be used in further calculations then, are as follows:
GRmin = 38.0
GRmax = 92.0