Lower-bound conjecture for type-2 zero-problem 3M-DAPs

Let $P=(T;U,V)$ be a 3M-DAP, with parameters $t,v,s_t,s_v,x_t,x_v$, and let $f(P)$ denote its optimal value.

Type-2 zero-problem lower-bound conjecture. If $(v-1)t-v>0$ and $s_t>(v-1)s_v$, then

$$f(P)>\frac{(v-1)x_t-x_v}{(v-1)t-v}.$$

The source says that this inequality is used to justify a structural lemma for optimal solutions, but gives no resolution in the supplied context.