Preheat the oven to 400°F Wrap the beets in foil and roast until fork-tender, about 45 minutes. Let cool slightly. Using your fingers, peel the beets under running water.
Meanwhile, in a bowl, whisk together the orange juice, vinegar and mustard. Slowly whisk in the oil; season with salt and pepper. Place the pork chops and half of the orange vinaigrette in a resealable plastic bag and marinate for 1 hour.
Preheat a grill pan over medium-high heat. Add the pork chops and grill, turning once, until just cooked through, 8 to 10 minutes. Let rest slightly, remove the bones and thinly slice.
Meanwhile, halve the beets lengthwise, then slice crosswise 1/4 inch thick. In a medium bowl, toss the beets with half of the remaining vinaigrette. In a large bowl, toss the lettuce with the remaining vinaigrette. Divide the lettuce among 4 plates and top with the pork and beets. Sprinkle with the almonds.